Enterprise and Industry

Let’s embrace spaceVolume II

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Acknowledgements Let’s embrace space, volume II - Space Research achievements under the 7th Framework Programme is published by the Space Research and Development Unit in the European Commission’s Directorate-General for Industry and Enterprise.

The editing of this book was undertaken by Reinhard Schulte-Braucks, Peter Breger, Hartwig Bischoff, Sylwia Borowiecka and Sofia Sadiq.

Articles published in this volume were reviewed by an editorial board consisting of Peter Breger, Hartwig Bischoff, Thierry Brefort, Mats Ljungqvist, Richard Gilmore, Tanja Zegers, Dirk Zimmer and Hugo Zunker.

The views expressed in the articles are those of the authors, whom the European Commission wishes to thank for their work.

Photo creditsCover: Sunspot 1112 with solar flares, © NASA Page 4: © REDBUL74, fotoliaPage 8: © AntonBalazh, istockphotoPage 12: ‘Milky Way’, © Steve Jurvetson, FlickrPage 28: © Glenn Jenkinson, fotoliaPages 30-31: ‘Araguaia River’, © Phototreat, istockphotoPages 44-45: © photlook, fotoliaPages 56-57: ‘Mount McKinley’, © HBPages 80-81: © ViStas, fotolia Pages 92-93: ‘River in Alaska’, © HBPages 104-105: ‘Tudra’, © Pro-syanov, istockphotoPages 116-117: © luoman, istockphotoPages 128-129: ‘Satellite view of coastal El Salvador’, © edfuentesg, istockphotoPages 136-137: ‘Suburbs in California’, © pastorscott, istockphotoPages 146-147: © DariuszPa, istockphotoPages 154-155: ‘Rainforest in Panama’, © FernandoAH, istockphotoPages 162-163: ‘Victoria Falls’, © Wolfgang_Steiner, istockphotoPages 172-173: ‘Prince William Sound’, © HBPages 184-185: © Anders Peter Amsnæs, fotoliaPages 196-197: © Centrano, fotoliaPages 218-219: ‘Hurricane Katrina on 25 August 2005’, © ESAPages 230-231: © DX, fotoliaPages 242-243: © KoMa, fotoliaPages 252-253: ‘Sentinel 3’, © ESA

Page 274: © parameter, istockphotoPages 276-277: © inhauscreative, istockphotoPage 286: © ‘Frank De Winne on ISS’, © NASAPages 294-295: ‘Helix nebula’, © ESAPages 300-301: ‘ENVISAT’, © ESAPage 318: ‘Ariane 5’, © ArianespacePages 340-341: © titimel35, fotoliaPages 350-351: © adventtr, istockphotoPages 358-359: © teekid, istockphotoPages 376-377: ©Mike Kiev, fotoliaPages 384-385: © Trifonov_Evgeniy, istockphotoPage 394: ‘Exomars rover’, © ESAPage 397: © ESA/Herschel/PACS/SPIRE/Hill, Motte, HOBYS Key Programme ConsortiumPages 402-403: ‘Planck’, © ESAPages 412-413: ‘Herschel’, © ESAPages 438-439: © V. Yakobchuk, fotoliaPages 450-451: © Neo Edmund, fotoliaPages 472-473: © Terry Morris, fotoliaPages 496-497: ‘Aurora Borealis’, © antonyspencer, istockphoto Pages 504-505: © AlexBannykh, istockphotoPages 514-515: © smn, fotolia Pages 524-525: © Tjefferson, fotoliaPages 550-551: © RapidEye, istockphoto

Let’s Embrace Space

Volume II

Directorate-General for Enterprise and Industry

EUROPEAN COMMISSION

Foreword by European Commission Vice-President Antonio Tajani, with responsibility for Industry and Entrepreneurship . . . . . . . . . . . . . . . . . . . . . . . .9

Summary: Space Research under the Seventh Framework Programme of the European Union . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Part I Earth Observation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Land monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

CHAPTER 1: Biodiversity multi-source monitoring system: from space to species (BIO_SOS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

CHAPTER 2: GMES service snow and land ice (CryoLand) . . . . . . . . . . . . . . . . . 46

CHAPTER 3: Endorse (Energy downstream services) — Providing energy components for GMES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

CHAPTER 4: Information service on agricultural change (ISAC) . . . . . . . . . . . . 63

CHAPTER 5: MOCCCASIN (Monitoring crops in continental climates through assimilation of satellite information) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

CHAPTER 6: Multi-scale service for monitoring Natura 2000 habitats of European Community interest (MS.Monina) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

CHAPTER 7: MyWater: GMES specific services for operational water management (LULC, LAI, evapotranspiration and soil moisture) . . . . . . . . . . . . . 94

CHAPTER 8: ReCover: Services for the monitoring of tropical forest to support REDD+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

CHAPTER 9: Reducing emissions from deforestation and degradation in Africa (REDDAF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

CHAPTER 10: REDDiness — Support EO-driven forest and carbon monitoring in central Africa for REDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

CHAPTER 11: REDD-FLAME — REDD fast logging assessment and monitoring environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

CHAPTER 12: WATPLAN — Spatial Earth observation monitoring for planning and water allocation in the international Incomati Basin — Managing water from catchment down to field scale. . . . . . . . . . . . . . . . . . . . . . 148

CHAPTER 13: GMES4Regions and local authorities — Bridging the gap between European local and regional authorities and GMES . . . . . . . . 156

CHAPTER 14: ZAPÁS: Assessment and monitoring of forest resources in the framework of EU–Russia space dialogue . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

Table of contents

6T A B L E O F C O N T E N T S

Marine monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

CHAPTER 15: AquaMar: Towards sustainable marine and coastal space-based services in support of European water quality… legislation . . . . . 174

CHAPTER 16: ASIMUTH: applied simulations and integrated modelling for the understanding of toxic and harmful algal blooms . . . . . . . . . . . . . . . . . 186

CHAPTER 17: NEREIDS: New service capabilities for integrated and advanced maritime surveillance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

CHAPTER 18: SIMTISYS: Simulator for MTI system . . . . . . . . . . . . . . . . . . . . . 206

Emergency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219

CHAPTER 19: EVOSS: European Volcano Observatory Space Services . . . . . 220

CHAPTER 20: MALAREO: Earth observation in malaria vector control and management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

CHAPTER 21: PanGeo: Enabling access to geological infomation in support of GMES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244

CHAPTER 22: Pre-Earthquakes: Processing Russian and European Earth observations for earthquake precursors studies . . . . . . . . . . . . . . . . . . . . . . . . . . 254

CHAPTER 23: SEMEP: Search for electro-magnetic earthquake precursors 263

Part I I Strengthening Space Foundations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275

Space science . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277

CHAPTER 24: BIOSMHARS: Biocontamination specific modelling in habitats related to space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278

CHAPTER 25: ESPaCE: European Satellite Partnership for Computing Ephemerides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

CHAPTER 26: EU-UNAWE: EU universe awareness . . . . . . . . . . . . . . . . . . . . . 296

Space propulsion and transportation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301

CHAPTER 27: E-SAIL: Electric solar wind sail technology . . . . . . . . . . . . . . . . 302

CHAPTER 28: HPH.com: Helicon plasma hydrazine.combined micro . . . . . . 309

CHAPTER 29: MicroThrust: MEMS-based electric micropropulsion for small spacecraft to enable robotic space exploration and space science . . . . . 319

CHAPTER 30: ORPHEE: Operational research project on hybrid engine in Europe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326

CHAPTER 31: SPARTAN: Space exploration research for throttable advanced engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333

Space data exploitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341

CHAPTER 32: HESPE: High energy solar physics data in Europe . . . . . . . . . . 342

CHAPTER 33: POPDAT: Problem-oriented data processing and ionospheric wave catalogues creation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352

CHAPTER 34: SEPServer: Data services and analysis tools for solar energetic particle events and related electromagnetic emissions . . . . . . . . . . . 360

CHAPTER 35: Space-data routers for exploiting space data . . . . . . . . . . . . . 367

7T A B L E O F C O N T E N T S

Space technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377

CHAPTER 36: DEPLOYTECH: Large deployable technologies for space . . . . 378

CHAPTER 37: Data Signal Processor (DSP) for Space Applications (DSPACE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386

CHAPTER 38: E-SQUID: SQUID-based multiplexers for large Infrared–to-X-ray imaging detector arrays in astronomical research from space . . . . . . . . . . . . . 395

CHAPTER 39: High Quality European GaN-Wafer on SiC Substrates for Space Applications (EuSiC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404

CHAPTER 40: FOSTERNAV: Flash Optical Sensor for Terrain Relative Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414

CHAPTER 41: Magnetic-Superconductor Cryogenic Non-contact Harmonic Drive (MAGDRIVE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423

CHAPTER 42: Technologies for Safe and Controlled Martian Entry (SACOMAR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430

CHAPTER 43: SkyFlash Development of Rad Hard non volatile Flash memo-ries for space applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440

CHAPTER 44: Smartees: Multifunctional Components for Aggressive Environ-ments in Space Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446

CHAPTER 45: Towards Neutral-atom Space Optical Clocks (SOC2): Development of high-performance transportable and breadboard optical clocks and advanced subsystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 452

CHAPTER 46: SpaceWire-RT (SpWRT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 464

Space weather . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 473

CHAPTER 47: AFFECTS: Advanced Forecast For Ensuring Communications Through Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474

CHAPTER 48: EURISGIC : European Risk from Geomagnetically Induced Currents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 482

CHAPTER 49: PLASMON: A new, ground based data-assimilative model of the Earth’s Plasmasphere — a critical contribution to Radiation Belt modelling for Space Weather purposes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 488

CHAPTER 50: Space Weather Integrated Forecasting Framework (SWIFF) . 498

Space debris . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 505

CHAPTER 51: BETs: Propellant less deorbiting of space debris by bare electro-dynamic tethers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506

CHAPTER 52: DEORBITSAIL: De-Orbiting of Satellites using Solar Sails . . . 516

CHAPTER 53: P2-ROTECT: Prediction, Protection & Reduction of OrbiTal Exposure to Collision Threats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 526

CHAPTER 54: ReVus: Reducing the Vulnerability of Space Systems . . . . . . 534

CHAPTER 55: SPA: Support to Precursor Space Situational Awareness Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 553

Foreword

Although space and the universe often seem remote to us, they are in fact very close to our mundane activities. For the average European citizen, they are constantly present in their daily life. Quite often the achievements of space research and development are not immediately visible. However, due to technological innovations, we can drive cars safely, tackle natural dis-asters efficiently and prevent emer-gencies. The projects presented in the second volume of the Let’s embrace space book clearly show that research in space provides an ‘invisible help-ing hand’ reaching Earth from the universe.

It is undeniable that space has always been perceived by human beings as a challenge; however, it is also full of possibilities. Space creates a unique opportunity to boost the eco-nomic performance of our continent. Indirectly linked to this opportunity was the launch of the two Galileo sat-ellites from the European Space Port in Kourou, French Guiana, on 21 October 2011 — a great step on Europe’s way to strengthening the ’helping hand’ from space, as well as increasing Europe’s independence at international level. The event marked the beginning of a new phase in the European space policy and reflects the EU’s willingness to play a vital role in this area.

In this context, it is appropriate to underline that international coopera-tion in the space area has been gaining in importance, which allows European scientists to cooperate on various space issues with their counterparts from a large number of countries. In this context I would like to stress the excellent collaboration with US and Russian scientists but also the strong support the EU provides to the African community in using space-based infor-mation tools.

The continuous effort of the European Union to contribute to research in the space area is reflected in the new proposal of ‘Horizon 2020’, the suc-cessor to the FP7 space research pro-gramme. The proposal, adopted by the

by EUROPEAN COMMISSION Vice-President Antonio TAjANI, wITH RESPONSIbILITy for industry And ENTREPRENEURSHIP

10F O R E W O R D

European Commission one month after the launch of the Galileo satellites, will cover the years 2014–20 and is now being negotiated in the European Parliament and in the Council.

This book contains around 50 projects from the third call of the FP7 space research programme. It gives an inter-esting overview of the topics ranging from land monitoring, through space propulsion and space weather, to the removal of space debris. I encour-age you to have a closer look at the chapters, discover the innovative pro-jects presented in this book and gain a deeper insight into the possibilities of European space research.

Antonio Tajani

Authors: Reinhard Schulte-Braucks, Hartwig Bischoff, Sylwia Borowiecka, Peter Breger, Thierry Brefort, Richard Gilmore, Mats Ljungqvist, Tanja Zegers, Dirk Zimmer, Hugo Zunker

AbSTRACT

The following summary presents the results of almost 50 projects funded under the third call for proposals of the FP7 Space Research Programme. This edition comprises also several projects from the first and the second calls that were not included in the first volume.

The summary aims at giving an over-view of the EU-funded space research. However, it should be emphasised that the list of the projects included in the book is not exhaustive. As a number of projects selected under the third call are, at the date of the publication of this book, still ongoing, the relevant papers published in this edition might present only preliminary or expected results. Missing projects from the call may find a place in a third edition of the publication.

All papers in the area of land and marine monitoring, emergency response, space science and technology, space propulsion and transportation, space data exploita-tion, space weather and space debris are

presented in two parts: Earth Observation and Strengthening Space Foundations.

oBserVAtion of LAnd

Land monitoring is one of the most mature GMES areas, where opera-tional services are already provided at local level (GMES Urban Atlas: har-monised land use/land cover mapping of 305 European cities) and will soon be provided at continental and global level in line with the GMES regulations and the GMES Initial Operations Work Programme.

The FP7 research programme builds on these services by providing more spe-cialised services in specific areas for a more specialised user community.

Fifteen projects present their results in this publication, and provide concrete support in domains like water resource management, including snow and ice monitoring, forest monitoring and for-est degradation, especially in support of the REDD1 initiative, agricultural development, biodiversity protection or renewable energy.

Water management is widely covered, under different areas. Addressing the

1 Reducing Emissions from Deforestation and Forest Degradation.

Summary

Space Research under the Seventh Framework Programme of the European Union

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issue of snow accumulation and deple-tion (which is key for water resource management but also for impor-tant economic areas like winter tour-ism), the project CryoLand provides a set of tools for monitoring the extent and state of snow cover, glacier ice and lake/river ice based on satellite data, integrated with ground-based measurements.

Water scarcity has increased in many other areas in the world, especially in Africa, and water usage has been opti-mised. Based on high resolution sat-ellite imagery, wATPLAN provides the local stakeholders with weekly water management indicators for equitable and efficient water allocation of the Incomati basin (south-west Africa). Integrating information from EO, meteorology, and catchment models, together with in situ data, Mywater helps to cross-validate the estimates of water quantity and quality in catch-ments. It also supports water manag-ers and users in determining long-term strategies and in making their daily operational decisions.

In recent years, estimates for defor-estation and forest degradation were shown to account for a large fraction of greenhouse gas emissions, similar to the transportation sector. redd is a set of steps designed to reduce the emissions of greenhouse gases from deforestation and forest degradation. Earth Observation-based services are a very useful tool to support the REDD process, in providing efficient monitor-ing solutions to the users, especially in tropical regions. Working in close collaboration with users from Africa, South and Central America and South-East Asia, projects ReCover, reddAf, reddiness and redd-fLAMe all investigate complementary tools and

monitoring solutions based on optical and radar satellite imagery. Similarly, in the framework of the EU–Russia Space dialogue, the EU–Russian team of the project ZAPÁS addresses the important issue of assessing forest resources in the boreal zone, particularly in Siberia.

Modern and environmental-conscious agricultural, governmental services and food relief agencies will greatly ben-efit from the monitoring and forecast of crop growth and development. The project ISAC provides such monitoring and forecasts, based on high resolution imagery, both for western Europe and Africa, where the project MOCCCASIN focuses on the specifics of crop growth in continental climate regions like Russia, China or Central Asia.

In the fourth application of land mon-itoring, biodiversity and habitat pro-tection is supported by FP7 projects. While bIO_SOS provides high defini-tion land cover and helps local authori-ties to better protect biodiversity, the Ms.Monina project provides EO-based tools and services, supporting the pol-icies on biodiversity at local, regional and EU level, in particular the reporting required by the habitats directive.

Finally, satellite based services for land can play a major role for efficient renewable energy planning and imple-mentation. Endorse will offer a set of pre-market services to policymakers and investors, like irradiance forecasts for electricity production, annual energy output estimation, wind resource esti-mation for wind farms, or biomass potential maps for forested areas.

Although not limited to land observa-tion issues, two projects, doris_net and GRAAL, aim to optimise the local and regional uptake of GMES products

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and services in several areas ranging from refined land cover maps to local air quality forecasts, for example by establishing a downstream observa-tory. These two projects are also coop-erating together under the banner of GMes4regions.

MONITORING THE MARINE ENVIRONMENT

We all make use of our seas and oceans. Traditional uses (transport, fishing, tourism) now sit alongside more recent activities (mineral extrac-tion, wind farms). The seas have enor-mous intrinsic value. Unlike our cities, they provide us with a free horizon; we enjoy clean coastal and marine envi-ronments and the wildlife they support, and we benefit from their role in keep-ing our climate stable.

But the unsustainable use of our seas threatens the fragile balance of marine ecosystems. Human activities that depend on the sea, such as fishing and tourism, suffer from damaged ecosys-tems and use-related competition will become increasingly serious.

The protection of the marine environ-ment is the responsibility of everyone. We must be conscious of the pollu-tion threats to our waterways and oceans and the serious effects that may result.

A major challenge in the coming years will be to improve and enrich our scien-tific knowledge of the marine environ-ment. Researchers from all disciplines are working together to better under-stand the environmental processes, the impacts of human activities and climate change on marine environ-ments, and the socioeconomic aspects

of marine life. Among other things, we need to know more about:

(i) marine environmental processes;

(ii) the functional role, evolution, pro-tection and exploitation of marine biodiversity;

(iii) the impact of human activi-ties (land-based and marine) on coastal and marine ecosystems and how to manage these (includ-ing via eco-efficient technologies);

(iv) applying an ecosystem approach to resource management and spa-tial planning so as to come up with the best options for coastal and Maritime Spatial Planning;

(v) sediments in continental margins and deep seas, gas hydrate behav-iour, deep-sea ecosystems and technologies to enhance deep-sea observation.

The EU Coastal and Marine Policy pro-vides the legal impetus for the EU to protect and clean up its coasts, seas and oceans as part of an integrated strategy that will enable us to use them sustainably.

These efforts are supported by the Space Theme of FP7 and research on GMES downstream services. Some projects in this call are funded on environmental issues, whereas others address the security issues related to the sea.

ASIMUTH aims at developing mech-anisms for short-term forecasting of algal blooms along Europe’s Atlantic coast. Harmful algal blooms (HABs) make shellfish toxic and can some-times kill farmed fish. It cannot be

16S U M M A R Y

prevented, but with the right technol-ogy, using remote sensing satellite data, monitoring images of chlorophyll and water temperature it can be pre-dicted. It will result in fish and shell-fish farmers adapting their harvesting practices and therefore reduce poten-tial losses.

The two other funded projects — nereids and SIMTISyS — aim to enhance the security situation at sea in general.

NEREIDS explores new ways to improve security through maritime surveillance by developing techniques and products for GMES users in the context of an integrated maritime policy. The aim is to provide an open architecture toolbox for integration of existing and recently developed space infrastructure infor-mation, resulting in enhanced capa-bilities for maritime surveillance in the GMES context. This will include defin-ing, implementing, testing and running live demonstrations with new earth observation capabilities.

SIMTISYS supports the development of the next generation radar satellite capabilities to improve efficient mari-time surveillance. This project is based on the former FP7 project NEwA. The development of a European capability for effective moving target indication through space-based radar technology can be exploited by numerous policy purposes, such as border surveillance, maritime traffic monitoring, environ-mental protection and fisheries control. The development of a simulator for a moving target indicator system forms an important precursor for advanced operational services.

AquaMar is a network of SMEs aiming at establishing a common European

reference point for validated water quality services, taking full benefit of services provided by the GMES Marine Service. Through an open partnership between water quality service pro-viders, AquaMar proposes services that will deliver (1) indicators for the reporting requirement of the Water Framework Directive and the European Marine Strategy, (2) algal bloom fore-casting, (3) monitoring the impact of large infrastructure near the coast, (4) services supporting the Bathing Water directive monitoring, and (5) aquacul-ture precision farming.

EMERGENCy RESPONSE

Some natural disasters cannot be pre-vented, but if we can predict when and where they may occur, at least we can prepare for such events and minimise the loss of human life and property. Perhaps earthquakes are one of the most obvious examples of catastrophi-cally powerful events that occur without warning. Whilst plate tectonics allow us to identify the regions most likely to suffer earthquakes, they are noto-riously difficult to predict. Throughout the world, thousands of citizens live with the constant risk of being hit by an earthquake. The recent disaster in Japan gave us a stern reminder of this. Europe is also at risk, as its southern regions are highly seismic.

And yet, even only a very short, but reliable, warning could potentially save thousands of lives. Several FP7 projects are looking at different ways of iden-tifying and understanding earthquake precursors. The SEMEP project aims to use electromagnetic measurements in the global lithosphere-atmosphere-ionosphere, combining satellite- and ground-based observations to pave the

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way for a new methodology to enable earthquake forecasting. If successful, the project would constitute a major breakthrough with enormous benefits for populations.

Similarly, the Pre-Earthquakes pro-ject aims to combine and cross-vali-date the extensive datasets of satellite observations available at the European and Russian space agencies (ESA and Roscosmos, respectively). It focuses specifically on regions in far-east-ern Russia, Italy and Turkey, which are well-monitored seismic regions for which the integration of different observations and methodologies will yield the best results. The study will closely examine multiple sources of data before, during and after earth-quake events to search for reliable earthquake precursors.

The PanGeo project also aims to con-tribute to the mitigation of the effects of earthquakes and other geohazards, such as landslides and subsidence. By using geological information available through the GMES Urban Atlas, which provides detailed information on hun-dreds of European cities, the project aims to provide free and open access to geohazard information through a geohazard data layer for the 52 larg-est towns. This information can then be used for better planning control and mitigation strategies, ultimately saving lives and property.

Volcanic eruptions, like earthquakes, are difficult to predict and, when they do occur, can cause significant dam-age to property and loss of life. The EVOSS project aims to support cur-rent ground-based monitoring sys-tems using space-based observations to ensure that the speed and quality of response to major volcanic crises

is optimised. EVOSS focuses on the development of advanced data pro-cessing techniques that monitor ash, gas, ground deformation and tempera-ture, and to provide substantial support in scenario building and emergency decision-making. Europe — including overseas territories — and neighbour-ing Africa host dangerous volcanoes and high costs prohibit the installa-tion of modern observatories for all of these, or terrestrial networks already in place can be destroyed in the event of an eruption. Space-based monitoring can reinforce capacity when needed and act at supra-national scales.

Another form of natural disaster is that of disease. Malaria is a deadly disease, of which there are 225 mil-lion cases annually, with 212 million of these cases affecting Africa alone, leading to close to 800 000 deaths per year. And yet, unlike earthquakes, we can do something to prevent this. The MALAREO project aims to use Earth Observation technologies in this fight to reduce malaria-related mortal-ity. Certain anthropogenic factors like deforestation, irrigation, urbanisation, movement of populations and eco-nomic changes can determine where the malaria outbreaks eventually occur, and the careful monitoring of these features may contribute to a solution. Whilst it is not possible to monitor the mosquitoes themselves from space, it is possible to observe extensive areas and identify where the conditions are most likely to allow malaria develop-ment and provide vital information to the malaria vector control and man-agement programmes, so that they can optimally use their limited resources to maximise impact, range and effi-ciency. The MALAREO project also seeks to facilitate capacity develop-ment in Africa to support a permanent

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Earth Observation monitoring cell. This work will support the existing national malaria control programmes and help to refine the parameters used to iden-tify the location of optimal malaria breeding conditions.

SPACE SCIENCE

Man has always been fascinated by space, the stars and the planets and sought to understand our place in the universe. As our understanding pro-gresses and our capability to travel to space increases, we are faced with fundamental questions that intrigue and fascinate. Is there life elsewhere in the universe? How are stars born and how do they die? What are the medical challenges of space travel? The space theme of FP7 supports numerous pro-jects that address such issues, pushing back the frontiers of our understanding of the universe we live in and inspiring the curiosity of the general public.

And what better place to start than with the youngest and most curious members of society. The UNAwE pro-ject uses this fascination with space to inspire children by harnessing their desire to learn and by generating real excitement for astronomy and space science. This in turn will help very young and underprivileged children to broaden their minds and develop European and global citizenship. The project builds on Universe Awareness (UNAWE), a unique and proven pro-gramme for children aged 4 to 10. The project capitalises on the very high degree of curiosity in this age group, fostering an interest in space and the establishment of a value system. It will also contribute to the integration of underprivileged communities and stim-ulate the next generation of European

engineers and scientists, especially focusing on encouraging girls to take an interest in these areas.

When humans go into space, numerous health issues can arise, which need to be understood and mitigated to make future deep space travel possible. Many are already aware of the effects of the weightlessness in space on bone and muscle strength, and the benefits of research in this area for understand-ing and treating analogous diseases, such as heart disease and osteoporo-sis, common on Earth and becoming increasingly prevalent with an ageing population.

Another aspect is that of biocontam-ination in space. When humans go into space, so do bacteria, and there is a need for effective biocontamina-tion control measures to ensure that there is no health risk for astronauts. The bIOSMHARS project will address this challenge by developing and cal-ibrating mathematical models to pre-dict the transportation of bioaerosols in a closed environment and develop the appropriate countermeasures, to be tested at the Russian BIOS-3 con-finement facility. It is expected that the insights gained in this field will also have a range of terrestrial applications for health and safety.

Man has also long held a fascination for the movement of heavenly bodies and over several millennia has mapped the position and movement of astro-nomical objects. After getting over the initial shock of discovering that the Earth is not flat and not the centre of the universe, man has moved on to make practical use of this knowledge, which served as a navigation tool and even allowed Columbus to extract him-self from a precarious situation when

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stranded in Jamaica, allowing him to successfully predict a lunar eclipse and thus impress the locals. In the space age, this knowledge has been used to guide spacecraft on missions to new worlds. The ESPaCE project aims to combine new space-based measure-ments of astrometric data with clas-sical ground-based measurements to generate new dynamic models which can predict planetary orbits with even greater precision. This new knowledge will allow better and more precise planning of future space missions and, just as Columbus used the astronomi-cal navigation techniques of the time to discover the New World, the efforts of ESPaCE will contribute to our explo-ration of new worlds.

SPACE PROPULSION And trAnsPortAtion

Non-dependent access to space is a prerequisite for Europe to achieve its strategic space objectives. In technical terms, access to space encompasses launch, propulsion and transport tech-nologies to enable a cost, energy and mass efficient voyage of space assets to their operational position, whether in Earth orbit, planetary or lunar orbit, or on the surface of another planet or moon.

Overcoming our Earth’s gravity is the starting point for any space-based activity. Large rockets such as the Saturn V rocket of the sixties (a multi-stage liquid-fuel vehicle), or the more recent Space Shuttle with its solid fuel boosters have become iconic in the pub-lic’s perception of how to propel large payloads into orbit. Given that these and all other current rockets are based on chemical propulsion, even after so many years of launching large loads

into space, the search for better and more innovative propellants contin-ues. A key question is how to achieve more controllable and efficient rockets. One research approach strives to com-bine the best features of solid and liquid fuels. The project ORPHEE is pursuing breakthroughs in hybrid rockets, which burn the liquid oxidiser with a solid fuel. This combination provides opportunities to lower cost through use of solid fuel, while introducing adjustability of thrust through the liquid component. Such an element of control is for instance partic-ularly critical when soft touch-down on a planetary surface is the goal, a chal-lenge taken up by the project SPARTAN.

Once in space, several very different propulsion mechanisms are employed. Here efforts are concentrating on small, efficient and lightweight engines, which provide high precision. As satellites and probes have to operate reliably over many years in extreme environ-ments, stability of fuels and their low weight are of paramount importance. Small correction manoeuvres, as well as sending payloads on long jour-neys need to be catered for. Electric engines, utilising the thrust provided by the highly accelerated charged par-ticles of electrically produced plasma, provide the means. The project HPH.com is developing a specific engine type, in which the hot plasma is cre-ated through heating of atoms by low frequency radio waves. While such a plasma drive leads to high efficiency — low thrust drives, utilising these plas-mas to heat a secondary propellant, could possibly lead also to the variant of a high thrust drive, albeit at reduced efficiency. The project Microthrust is pursuing lower cost space missions by introducing a high degree of subsys-tem integration with the ultimate goal being a thruster-on-a-chip.

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For long distance space missions, or orbit corrections over long periods, the natural forces of the solar wind can be utilised, thus obviating the need for fuel supplies. The project E-SAIL aims to develop a prototype for harvesting this natural source of interaction between fast flowing sub-atomic charged par-ticles from the sun and a large sail consisting of charged tethers. Along the same principle, bETs is focused on the propellantless de-orbiting of space debris by bare electrodynamic tethers. A different sail design is developed by deorBitsAiL, which intends to utilise a deployable 25 m2 solar sail to drive a satellite down towards earth at the end of its useful life. The challenge of returning spacecraft is investigated in ritd, which is extending the use of an inflatable lander system developed for planetary exploration, enabling the descent through the atmosphere back to earth.

sPAce dAtA eXPLoitAtion

The main result of all our activities in space is that they provide information, from a unique vantage point, on our ter-restrial environment, our solar system, and the universe at large. This informa-tion may be used in our daily life, such as satellite images, satellite television, navigation signal to find our way in traf-fic. Or it may drive scientific discoveries, such as the presence of water ice on Mars or planets orbiting distant stars. Information from space is also crucial to better understand the space environ-ment and its threats to our planet and all human activities. For example, solar storms play a major role in the outage of electricity grids, in particular at higher latitudes, and man-made and natu-ral debris in space poses an important threat to satellite systems.

Whereas Europe has an excellent track record of building and operating space systems, only a limited amount of the data produced and down-linked from space missions is actually used. Data exploitation should be the crown on the success of any space mission, but is frequently lacking in the European context. In Europe, data exploitation of ESA missions is fragmented in national programmes, and the resources at the disposal of the community involved in space data exploitation are frequently insufficient or earmarked for specific instruments on specific missions. This has led to a situation where is some cases data from European missions is better used in the United States than in Europe.

The actions under FP7 Space in the field of data exploitation provide the opportunity for cross national consor-tia to start addressing this gap in the European space research landscape.

The currently active projects in this field under FP7 predominantly focus on solar physics (SEPServer, HESPE) or ionosphere data (PoPdAt). In those cases, data is collected by satellites at a given location and at a given time. Ultimately, the phenomena studied vary in extent and in time and space. For example a solar flare is a tran-sient phenomenon, which can only be studied in detail by combining a large amount of information, often from dif-ferent instruments on different mis-sions. Equally, the perturbation of the ionosphere, potentially as a result of an earthquake, requires a three dimen-sional image over time of the changes in the ionosphere. Different projects address different parts of chain, from raw data to a scientific or opera-tional product. SEPServer focuses on the derivation of high level data of

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Solar Energetic Particle (SEP) events and their dissemination to the sci-entific community. HESPE focuses on the highly complex data processing of high energy solar data, using sophis-ticated ICT tools, incorporating theo-retical solar physics models. POPDAT addresses the variable patterns of the ionosphere by integrating data from different missions and instruments.

The project Space-data routers addresses data exploitation from a dif-ferent perspective by focusing on the communication aspects, both from space to ground, and data dissemination via Internet. Space data usually comes in huge quantities, resulting in com-munication bottlenecks, both in space and on the ground. This project aims to facilitate exploitation of space data by integrating the interfaces of various space and Internet Communication and Networking Protocols, thus focusing on the ICT component of space data.

None of the projects described here focuses on a single instrument or even a single mission. One of the challenges in space data exploitation is to combine the use of data from different instru-ments and missions. This is not a simple task and frequently requires analysis and inter-adjustment of the original calibration methods of the individual instruments. The data used in those pro-jects will be derived from European mis-sions, such as Integral, PROBA-1, Mars Express, and the GMES Sentinels, and US missions, such as the Polar Orbiting Environmental Satellites of NOAA.

Space data exploitation is a very impor-tant topic and has been taken up as one of the specific objectives of Horizon 2020 of the European Commission to be addressed more comprehensively in the period 2014–20.

SPACE TECHNOLOGy

Another important element of the space theme is the use of technol-ogy. Satellites, robots, or space ships are high-tech devices and they are needed for any presence in space and for achieving any objective in the space environment. Thus, leading edge tech-nology is an essential element for stra-tegic projects, for space-based services and applications, as well as for vision-ary concepts of future programmes and space exploration.

Access to certain technologies can be crucial for European industry to sustain its competitiveness or to implement large programmes, such as Galileo or GMES. A certain subset of those tech-nologies is subject to expert restric-tions or is provided by a single source. In those cases foreign governments or competitors could hinder European industry to achieve its goals and objec-tives. Thus, the space theme comprises the development of a European supply chain for technologies which are sur-veyed and monitored by the Joint Task Force of the European Commission, the European Space Agency, as well as the European Defence Agency (EC–ESA–EDA) on critical technologies. Activities under this actionline span a wide range of topics, which range from sensor developments and electronic compo-nents to mechanical components.

In this book this is illustrated for exam-ple by e-sQuid which will advance the European technologies avail-able (Superconducting Quantum Interference Device (SQUID) amplifiers) to integrate sensors for x-ray, visible and infrared wavelengths.

The project dsPAce is addressing a potential bottleneck for complex space

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missions, namely the on-board pro-cessing capacity which ultimately lim-its the capability to compress, store and downlink data to the investigators on earth. A new Digital Signal Processor prototype and the related development kit will be developed by the DSPACE consortium.

The Gallium Nitride-based semiconduc-tor technology can deliver much higher performances than the classical one. eusic is contributing high-quality semi-insulating 3-inch SiC-substrates, which are superior to those available from non-European sources. Together with the results from other complementary projects under this scheme the main elements of a European supply chain will eventually become available.

The project SkyFlash aims at fur-thering approaches to build radia-tion hardened flash memory based on classical semiconductor technology (CMOS). SkyFlash is considering radi-ation hardening by design on different levels, such as architecture, circuit, and finally layout level.

Many ambitious science missions, as well as satellite communication and navigation systems rely on the avail-ability of a precise system time. SOC2 is a follow-on phase of a long-term development activity aiming at devel-oping a space qualified optical atomic clock. This activity is in particular rel-evant to the industrial work of the Galileo programme.

In the area of materials and mechan-ical components, research is funded by Smartees into ceramic composites structures which are exposed to hot and aggressive environmental condi-tions, for instance during re-entry of reusable launcher vehicles. In the case

of extreme environmental conditions, Magdrive is aiming to build a harmonic drive able to work under cryogenic con-ditions, with an extremely low friction, long life time and no wear. This har-monic drive is based on magnetic teeth and will not use any lubrication.

Further to those critical technologies, there is a number of projects investi-gating various challenges in the area of space utilisation, which can be charac-terised by the following factors: an even more intense use of the low-Earth orbit for Earth observation, mobile satellite communication, and manned space-flight in the International Space Station. In the context of ISS the demand for a re-entry vehicle will increase after the decommissioning of the space shuttle in the near future. In particular, robotic missions are key elements for the next European steps in space exploration of our solar system and to prepare for potential future human exploration mis-sions. Planetary exploration conducted by orbiting and landing spacecraft or by sample-return missions will require a set of enabling technologies related to space transportation.

A telling example for this type of activ-ity is the project FOSTERNAV. It aims at the improvement of spacecraft atti-tude and position control, by introduc-ing a new type of Light Detection and Ranging (LIDAR) sensor to fulfil the challenging requirements of several future mission scenarios. The required technology will be developed and even-tually tested in dedicated test facilities.

Many new space missions will ben-efit from large structures to sup-port antennae, reflectors, shields or other similar structures. A technol-ogy is needed to pack these struc-tures as small as possible during the

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launch and to deploy them in orbit. dePLoytecH is investigating three specific examples which will be devel-oped and validated, possibly involving space validation on cube sats.

Hybrid rocket engines offer a specific combination of high power, versatil-ity and restart-capability. These fac-tors make them interesting for small launchers, upper stages of launchers, or lunar or planetary landers. Detailed studies and sub-scale demonstrations of these engines are being carried out by ORPHEE.

Another important aspect of space technology research is the interna-tional cooperation in certain thematic areas with emerging or established space powers, such as the United States, Russia, Canada, People’s Republic of China, India, and Ukraine. The following example studies were done in collaboration with Russia. Sacomar is investigating in more detail the aerodynamic load on vehi-cle surfaces during the atmospheric descent onto the Martian surface. In terms of spacecraft technology, spaceWire-rt will develop a flexi-ble, robust, responsive, deterministic and durable standard network tech-nology that is able to support both avionics and payload data-handling. Increasingly, international collabora-tion on scientific and Earth observa-tion spacecraft will require standard network technology to facilitate the interaction of equipment contributed by different international partners.

SPACE wEATHER

The constantly varying ambient con-ditions of the magnetic fields, plasma, radiation and particles near Earth are driven by solar energy and interactions

in interplanetary space between the sur-face of the Sun and the Earth’s atmos-phere. These phenomena are commonly referred to as ‘space weather’.

Space weather affects the Earth in various ways. Major solar events may generate severe space weather in the near Earth environment, e.g. geomag-netic storms. Most of the time, space weather effects are limited to beautiful auroral displays, e.g. ‘Northern Lights’, but occasionally, undesired effects occur. Those could include damage to satellites, induced currents in electric grids that could cause instabilities and power outages, rerouting of air traf-fic from polar routes made necessary by increased radiation risk and, poten-tially, reduced accuracy in satellite navigation systems due to ionospheric disturbances. Very severe events have the potential to create major disrup-tion to critical societal functions as our societies grow increasingly more dependent on electronic communica-tion networks and extremely precise timing from satellites.

Fortunately, there is an increased international awareness of the need to address the challenges posed by space weather to space and ground-based systems. It is a global issue and in the past years several interna-tional workshops in Europe and in the US have looked into the possibilities of joint activities in this domain, address-ing research as well as awareness and preparedness.

In this context, the EU FP7 research programme is supporting a number of international research teams that cover important aspects of under-standing, modelling and forecasting of space weather phenomena and their effects. The teams draw expertise and

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resources from Europe and beyond, including USA, Russia, Ukraine, New Zealand and South Africa.

The SwIFF project attempts to develop mathematical and computational models for space weather events from their solar origin to the impact on Earth. This includes integrating physi-cal models on different scales in order to model small-scale processes within larger scale evolution. The validity of the models will be demonstrated for space weather forecasting.

In the PLASMON project, the goal is to improve the modelling of the Earth’s plasmasphere and of Van Allen radia-tion belt phenomena by exploiting and further extending existing ground based sensor networks. This is an international effort that will increase our understand-ing of the physical processes involved and will lead to more accurate space weather forecasting services.

To date no dedicated operational space weather forecast system exists for ion-ospheric applications. The goal of the AFFECTS project is to develop such a prototype service based on state-of-the-art modelling of space weather effects on the Earth’s ionosphere and their impacts on communication and navigation systems.

EURISGIC is focusing on the particular problems associated with induced cur-rents in power networks that result from major space weather events. By using solar wind observations, geomagnetic recordings and simulations, the project will derive maps of the occurrence prob-ability of large GICs (Geomagnetically Induced Currents) in Europe and provide data for design of robust and secure protection against GIC in European power transmission grids.

These four projects are providing key knowledge in the broader effort to build space weather services in Europe. They complement the endeavours by other European projects supported by FP7 (such as the PoPdAt, HESPE and SEPServer projects described under the chapter space data exploitation in this book) and by actions under the European Space Agency’s prepara-tory programme on Space Situational Awareness as well as by EU Member States’ own research programmes.

sPAce deBris

Space infrastructure is a critical infra-structure on which services that are essential to the smooth running of our societies and economies, as well as our citizens’ security, depend. The protec-tion of this infrastructure was under-lined as a major issue for the EU, going beyond the individual interests of indi-vidual satellite owners.

Space infrastructures are increasingly threatened by man-made hazards, mainly space debris. In order to reduce the risks stemming from these hazards, it is important to understand and moni-tor the space environment around the Earth, including orbiting objects (satel-lites, space stations, or debris caused by collisions of space objects or rocket debris). This is instrumental for ensur-ing the good functioning and security of space-based and ground-based crit-ical infrastructure and space activities.

Whether on Earth or in space, human activity creates waste. Like the Earth’s environment, the space environment is getting more and more cluttered. There are currently millions of man-made orbital ruins that make up ‘space junk’. Unfortunately, the past 45 years of

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space exploration have generated a lot of junk. Orbital debris includes things such as hatches blown off space mod-ules, paint fragments from the space shuttle, or satellites that are no longer in use.

During the past half century objects have been launched into space regu-larly, reaching in peaks 140 items per year. Every time a vehicle boosts a sat-ellite into space, some debris is pro-duced. Examples of space debris are: discarded rocket bodies, fuel tanks, satellite components, non-functional satellites and debris from collisions and explosions. This material, orbit-ing the Earth at very high speed and in an uncontrolled manner, poses an ever increasing potential risk for the launch and operation of spacecrafts due to collision with other debris or other spacecrafts in orbit.

According to latest estimates, there are 16 000 objects orbiting Earth larger than 10 cm, which are catalogued and between 300 000 and 600 000 or 740 000 objects larger than 1 cm, not catalogued. The objects larger than 1 cm will continue to grow, and will reach a total of approximately 1 mil-lion debris in 2020. Furthermore, it is estimated that there are more than 300 million objects larger than 1 mm.

The vast majority of these space objects are not in deep space, but in the commercially most exploitable areas of the outer space region. These include the geostationary earth orbit (GEO), the medium earth orbit (MEO) where all satellite navigation constel-lations orbit including Galileo satellites, and the low earth orbit (LEO), mostly used for Earth Observation satellites such as the future European GMES satellites.

At a speed of 10 km/s, space objects can cause serious harm to operational spacecraft, from total destruction (which would inevitably be the con-sequence of a collision with a space object larger than 10 cm) to perma-nent damage to sub-systems on-board spacecraft (which will cause the mini-mum impact of a collision with a space object larger than 1 cm). Satellites can partly be protected against dam-age from space debris by using defen-sive systems such as debris shields. However, even state-of-the-art defen-sive systems cannot prevent damage or total loss of a satellite from space debris above 1 cm in diameter. The only solution for satellite operators is to avoid collisions by performing col-lision avoidance manoeuvres, which is only possible where debris has been detected and tracked through a sur-veillance system.

The collision risk with partially trace-able space debris (between 1 cm and 10 cm), is estimated at 1 every 3 years. Collision with space debris of this size is likely to lead to a complete or partial loss of the satellite.

In addition, taking into account debris smaller than 1 cm and under the same assumptions made above, the risk of collision with a satellite could rise dras-tically up to 500 every three years (i.e. around 170 per year). This kind of col-lisions may lead just to minor failures which, nonetheless, can have the effect of shortening the lifetime of a satel-lite. All these effects created a topic for research on space debris in the FP7 call, under which some projects dealing with space debris are funded.

BETs will provide a propellantless de-orbiting system of space debris by bare electrodynamic tethers. The system

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shall be carried on future space-craft, which will then be extended at the end of their lifetime in order to remove orbital energy. This will result in decrease of altitude and therefore a faster re-entry and destruction of the old satellites in Earth’s atmosphere. The system involves magnetic drag without propellant or power supply.

DEORBITSAIL will use solar sails for the de-orbiting of smaller satellites, weighing less than 500 kg orbiting in LEO below 900 km. The aim is to produce a low cost, low risk device by using a 25 m2 solar sail with a max-imum weight of 3 kg. Upon end of its lifetime, the solar sail would be deployed; solar winds would drive the spacecraft downward to burn during the re-entry phase.

P2-protect calculates the risk of col-lision for satellites in low earth orbit (LEO), medium earth orbit (MEO) as well as for the geostationary orbit (GEO). By improving existing calculation methods for collision prediction, the project aims to improve prediction, protection and help to reduce orbital exposure to col-lision threats. Furthermore one more intention is to provide recommen-dations for new designs to limit the impact on spacecraft by colliding with space debris.

REVUS is an attempt to reduce the vulnerability of space systems by defining new design rules and test shielding materials. They will carry out a resilience analysis to evaluate the proposed solutions. The efforts to be made are threefold; fractioning of the spacecraft functions on system level, segregation of design rules at the architectural level and better shield-ing for LEO satellites.

Finally, the SPA project is studying the complex issue of governance and data policy of a Space Surveillance and Tracking system of systems, in which various elements (civil and military, national and EU) provide tracking infor-mation, and where the information may be used for both public and pri-vate applications with a strong security dimension.

THE INTERNATIONAL diMension of euroPeAn SPACE RESEARCH

International cooperation is an impor-tant element both in relation to imple-menting the European Space Policy and in contributing to the external action-line of the EU in general, as well as in terms of reaching the objectives of the relevant annual work programmes under the FP7 Space Theme.

Monitoring the Earth and exploring the universe and our solar system are, by nature, global ventures and are strongly dependant on international cooperation. Europe is not alone in this space endeavour and international cooperation is often perceived as a crit-ical element to reach our goals.

A diversified approach has been iden-tified as a key element in Europe’s international relations in the space sector. Partnerships under the FP7 space work programme have been set up, among the established and emerging space powers, with the United States, Russia, Japan, China, India, Ukraine and South Africa.

As specific arrangements to strengthen international cooperation both on space policy issues, as well as to advance cooperation in concrete fields of R & D,

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structured space dialogues have been launched in recent years with the US, Russia, South Africa and Israel.

In all cases, the European Space Agency, as a separate European stakeholder, is participating in those dialogues. Contacts have been also established with China, Brazil and Ukraine, with the objective to launch similar dialogues in the future.

The 3rd call for proposals under the FP7 Space programme was supposed to specifically address international cooperation activities. For this pur-pose, specific FP7 instruments were used like targeted actions and Specific International Cooperation Actions (SICAs), which ease the inclusion of third country partners in EU-funded research projects.

Since the start of FP7, there is a strong participation of research organisations from the Russian Federation in nearly all fields of space research, which is also a result of the efficient Space Dialogue inaugurated in 2006. Main fields of cooperation with European and international scientists concern the monitoring of land and marine eco-sphere, microgravity research, pro-cessing of data from experiments on the International Space Station, space transportation, as well as propulsion and planetary re-entry technologies. Under the 3rd call, two SICAs have been opened in the fields of Earth observa-tion and space technology devoted

to enhancing participation of Russian researchers, resulting in the involve-ment of 12 European research projects with 28 Russian organisations. Two other SICAs were successfully opened to African and APC countries. Several projects (REDDiness, ReCover, REDDAF and REDD-FLAME) were selected in the fields of forest and carbon monitoring, which support the United Nations pro-gramme on reducing emissions from deforestation and Forest degradation in developing countries. Overall, 95 partners from African countries have participated in proposals, among which 35 have been retained in successful projects.

The scientific partnership with the United States has been deepened in a number of areas. In the field of Solar–Earth interactions, called ‘space weather’, which has a strong influence on many important activi-ties on Earth like air traffic, commu-nications and navigation, close ties have been built with NOAA, the US National Oceanic and Atmospheric Administration. The AFFECTS project is building a transatlantic network to investigate solar storms and to issue warnings in case of hazardous situa-tions. High-technology projects cover the deorbiting of small satellites by solar sails or electro-dynamic tethers (DEORBITSAIL and BETs). As a result of an intensive exchange of views, a specific arrangement on participation of NASA establishments in EU funded projects could be signed in 2012.

Land monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Marine monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

Emergency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219

Part I Earth Observation

CHAPTER xx Land monitoring

CHAPTER 1

Authors: Palma Blonda, Panayotis Dimopoulos, Maria Petrou, Rob Jongman, Harini Nagendra, Daniela Iasillo, Alain Arnoud, Paola Mairota, Joao Jhonrado, Emilio Padoa Schioppa, Richard Lucas, Laurent Durieux, Laura Candela, Jordi Inglada

consortium members: Consiglio Nazionale delle Ricerche (CNR), Italy; University of Ioannina (UOI), Greece; Centre for Research and Technology Hellas (CERTH), Greece; Alterra, Wageningen UR, the Netherlands; Ashoka trust for Research in Ecology and the Environment (ATREE), India; Planetek Italia SRL (PKI), Italy; Altamira Information SL (Altamira), Spain; Universita degli Studi di Bari ‘ALDO MORO’ (UNIBA), Italy; CIBIO- Instituto de Ciências e Tecnologias Agrárias e Agro-Alimentares, Portugal; Università degli Studi de Milano-Bicocca (Unimib), Italy; Aberystwyth University (ABER), United Kingdom; Institut de Recherche pour le Developpement (IRD), France; Planetek Hellas (PKH), Greece; Agenzia Spaziale Italiana (ASI), Italy; Baraldi Consultancy in Remote Sensing (Bacres), Italy; Université Paul Sabatier (UPS), France

AbSTRACT

bIO_SOS is a response to the Call for proposals FP7-SPACE-2010-1, addressing topic ‘Stimulating the

development of GMES services in specific areas’ with application to (B) Biodiversity. It is a 3-year project: start-ing date 1 December 2012.

Whilst the establishment of Natura 2000 sites in Europe provided protec-tion for a diverse range of important habitats, human activities have resulted in changes in the surrounding landscape that are influencing the condition of contained habitats and their associated biodiversity. Recognising the ability of remote sensing data, particularly those provided by high (HR) and very high res-olution (VHR) sensors, the BIO_SOS pro-ject aims to develop a cost-effective pre-operational ecological modelling system suitable for timely multian-nual monitoring of natura 2000 sites, including their surrounding areas, with this referred to as EO Data for Habitat Monitoring (eodHaM). As input, EODHaM is using satellite-derived and in situ data to drive models of species distributions and dynamics at both the habitat and landscape levels. The pro-posed system is characterised by a two-stage knowledge-based (i.e. deductive learning) classification scheme for land cover (LC) and habitat mapping and includes components for change moni-toring. A third stage is devoted to auto-mated biodiversity indicator extraction and analysis of change under a range of scenarios. Ontologies and semantic networks are used to formally represent

Biodiversity multi-source monitoring system: from space to species (BIO_SOS)

33B I O D I V E R S I T Y M U L T I - S O U R C E M O N I T O R I N G S Y S T E M : F R O M S P A C E T O S P E C I E S ( B I O _ S O S )

the expert knowledge and allow auto-matic inferences that provide guidance to the image analysis and processing. The EODHaM system, which is expected to provide improved operational core service products, is being developed for sites in the Mediterranean countries of Italy, Portugal and Greece and west-ern Europe (the Netherlands and Wales) and further evaluated for tropical envi-ronments in Brazil and India, where the availability of advanced monitor-ing systems is critical for conservation of biodiversity. The modelling frame-work developed is expected to provide a deeper understanding of the impacts of human-induced pressures (e.g. agricul-tural expansion, mining and road con-struction) on biodiversity conservation, which will lead to the development of new downstream services. Key out-put products include LC and LCC maps based on the Food and Agricultural Organisation (FAO) land cover classifi-cation scheme (LCCS) with these trans-lated to general habitat categories (Bunce et al., 2008), Annex I and EUNIS habitat categories. The products gen-erated by the BIO_SOS project will be available to allow the impacts of past, current and present policies on Natura 2000 sites and their surroundings to be better evaluated.

AcHieVed resuLts

The major technical activities of BIO_SOS have been elaborated to date into eight work packages (including project management). The results achieved during the first year of the project are synthesized below with reference to the corresponding WP activity and deliverables (www.biosos.eu).

user requirements completion: Across Europe, and with emphasis on the

Mediterranean, 11 sites have been selected for testing and ground veri-fication of the methods developed in the project, with these being protected because of their high conservation value and richness in biodiversity. For each site, pre-existing information and data-sets have been obtained and authori-ties responsible for managing the sites have been contacted and involved in the development of the EODHaM sys-tem. The structure and composition of the landscape at each site and also the human pressures and threats have been identified by stakeholders and experts. In many of the sites, habitat loss and fragmentation are real threats and systematic monitoring is essential to ensure their long-term protection.

Appropriate indicators of biodiversity were identified and their relevance to monitoring reviewed through use of literature and previous expert assess-ments (e.g. Streamlining European 2010 Biodiversity Indicators (SEBI) and the Convention on Biological Diversity targets for the period 2011–20 (CBD 2020)). A workshop involving consor-tium members and also representa-tives of the managing authorities of several of the test sites was held to define stakeholder needs and to con-firm the selection of biodiversity indi-cators. Service level agreements (SLAs) were organised based on end-user requirements and also analysed. These indicators needed to consider the abundance and distribution of selected plant species as well as to make reference to the importance, in terms of European conservation inter-est, and to the level of fragmentation and functional connectivity of natural and semi-natural habitats within the test areas. The spatial and temporal resolution requirements for optimising biodiversity monitoring through remote

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sensing data across the range of study sites were also assessed and the importance of classifying land covers (LCs) and habitats and their changes at very high resolutions was emphasised.

on-site data collection: For each of the sites, metadata on pre-existing datasets were collected, with these following a simplified metadata profile, and an evaluation of their quality and relevance to the project was under-taken based on metadata provided by the site partners. A metadata geo-portal was also specified and devel-oped and a standard methodology for evaluating the quality of new spatial datasets used or generated during the lifetime of the project was proposed, tested and implemented as a qual-ity evaluation routine being integrated in the metadata geo-portal. Criteria for the selection of Earth observation (EO) datasets considered most appro-priate for discriminating, mapping and monitoring habitats and captur-ing the ecological scales of fragmen-tation, human pressures and scales of impacts (Nagendra et al., 2012) were established, with these focusing on their spatial, spectral and temporal characteristics. Connections to other ongoing projects were also established to facilitate the exchange of knowl-edge and experiences gained in other ongoing and previous projects and ini-tiatives. Protocols for in-field collection of data relating to general habitat cat-egories (GHCs) as well as flora, fauna and soil data were defined as well as those for validating EODHaM output products. Training sessions on in-field protocols relevant to the field identifi-cation of GHCs were also held in Bari, Italy, and Aberystwyth, Wales, and field tests of protocols developed in previ-ous projects were conducted in Wales and Portugal.

eodHaM modelling modules devel-opment: A key component of the EODHaM was to identify the LC tax-onomy that provided class descrip-tions that were most similar to those used to describe habitats. For this, a systematic comparison of LC taxono-mies (Corine, IGBP and the Food and Agricultural Organisation (FAO) land cover classification system (LCCS)) as well as habitat classification systems (e.g. Annex I to the European Directive, Eunis, Corine Biotope and GHCs) was undertaken, with precedence given to the Mediterranean regions. The FAO-LCCS taxonomy (Di Gregorio and Jansen, 2005) was considered to be the most useful for consistent transla-tion of habitat maps from LC maps and for reliable long-term monitoring of biodiversity within Natura 2000 sites and their surrounding areas.

To generate GHC and Annex I habitat maps from the LC maps in FAO-LCCS taxonomy, rules for translation were generated through analysis of the intrinsic characteristics of the two dif-ferent taxonomy domains. Approaches to mapping LC categories were devel-oped in WP5 for a number of sites, with the rules for translation evaluated. As an example, the rule-set for translat-ing between the A12 LCCS categories to GHCs is illustrated in Figure 1.

A review of literature was conducted with this focusing on landscape struc-ture and functioning quantitative anal-ysis and the application of an array of techniques available for captur-ing information on major landscape structural features that reflect human impacts, habitat composition and con-figuration across a range of scales (site, focal habitat and observation). In each case, these impacts were con-sidered threatening to biodiversity and

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the integrity of ecosystems. These techniques were tested on a bench-mark dataset relating to the Murgia Alta 2000 site in Italy (Mairota et al., 2012). The study established that the integration of different approaches (e.g. landscape pattern analysis, mor-phological pattern analysis, landscape mosaic analysis and discontinuities detection) was appropriate for (a) exploring the relationships between landscape heterogeneity and habitat fragmentation and (b) generating a baseline that can be used to identify problematic areas requiring greater future monitoring effort and provide early warning signals that can prompt an immediate response to pressures leading to habitat loss or fragmen-tation. The construction of models of ecological niches for the biodiver-sity indicators selected, with or with-out GHCs as variables of the niche, is ongoing and is anticipated to lead to a better understanding of how GHCs can be linked with the diversity of flora and also fauna.

eodHaM analysis of different sam-pling sites and validation: For the BIO_SOS, chains for pre-processing high resolution (HR) and VHR EO data have been established, with these relating to radiometric calibration, atmospheric correction and ortho-rectification. Procedures have been compared based on a diversity of multi-spectral data obtained for study sites in Wales, the Netherlands, Italy and Greece, as well as India and Brazil.

EO data processing modules imple-mentation: Using EO data, the two-stage classification scheme proposed in BIO_SOS for LC map production includes (a) a first stage based on the analysis of spectral features only for providing a preliminary spectral sketch of an input image and (b) a second stage where context-sensitive features, including texture, morphology, topological/non-topological and temporal relations, are adopted to map the LC classes. Whilst a single-image (pixel-based) classification scheme was proposed initially (Baraldi

Figure 1. The mapping rules

between the A12 LCCS category and

the corresponding GHC classes (from

D6.10, V. Kosmidou et al. 2012)

36B I O D I V E R S I T Y M U L T I - S O U R C E M O N I T O R I N G S Y S T E M : F R O M S P A C E T O S P E C I E S ( B I O _ S O S )

et al. 2010), this was subsequently sub-stituted by a standard two-stage pro-cess tree designed and implemented to explicitly include multi-temporal infor-mation. This was undertaken largely because class phenology was consid-ered to be a key element for describ-ing and discriminating LC and habitats based on the descriptions provided by expert ecologists. The approach to classification mirrors that of the LCCS and utilises a variety of image-derived indices (including the Normalised Difference Vegetation Index (NDVI), the Plant Senescence Reflectance Index (PSRI) and the Water Band Index (WBI), end member fractions (e.g. non-photo-synthetic/photosynthetic vegetation and water) in the first classification spectral stage, with these corresponding approx-imately to the second level of the LCCS dichotomous scheme, and additional contextual features (e.g. proximity or adjacency, temporal relations) in the second system stage, with these corre-sponding to the additional dichotomous and hierarchical LCCS levels. For the latter, the inclusion of additional ancil-lary (e.g. digital terrain model) data is a requirement. The classification was undertaken using prior-knowledge rules

applied successively and using the same hierarchical levels as the LCCS. In each case, rules were only applied if these were readily interpretable from both an ecological and remote sensing point of view, with semantic nets generated to support the design of the system.

In the development of the classifica-tion system, expert knowledge elicita-tion for LC and habitat mapping from remote sensing data was achieved for three training sites in Italy, Wales and the Netherlands, with these rep-resented in ontologies undertaken to aggregate, share and use this knowl-edge for automated mapping. A con-ceptual description of the protocols for mapping given LC or habitat classes from remote sensing imagery was formulated through Unified Modeling Language (UML) diagrams, which can be integrated into ontologies. The ontol-ogies identify the concepts and their relationships within a scientific domain. To best represent the knowledge and ensure integration with other scientific domains, multi-level ontologies have been developed, as indicated in Table 1, with these containing the expert knowl-edge described in the UML.

Ontology description Examples

Top level Defines very general concepts independent of a specific domain or problem

The Semantic Web for Earth and Environment Terminology (SWEET)

Domain Describe the terminology of a specific domain

Land cover and habitat mapping, image description, spatio-temporal relations, remote sensing instruments

Task Describe a task or activity Methods used in remote sensing, and the software tools for applying these methods

Application Describe the terms that are on the one hand dependent on a domain and on the other hand on a very specific task in an applicative context

Table 1. Ontologies used in the BIO_SOS project

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The ontologies were used, in part, to design and develop the classifi-cation process tree for LC and habi-tat classification from EO data using the FAO-LCCS taxonomy (with subse-quent translation to GHC and Annex I classes), with focus initially on sites in Italy, Wales and the Netherlands. The classification at these sites has focused largely on the use of very high resolu-tion (VHR) imagery. As an example, for Wales, time-series of 2 m spatial reso-lution 8-band Worldview (WV-2) data were acquired over the Natura 2000 site of Cors Fochno, with these includ-ing pre-flush (March 2012), peak flush (July 2011) and post flush/senescence (November 2011) acquisitions. To sup-port the interpretation of these data, plot-based inventories of the major LCCS categories occurring were under-taken during 2011 and in 2012. Field-based transect measurements of key biophysical variables (e.g., percentage

cover of photosynthetic and non-pho-tosynthetic vegetation) were acquired in 2012 along with spectro-radiometer measurements to support interpreta-tion of the WV-2 data.

An example of the imagery and the classification of the LCCS levels 1–3 categories (vegetated versus non-vegetated, aquatic versus terrestrial, natural or artificial water bodies and surfaces and cultivated/managed ver-sus natural or semi-natural vegetation) are shown in Figure 2(a) and (b) respec-tively. To provide a more detailed clas-sification of vegetated LC for the site, information on height, cover, phenol-ogy and leaf type is needed. The height of vegetation was extracted primarily from LiDAR data. Cover was estimated as the proportion of vegetated pixels within larger objects, with these includ-ing both photosynthetic (e.g. as defined using the measures of productivity)

Figure 2(a). Worldview2 image of Cors Fochno, November 2011, showing the active raised bog (centre).

Figure 2(b). LC map in LCCS taxonomy, corresponding to the level III LCCS dichotomous phase, generated from WV-2 data.

38B I O D I V E R S I T Y M U L T I - S O U R C E M O N I T O R I N G S Y S T E M : F R O M S P A C E T O S P E C I E S ( B I O _ S O S )

Figure 3(a). June 2009 QuickBird image; RGB = B3,B4,B1

Figure 3(b). Classified images from two input images

39B I O D I V E R S I T Y M U L T I - S O U R C E M O N I T O R I N G S Y S T E M : F R O M S P A C E T O S P E C I E S ( B I O _ S O S )

Figure 3(c). GHC map for only Natura 2000 site. It is overlayed to the QuickBird image RGB = 3,4,1

and non-photosynthetic vegetation. The use of multi-temporal imagery allowed differences in phenology between vegetation types to be cap-tured. The leaf type was established

by considering differences in the reflec-tance characteristics of sunlit vegeta-tion in the red edge and near infrared wavelength regions. By combining the derived information, the classification

Figure 3(d). Potential Annex 1 map overlayed to the QuickBird image

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of the major LCCS categories occurring within Cors Fochno was achieved. The approach is being applied to other sites but is sufficiently adaptable to allow integration of data from a diversity of sensors observing across different spa-tial and temporal scales. Research into method development has also been conducted in Italy and the Netherlands. An example image and derived LC, GHC and Annex I maps for the Le Cesine site illustrated in Figures 3(a)–(d). In this case, the height of vegetation was approximated using texture measures (Petrou et al., 2012) as LiDAR data were not available.

eodHaM system and service: To describe the service chains as a func-tion of expected products, the avail-able inputs and processing stems are outlined in a service design docu-ment. Concrete service chains relate to the products defined for the SLAs. The architecture is based on common SOA standards and ISO 19139 meta-data as a base for the exchange of product metadata between processing steps and as a description of process-ing results, in order to be further dis-tributed easily. The architecture of the System has been drafted with a strong focus on the support of generalisation and site specific parameterisation of processing. A template to describe the system sub-component to be used by partners involved in system develop-ment has been established.

dissemination, exploitation and other: To communicate the results of the BIO_SOS project to stakehold-ers and users, activities have included the establishment of a project web-site where publicly available deliver-able documents are uploaded. Direct communication with stakeholders has been achieved through the generation

of flyers, posters and presentations, as well as direct visits. Important stakeholders (e.g. NGOs operating at the European level, the European Commission and the European nature conservation agencies (ENCA) net-work) are being informed of progress through periodic visits and the presen-tation of results at tailored workshops and meetings. Links are also being established with relevant European agency-level groups and national envi-ronment protection agencies (EPAs) to convey information on project contents and to discuss use of the BIO_SOS products (e.g. for national reporting). A cost comparison between traditional and the proposed EO-based approach is being undertaken and updated as the project progresses.

CONCLUSIONS

The main outcome proposed by the BIO_SOS project is a pre-operational automatic system able to provide a flexible service chain with ready-to-go processors that can be easily adopted through parameterisation and the selection of ancillary data appropriate to the sites being considered. The main outputs anticipated include HR and VHR LC and LCC maps, as an improve-ment of GMes core services, as well as habitat maps and habitat change maps to be used for biodiversity indi-cator extraction and scenario analysis. This will lead to new GMES down-stream services.

A standardised method for mapping LC and habitat categories from EO data has been developed; this is a knowl-edge-based approach and places focus on the derivation of key attributes (e.g. height, cover, topological and tempo-ral relations) from a diverse choice of

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remote sensing data and in situ data. Hence, it is adaptable to a wide range of environments. The methods are cur-rently being developed for application beyond the initial test sites of Wales, Italy and the Netherlands, with a view to automation for biodiversity monitor-ing of Natura 2000 sites and their sur-rounds. Links with other projects are also being established to maximise the utility and integration of the methods developed through BIO_SOS.

Habitat maps and biodiversity sta-tus and trend indicators automatically extracted from multi-scale EO data and in situ data are not standard prod-ucts. In order to define the market, the usefulness of the proposed system and its products has to be considered, since it is composed of several innova-tive components. Each of these compo-nents has a different potential market and different users, and the system as a whole has its own well-addressed target and exploitation plan. Moreover, as these are not standard products, training on the methodology to gener-ate each product and on the EODHaM system functionalities is needed for the users. The training will be partly carried out by SMEs involved in the data analy-sis of different test sites, in continuous dialogue with the end-users. Also the partners responsible for local site data analysis within WP7 will be involved in the training of the local users.

A key component of the project is to inform the scientific community of the outcomes of BIO_SOS through scientific publications and presenta-tions at major conferences. Popular articles are also planned by national partners in their respective languages for publication in magazines which address stakeholder and decision-maker requirements. Policy-makers

and management authorities are expected to benefit from BIO_SOS out-puts in that a better understanding of the pressures exerted in environments with multiple uses will be provided together with options for address-ing the impacts of, for example, policy and land management practices. The system will also allow for compliance checking and inform the development and implementation of new policies as well as the placement of buffer zones around Natura 2000 sites. Overall, the BIO_SOS project is anticipated to pro-mote the long-term conservation and sustainable utilisation of protected areas and their surrounds.

REFERENCES

   BIO_SOS project website: www.biosos.eu.

   Baraldi, A., Durieux, L., Simonetti, D., Conchedda, G., Holecz, F. and Blonda, P., ‘Automatic spectral rule-based preliminary classification of radiometrically calibrated SPOT-4/-5/IRS, AVHRR/MSG, AATSR, IKONOS/Quickbird/OrbView/GeoEye and DMC/SPOT-1/-2 imagery — Part I/II, System design and implementation’, IEEE Trans. Geosci. Remote Sensing, March 2010, Vol. 48, No 3, pp. 1299–1354.

   Bunce, R. G. H., Metzger, M. J., Jongman, R. H. G., Brandt, J., de Blust, G., Elena-Rossello, R., Groom, G. B., Halada, L., Hofer, G., Howard, D. C., Kovàř, P., Mücher, C. A., Padoa Schioppa, E., Paelinx, D., Palo, A., Perez Soba, M., Ramos, I. L., Roche, P., Skånes, H. and Wrbka, T., ‘A standardized procedure for surveillance and monitoring European habitats and provision of

42B I O D I V E R S I T Y M U L T I - S O U R C E M O N I T O R I N G S Y S T E M : F R O M S P A C E T O S P E C I E S ( B I O _ S O S )

spatial data’, Landscape Ecology, 2008, No 23, pp. 11–25.

   Di Gregorio, A and Jansen, L. J. M., ‘Land cover classification system (LCCS): classification concepts and user manual for software version 1.0. GCP/RAF/287/ITA Africover — East Africa project in cooperation with AGLS and SDRN’, Nairobi, Rome, 1998.

   Kosmidou, V., Mairota, P. and Petrou, M., ‘Landscape connectivity measures: a review’, submitted to Landscape Ecology on 3 October 2011.

   Mairota, P., Cafarelli, B., Boccaccio, L., Leronni, V., Labadessa, R., Kosmidou, V. and Nagendra, H., ‘The use of landscape structure to develop quantitative baseline

definitions for an early warning system to use for habitat monitoring and change detection in protected areas’, submitted to Ecological Indicators on 3 April 2012.

   Nagendra, H., Lucas, R. M., Honrado, J. P., Jongman, R. H. G., Mairota, P., Tarantino, C. and Adamo, M., ‘Remote sensing for protected area assessment: monitoring habitat area, condition, biodiversity and threats’, submitted to Ecological Indicators on 13 January 2012.

   Petrou, Z. I., Tarantino, C., Adamo, A., Blonda, P. and Petrou, M., ‘Estimation of vegetation height through satellite image texture analysis’, accepted by the ISPRS Conference which will be held in August 2012 in Melbourne, Australia.

CHAPTER 2

Authors: Thomas Nagler, Gabriele Bippus, Helmut Rott, Gerhard Triebning, Christian Schiller, Sari Metsämäki, Juha-Petri Karna, Jouni Pulliainen, Hans E. Larsen, Rune Solberg, Eirik Malnes, Andrei Diamandi, Andreas Wiesmann, David Gustafsson

consortium members: ENVEO IT GmbH, Austria; EOX IT Service GmbH, Austria;

Finnish Environment Institute, Finland;

Finnish Meteorological Institute, Finland; Kongsberg Satellite Services AS, Norway; Norwegion Computing Center, Norway; NORUT AS, Norway; National Meteorological Administration, Romania; GAMMA Remote Sensing AG, Switzerland; Swedish Meteorological and Hydrological Institute, Sweden.

AbSTRACT

Climate change has a strong impact on snow- and ice-related environments. Temperature rise causes retreat of snow and ice, jeopardising the supply of fresh water for human consump-tion, agriculture and hydropower gen-eration, and affecting ecosystems and biodiversity. Accurate and timely observations of snow and ice are nec-essary to assess the impact of climate change and to support the present and future management of snow and ice resources. To this end, the project ‘CryoLand — GMES service snow and land ice’ has been initiated in order

to develop, implement and validate standardised, interoperable and sus-tainable services on monitoring sea-sonal snow cover, glaciers and lake/river ice parameters from satellite data within a GMES downstream service. The provided services are accessible through the corporate ‘CryoLand geo-portal’ following the recommendations provided by GIGAS (GEOSS, Inspire and GMES an action in support). CryoLand is a 4-year project which started in February 2011 and is supported by the seventh framework programme of the European Commission.

introduction

Snow and land ice are key elements of the water cycle in many parts of Europe, as well as in mountain regions and mid- and high-latitude zones of Asia and the Americas. Snow, lake ice and river ice are characterised by high temporal variability. Accurate obser-vations of extent and physical prop-erties of snow are not only of interest for climate change research, but are of great socioeconomic importance. Snow and glacier melt is a dominat-ing source of runoff in many parts of northern Europe, the Alps and other European and Asian mountain ranges. Melt water is also an important water resource in lowlands downstream of the mountain ranges, as it is for a main part of the northern hemisphere land masses at large (Barnett et al., 2005).

GMES service snow and land ice (CryoLand)

47G M E S S E R V I C E S N O W A N D L A N D I C E ( C R Y O L A N D )

UNEP (2007) reports that 1.5 billion to 2 billion people live in regions where reduced water flow, due to retreat of the seasonal snow cover and glaciers, may cause water shortages.

CryoLand addresses the need for up-to-date information on snow and land ice parameters for users in vari-ous application fields by implement-ing a downstream service within GMES. Earth Observation data from the GMES Space Component and other satellite data will be used as basis for this ser-vice. Operational processing lines and service infrastructure for a range of snow, glacier and lake/river ice prod-ucts are developed on top of existing OGC web service standards in order to support the publication, provision and chaining of geospatial data services. The services include interactive maps, search and data access functionali-ties, all accessible through a corporate ‘CryoLand geoportal’.

The CryoLand project is carried out by an international consortium of 10 part-ners coordinated by ENVEO IT GmbH, Austria. The project partners have long-term experience in algorithm develop-ment and satellite data processing for cryospheric applications, in designing and implementing geo-spatial infor-mation infrastructures, with special emphasis on satellite Earth observation data, and in services on EO products in near real time for various applications.

ProJect oBJectiVes And wORKING STRUCTURE

In the CryoLand project a GMES down-stream service on monitoring snow and land ice is developed, implemented and validated. The service provides geospatial products on the seasonal

snow cover, on glacier parameters and on fresh water ice, derived from Earth observation satellite data. The project prepares the basis for a future cry-ospheric component of the GMES land monitoring service.

CryoLand is organised in four main building blocks.

• The service requirements and infra-structure component deals with the collection of user requirements and the setting-up of the spatial data infrastructure, including the inter-faces to the users and the public. Online data download interfaces are foreseen to the land monitoring core service and for GMES space compo-nent data access.

• The product development and val-idation component deals with the improvement and validation of prod-ucts and services according to user specifications. The technical work builds largely on existing techniques and tools which are enhanced to match user needs. Improved pro-cessing tools are in development to capitalise on the enhanced sen-sor characteristics of the upcoming GMES Sentinel satellites.

•Service qualification and demon-stration is enabled through various user interfaces. In addition to rigor-ous testing and qualification of the service, these activities will prepare for the transition of the pre-opera-tional services to a self-sustained operational snow and ice monitoring service.

•User support and training ensures a close link between the CryoLand project and the user community throughout the project.

48G M E S S E R V I C E S N O W A N D L A N D I C E ( C R Y O L A N D )

Figure 1. Examples for primary snow products: (a) Fractional snow extent for Eastern Alps and statistical snow information for basin Ötztal based on MODIS data (produced by ENVEO); (b) Fractional snow extent for Baltic regions based on MODIS data (produced by SYKE); (c) continental-scale map of snow water equivalent based on passive microwave data (produced by FMI); (d) map of melting snow (red colour) of Eastern Alps, 9 June 2006, from Envisat ASAR Image Mode data, superimposed to ASAR amplitude image (Yellow — areas of layover and foreshortening; produced by ENVEO).

Figure 1 (a).

Figure 1 (b).

Figure 1 (c). Figure 1 (d).

49G M E S S E R V I C E S N O W A N D L A N D I C E ( C R Y O L A N D )

cryoLAnd Products

The product and service requirements for different applications are speci-fied in cooperation with users from various domains. Requirements have been defined in user workshops held in Vienna, Oslo, Saariselka and Bucharest in May and June 2011. The outcome of the workshops guided the speci-fication of products that are tailored towards the needs in various applica-tion domains, taking into account the characteristics of available and near future satellites (in particular those of the GMES Sentinel satellite family). The product specifications and priorities for implementation have been consoli-dated jointly with users in a user coor-dination meeting, held in Stockholm in May 2012.

Snow products with highest priority for implementation in the CryoLand ser-vices are snow extent, snow water equivalent (presently available at low spatial resolution) and snow melt areas. Follow-up products include wet-ness, surface temperature and spec-tral albedo of snow. The snow extent includes products at regional to con-tinental scale, utilising high resolu-tion optical satellite data (e.g. ASTER, Landsat TM/ETM+, SPOT, the near future Sentinel-2) and medium reso-lution optical sensors (e.g. MODIS, the near future Sentinel 3 with the SLSTR and OLCI instruments). Improvements for snow mapping algorithms are ongo-ing for different environments and sur-face cover, in order to improve the compensation of topographic effects in alpine areas, and to account for impact of forest cover on the reflectiv-ity of snow covered regions (Metsämäki et al., 2012). Further enhancement of snow products is achieved by integrat-ing accurate land cover data from the

GMES land monitoring service database into the fractional snow cover (FSC) retrieval algorithms (Figure 1). Beside the regional snow products, the project team works towards a fully validated pan-European snow extent product.

For snow melt runoff modelling, up-to-date information on the extent of melt-ing snow is important (Nagler et al., 2008). Synthetic aperture radar (SAR) images are used as input for an auto-mated method for mapping snow melt areas. The SAR snow mapping proce-dure uses multi-temporal C-band SAR data as input, exploiting the character-istic backscattering signature of melt-ing snow cover (Nagler and Rott, 2000; 2005). As C-Band SAR enables obser-vation of the Earth’s surface also in case of clouds, but is sensitive only to wet snow, these sensors provide com-plementary information to snow maps from optical satellite data. The method has been applied for ERS, Envisat, TerraSAR-X and Radarsat data and will be adapted to support Sentinel-1 single and dual-polarised C-Band SAR data. Figure 1(d) shows an example map of melting snow area derived from Envisat ASAR data covering the Eastern Alps.

CryoLand’s glacier products are based on high resolution, multi-spectral opti-cal satellite data and SAR data. The format follows international stand-ards of the ‘Global land ice measure-ment from space’ (GLIMS) programme (Bishop et al., 2004; Kargel et al., 2005). The products include glacier outlines (boundaries), maps of snow and ice areas and ice velocities, and maps of glacial lakes. Figure 2 shows examples of glacier products of the CryoLand glacier service. The gla-cier outline (defining the total gla-cier area) is basic information which is also required to derive other glacier

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Figure 2. (a) Glacier outline (red line) and snow/ice areas (cyan colour), Hohe Tauern, Eastern Alps, 1 September 2009; (b) Map of snow areas (red) on Ötztal glaciers, from TerraSAR-X data, 12 August 2010; (c) Ice velocity from multi-temporal TerraSAR-X data derived by cross- correlation technique, Skeidararjoekull, Iceland, 7–18 September 2010 (ENVEO).

products from satellite images. The processing line uses multi-spectral, optical satellite images from high reso-lution sensors (SPOT-5, Ikonos, Landsat ETM+, ASTER, etc.). Time sequences of snow and ice area extent on glaciers during the melting period, supplied by the project, are key information for computing the melt water contribution and estimating glacier mass balance.

At the end of summer, the ratio of snow to ice area extent is a proxy for the annual mass balance of a glacier, which is an essential climate variable (Oerlemans, 2001).

The algorithm for mapping snow and ice areas on glaciers utilises multi-spectral optical or SAR imagery. The automated algorithm for optical images starts with

Figure 2 (a). Figure 2 (b).

Figure 2 (c).

51G M E S S E R V I C E S N O W A N D L A N D I C E ( C R Y O L A N D )

Figure 3. (a) Lake ice extent, Lake Peispi, Estonia; (b) Fractional snow cover on top of lake ice, for Lake Inari (Finland) 24 April 2011; (c) Lake ice extent from SAR, Lake Päijäne, 4 January 2009.

Figure 3 (a). Figure 3 (b).

Figure 3 (c).

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the top-of-atmosphere albedo in vis-ible channels, applies parametric cor-rections for atmospheric propagation and compensates for terrain effects of solar illumination. Ice motion data are needed to determine and predict a glacier’s dynamic response to climate change. Repeat pass SAR images enable the mapping of ice motion at high accu-racy by means of differential processing techniques, separating the phase con-tributions of surface motion and topog-raphy (Rott, 2009). If decorrelation of the radar phase due to snow fall, wind drift or melt prohibits the application of repeat pass interferometry, correlation of templates in SAR amplitude images is applied as an alternative for mapping glacier motion. This technique requires stable features on the glacier’s surface.

Primary lake and river ice products include lake ice extent and snow cover on ice, both derived from optical satel-lite data, and ice extent on lakes and rivers from SAR data. Additionally, users are interested in lake ice con-centration, snow depth and snow water equivalent (SWE) on ice (to be derived from passive microwave data at low resolution), lake water and ice sur-face temperature. For these products experimental algorithms are available. Examples for primary lake ice products of the CryoLand project are shown in Figure 3.

cryoLAnd systeM

The design of the CryoLand service system follows the recommendations provided by GIGAS, and applies the Open Geospatial Consortium Reference Model of Open Distributed Processing (OGC RM-ODP 08-062r4). OGC pro-vides an internationally accepted set of standards for geospatial web services,

which foster interoperability at ser-vice interfaces. The recommendations include the standards developed within OGC providing mechanisms and inter-faces such as catalogue service for the web (CSW, to search for data), web map service (WMS, to portray maps), web feature service (WFS, to access vector data), web coverage ser-vice (WCS, to access raster data), and web processing service (WPS, to trig-ger server-side processing). These ser-vice types are also recommended by Inspire where they are named discov-ery, viewing, download, and invoke ser-vice. The CryoLand system consists of different service providers, generating the various products. Figure 4 gives an overview on the CryoLand system indi-cating the flow of data and information (bottom to top) as well as the dual-ity inside each CryoLand Facility (CLF), containing the Thematic Production Software System (TPSS) and the Access & Integration Software System (AISS). While the TPSS implements the thematic and scientific expertise to produce the CryoLand products, the AISS takes care of process communi-cation, data ingestion and delivery as well as security and user management issues. The interlinked communication between CLFs is indicated by showing a CLF also at the level of an external processing resource. Further, the AISS also provides the standardised inter-faces towards the users. These cur-rently include WMS, WFS and WCS, while WPS is under discussion.

In short, the above services ena-ble the standardised provisioning of online services which can be consumed by different clients for an easy and direct integration of CryoLand func-tions and products into the user’s GIS, modelling tools and decision support environments.

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Figure 4. System overview of CryoLand, its service facilities and the connection to external resources.

CONCLUSIONS

CryoLand designs and implements a GMES-embedded, pre-operational, Internet-based service infrastructure supporting the generation and pro-vision of satellite-based, near real time products on seasonal snow, lake and river ice and glaciers. The pro-ject extends over the period February 2011 to January 2015, with service pre-operations and consolidation dur-ing 2013–14. CryoLand utilises a port-folio of different satellite systems. Enhanced services and products will be enabled by data of the first GMES satellite Sentinel-1 (to be launched in 2013), followed by Sentinel-2 and Sentinel-3. It is planned to proceed with an operational multi-provider sys-tem at project end.

CryoLand fosters the development of advanced tools for generating up-to-date, spatially detailed information on various land ice and snow param-eters. Besides developing high qual-ity information, the project makes use of modern and efficient mech-anisms for online data access and timely provision of products. To gen-erate high quality products in a fast and cost-effective way and to offer potent services to a global commu-nity, interfaces implemented in the CryoLand system adhere to OGC standards, supporting online services which can be accessed by different clients and offer wide functionalities. This allows the easy and direct inte-gration of CryoLand results into users’ GIS, modelling tools and decision sup-port environments.

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Information on the progress of the CryoLand project and demonstra-tion services can be accessed via the CryoLand project website (http://www.cryoland.eu). The project is sup-ported by the seventh framework pro-gramme of the European Commission (FP7/2007–13) under the Grant Agreement No 26925.

REFERENCES

   Barnett, T. P., Adam, J. C. and Lettenmaier, D. P., ‘Potential impacts of a warming climate on water availability in snow-dominated regions’, Nature, 438, 2005 (doi:10.1038).

   Bishop, M. P. et al., ‘Global land ice measurements from space (GLIMS): Remote sensing and GIS investigations of the Earth’s cryosphere’, Geocarto International, 19(2), 2004, pp. 57–85.

   CryoLand project web page: http://www.cryoland.eu/.

   GIGAS — GEOSS, Inspire and GMES an action in support (FP7-224274)

   Kargel, J. S. et al., ‘Multispectral imaging contributions to global land ice measurements from space’, Remote Sensing of Environment, 99(1/2), 2005, pp. 187–219.

   Metsämäki, S., Mattila, O.-P., Pulliainen, J., Niemi, K., Luojus, K. and Böttcher, K., ‘An optical reflectance model-based method for fractional snow cover mapping applicable to continental scale’, Remote

Sensing of Environment, 123, 2012, pp. 508–521.

   Nagler, T. and Rott, H., ‘Snow classification algorithm for Envisat ASAR’, Proceedings of the Envisat & ERS Symposium, 6–10 September 2004, Salzburg, Austria, ESA SP-572, 2005, 8 pp.

   Nagler, T. and Rott, H., ‘Retrieval of wet snow by means of multitemporal SAR data’, IEEE Trans. Geosci. Remote Sensing, 38(2), 2000, pp. 754–765.

   Nagler T., Rott, H., Malcher, P. and Müller F., ‘Assimilation of meteorological and remote sensing data for snowmelt runoff forecasting’, Remote Sensing of Environment, 112, 2008, pp. 1402–1408.

   Oerlemans, J., Glaciers and Climate Change, A.A. Balkema Publ., Lisse, 2001.

   OGC 08-062r4, 2008, OGC Reference Model, 2008-11-11, Version 2.0, 35 pp.

   Rott, H., ‘Advances in interferometric synthetic aperture radar (InSAR) in earth system science’, Progress in Physical Geography, 2009 (doi:10.1177/0309133309350263).

   The ‘GIGAS Forum’: http://www.thegigasforum.eu/project/material/deliverables.html.

   UNEP, Global outlook for ice and snow, United Nations Environment Programme, 2007, 235 pp. (ISBN: 978-92-807-2799-9).

CHAPTER 3

Author: Lucien Wald

consortium members: DLR — Deutsches Zentrum für Luft- und Raumfahrt, Germany; iCons, Italy; Transvalor Innovation, France; Flyby (IT), Italy; Hochschule Ulm, Germany; University of Genova, Italy; École Nationale des Travaux Publics de l’État, France; 3E, Belgium; Joint Research Centre, European Commission, Italy

AbSTRACT

Sustainable energy strategies are a priority for the EU at present. The Endorse Consortium contributes to this goal by supporting and pro-moting the exploitation of environ-mentally-friendly energy resources through the development of down-stream services enabling their effec-tive evaluation. Renewable energies benefit significantly from Earth obser-vation (EO) data. Endorse makes use of GMES services and other EO data and takes them a step further by developing new leading services that provide energy components. It permits and promotes further innovation as well as advances in the environmental modelling. Endorse puts emphasis on extending the development of infor-mation technologies in, for example, geography and interoperability, used

as tools for more accurate evaluations of resources which are greatly needed for predicting the outcome of invest-ments in sustainable energy. Endorse has identified ten services focusing on solar, wind and biomass energy, elec-tricity management and daylighting in buildings. These services have a mar-ket potential and their benefits to daily work and decision-making processes will be demonstrated. In this first year, an efficient interaction has taken place between the providers of products and their users. Users’ requirements were collected in a homogeneous man-ner; they can be compared and pos-sible synergies identified. Research activities brought solutions support-ing development and improvement of products. A new method allows a fast and accurate computation of the course of the Sun in the sky. A series of automatic procedures has been developed to assess the plausibility of meteorological measurements made at ground level by ground stations or to benchmark products from GMES services or Endorse. A new method has been developed for producing local maps of air temperature at sur-face at fine scale, together with its uncertainty. Inputs are infrared images from satellites. The 10 products have been developed and validated on sci-entific grounds. They will be presented in January 2012 to the users for their assessments and further refinements.

Endorse (Energy downstream services) — Providing energy components for GMES

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AcHieVed resuLts

The project objectives for this first period (year 2011) were: (i) the effec-tiveness of the management; (ii) spec-ification of products by the already identified users, and definition of the procedure to assess the products; (iii) advances in environmental modelling to support the development of prod-ucts; (iv) delivery of a first version of products to be assessed in January 2012 by prime-users using the above-mentioned procedure; and (v) creating awareness by communicating about the project through a website and spe-cific documents and presentations in various conferences and forums.

A good spirit of cooperation has been installed within the consortium. There is a common commitment towards the achievement of the objectives of Endorse. Progress meetings and other means of communication help in exchanges of information, best prac-tices and expertise. Actions are pro-posed and decided during progress meetings and WP leaders play a very effective role.

Several communications tools have been set up to ensure an efficient man-agement of the project. They include progress meetings, general assem-blies, the website (both public and pri-vate), the monitoring of the progress of the work, deadlines for delivera-bles submission and milestones, and decisions.

An efficient interaction has taken place between the providers of products and the corresponding users. These users were identified prior to the beginning of the project. In two cases, users have withdrawn and been replaced and their requirements collected, thus permitting

the start of the development of prod-ucts. The requirements were collected in a homogeneous manner, so that they can be compared and possible synergies identified. For example, a same source of data may serve sev-eral products. It will also facilitate the development of operational services based on these prototypes. In addi-tion to technical specifications, the collection activity focused on the defi-nition of procedures and measures for the assessment of the acceptance of the products by users. Finally, for each product, a plan for scientific validation has been elaborated and documented.

Research activities brought solutions supporting development and improve-ment of products. A new method allows a fast and accurate computation of the course of the Sun in the sky. Based on existing recommendations from the World Meteorological Organization, a series of automatic procedures has been developed to assess the plausi-bility of meteorological measurements made at ground level by ground sta-tions, in particular for irradiation, air temperature, relative humidity and wind. Automatic procedures have been adapted from the International Energy Agency (SHC-36) to benchmark products from GMES core services or Endorse products against meteorolog-ical measurements considered as ref-erence for validation. A new method has been developed for producing local maps of air temperature at surface at fine scale. Inputs are infrared images from satellites. This method also pro-duces a map of the uncertainty associ-ated to air temperature.

First versions of the 10 products have been developed and validated on sci-entific grounds. They will be presented in January 2012 to the associated

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users and assessed by them. Feedback will help to improve the products.

The Endorse website aims at increas-ing the awareness of possible end-users and stakeholders and at disseminating the results of the pro-ject to a broad audience. Endorse has been presented to the GEO Secretariat and in various conferences and forums, such as the FP7-Space Conference or preparatory workshops for the GMES Users Forum. Promotional material has been prepared for these presentations. Scientific articles are being prepared for disseminating advances in environ-mental modelling and will be submit-ted to international journals.

Figures 1 and 2 are an example of a product. The high resolution maps displayed in Figure 1 result from a

processing of the GMES MACC radia-tion data that are firstly organised in a map format and then downscaled to increase the spatial resolution from 3 km to 200 m. The horizon is taken into account in this process. Radiation data are merged with data measured by Meteo-France to produce an accurate set of monthly maps depicting changes in radiation in Provence, south-east of France. Other layers relating to admin-istrative, geographical or electricity grid matters (Figure 2), are added to the radiation maps, offering a comprehen-sive product with identification of the most suitable sites for electricity pro-duction or the planning of incentives for renewables by local authorities. These additional layers can be obtained from other providers, e.g. IGN-France, using interoperable technologies for efficient communication between computers.

Figure 1. Maps of yearly irradiation in Provence for beam on horizontal surface (foreground), beam at normal incidence (BNI) and global on horizontal surface (GHI, forefront). Irradiation increases from blue to yellow to red. The influence of the Alps is clearly visible. Agreement of these computed irradiations with ground-based measurements is very good; the relative bias is less than 1 % for GHI and BNI and the root-mean-square error (RMSE) is less than 5 % for GHI and 8 % for BNI.

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Figure 2. Examples of cartographic layers that can be added to the radiation map in decision-making: territorial and district units tell the administration level in charge, natural resources are areas to be protected, flood risk areas should be avoided as well as steep slopes or northern exposures as derived froma digital elevation model (DEM), land use indicates the possible conversion of land for energy use, and distance to electricity source points quantifies the difficulty in connecting the power system to the electricity grid.

CONCLUSIONS

In this first year, an efficient interaction has taken place between the provid-ers of products and their users. Users’ requirements were collected and this has allowed 10 products to be devel-oped efficiently. The first versions of these products were made available in January 2012 to users after scientific validation and will be assessed by the users ; further refinements will then be made.

Several innovative methods were developed to support development and improvement of products. A new method allows a fast and accurate computation of the course of the Sun

in the sky. A series of automatic proce-dures has been developed to assess the plausibility of meteorological measure-ments made at ground level by ground stations or to benchmark products from GMES Services or Endorse. A new method has been developed for produc-ing local maps of air temperature at surface at fine scale. Inputs are infra-red images from satellites. Scientific articles are being submitted for publica-tion on these results. Relevant software is available on the website.

No major problem was encountered. Users are prominent in Endorse and a lot of attention is paid to interactions with them.

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REFERENCES

  Blanc, P. and Wald L., ‘The SG2 algorithm for a fast and accurate computation of the position of the Sun’, submitted to Solar Energy, 2012.

  Blanc, P., Espinar, B., Gschwind, B. , Menard, L., Thomas, C. and Wald, L., ‘High spatial resolution solar atlas in Provence-Alpes-Côte d’Azur’, in Proceedings ISES Solar World Congress 2011, 28 August – 2 September 2011, Kassel, Germany, Vol. ‘Resource Assessment’, paper #34552.

  Wald, L., Thomas, C., Cousin, S., Blanc, P., Ménard, L., Schroedter-Homscheidt, M., Gaboardi, E., Simeone, E., Heilscher, G., Jacques, S., Serpico, S., Huld, T. and Dumortier, D., ‘The project Endorse: exploiting EO data to develop pre-market services in renewable energy’, EnviroInfo, 5–7 October 2011, Ispra, Italy.

CHAPTER 4

Authors: Isabelle Piccard, Yetkin Özüm Durgun, Walter Heyns, Herman Eerens

consortium members: Vlaamse Instelling voor Technologisch Onderzoek (VITO), Belgium; Deimos Imaging, Spain; Internationales Institut für Angewandte Systemanalyse (IIASA), Austria; GeoSAS Consulting Service PLC, Ethiopia; Astrium-GEO, United Kingdom

AbSTRACT

ISAC aims to develop and demon-strate three generic services for pro-viding timely, objective and detailed information on crop growth and development and on crop damage due to extreme weather conditions such as drought. The project thereby addresses the needs of the commer-cial insurance sector in Europe and the food security sector in Africa (as input for early warning and micro-insurances). To this aim, images from optical high resolution (20–30 m) satellite sensors such as DMC/Deimos-1 and Landsat-TM/ETM+ are used, whereas traditionally such ser-vices make use of frequently availa-ble medium to low resolution images (250 m up to 1 km). The first ISAC service provides biophysical param-eters such as NDVI, DMP, fAPAR, LAI and fCover. The second service uses these parameters to provide

information on drought phenomena and damage caused by these phe-nomena. Finally, the third service aims to determine the associated risk (probability of occurrence), by ana-lysing past observations and making projections towards the future, taking into account different climate change scenarios.

For crop monitoring and dam-age assessment, actual images are often compared with a reference image, based on a long time series of observations and representing a ‘normal’ situation. Disadvantage of using high resolution images is the lack of archive data. This has sev-eral reasons: the frequency of acqui-sitions is low (as for Landsat-TM/ETM+, overpass frequency of 16 days), the satellite is relatively new (as for Deimos-1, since end-2009) or the acquired images simply can-not be used because of the presence of clouds.

This paper describes the proce-dure developed within ISAC to derive high resolution (25–30 m) reference images for DMC-1 and Landsat-ETM+ images from time series of medium resolution (250 m) images of the TERRA-MODIS sensor (operational since 2000) and shows examples of the use of NDVI reference images for crop monitoring and damage assess-ment in Belgium and Ethiopia, two of the ISAC demonstration sites.

Information service on agricultural change (ISAC)

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AcHieVed resuLts

In the frame of the ISAC project, a pro-cessing chain for high resolution images was developed by VITO. The processing chain comprises the following compo-nents: data import, geometric correc-tion, atmospheric correction, cloud and cloud shadow detection and calculation of vegetation and yield indices NDVI and DMP and biophysical parameters LAI, fAPAR, fCover and albedo.

A procedure was developed within ISAC to derive high resolution refer-ence images for DMC-1 (32 m) and Landsat7-ETM+ (30 m) images from time series of medium resolution (250 m) images of the TERRA-MODIS sensor (operational since 2000), under the hypothesis that these sen-sors are comparable from a spectral point of view. The MODIS land bands have corresponding bandwidths to the Landsat7-ETM+ and DMC-1/2 and Deimos-1 sensors except their band-widths are narrower (Gao et al., 2006).

A total of 10 DMC-1 images from 2009 over Belgium and 11 Landsat7-ETM+ images from 2008 over Ethiopia — well spread over the growing season — were processed up to the level of NDVI, resampled to a spatial resolution of 25 m and finally downsized to 250 m pixel sizes, in order to be compatible with the MODIS images (retrieved from JRC-MARS archives). To remove noise caused by geometric effects, a 3 × 3 cir-cle filter was applied on the high reso-lution images. By means of orthogonal regression, the relation between NDVI values of MODIS and DMC-1 and of MODIS and Landsat7-ETM+ was deter-mined (scatter plots, see Figure 1):

NDVI DMC-1 = 0.0024 + 0.791 × NDVI MODIS

(Eq. 1, for Belgium)

NDVI Landsat7-ETM+ = – 0.0686 + 1.086 × NDVI MODIS

(Eq. 2, for Ethiopia)

The correlation coefficients of the obtained equations are equal to 79 % (Eq. 1) and 94 % (Eq. 2). Whereas equation 2

Figure 1. NDVI scatter plots of DMC-1 and MODIS for Belgium (left) and Landsat7-ETM+ and MODIS for Ethiopia (right). © VITO

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is based on all available pixels, for equation 1 only those pixels were retained from the 10-day MODIS composites which were registered on the same day as the DMC-1 scenes. Sampling of pixels within equal NDVI intervals (0.1) led to an optimal distri-bution of the NDVI values used for the DMC-1/MODIS comparison.

For Belgium (Flanders), crop type infor-mation at field level from farmers’ dec-larations from 2003 until 2011 was used to ‘unmix’ the MODIS spectral val-ues. First, weighted mean MODIS NDVI values were computed for the main crops per municipality (Genovese et al., 2001) on a 10-daily basis and stored in a database. Secondly, equation 1 was applied. The resulting DMC-1 NDVI val-ues were then reconverted to images with a spatial resolution of 25 m, com-patible with the (resampled) DMC-1 images. Finally, the long-term aver-age NDVI was computed from these images (one image per dekad). As an example, the DMC-1 long-term aver-age NDVI for winter wheat for the first dekad of June is shown in Figure 2.

For Ethiopia (West Shewa province), a slightly different procedure had to be applied as no detailed crop type infor-mation is available for the country.

Long-term average NDVI values were computed from 10-daily MODIS NDVI images from the period 2000–11. In order to obtain Landsat7-ETM+ NDVI averages, equation 2 was applied. Finally, the images (250 m pixel size) were resampled to a spatial resolution of 30 m, compatible with the Landsat7-ETM+ images. Figure 2 shows the Landsat7-ETM+ long-term average NDVI for agricultural land for the sec-ond dekad of December. For Ethiopia, only those pixels which are labelled as ‘agricultural land’ in the ‘global crop-land map’ of the JRC (Van Cutsem et al., 2011) were used.

Anomaly detection was performed by calculating the absolute differ-ences between the actual daily DMC-1 (Belgium 2009) or Landsat7-ETM+ images (Ethiopia 2008) and long-term average NDVI values of the corre-sponding dekad.

The main crops cultivated in Belgium are winter wheat and winter barley, grown from October/November until the end of July and maize and sugar beet, sown in May and harvested in September/October. Belgium, espe-cially the northern part, is charac-terised by small agricultural parcels (average size 1.7 ha).

Figure 2. DMC-1 NDVI long-term average for winter wheat in Belgium (Flanders); Landsat7-ETM+ NDVI long-term average for agricultural land in Ethiopia (West Shewa) ©VITO

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The 2008/09 growing season in Belgium was quite normal, although after the winter it started with a short delay, as can be seen in Figure 3 show-ing for DMC-1 (1 April 2009) and MODIS (1 to 10 April 2009) below average NDVI values (orange colour) for winter wheat for the municipality ‘Zwevegem’. By mid-April the situation was normal-ised again, as can be seen from the

MODIS temporal profile in Figure 3. At the end of April the NDVI was well above average. In May, crop growth slowed down a little bit because of the cool temperatures and the abundant rainfall. Winter wheat yield at harvest was not influenced, however, and aver-age yields were obtained for most of the country (Agrometeorological bulle-tins, 2009).

Figure 3. DMC-1 NDVI of winter wheat on 1 April 2009 in the municipality ‘Zwevegem’ in Flanders (Belgium): absolute differences with the long-term average. Evolution of the NDVI differences for one field of winter wheat from 1 April to 30 June (arrow below). MODIS NDVI of winter wheat for the same municipality: absolute differences with the long-term average for the first dekad of April 2009 and temporal evolution of the MODIS NDVI from April to June 2009 (green line) compared to the long-term average for this period (blue line). © VITO

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Time series of high resolution images allow us to monitor crops and to detect anomalies at field level, as illustrated in Figure 3. The DMC-1 images show more detail compared to MODIS. In practice, however, it is found that crop monitoring with (daily) high resolution images is often hampered by the pres-ence of clouds, whereas low/medium resolution 10-daily composite images are obviously less sensitive to this problem. For the Belgian study area no images could be acquired in the first three weeks of May and at the begin-ning of June 2009 (Figure 3).

In Ethiopia, there are two major rainy seasons: the Belg (minor) rains

normally start in February and end in May. The Belg season supports both short-cycle crops which are harvested in June/July, and longer cycle crops, harvested up to September. The Meher (major) rains which start in June and end in October, support crops planted in or before the Meher season that are harvested from October to February (FAO/GIEWS, 2009).

In the 2008 growing season, the Belg rains were poor and delayed by 1 to 2 months (FAO/GIEWS, 2009; FEWS NET, 2008). The performance of the rains was below normal in February and March 2008 (dekads 5 to 9), but the distribution and amount of rain

Figure 4. NDVI absolute differences with the long-term average (for agricultural land only) in the Jeldu Woreda in West Shewa (Ethiopia) based on Landsat7-ETM+ (image of 21 March 2008) and MODIS (composite of 21 to 31 March 2008). Temporal evolution of MODIS NDVI (dashed lines) and FEWS NET rainfall values (full lines) for 2008 (blue) compared with the average (orange), minimum (red) and maximum (green) values. © VITO

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fall slightly improved in April to May. Besides the crop production which was lower than average, the below-normal Belg rains also affected land prepara-tion and planting of long-cycle crops. In contrast to the Belg rains, the over-all performance of the Meher rains was favourable and the Meher crops developed normally. However, from mid-October until the beginning of November, unseasonable rains began and light to heavy rains were received in all parts of Ethiopia. The temporal evo-lution of the rainfall (FEWS NET data, full lines) and the MODIS NDVI (dashed lines) for 2008 (blue) compared to the average (orange), minimum (red) and maximum (green) values is shown on the graph in Figure 4.

The below normal crop development at the beginning of 2008 can clearly be seen from Figure 4, showing both for Landsat7-ETM+ (image of 21 March 2008) and MODIS (21 to 31 March 2008) negative NDVI differences with the long-term average for the Jeldu Woreda in West Shewa. However, the Landsat7-ETM+ derived image reveals much more details, compared with the coarser resolution MODIS image.

CONCLUSIONS

In recent years, new high frequency, high resolution wide swath sensors such as DMC-1/2 and Deimos-1, have become available and in the near future many more sensors of this type will be launched (Sentinel-2, Deimos-2, Landsat-8, …). This paper describes how these spatially detailed images can be used for time series analysis — despite the lack of historical data —by using information from spectrally simi-lar medium resolution sensors with a long archive.

The method is illustrated for DMC-1 and Landsat7-ETM+ versus MODIS, at the level of the NDVI, but it can eas-ily be extended to other high and medium resolution combinations of similar sensors and to other vegeta-tion parameters such as fAPAR or LAI. The equations for describing the rela-tion between DMC-1 and MODIS and Landsat7-ETM+ and MODIS, as shown in this paper, have been derived for Belgium and Ethiopia respectively. Their validity in other regions of the world is still to be checked, but it is expected that region specific equations are needed.

Although this paper discusses the use of time series of high resolution images for agricultural applications, it is clear that the methodology can easily be applied in other thematic domains.

Time series of high resolution images allow us to monitor crops and to detect anomalies at field level, which is a major improvement compared to what is possible with medium or low resolu-tion satellite sensors with pixel sizes of 250 m up to 1 km.

In this paper, daily high resolution images are compared with the 10-daily reference image, which might lead to small errors.

Crop monitoring at field level impli-cates that crop type information has to be available at this detailed scale, which could be a problem in reality, as for the Ethiopian test site. In such cases, the comparison between actual and historical index values can only be done for ‘agricultural crops’, whereas in practice different crops are grown on the field every year. Of course, this introduces errors.

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Also, the presence of clouds is a still limiting factor for the use of opti-cal high resolution images for crop monitoring purposes, especially when images are lacking during critical peri-ods for crop growth. The combination of high resolution images from dif-ferent sensors with different overpass times could offer a solution. In this case, the analysis has to be based on sensor-independent indices. The use of 10-daily or (bi-)weekly composites of high resolution images might also be considered.

REFERENCES

  Agrometeorological bulletins for Belgium, published in May, July and September 2009 by ULg, CRA-w and VITO (http://b-cgms.cra.wallonie.be/en/Agrometeorological_Bulletins/Bulletins_NL.aspx, accessed on 15 March 2012).

  FAO/GIEWS, ‘Special report — FAO/WFP Crop and Food Supply Assessment Mission to Ethiopia, FAO/Global Information and Early Warning System on Food and Agriculture World Food Programme’, January 2009 (www.fao.org, accessed on 22 February 2012).

  FEWS NET, Ethiopia Food Security Update, April/May — September — October — November, Famine Early Warning System Network, 2008 (www.fews.net, accessed on 1 March 2012).

  Gao, F., Masek, J., Schwaller, M. and Hall, F., ‘On the blending of the Landsat and MODIS surface reflectance: predicting daily Landsat surface reflectance’, IEEE Transactions on Geoscience and Remote Sensing, Vol. 44, No 8, August 2006.

  Genovese, G., Vignolles, C., Nègre, T. and Passera, G., ‘A methodology for a combined use of normalised difference vegetation index and Corine land cover data for crop yield monitoring and forecasting — A case study in Spain’, Agronomie, 21, 2001, pp. 91–111.

  Van Cutsem, C., Kayitakire, F., Pekel, J. F. and Marinho, E., ‘Mapping of cropland areas over Africa combining various land cover/use datasets’, presentation given at the third Crop and Rangeland Monitoring (CRAM) workshop, Nairobi, 26 to 30 September 2011 (http://mars.jrc.ec.europa.eu/mars/News-Events/3rd-CRAM-Workshop/0503b, accessed on 1 March 2012).

CHAPTER 5

Authors: Allard de Wit, Raphaël d’Andrimont, Sergey Bartalev, Pierre Defourny, Alexander Kleshchenko, Gerbert Roerink, Igor Savin, Oleg Virchenko

consortium members: Alterra, Wageningen-UR, Netherlands; Université Catholique de Louvain, Belgium; Space Research Institute of Russian Academy of Sciences, Russian Federation; State Enterprise National Scientific & Research Institute on Agricultural Meteorology, Russian Federation

AbSTRACT

Information on the outlook of yield and production of crops over large regions is essential for government services, food relief agencies and international organisations monitoring world food production and trade. In Europe, agricul-tural monitoring has been implemented through the MARS Crop Yield Forecasting System (MCYFS) operated by the Joint Research Centre and also embedded in the European Union’s GMES initiative. Recently, the MCYFS was extended and now includes the monitoring of crops in the Russian Federation, central Asia and China. These regions are characterised by harsh winter and warm and dry sum-mer conditions. During the winter, win-ter wheat is particularly affected by low

temperatures which determine whether rapid regrowth is possible in spring. However, the effects of winter-kill are poorly described in the crop models used by MCYFS. Earth observation data provide an opportunity to derive such information and can form a basis for real-time updating of wheat growth parameters in the MCYFS. Over the 2011 growing season, an intensive field campaign was carried out to observe winter wheat fields in the Tula region in Russia. These observations included camera images of the fields to estimate the amount of green leaves, spectrom-eter observations that characterise the reflectance properties, and crop cut-ting experiments that characterise the crop biomass and yield. Moreover, work was carried out on winter wheat map-ping, vectorisation of fields in Tula, sat-ellite data processing, crop simulations and winter-kill modelling. This paper describes some of the preliminary results from the project.

AcHieVed resuLts

Fieldwork, meteorological and ancillary data acquisition

An intensive field campaign in the Tula region of Russia was carried out during the 2011 growing season in order to collect information about winter wheat regarding growth pattern, canopy

MOCCCASIN (Monitoring crops in continental climates through assimilation of satellite information)

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status, spectral response and crop bio-mass. Two test sites were selected in the region of Odoyev (10 fields) and Plavsk (13 fields) and were visited at fortnightly intervals (Figure 1). At each visit, several measurements were made for each field:

• estimates of crop biomass by sam-pling (cutting) the crop and visual estimates of the crop status on the field (canopy thinness, pest or weed infestations, etc); the estimates of crop biomass will be used to evalu-ate modelled estimates of crop bio-mass derived from the Wofost crop growth model;

• hemispherical camera images of the crop canopy that are being used for estimation of canopy green leaf area index (Figure 2, right); estimates of the green leaf area index (GAI) will be compared with the estimates that are derived from satellite observa-tions of MODIS and possibly MERIS;

•measurements of spectral response of the crop canopy that provide important information about the spectral properties of wheat leaves and the soil (Figure 2, left); these measurements will be compared against the simulations from the Prosail canopy reflectance model.

The Prosail model provides the link between satellite observations and crop canopy properties and is there-fore an important component for the satellite retrievals of crop GAI.

Moreover, data were collected from a network of synoptic and agrometeor-ologic stations in and around the Tula region (Figure 1). The synoptic data consisted of 3-, 4- or 6-hourly observa-tions of basic weather variables (tem-perature, humidity, rainfall, sunshine duration), which were processed into sets of daily values (rainfall sum, min./max. temperature, etc.). These point observations will be used to interpolate the station measurements to a regular 25 × 25 km grid for setting up the crop model. Figure 2 shows an example of the minimum and maximum temper-ature, clearly showing the 2010 sum-mer drought that struck large parts of Russia.

Besides the synoptic measurements, agrometeorological observations were also conducted for these stations at 10-daily intervals. These agrometeor-ological observations were conducted on a nearby winter wheat field and were an important source of infor-mation regarding crop-specific varia-bles (sowing date, phenological stage, yield and crop management) as well as

Figure 1. The measured reflectance spectrum (left) and the corresponding crop canopy (right).

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observations regarding snow depth and the effect of frost on the win-ter wheat crop (temperature on node depth).

Finally, a considerable effort has been spent on obtaining the field boundaries of all fields in the Tula region by digit-ising them from a recent LandSat TM image. A soil type has been assigned to each field, based on Russian soil maps. The use of the field boundaries has important consequences for the design of the final winter wheat moni-toring system.

• The winter wheat masks can be applied to determine which fields are sown with winter wheat. Within the winter wheat monitoring system, fields can be switched ‘on’ or ‘off’ in the crop simulation depending on the crop mask.

• The crop simulations can be applied on a per-field basis, allowing for fine-grained monitoring of the region, par-ticularly if estimates of sowing or

emergence can also be obtained on a per-field basis.

• Retrieval of the crop GAI, can be done on a per-field basis and fields that are too small to monitor with MODIS and/or MERIS can be easily discarded.

Winter wheat mapping

As the total crop production for a region is defined by the crop yield times the total area, the mapping of the cultivated area is an important aspect of a winter wheat monitoring system. Moreover, for retrieval of the crop GAI it is necessary to know which fields are planted with winter wheat, otherwise the estimated GAI will be derived for the wrong crop or land cover types. The mapping of win-ter wheat is done already in autumn in order to provide an estimate of the planted area before the winter.

Within IKI, a semi-operational pro-cessing chain was developed which will be validated and improved within

Figure 2. Overview of the Tula region, available synoptic stations and the MOCCCASIN test sites. In grey, the regular 25 km grid; in the background, a digital elevation model.

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the MOCCCASIN project. This processing chain uses time series of daily MODIS 250 m observations (MOD09) to gener-ate 4-day composite images of the sur-face spectral reflectance in the red and near-infrared (NIR) MODIS bands. The daily MODIS data processing includes removing pixels with values unreliable due to extreme sensor view angles and pixels contaminated by clouds, cloud shadows or snow.

After processing the MOD09 product into a composited product, two dif-ferent algorithms are available for determining which pixels in the image predominantly represent winter wheat crops. The first algorithm uses the per-pendicular vegetation index (PVI) and searches the time-window between day-of-year 200 and 365 for the minimum and maximum PVI values (Plotnikov et al. 2008, Plotnikov, 2010). The corresponding dates are chosen as the boundaries of the analysis inter-val. If the maximum value of PVI was reached before the minimum, then the current pixel is considered not to belong to the winter crops class and the analysis for this pixel stops. A pixel is considered as a winter crop class if

the PVI time series is increasing con-tinuously for at least three consecu-tive measurements inside the interval of interest, while allowing for small decreases in the trend of the PVI time series which are often caused by sys-tem noise.

The second algorithm uses a super-vised locally adaptive maximum likeli-hood classification to classify pixels as winter wheat. Locally adaptive classifi-cation means that the area to be clas-sified is covered by the regular grid, and for every node of the grid unique local class signatures are derived, so that spatial variability of spectral char-acteristics of vegetation is taken into account. Comparisons with the official regional statistics demonstrate that the estimated winter wheat area has an average error of 7.6 %.

Figure 3 shows the winter wheat mask for the Tula region derived from the MODIS 250 m observations for the 2011/12 season. The accuracy of this map can be increased by combining the map with the digitised field boundaries through an overlay procedure.

Figure 3. Example of available meteorological information for station Virkhovie. The summer drought in 2010 is clearly visible with the maximum temperature > 30 °C.

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Figure 4. Map of winter wheat planted area in the Tula region for the 2011/12 growing season

Satellite GAI retrieval

Time series of satellite GAI provide an opportunity to derive information on key crop growth parameters with high spatial and temporal resolution. If this is this case, the satellite GAI can be used for an objective estimation of wheat conditions after the winter dor-mant period. Depending on how the crop survives the winter, it will have a large impact on the recovery and the shape of the GAI profile later in the season. The latter can be monitored with satellite data which can form a basis for real-time updating of wheat growth parameters in the model.

A variety of methods have been devel-oped to retrieve biophysical variables from remote sensing data using radia-tive transfer theory (see Dorigo et al. (2007) and Baret and Buis (2008) for a recent review). For the MOCCCASIN project, the GAI will be retrieved as

described in Duveiller et al. (2011b), as summarised below. GAI is retrieved from multispectral reflectance using neural network techniques (NNT) trained over canopy radiative transfer simulations. This hybrid approach com-bines advantages of statistical and physical approaches in biophysical var-iable retrieval (Baret and Buis, 2008, and Dorigo et al., 2007). The approach is based on the algorithm conceived by Baret et al. (2007) to derive the global GAI product developed within the Cyclopes (Carbon cycle and change in land observational products from an ensemble of satellites) project from spot/vegetation data. The radiative transfer model used is Prosail (Baret et al., 1992), a coupling of the canopy reflectance model SAIL (Verhoef, 1984) to the leaf optical properties model Prospect (Jacquemoud et al., 1995). The Cyclopes algorithm was later adapted for winter wheat GAI retrieval from the SPOT/HRV(IR) imagery in the

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ADAM database by Duveiller et al. (2011a).

Within MOCCCASIN, the retrieval algo-rithms have been set up for the Tula region and used for a preliminary retrieval of the crop GAI for selected fields near Tula for several years (Figure 5). The results demonstrate that there is a considerable inter-annual variability in the retrieved GAI profiles. As such inter-annual variabil-ity is sometimes difficult to capture with crop simulation models, these results indicate that there are opportu-nities to take advantage of combining both sources of information.

Crop model development and adaptation

The World Food Studies (Wofost) model is used as a basis for implementing the crop simulations in MOCCCASIN (van Diepen et al. 1989). This model is also used in the MARS Crop Yield Forecasting System (MCYFS) and

applied operationally for crop monitor-ing and yield forecasting. Originally, the MCYFS targeted Europe, the Maghreb and Turkey, where winters are rela-tively mild. As a result, the Wofost model does not include the effect of frost damage on the simulated stand-ing biomass and the impact on the recovery in spring.

Three approaches for integrating frost damage in Wofost have been selected from a review of available literature. Also, for these approaches source code of the actual implementation is available.

• The ClimCROP model (Oleson, et al 2000) uses a reduction factor which directly impacts on the crop leaf area index development. As crop leaf area index in ClimCROP is defined using a functional relationship this is easy to combine. However, the leaf area index in Wofost is defined by the leaf biomass so specific leaf area is less suitable to combine with Wofost.

Figure 5. Time series of green leaf area index estimates for winter wheat fields near Tula derived from MODIS.

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• The Frostol model (Bergjord et al. 2008) uses a rate/state-based approach for simulating the temper-ature where 50 % of the plants get killed due to frost (LT50). The LT50 state variable decreases due to hard-ening which occurs when plants are exposed to a suitable temperature range. LT50 increases due to de-hard-ening, which occurs when plants are exposed to temperatures above a cer-tain level or due to stress factors. As Wofost also has a strong rate/state-based approach, the Frostol model seems most suited for coupling to Wofost. Figure 6 shows an example of the results from the Frostol model.

The approach that was originally devel-oped for the CERES-Wheat model has some similarity to the Frostol approach. In this approach, a hardening index is calculated as a measure of the cold resistance of the crop. The hardening index is used to calculate a killing tem-perature; if the crown temperature is below the killing temperature, the crop

is killed completely. Partial damage to the crop is calculated as a function of the hardening index and an empirical relationship, which acts as a reduction factor to the leaf biomass.

Integrating the simulation of frost damage into Wofost requires a con-siderable change in the structure of the model. We therefore decided to restructure components of the model in order to allow easier integration of functionally similar model compo-nents within the whole framework. A prototype implementation of the Frostol model is already available; a final implementation of the model still needs to be done in order to fit it into the modelling system.

Testing of the simulations will be done using the measurements at the agro-meteorological stations and it will be tested if the inter-annual variability of the regional statistics on winter-kill can be reproduced by the winter-kill model.

Figure 6. Example of a simulation of the killing temperature (LT50) and the crown temperature. In this particular example, the crown temperature is always above the killing temperature, so no crop damage is expected.

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CONCLUSIONS

Considerable progress has been made within the first 15 months of the MOCCCASIN project.

• A field campaign has been carried in the Odoyev and Plavsk test sites, where a considerable amount of data on crop canopy structure, crop spectral reflectance and crop bio-mass has been gathered. These data sources are currently being pro-cessed and will be used for calibrat-ing and validating the Wofost crop simulation model, Prosail canopy reflectance model and the accuracy of the GAI from satellite time series

•Meteorological and agrometeoro-logical data have been collected and processed into a consistent dataset. Analysis of the temporal and spatial patterns of temperature and rainfall demonstrate that the meteorological dataset is consistent.

• The winter wheat mapping was executed in the autumn of 2011 and the results will be validated and fine-tuned in the coming year. Moreover, the winter wheat masks are being generated for the historic MODIS archive starting in the year 2000, which will ensure that the GAI retrieval can be carried out over the complete MODIS archive.

• The GAI retrieval algorithms have been set up for the Tula region and a first set of retrievals has been car-ried out for selected fields near Tula.

• Algorithms for winter-kill simulation have been reviewed and selected. Moreover, the Wofost source code has been restructured in order to incor-porate the winter-kill component.

The second part of the MOCCCASIN project will focus on integrating and validating the different components of the project. Moreover, these compo-nents have to be incorporated into a winter wheat monitoring system that can run a semi-operation or whose components can be embedded in the operational MCYFS.

REFERENCES

  Baret, F. and Buis, S. (2008), ‘Estimating canopy characteristics from remote sensing observations: review of methods and associated problems’, in Shunlin Liang (ed.), Advances in land remote sensing — System, modeling, inversion and application, Springer Netherlands, 2008, pp. 173–201.

  Baret, F., Hagolle, O., Geiger, B., Bicheron, P., Miras, B., Huc, M., Berthelot, B., Nino, F., Weiss, M., Samain, O., Roujean, J. L. and Leroy, M., ‘GAI, fAPAR and fCover Cyclopes global products derived from vegetation — Part 1: Principles of the algorithm’, Remote Sensing of Environment, 110, 2007, pp. 275–286.

  Baret, F., Jacquemoud, S., Guyot, G. and Leprieur, C., ‘Modeled analysis of the biophysical nature of spectral shifts and comparison with information content of broad bands’, Remote Sensing of Environment, 41, 1992, pp. 133–142.

  Bergjord, A. K., Bonesmo, H., Skjelvag, O. A., ‘Modelling the course of frost tolerance in winter wheat: I. Model development’, Europ. J. Agronomy, 28, 2008, pp. 321–330.

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  Dorigo, W. A., Zurita-Milla, R., de Wit, A. J. W., Brazile, J., Singh, R. and Schaepman, M. E., ‘A review on reflective remote sensing and data assimilation techniques for enhanced agroecosystem modeling’, International Journal of Applied Earth Observation and Geoinformation, 9, 2007, pp. 165–193.

  Duveiller, G., Weiss, M., Baret, F. and Defourny, P., ‘Retrieving wheat green area index during the growing season from optical time series measurements based on neural network radiative transfer inversion’, Remote Sensing of Environment, 115, 2011a, pp. 887–896.

  Duveiller, G., Baret, F. and Defourny, P., ‘Crop specific green area index retrieval from MODIS data at regional scale by controlling pixel-target adequacy’, Remote Sensing of Environment, 115, 2011b, pp. 2686–2701

  Jacquemoud, S., Baret, F., Andrieu, B., Danson, F. M. and Jaggard, K., ‘Extraction of vegetation biophysical parameters by inversion of the Prospect + SAIL models on sugar beet canopy reflectance data — Application to TM and Aviris sensors’, Remote Sensing of Environment, 52, 1995, pp. 163–172.

  Olesen, J. E., Jensen, T. and Petersen, J., ‘Sensitivity of field-scale winter wheat production in Denmark to climate variability and climate change’, Climate Change, Vol. 15, 2000, pp. 221–238.

  Plotnikov, D., Bartalev, S. and Loupian E., ‘A method of detection of summer–autumn–winter crops shoots using MODIS data’, Current problems of Earth remote sensing, 5(2), 2008, pp. 322–330 [in Russian].

  Plotnikov, D., ‘Method of crops area estimation using MODIS data, based on the locally adaptive classification of vegetation index composite images time series’ [in Russian], VIIth young scientists’ conference ‘Fundamental and applied space research’, Moscow, 12–13 April 2010.

  van Diepen, C. A., Wolf, J., van Keulen, H. and Rappoldt, C., ‘Wofost: a simulation model of crop production’, Soil Use and Management, 5, 1989, pp. 16–24.

  Verhoef, W., Light scattering by leaf layers with application to canopy reflectance modeling: The SAIL model’, Remote Sensing of Environment, 16, 1984, pp. 125–141.

CHAPTER 6

Authors: Stefan Lang, Jeroen Vanden Borre, Birgen Haest, Lena Pernkopf, Oliver Buck, Kian Pakzad, Michael Förster, Rik Hendrix

consortium members: Centre for Geoinformatics (Z_GIS), University of Salzburg, Austria; Research Institute for Nature and Forest (INBO), Belgium; Flemish Institute for Technological Research (VITO), Belgium; EFTAS Fernerkundung Technologietransfer GmbH, Germany; Department for Geoinformation in Landscape and Environmental Planning, Technische Universität Berlin, Germany

AbSTRACT

Natura 2000, the European answer to the Convention on Biological Diversity (CBD), is one of the world’s most effec-tive legal instruments concerning bio-diversity and nature conservation and a success story among pan-European initiatives. The EU habitats directive (Council Directive 92/43/EEC) requires standardised monitoring and report-ing for which the project will offer an objective operational, yet economi-cally priced solution. Users are in need of data and information, as imposed by the legally binding character of the directive. MS.Monina fosters the use of GMES space and in situ infrastructure and advanced EO-based analysis and

modelling tools, specifically tailored to user requirements in terms of rele-vance, level of detail and scale, steadi-ness and reliability, uptake and fitness to existing workflows. The project fol-lows a pan-European, multi-scale approach on different levels reflecting the specificity and variety of habitats in the different biogeographical regions. The services are under final specifi-cation and first results of the project show the great potential of a multi-scale EO-based service ranging from biodiversity-related indicators to direct habitat mapping.

A MuLti-scALe serVice to SUPPORT THE EU HAbITAT directiVe

MS.Monina operates on three inter-related user and scale levels for the successful implementation of the EU habitats directive (HabDir) and the linked Natura 2000 concept (cf. Vanden Borre et al., 2011a). Three (sub-)services are offered, reflecting these three levels of operation, i.e. MS.Monina EU, MS.Monina state, and MS.Monina site. Each of the service devel-opments follows the same overall logic in three steps, but tailored to the (user) and technical requirements that are specific for each service level (Fig. 1). User requirements collect all details on existing workflows, data usages and

Multi-scale service for monitoring Natura 2000 habitats of European Community interest (MS.Monina)

83MULT I -SCALE SERV ICE FOR MONITOR ING NATURA 2000 HAB ITATS OF EUROPEAN COMMUNITY INTEREST (MS .MONINA)

Figure 1. Specific needs for users on three levels of implementation © S. Lang

the responsibilities imposed by the directive. Based on these requirement specifications, testing, comparison and integration of state-of-the-art meth-odologies are performed, resulting in the actual development of the ser-vices. Demonstrators, accompanied by a user validation exercise, complete the service evolution plan and the final

market scoping. In order to facilitate the uptake by users, an operational service is expected to fully integrate the recent potential of EO techniques and image analysis routines, but at the same time deliver conditioned informa-tion products (Lang, 2008) in a familiar and ready-to-use format. MS.Monina thereby addresses: (1) agencies at EU

84MULT I -SCALE SERV ICE FOR MONITOR ING NATURA 2000 HAB ITATS OF EUROPEAN COMMUNITY INTEREST (MS .MONINA)

level, i.e. ETC Biodiversity, the EEA and the Environment DG, in their report-ing requirements to CBD-related envi-ronmental policies by providing added value information products on biodi-versity status and following the wider SEIS developments; (2) national and federal agencies in reporting on sensi-tive sites and habitats within biogeo-graphical regions on the entire territory by utilising advanced image analysis, modelling and information integra-tion techniques; (3) local management authorities by advanced mapping methods for status assessment and change maps of sensitive sites and their surroundings in a spatial explicit manner; (4) all three groups by pro-viding transferable and interopera-ble monitoring results for an improved information flow between all levels.

Four important criteria for such ser-vices to be suitable have been identi-fied by Vanden Borre et al. (2011b): (1) multi-scalability, i.e. addressing multi-ple scales on all levels of implementa-tion and enabling up- and downscaling between scale levels; (2) versatility, with algorithms tailored to the habitat type of interest and designed to best exploit certain image types; (3) user-friendli-ness, allowing seamless integration of resulting products into GIS-workflows already in place with users; (4) cost-efficiency, providing reliable and repro-ducible products at an affordable cost, compared to traditional field methods and other EO-based methods.

AcHieVed resuLts

Site-level service

While specific information needs at the local level obviously vary from one site to another, in general thorough

knowledge of actual habitat locations and distributions is required, and the conditions in terms of overall quality, existing threats and pressures need to be known, as well as their trend of development. Such up-to-date infor-mation is also of high value to site managers, to make informed decisions about the measures to be applied, as well as the effects of such meas-ures, in order to steer adaptations and improvements (Vanden Borre et al., 2011b).

The mapping sub-services could be grouped based on ecologically relevant characteristics of the output, in order to provide a user-adaptive structure for the final MS.Monina site service:

(1) maps and indicators on a larger scale, related to connectivity and landscape configuration;

(2) maps of patches of vegetation types or habitats;

(3) maps of conservation status of veg-etations/areas, showing indicators;

(4) maps documenting land use/land cover changes.

Figure 2 shows a very basic infor-mation product, a pre-cursor to type (1), but with specific information on altered conditions in a Natura 2000 site, and under both aspects: improved and deteriorated habitat conditions. This is only a simple visual assess-ment using up-to-date EO data, but it already serves quite a few purposes from a site management perspective. Note that for illustration purposes, the map content has been zoomed to two particular areas, but otherwise includes information that covers the entire site.

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continental biogeographical region (BGr)

riparian forest habitats 91E0*, 9180*, 91F0, 9170 Object-based class modelling

Heathland and inland dunes 4030, 2310, 2330 Knowledge base, training pixels, training pixels are clustered and homogeneous signatures are created, maximum likelihood classification

Mediterranean BGr

Lowland alluvial plains 7230, 7140, 6410, 6510, 6120, 6230, 3150, 9170

Classification algorithms are based on hybrid methods, exploiting both object-based and pixel-based approaches. Classification procedures include decision tree and supervised routines.

Benthic habitats 1150 * Fusion of 3 models: a model of attenuation of the signal in its path through water, a spectral model of pixel unmixing, and a model of the underwater bathymetry

freshwater habitats (not specified) Kernel-based reclassification (KRC) and support vector machines (SVM)

Atlantic BGr

Lowland habitats 2310, 4010, 4030, 2330, 6410, 6510, 7120, 7140

Knowledge-based

Heathland and inland dunes 4010, 4030, 2310, 2330, 2110, 2120, 2130, 2150, 2160, 2170, 2180, 2190

Supervised classification in combination with ecologically based knowledge decision rules

Alpine BGr

Alpine forests (not specified) Supervised classification, maximum likelihood approach. Change classification

Alpine habitats 4060, 4070, 6150, 6170, 6230, 6430, 6510, 6520, 7140, 7240, 8110, 8120, 9410, 9420

Stratified sampling, ensemble classifier (e.g. maximum likelihood, See 5, support vector machine)

cross-biogeographical

indicator Bush and tree encroachment

5210, 6210, 6220, 8210, 92A0, 9340

Object-oriented classification (Boolean or fuzzy membership functions)

indicators compositional variation in (semi-) natural plant assemblages; α, β- biodiversity measures

Inland dunes (2xxx), heath and scrub (4xxx), grassland formations (6xxx) and raised bogs (7xxx)

Ordination methods to extract major floristic gradients. linkage hyperspectral imagery by partial least-squares regression

Table 1. Specificities of site-level pilots listing ecosystems, N-2000 habitats addressed, and image analysis methods applied (partly also applicable at state level)

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Figure 2. Pilot site Salzachauen, ‘zoom’ to critical changes in habitat conditions (© PLUS/Z_GIS; orthophoto: Federal state of Salzburg; habitat delineation: Revital; figure composition: T. Strasser)

State-level service

The MS.Monina state service estab-lishes integrating links to the regional/site level and the European level. To support the reporting obligations imposed by HabDir, this service will utilise mapping and image analysis capabilities to provide critical infor-mation, even outside the network of protected sites. The service cases require adjusted developments (local user needs, biogeographic conditions, partner expertise, tools, etc.). Methods should be transferable to other ser-vice cases and a (technical) exchange between service cases and partners should be possible. To make this pos-sible, a concept of interpretation lay-ers has been developed. The idea

behind this is that new data analysis methods could be potentially applied in several service cases. These inter-pretation layers will act as a ‘con-tainer’ for relevant class features, and should be easy to integrate into differ-ent systems with a commonly known exchange format. The features can be mono- or multi-temporal/multi-sea-sonal reflecting spectral, textural and structural information. The advantage is that a focus is put on method devel-opment tackling habitat-specific prob-lems (shrub encroachment, temporal habitat variation, etc.) and that core image analysis models and compo-nents can be tuned to service cases. Class model developments in themat-ically overlapping service cases can then ‘learn’ from each other.

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Figure 3. Interpretation layer concept with interlinkages to the MS.Monina SDI and toolbox © EFTAS

EU-level service

Based on the Member States’ reports, the European Commission compiles a 6-yearly composite report with an over-view of the actual conservation status of all habitats and species protected by the HabDir. Data are integrated to the level of nine biogeographical regions (Atlantic, Continental, Alpine, Boreal, Mediterranean, Macaronesian, Pannonian, Steppic and Black Sea), to reflect the large variety in environ-ments across the European continent. The latest composite report appeared in 2009 which had to face the challenge of lacking harmonisation in data col-lection and reporting among Member States (Vanden Borre et al. 2011b). The EU-level service will support the

requirements from EU administration for independent, complementary infor-mation in two ways: (1) biodiversity indicators which are derived from pan-European products including the GIO high-resolution layers (HRL), on e.g. forest, grasslands, wetlands; and (2) selected local level information for val-idating specific ambiguous cases.

Multi-scale service chain

The multi-scale approach will be real-ised and demonstrated through ver-tical service chains. There are many possible hierarchical relations between the EU (on top), the individual protected sites (on the bottom), and Member States in between, located in different biogeographical regions. Connected

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vertical elements (e.g. EU–Member State A–sites b, c) together outline a service chain. Service chains are hence formed by ‘trans-level’ applications within BGR, complemented by the EU level. To reach from site level moni-toring to Member State-relevant infor-mation, upscaling methods need to be coupled with additional tools. Habitat modelling techniques will be utilised and combined with advanced analysis techniques of satellite data at different spatial resolutions (very high to high) using e.g. object-based image analy-sis. By this, the ‘multi-scale’ concept of the Natura 2000 implementation mim-ics an ecological scaling ladder with a focal level embedded in a nested hier-archy (Lang et al., 2011).

Service level agreements with different user groups

Next to the actual service develop-ments, the project consists of a num-ber of supportive tasks to ensure the interoperability and information and data flow between the three service levels. The framework for this is pro-vided by the user engagement pro-gramme. Dedicated user workshops are held and interviews are conducted that lead into service level agree-ments (SLAs) to specify the informa-tion demanded. Demonstration of the service cases in the respective pilots as well as a validation exercises also belong to the user-oriented activities, which are considered crucial for the success of this GMES project.

EO data acquisition

The EO data management is a crucial task within the project and involves the data acquisition procedure utilis-ing the GMES Data Warehouse. For the first year, VHR data has been ordered

for 21 sites within two acquisition win-dows: the first from June to July 2011 and the second in September 2011, whereas the first had to be extended to August 2011 to allow for further acqui-sitions. The results are very satisfying with scenes for 15 sites in the first acquisition window and only two rejec-tions, due to cloud cover. Data acqui-sition was not successful for three sites. In the second acquisition window, data has been acquired for 11 sites. All data are provided by WorldView-2 (0.5 m/pix ground resolution), most with eight bands. Additionally, multian-nual HR datasets covering more than 130 000 km² have been obtained from the RapidEye data archive.

Tools repository, SDI and interoperability

Available tools and methods for hab-itat mapping and monitoring are col-lected from different sources and put into a common knowledge database, the ‘Body of Knowledge’ (BoK), where functionality, architecture and valida-tion state of the tools are described. A comprehensive compilation of different in-house and/or open methodological tools has already been undertaken and the tool repository has been set up and is now accessible for registered users.

For discovery, viewing and access of MS.Monina products (spatial data and services) an operational interface is set up by developing a project specific spatial data infrastructure (SDI) portal. This portal adheres to Inspire stand-ards and realises semantic interopera-bility issues. Possible technologies and solutions for the SDI have been iden-tified and the development of an SDI prototype has already started, mainly building on open source software com-ponents. Specific challenges for the

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SDI are the diversity of data sources (raster/vector, file formats, coordi-nate systems, etc.) and the design of an efficient, easy-to-use workflow to ingest data and metadata in one pass. Metadata profiles suitable for nature conservation have been identified. With respect to interoperability issues, ontology has been developed contain-ing selected classes to define neces-sary indicators. Semantic properties like habitat types, plant species, water activity, soil, coverage and temperature are included and semantic relations between classes have been generated. Remote sensing indicators of state and EU-levels can be introduced when out-put data structure and classification methodology were defined.

Links to related (past or ongoing) activities

Experiences from the Belgian Belspo-funded project Habistat serve as a foundation to build on. The geoland2 core information services (CIS), partic-ularly agri-env, water, forest and spa-tial planning, are likely to work in a complementary fashion to MS.Monina, resulting in the sharing of products and services. The SATChMo core map-ping service offers the opportunity to test or extrapolate MS.Monina outputs in order to be representative for the whole of Europe. At state level, coop-eration with national GMES-related projects like DeCOVER is foreseen to ensure a knowledge exchange for state-specific requirements. MS.Monina will also complement the efforts taken in EBONE (in terms of data gathering, indicator usage, and institutionally in terms of mandates and capacities) and Nature-SDIplus (in terms of data infra-structure, data models, and best prac-tices of geodata handling in general). The Nature-SDIplus metadata profile

has been adopted, as it is specifically developed for nature conservation. In a complementary way, MS.Monina links up with BIO_SOS and the other funded pre-operational services that strive to explore new emerging areas for GMES services in support of natural resource protection and management. It inter-faces Interreg project HabitChange in terms of adaptive management for changes due to external drivers.

CONCLUSIONS

MS.Monina, in its multi-scale approach, will demonstrate to users the benefit of using services based on EO data. Therefore it will set the crucial condi-tions for a significant uptake of prod-ucts and a long-term sustainability of the services. The general goal of the user communities is to feed their deci-sion-making process on status evalu-ation with indispensable information. Such information is currently largely lacking or very expensive and time-con-suming to obtain (i.e. almost exclusively by field work). At site level, manag-ers will use MS.Monina services to find out where habitat status is deteriorat-ing or habitats are even disappearing, and what internal or external pressures and threats cause these deteriorations. Site managers are expected to use this knowledge to make informed decisions about where to apply dedicated man-agement measures in order to obtain an optimum result, and will later on be able to monitor the effects of this man-agement. At EU and state levels, the services will be used to evaluate poli-cies at different scales and adapt them when necessary.

Ultimately, to reach European citizens, stakeholders and entrepreneurship, the project promotes activities aiming at

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communicating, integrating, sharing knowledge and disseminating achieve-ments, building on the momentum gen-erated at the close of the International Year of Diversity, in December 2010.

REFERENCES

  Lang, S., ‘Object-based image analysis for remote sensing applications: modeling reality — dealing with complexity’, in T. Blaschke, S. Lang and G. Hay (eds), Object-based image analysis — Spatial concepts for knowledge-driven remote sensing applications, Springer, Berlin, 2008, pp. 3–28.

  Lang, S., Pernkopf, L., Vanden Borre, J., Förster, M., Haest, B., Buck, O. and Frick, A., ‘Fostering sustainability in European nature conservation Natura 2000 habitat

monitoring based on Earth observation services’, Proceedings of the first World Sustainability Forum, 2011 (available online, open access).

  Vanden Borre, J., Paelinckx, D., Mücher, C. A., Kooistra, L., Haest, B., De Blust, G. and Schmidt, A. M., ‘Integrating remote sensing in Natura 2000 habitat monitoring: prospects on the way forward’, Journal for Nature Conservation, 19, 2011a, pp. 116–125.

  Vanden Borre, J., Haest, B., Lang, S., Spanhove, T., Förster, M. and Sifakis N., ‘Towards a wider uptake of remote sensing in Natura 2000 monitoring: Streamlining remote sensing products with users’ needs and expectations’, Proceedings of the second International Conference on Space Technology (ICST), Athens, 2011b.

CHAPTER 7

Authors: António Araújo, António Nunes

consortium members: GMVIS Skysoft, Portugal; Instituto Superior Técnico, Portugal; Hidromod, Portugal; Unesco-IHE Institute for Water Education, the Netherlands; HydroLogic Research BV, the Netherlands; Joint Research Centre — European Commission, Belgium; Instituto Nacional de Pesquisas Espaciais, Brazil; Pannon Egyetem, Hungary; Aristotelio Panepistimio Thessalonikis, Greece; Universidade Eduardo Mondlane, Mozambique

AbSTRACT

The MyWater project aims to provide reliable information on water quan-tity, quality and usage for appropriate water management. This objective is to be reached by conducting coordinated research in three areas: Earth obser-vation (EO), catchment modelling and meteorology. Data from these differ-ent sources will be integrated through a unique interface platform, which pro-vides to the water manager user-tai-lored results, such as agriculture water needs, flood scenarios and deserti-fication scenarios. EO can be used to

identify land use and land cover (LULC), and to estimate actual evapotranspira-tion (ETa), leaf area index (LAI) and soil moisture (SM). Catchment models will use these parameters as input or cali-bration/validation data. Meteorological information, such as precipitation and temperature is needed as input to the catchment models to determine the water availability. Integrating informa-tion from EO, meteorology and catch-ment models, together with in situ data, will help to cross-validate the estimates of water quantity and qual-ity in catchments. These estimates will therefore become less uncertain and more reliable. This will support water managers and users in determining long-term strategies and in making their daily operational decisions.

This paper will focus on the work developed during the first year of the MyWater project in the research and development of methodologies for the operational exploitation of EO data to produce LULC, LAI, ETa and SM maps.

AcHieVed resuLts

The MyWater project focus is on obtaining reliable information on

MyWater: GMES specific services for operational water management (LULC, LAI, evapotranspiration and soil moisture)

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water quantity, quality and usage for appropriate water management. This objective is to be achieved by com-bining research from three scientific research areas: Earth observation (EO), catchment modelling and mete-orology (Figure 1).

The EO derived products (i.e. LULC, LAI, ETa and soil moisture, hereafter also called land core data) are an essential constituent of the catchment model and a component of the MyWater concept. They enable the improve-ment of watershed prediction models and their present state representa-tion, and result in better hydrological forecast for water management (van Andel, 2009). This improvement fol-lows two different paths; one is the

offline improvement of model struc-ture and parameters in calibration and validation phase; and the other is the online improvement of predictions through data assimilation.

The offline mode improvements con-sist in using the outputs from EO (e.g. LULC, LAI, ETa and soil moisture) to calibrate the parameters and validate the outputs of the models. For exam-ple, in catchment models that do not have crop growth models, LAI can be used to dynamically represent related model parameters, such as intercep-tion capacity and potential evapotran-spiration, instead of climatological (monthly) values. In catchment mod-els with crop growth models, LAI can also be used as a calibration variable.

Figure 1. MyWater conceptual diagram.

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In online data assimilation the out-puts from EO can be used for parame-ter updating. For example, ETa and soil moisture can be used for state updating and LULC is used in catchment model-ling for the estimation of environmen-tal variables indispensable for water quantity assessment in watersheds.

Together the offline and online use of the satellite derived LULC, LAI, ETa and soil moisture will provide an improved assessment of the real-time hydrologi-cal state of the catchment. It has been shown that this results in improved hydrological predictions for the short, medium, and long term (e.g. van Andel, 2009). The benefit of sound hydrologi-cal predictions that account for uncer-tainty (probabilistic predictions) in anticipatory water management has been explicitly shown in several case studies (Roulin, 2007; van Andel, 2009).

The following sections address the development of the land core data that will be used with the catchment models; these sections compile the outcomes of the research and devel-opment work produced during the pro-ject’s first year for the definition of the methodologies for the operational exploitation of EO data, to produce LULC, LAI, ETa and SM maps.

Land use land cover (LULC)

Considering that the MyWater services address local and regional scales, the LULC maps will be developed at differ-ent scales: regional and local (refer-ence scales 1:1 000 000 and 1:50 000 respectively). LULC maps for the test site areas are required to be developed once at the beginning of the imple-mentation phase. These will not be updated during the project’s lifetime. Thus, two recent LULC maps for each

test site will be produced, one for each reference scale.

Land use and land cover maps will be generated, based on medium and high spatial resolution satellite images from ESA or ESA third-party missions. A pre-liminary evaluation of possibilities points to the following data sources.

• Regional scale: moderate spatial res-olution imagery, specifically MERIS (medium resolution imaging spec-trometer) or MODIS (moderate res-olution imaging spectroradiometer). For low resolution LULC and LAI, there are already global products avail-able, namely Globcover and MODIS LAI. These products have been tested and validated extensively at various sites worldwide, thus are products of high quality. Also, they are produced globally and have the advantage of being homogenous and comparable within and across test sites. These products will be incorporated in MyWater’s services ‘as is’, after some limited validation.

• Local scale: high spatial resolution imagery, specifically SPOT-4/HRVIR, Landsat and/or IRS-P6/LISSIII (or similar).

The use of this satellite data is con-strained by its availability and also its simultaneous suitability for developing the other land core data (i.e. LAI, ETa, soil moisture).

The LULC maps nomenclature was already defined. It is based on the Land Cover Classification System (LCCS) developed by FAO (Di Gregorio and Jansen, 2000) in order to: (1) be rep-resentative of the landscape types existent in the study areas; and (2) to allow easy harmonisation with other

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LULC products and to be compatible to previous efforts (e.g. Corine land cover, Geoland2, Globcover). The use of widely accepted nomenclatures is strongly supported by the scientific community. The nomenclature fol-lows a hierarchical approach in order to adapt to different levels of detail, having 12 classes at the lowest level of detail and 37 classes at the highest level of detail.

The methods used for information extraction from the input (remotely sensed) data will be adequate for the different imagery spatial resolutions we will be dealing with. At the same time, advantage will be taken in some cases from the multi-temporal nature of satellite images, in order to improve crop identification based on the dif-ferent crop phenologies. In all cases, automated methods will be applied, followed by a manual edition in the image post-processing phase. Images will be processed with automatic clas-sification algorithms (e.g. maximum likelihood, linear discrimination classi-fier, neural networks — all currently in research) using the pixel as the spatial unit of analysis, complemented with object-oriented analysis. In all cases, satellite data pre-processing (geomet-ric and radiometric correction) will be applied as needed.

For the production of the LULC maps, a series of ancillary data (Globcover, Corine land cover, specific local land cover data, high resolution imagery such as ortho-imagery, etc.) and fieldwork is envisaged to be used both to assist the classification and validation procedures. To support the ancillary data collection, a detailed data inventory was produced by means of web search and also ques-tionnaires that were sent both to users and local partners.

The validation of the LULC maps shall follow a statistically sound accuracy assessment strategy involving the construction of confusion matrices based on the comparison of the map with a reference database (based on a sound probability design — e.g. strat-ified random sampling) representing the ‘ground truth’. This comparison will allow for the estimation of the maps standard accuracy measures, i.e. over-all accuracy, user’s accuracy and pro-ducer’s accuracy and reliability, i.e. K-hat statistic.

Leaf area index (LAI)

The leaf area index (LAI) is an impor-tant vegetation biophysical parameter that corresponds to the ratio of leaf area per unit ground surface area. It is an important input in spatially dis-tributed modelling of several variables, such as evapotranspiration and vege-tation productivity.

The advantages of remote sensing techniques are dynamic, rapid and provide large spatial coverage, which overcome the labour-intensive and time-consuming character of direct ground-based field measurements, thus allowing successful estimates of LAI from space The technique relies on the unique spectral response char-acteristic of green leaves compared with other land surface materials. The selective absorption of solar radiation by green leaves makes it possible to generate vegetation indices such as simple ratio (SR), normalised difference vegetation index (NDVI), enhanced veg-etation index (EVI) and reduced simple ratio (RSR).

Several empirical relationships between LAI and spectral indices are known. Equations describing these

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relationships vary both in mathemat-ical forms (linear, exponential, power, inverse of exponential, etc.) and in empirical coefficients, depending on the experiments, the indices used, and the vegetation type (Qi et al., 2000). The common procedure is to establish an empirical relationship between a given spectral index and LAI by statis-tically fitting measured LAI values and corresponding values of that spectral index.

Radiative transfer models are another indirect way of retrieving vegetation biophysical properties (Goel, 1989; Baret et al., 1992). Also, in recent years, due to the emergence of light detection and ranging (LiDAR) tech-niques and equipment, numerous methodologies are being developed for point cloud datasets obtained from LiDAR to assess vegetation (Houldcroft et al., 2005).

In the MyWater project we plan to esti-mate LAI using the most common least square regression (LSR) model, based on empirical correlations between LAI and spectral vegetation indices (SVI) (e.g. SR, NDVI, EVI, RSR). The SVI to use for mapping and monitoring LAI will be derived from satellite data. Preliminary tests indicate that NDVI is the best index for estimating LAI. For each test site of MyWater, these indi-ces will be assessed in terms of their sensitivity to vegetation biophysical parameters, as well as to external fac-tors affecting canopy reflectance.

As base data for the estimation of the SVI, we plan to use ESA or ESA third-party missions’ satellite imagery. The selection of the images will depend not only on availability but also on the scale the service will address (e.g. MERIS, MODIS for the low resolution

scale; and Landsat, SPOT-4/HRVIR for the high resolution scale). Images will also be selected considering their potential for developing the other land core data (i.e. LCLU, ETa, soil moisture). It is important to note that for low res-olution LAI the use of the global and freely available MODIS LAI product is preferred.

Different LSR models will be tested in order to select the one that best fits the LAI/SVI correlation. Most of LAI/SVI statistical relationships reported in the literature follow one of the following LSR models: (1) linear: LAI = a + bX; (2) exponential: LAI = a ebX; (3) power: LAI = aXb; and (4) quadratic: LAI = aX2 + bX + c; where, X is the SVI, and a, b and c are coefficients that vary with the index chosen and the type of vegetation. These mathemati-cal forms shall be tested.

The outlined methodology for develop-ing the LAI models will consist of the following three steps:

• ground-truth data collection, which has already been performed for two of the five study sites (Tamega in Portugal — Figures 2 and 3, and Nestos in Greece).

• pre-processing (geometric and radi-ometric correction) of the satellite data (if needed);

• development of an SVI–LAI model;

• test and validation of the developed SVI–LAI model.

LAI maps for the test site areas will be developed preferably once every two months during the implementa-tion phase. However, image availability may be a restricting factor.

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Figure 2. Field sample database in the Tamega study site.

Evapotranspiration (ETa)

Actual evapotranspiration (ETa) is a good estimate of water use in large heterogeneous areas where limited information is available (e.g. no water meters, no regular flow estimates). ETa can be calculated by applying the surface energy balance algorithm for land (SEBAL) on satellite images which have a thermal band (Terra/Aqua MODIS, NOAA AVHRR, Landsat TM/ETM+, and Terra ASTER). SEBAL is a thermodynamically based model, using the partitioning of sensible heat flux and latent heat of vaporisation flux as described in (Bastiaanssen et al., 1998). A further customised SEBAL for operational performance under Mediterranean conditions (i.e. small parcel sizes, detailed crop pat-tern and lack of necessary data) is the ITA-Water tool, which has been

developed by AUTh within the frame of ESA’s GSE land project (Alexandridis et al., 2009).

In MyWater, ITA-Water will be employed to estimate ETa and further on the water used by agriculture and other land cover types at the pixel level for the entire basin of the study area. Terra/Aqua MODIS satellite images with will be used together with daily meteorological data from local sta-tions for a period of 8 days to com-pute broad-band reflectances, surface temperature and vegetation indices. Using extreme wet and dry pixels for calibrating the algorithm, these infor-mation layers are transformed into the terms of surface energy balance equation, which is solved to estimate the latent heat flux and further on the actual evapotranspiration in mm/day, for each one of the satellite images.

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Figure 3. Example of LAI collection.

This spatial component of ETa will be combined with the temporal compo-nent (daily potential evapotranspiration estimations from local meteorologi-cal stations during the irrigation sea-son) to generate daily simulated ETa values. The daily ETa values are then summed to produce the seasonal evapotranspiration (ETs) at desired time intervals (e.g. ETs per month, irri-gation season or hydrological year). In order to achieve higher spatial resolu-tion than that offered by Aqua/Terra MODIS (1 × 1 km), the modified Brovey resolution improvement algorithm is incorporated within ITA-Water (Chemin and Alexandridis, 2004). This algorithm redistributes the original value of ETs found in a pixel of 1 × 1 km to a higher

spatial resolution, using as guide the high spatial detail of the Landsat TM/ETM+ image. The advantage of the algorithm is that the initial values of ETs remain globally unchanged, which is an essential prerequisite for estimat-ing water use volumes.

Adaptation of the methodology for optimum operation within each site will be performed, and improvements using auxiliary datasets (e.g. soil type, soil moisture) will be examined.

ETa and ETs maps will be provided once every 8 days for the test site areas during the implementation phase. Availability of images may be a restricting factor.

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Soil moisture (SM)

SM storage is important for the man-agement of water resources. In fact, the amount of SM affects the growth of veg-etation and describes the environmental conditions (e.g. desertification risk).

As SM exhibits a large spatial and tem-poral variation as a result of hetero-geneity of soil properties, vegetation and precipitation, the use of remotely sensed data is particularly advanta-geous for such applications. More fre-quently, microwave remote sensors (SAR) are used for SM estimation. The theory behind microwave remote sens-ing of SM is based on the large con-trast between the dielectric properties of water and dry soil which results in a high dependency of the complex dielectric constant on volumetric SM. Given this dependency, it is possible to estimate SM by measuring the dielec-tric constant, which is in turn related to the intensity of the radar backscatter-ing coefficient.

SM can also be derived from visible, near-infrared and thermal satellite imagery. In fact, an empirical rela-tionship between evaporative fraction and the value of relative SM content was developed by Bastiaanssen et al. (2000) and can be applied to a wide range of soils. Since the evaporative fraction (Λ) is one of the energy bal-ance terms that can be calculated over large areas through the SEBAL model and using remotely sensed data (VIS, NIR and TIR), the SM conditions can then be estimated.

AUTh has already developed a mod-ule for GRASS GIS software that pro-vides a root zone empirical SM output following Bastiaanssen et al. (2000). In MyWater, the estimated ETa will

be used to retrieve the spatial distri-bution of soil moisture at the regional scale using an improved version of this module. Improvement and adaptation of the model, to take into account the specific type of soil unit for each loca-tion, is expected to increase the accu-racy of the results.

Field data will be used to calibrate and verify the developed methodology and alternative models may be applied for comparative reasons, based on data availability (e.g. top soil moisture estimation based on available radar images — e.g. ASAR).

Soil moisture maps will be provided once every 8 days for the test site areas during the implementation phase. EO images availability may be a restricting factor.

CONCLUSIONS

During the first year of the project, activities have mainly focused on the R & D component, specifically in the development, integration and testing of the data and methodologies that will be used to put the MyWater services in place and in pre-operational mode.

A major innovation that was pursued stands in the modelling approach that will combine diversified input data (EO-based maps and maps derived from hydrological models) in order to minimise the uncertainty of outputs and improve the quality of the predic-tions of the hydrological state at the watershed level.

A very strong effort was employed in the research and definition of the technical specifications, requirements and effective methodologies that will

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allow for the operational production of the land core datasets (i.e. LULC, LAI, ETa and SM maps). As a result, LULC maps have already been produced for two test sites achieving overall accu-racies better than 85 %; LAI products can already be produced in operational mode; evapotranspiration and soil moisture maps will soon be ready to be produced in operational mode.

Other of the main activities carried dur-ing this first-year period refer to: the preparation of the soil databases and meteorological outputs; the tuning of the hydrological models and their inte-gration with the land, soil and meteo data; and the initial development of the software platform through which the MyWater services and results shall be delivered.

In the end it is expected that the pro-ject will contribute to better access the hydrologic processes, improving knowledge and enhancing forecast-ing capabilities, whilst optimising the cost–benefit ratio of water resources monitoring. MyWater will contribute to help catchment managers support their decisions in order to estimate biomass production, satisfy irrigation needs and mitigate the risks of floods and droughts, while achieving at the same time a good ecological balance without compromising the local human activities.

REFERENCES

  Alexandridis, T. K., Cherif, I., Chemin, Y., Silleos, G. N., Stavrinos, E. and Zalidis, G. C., ‘Integrated methodology for estimating water use in Mediterranean agricultural areas’, Remote Sensing, 1, 2009, pp. 445–465.

  Andel, S. J. van, 2009. Anticipatory water management: Using ensemble weather forecasts for critical events, CRC Press/Balkema, Leiden, 182 pp. (ISBN: 978-0-415-57380-1).

  Baret, F., Jacquemoud, S., Guyot, G. and Leprieur, C., ‘Modeled analysis of the biophysical nature of spectral shifts and comparison with information content of broad bands’, Remote Sensing of Environment, 41, 1992, pp. 133−142.

  Bastiaanssen, W. G. M., Menenti, M., Feddes, R. A. and Holtslag, A. A. M., ‘A remote sensing surface energy balance algorithm for land (SEBAL): 1. Formulation’, Journal of Hydrology, 212–213, 1998, pp. 198–212.

  Bastiaanssen, W. G. M., Molden, D. J. and Makin, I. W., ‘Remote sensing for irrigated agriculture: examples from research and possible applications’, Agricultural Water Management, 46, 2000, pp. 137–155.

  Chemin, Y. and Alexandridis, T., ‘Improving spatial resolution of ET seasonal for irrigated rice in Zhanghe, China’, Asian Journal of Geoinformatics, 5, 2004, pp. 3–11.

  Di Gregorio, A and Jansen, L. J. M., Land Cover Classification System, FAO, Rome, 2000, 179 pp.

  Goel, N. S., ‘Inversion of canopy reflectance models for estimation of biophysical parameters from reflectance data’, in G. Asrar (ed.), Theory and applications of optical remote sensing, Wiley Interscience, 1989, pp. 205–251.

  Houldcroft, C. J., Campbell, C. L., Davenport, I. J., Gurney, R. J. and

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Holden, N., ‘Measurement of canopy geometry characteristics using LiDAR laser altimetry: A feasibility study’, IEEE Trans. Geosci. Remote Sens., 43, 2005, pp. 2270–2282.

  Qi, J., Kerr, Y. H., Moran, M. S., Weltz, M., Huete, A. R., Sorooshian, S. and Bryant, R., ‘Leaf area index

estimates using remotely sensed data and BRDF models in a semiarid region’, Remote Sens. Environ., 73, 2000, pp. 18–30.

  Roulin, E., ‘Skill and relative economic value of medium-range hydrological ensemble predictions’, Hydrol. Earth Syst. Sci., 11, 2007, pp. 725–737.

CHAPTER 8 ReCover: Services for the monitoring of tropical forest to support REDD+

Authors: Tuomas Häme, Laura Sirro, Edersson Cabrera, Jörg Haarpaintner, Johannes Heinzel, Jarno Hämäläinen, Bernardus de Jong, Fernando Paz Pellat, Donata Pedrazzani, Johannes Reiche

consortium members: VTT Technical Research Centre of Finland (Finland), Instituto de Hidrología, Meteorología y Estudios Ambientales (Colombia), Norut (Norway), Albert-Ludwigs-Universität Freiburg (Germany), Arbonaut Oy Ltd (Finland), El Colegio de la Frontera Sur (Mexico), Colegio de Postgraduados (Mexico), GMV AD (Spain), Wageningen University (Netherlands)

AbSTRACT

The ReCover project aims at develop-ing beyond state-of-the-art service capabilities to support fighting defor-estation and forest degradation in the tropical region. The service capabilities mean provision of a monitoring system of forest cover, forest cover changes, and biomass including a robust accu-racy assessment. This paper presents the forest monitoring concept and the first results on ReCover study sites.

ReCover contributes to the efforts to reduce the errors in the estimates of the terrestrial carbon balance that

result from uncertain rates of tropi-cal deforestation. It develops meth-ods for the REDD (Reducing emissions from deforestation and forest deg-radation) process by developing and implementing satellite image based methods for the monitoring of tropi-cal forests. The REDD will be a major driver for the development of more effective and more reliable procedures for the monitoring of tropical forests. Many developing countries lack human resources and funding for detailed for-est inventories.

This paper reports the achievements of the first year of ReCover and the results of services in Mexico, Guyana, the Democratic Republic of the Congo and Fiji. Altogether, 42 products were delivered to the users of ReCover. The accuracy in forest and non-forest clas-sification was from 85 % to 91 % with one exception (76 %).

INITIAL RESULTS

The ReCover project has completed successfully its first half, of 18 months. The work has focused on the develop-ment of the statistical concept for the monitoring of the forest, acquisition of data and computing preliminary empir-ical results. The delivery date of the first services was in March 2012. New services that utilise the user feedback

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from the first services and enhanced methods w ill be provided by May 2013. The whole study will be completed in October 2013.

The empirical forest monitoring is being performed on the five study sites for the local users: The Chiapas state in Mexico, a sub-region of Colombia, the entire Guyana, a selected site in the Democratic Republic of the Congo, and the territory of Fiji islands. Image data are available since the early 1990s from Landsat Thematic Mapper, Spot 4 and Spot 5, RapidEye, GeoEye, Kompsat 2, Quickbird 2, ERS-1&2 (SAR), Envisat (ASAR), and ALOS (Palsar and AVNIR-2) satellites, depending on the site and target year of image inter-pretation. The above-listed data are used for the principal production.

The user-defined variables of inter-est are land cover and forest cover, biomass, degree of disturbance and the changes of those variables from the early 1990s until today. The dis-turbance is predicted with the help of biomass and the crown closure

percentage of tree stems. The analy-sis of the spatial structure of the for-est patches is also used to evaluate the disturbance. Monitoring of the persistence of the disturbance dur-ing time enables the prediction of the degree of degradation. Change mon-itoring and degradation monitoring with accuracy assessment will be spe-cially focused during the second half of ReCover.

Monitoring concept

The overall forest monitoring concept that applies a two-phase (or multi-phase) stratified sampling design was preliminarily developed in an ear-lier study in Laos (Häme et. al 2011, Figure 1; Gautam et. al 2010). The first phase sample is taken from wall-to-wall medium resolution (Landsat, Spot, RapidEye in near future Sentinel 2) data and the second phase can be taken from 1-metre to sub-metre reso-lution very high resolution imagery, air-borne laser scanning (Light Detection and Ranging, LiDAR) data and (option-ally from) the field sample plots. The

Figure 1. Iterative processing chain to produce maps and statistical data.

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synthetic aperture radar (SAR) data can augment or even replace the optical data in the cloudy regions. In the first phase, the area of interest is divided into population units (PUs) that cover the whole surface. A 50 m × 50 m PU size has been selected. The variables of interest (land cover and forest cover, biomass, degree of disturbance and the changes) are predicted with wall-to-wall satellite imagery and available reference data for all the PUs.

In the second phase, a statistical sam-ple of the PUs is selected and evalu-ated. A stratified sampling to two or three strata is applied. Mapping of change requires a specific stratification because of the small area of the change classes. If ground reference data are not available or if their amount is low, the second phase sample is located on available VHR images that preferably are also selected by applying a random procedure. Field plot data and LiDAR data, when available, are used to aug-ment the VHR data sample.

In the estimation of biomass or grow-ing stock volume, field observations are mandatory. On some sites, particu-larly in the Mexican site Chiapas, a high number of field plots for the land cover classes are available. On several other sites, the available ground reference data are very limited. Thus, the method has to adapt to different degrees of ground reference data availabilities.

During the first service iteration, the two-phase sampling approach with utilisation of very high resolution data was applied on the DRC and Guyana sites because no other reference data were available. On the Mexican site, ground plots were used for the assess-ment. On the Fiji site and on the new Colombia site, the assessment will be

done during the second service itera-tion. During the second service iteration that is due in spring 2013 the approach will be extended to all the sites.

Image interpretation approach

Several image interpretation methods were used in the first service provision. The feedback of the results is used to harmonise the methodology and select the best practices for the second service round. The applied methods include the Probability method (Häme et al. 2001) and methods that are available in the commercial software packages ENVI/IDL and Gamma. The Probability method initially predicts all the variables, including the categorical variables, as continuous values, which enables flexible post-processing of the results.

The interpretation of wall-to-wall data aimed at processing as large units at the same time as possible. For this purpose, the optical data were cali-brated into surface reflectance values. Similarly, a radiometric calibration was performed to the SAR data in addition to the mandatory geometric correc-tion. For the change detection, among other things, AutoChange, the in-house method and software, is applied (Häme et al. 1998).

The independent reference data for the accuracy assessment are sampled from the reference data that are not used as training data for the computa-tion of the models to predict the var-iables of interest. The reference data includes ground plots and using visu-ally interpreted PUs from VHR images (Figure 2). With reference data, the accuracy figures with confidence inter-vals of the predicted variables are com-puted. For the assessment of biomass

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predictions, independent ground data have to be available.

In addition to the principal methods, novel methods for image interpretation are developed in a specific work pack-age. These methods test among other things the feasibility of machine learn-ing methods. A specific topic of inves-tigation in the work package of novel methods is application of airborne and space-borne LiDAR samples. These data can drastically support the estimation of biomass in the tropics where collec-tion of ground reference data is slow and expensive. For the forest areas with LiDAR coverage and difficult access, a vast number (e.g. thousands) of sur-rogate sample plots can be generated to supplement field-measured data (Gautam et. al 2010). Surrogate plot values are estimated using regression models based on the statistical rela-tionship between field observed values and LiDAR pulse data derived metrics.

Mapping results of first service iteration

In the Mexican study site that comprised the state of Chiapas of 73 240 km2, the first biomass estimates, land cover maps and land cover change maps were produced. The target years for mapping were 1992, 1994 and 2009. For the early 1990s Landsat Thematic Mapper data and for 2009 RapidEye data were used, respectively. Figure 5 shows an extract from the change and biomass maps. The estimates were generated with the help of ground plot data that correspond to the Mexican National Forest Inventory. The Probability method was applied to the EO and ground ref-erence data plot data sets (forest cover plot data courtesy of Conafor, biomass data courtesy of B. H. J. de Jong). The biomass model was first created using EO data and the ground plot data. The biomass estimate for each pixel was then computed using the model.

Figure 2. From left to right: Landsat TM image 1994, RapidEye image 2009, change map 1994–2009 (forest removal red), forest biomass map 2009 (maximum prediction 184 t/ha). Area siz:e 2.7 km × 2.9 km.

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The Democratic Republic of the Congo case service area is about 68 000 km2 and is located in the west of the coun-try, bounded by 0º 03´ N and 3º 15´ S, the Congo River in the west and Lake Mai-Ndombe (18º 30´ E) in the east.

Figure 3 shows the first iteration results of optical and SAR image mosaics and

their forest/non-forest (FNF) maps for year 2010. The FNF maps were derived by a supervised maximum likelihood classification (MLC) with training pol-ygons extracted from Kompsat-2 VHR data. A more complete overview of the first iteration results of the DRC including earlier years is presented in Haarpaintner et al. (2012).

(a) AVNIR-2 (b) AVNIR-2 (FNF) (c) ASAR (d) Palsar (e) C/L-band SAR (FNF)

Figure 3. Optical and SAR image mosaics and their respective FNF maps for the year 2010: ALOS AVNIR-2 (a) mosaic (RGB = bands 3, 2, 1) and (b) FNF map, (c) Envisat ASAR APS mosaic (RGB = VV, VH, VV/VH), (d) ALOS Palsar FBD (RGB = HH, HV, HH/HV) and (e) FNF map from a maximum likelihood classification using all polarisations VV & VH (ASAR) and HH & HV (ALOS Palsar). In (b) and (e): Black = outside ROI and masked areas, green = forest, beige = non-forest, and blue = water bodies.

An object-oriented forest change map-ping from 2007–09 was conducted over the main Guyanese mining area located around Mahdia in central Guyana, using dual-year ALOS Palsar Fine Beam Dual (FBD) data. Around Mahdia the main drivers for deforestation and forest degradation include large-scale min-ing, forestry, agriculture expansion and shifting cultivation (Pöyry Management Consulting (NZ) Limited, 2011). The dual-year FBD data was pre-processed to 25 m pixel resolution using Gamma software. A Gamma-MAP SAR filter was applied for speckle reduction of the dual-polarised intensity images. For the object-based analysis the commercial software package eCognition Developer was utilised. The dual-year FBD data was segmented using multi-resolu-tion segmentation (Baatz and Schäpe

2000) in order to create homogeneous image objects that comprise dual-year information. A bi-temporal difference change index (DCI) has been computed for HH and HV polarisation according to equation 1.

DCI(SARPolarisation) = SARPolarisation,YEAR1 – SARPolarisation,YEAR2 eq. 1

The DCI for HH and HV were employed into the object-oriented and knowl-edge-based classification scheme. Figure 5 shows the detected forest changes for 2007–08 and 2008–09. A comparison with a reference GIS data-set maintained by the Guyana Forestry Commission (GFC) indicates the high accuracy of the detected change areas that can mainly be traced back to the expansion of mining areas.

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Figure 4. ALOS Palsar FBD object-based forest change detection for the Mahdia mining area, central Guyana (2007–08; 2008–09). The detected changes (red) are overlaid over FBD HV intensity image.

Figure 5. Arrangements for model training and accuracy assessment in Guyana. Orange parts of RapidEye image were used for the accuracy assessment and the lower left half for training. The extract of RapidEye data shows the location of the 50 m × 50 m sample plots (white dots).

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Users can access the delivered products using the WebGIS platform developed in ReCover. The ReCover Toolbox 1.0 is a Web application that can be accessed by anybody with a standard Internet connection with Firefox 3.5 or more recent versions or Internet Explorer 6 and 7. Only registered users can access ReCover products; operations allowed are search, download and visualisation of products through the catalogue of the ReCover system. Figure 9 shows an example of the user interface.

Altogether 42 products were deliv-ered to the users. They included image mosaic maps and thematic maps. The accuracies in forest and non-forest classification varied with the optical data from 85 % to 91 % and between 75 % (ERS) to 88 % (ALOS Palsar) with SAR data on the three sites where the assessment was made. The results

will be published in more detail after the users have evaluated the prod-ucts. The biomass prediction model was unbiased with respect to the ground data but the accuracy at plot level was low.

CONCLUSIONS

The different approaches in image interpretation led to similar accuracies in image interpretation. Assessment of the accuracy with a sample of VHR imagery appeared a feasible procedure. The accuracy in forest and non-forest classification was similar with L-Band SAR data (ALOS Palsar) and with the optical data. The tropical environment with strong anthropogenic influence can be very dynamic, which means that frequent observations are needed to understand the change processes. The danger is particularly large in areas

Figure 6. Example of auser interface for the WebGIS. A product has been selected and visualised on a map.

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where the regrowth occurs fast after the clearing of forest. Such regrowth can be grass or shrubs, for instance. Another source of error is the vague border between forest and shrub land. Both these errors can be reduced by using VHR data as an additional source of information.

Assessment of the accuracy of change and degradation will be a subject of the latter half of ReCover. It is hypoth-esised that mapping of degradation at Landsat equivalent resolution is ques-tionable and VHR data should be used to support the estimation.

The differences between the acqui-sition times of wall-to-wall satellite imagery and reference data intro-duce challenges in the inventory. The image acquisition process is very complex and time consuming also for the research community that has got used to the ordering of the imagery. Another challenge is the large data volumes when the spatial resolution increases. For instance, the size of the RapidEye data mosaic that was used as input in interpretation was over 70 GB. The geometric accuracy even of the ortho-rectified image products by the suppliers was not good enough but an additional geometric correc-tion was needed to locate the field reference plots correctly and to per-form change detection successfully. Major attention should be paid on the improvement of the image acquisition system and geometric image accu-racy as well as radiometric calibration in the implementation of the GMES and Sentinel programs.

REFERENCES

   Baatz, M. and Schäpe, A., ‘Multiresolution segmentation — An optimization approach for high quality multi-scale image’ in J. Strobl, T. Blaschke, G. Griesebner (eds), Angewandte Geographische Informations-Verarbeitung XII — Beiträge zum AGIT Symposium Salzburg 2000. Wichmann, Karlsruhe, 2000, pp. 12–23.

   Gautam, B., Tokola, T., Hamalainen, J., Gunia, M., Peuhkurinen, J., Parviainen, H., Leppanen, V., Kauranne, T., Havia, J., Norjamaki, I. and Sah, B. P., Integration of airborne LiDAR, satellite imagery, and field measurements using a two-phase sampling method for forest biomass estimation in tropical forests — Proceedings of the International Symposium on ‘Benefiting from Earth observation’, 4–6 October 2010, Kathmandu, Nepal, 2010.

   Haarpaintner, J., Einzmann, K., Larsen, Y., Pedrazzani, D., Mateos San Juan, M. T., Gómez Giménez, M., Enßle, F., Heinzel, J. and Mane, L., ‘Tropical forest remote sensing services for the Democratic Republic of Congo case inside the EU FP7 “ReCover” project (1st iteration)’, Proceedings of International Geoscience and Remote Sensing Symposium, Munich, Germany, 2012 (submitted).

   Häme, T., Heiler, I. and Miguel-Ayanz, J., ‘An unsupervised change detection and recognition system

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for forestry’, International Journal of Remote Sensing, 19(6), 1998, pp. 1079–1099.

   Häme, T., Stenberg, P., Andersson, K., Rauste, Y., Kennedy, P., Folving, S. and Sarkeala, J., ‘AVHRR-based forest proportion map of the pan-European area’, Remote Sensing of Environment, 77(1), 2001, pp. 76–91.

   Häme, T., Kilpi, J., Ahola, H., Rauste, Y., Sirro, L. and Sengthong Bounpone,

‘Combining VHR imagery with medium resolution wall-to-wall data for the mapping of tropical forest cover and biomass’, 2011 (submitted manuscript).

   Pöyry Management Consulting (NZ) Limited, 2011. ‘Guyana REDD+ Monitoring, Reporting and Verification System (MRVS) — Interim Measures Report’ (Final, 16 March 2011).

CHAPTER 9 Reducing emissions from deforestation and degradation in Africa (REDDAF)

Authors: Thomas Haeusler, Sharon Gomez, René Siwe, Thuy Le Toan, Stephane Mermoz, Mathias Schardt, Ursula Schmitt, Christophe Sannier

consortium members: GAF AG (Co-odinator), Germany; Cesbio, Universite Paul Sabatier Toulouse, France; Joanneum Research Forschungsgesellschaft (JR), Austria; Système d’Information à Référence Spatiale (SIRS), France; MESAconsult, Germany; Geospatial Technical Group (GTG), Cameroon; Universite de Bangui, Laboratory of Climatology, Cartography and Geography Studies (LaCCEG-UB), Central African Republic

AbSTRACT

The REDDAF project aims to develop operational forest monitoring services in two Congo Basin countries that are engaged in the reducing emissions from deforestation and degrada-tion (REDD) policy process. The pro-ject which is being implemented from 2011 to 2013 will test and provide improved methodologies using both optical and radar Earth observation (EO) data for deforestation/degrada-tion assessment in Cameroon and the Central African Republic. The project started with initial assessments of

country-specific user requirements to identify the needs of stakeholders in terms of implementing REDD projects. Based on these specific national con-ditions, research and development of methods for improved EO/in situ data applications are being undertaken to estimate the areal extent of deforest-ation and forest degradation, as well as above-ground biomass per unit area. Improved pre-processing meth-ods for atmospheric and radiomet-ric adjustments for multi-sensor EO data have been developed. Existing methods for deforestation mapping have been optimised by the applica-tion of radar data. Advanced meth-ods for forest degradation mapping are developed, comprising a multi-temporal spectral mixture analysis as well as 3D mapping options. These methods will be further developed and tested in 2012. Existing methods for direct biomass assessment using radar data have been improved to fully exploit the potential of the avail-able EO data. The preliminary biomass mapping results will be calibrated and verified by using in situ biomass measurements. Specific technology transfer/capacity building activities in the country are ensuring that project results, methodologies and lessons learned are provided in a manner to best support the work of national and regional counterparts.

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BAcKGround And ObjECTIVES

A key requirement in the United Nations Framework Convention on Climate Change (UNFCCC) REDD process is the need for countries to develop national forest monitoring systems in order to ascertain deforestation/degradation rates and their spatial extent. The role of EO in combination with in situ data has been underscored as an impor-tant tool for forest cover and land use monitoring in the REDD methodologi-cal developments. The main objective in the REDDAF project which is being implemented from 2011 to 2013, is to test and provide improved method-ologies using both optical and radar EO data for deforestation/degrada-tion assessment in Cameroon and the Central African Republic. An additional research objective is the investiga-tion of radar data for direct biomass assessment. The improved meth-odologies will support the develop-ment of operational service chains which can be scaled up to national level and therefore contribute to the current national REDD+ Monitoring, Reporting and Verification (MRV) activ-ities in these countries. The REDDAF project was prepared drawing on the experience of the GMES service ele-ment on forest monitoring (GSE FM) REDD activities in Cameroon which were implemented during 2008–10 and formulated several research and development needs.

The project also emphasises the importance of involving the user community; the UNFCCC focal points in both Cameroon and the Central African Republic have supported and endorsed the REDDAF concepts and objectives in specific service level agreements (SLAs). The main

ministries involved are the Ministry of Environment and Ecology (MoEE) in the Central African Republic and the Ministry of Environment and Nature Protection (MINEP) in Cameroon.

wORK PROGRAMME And MetHodoLoGy

The work programme is organised on the understanding that there is on the one side a strong user require-ment for the REDD forest monitoring embedded in the UNFCCC policy pro-cess, and on the other side the indus-tries’ intention to offer cost-efficient services based on innovative scien-tific and technological developments. Additionally, the work programme addresses the strong demand of the user community for technology trans-fer and capacity building. Therefore, the project is being implemented and coordinated along the following five main tasks.

• Requirements: The project started with collecting the functional require-ments for the REDDAF service developments, building an optimal trade-off between the REDD policy requirements, operational user needs and technology constraints.

•Research/methods development: Several research topics such as improving the land use and forest change mapping in cloudy areas by utilising multi-sensor and multi-resolution techniques, improving degradation mapping and investi-gating direct biomass assessments with SAR data are being addressed. Additionally, methods are being developed to factor out anthropo-genic degradation, which is required for the policy reporting process.

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• Service development and integra-tion: The results from the research activities provide inputs to improve existing end-to-end REDD process-ing chains. In order to integrate the service into the user environment, a REDD user geo-database is being developed by the local counterparts in the Central African Republic.

•Validation and proof of concept: A validation system is being imple-mented which comprises an end-to-end verification of all items and processes of a technical process-ing and service chain to demon-strate and provide evidence to the end user that the service meets the pre-defined user specifications and is also fit for purpose. It defines the procedures for reviewing, inspect-ing, testing, checking, auditing and documenting. The user community in both the Central African Republic and Cameroon will perform a com-prehensive utility assessment of the REDD services and additionally an independent third party validation will be performed.

•Dissemination and training: The technology transfer to the user com-munity, as well as disseminating the project results to a wider exter-nal audience, is being undertaken via training workshops, on-the-job training and presentations at vari-ous forums.

As a result of this work programme, the services and products that will be delivered to the user community are as follows:

• forest cover maps for 1990, 2000 and 2010: forest and non-forest classes;

• forest cover change maps for 1990–2000 and 2000–10: forest land, cropland, settlement, grassland, wetland, settlement, other land (compliant with Intergovernmental Panel on Climate Change (IPCC) land use categories);

• degradation maps;

• above ground biomass maps for 2007, 2008, 2009 and 2010.

In the absence of national definitions for forest and/or mapping standards the REDDAF products and services will com-ply with international standards for for-est cover mapping in REDD as explained in the IPCC good practice guidelines (2006) and the GOFC-GOLD REDD sour-cebook (2011). Thus, the Food and Agriculture Organisation (FAO) definition of forest will be adopted as well as the definition of deforestation and forest degradation stipulated by the Central African Forestry Commission (Comifac) in its submissions to the Subsidiary Body on Scientific and Technological Advice (SBSTA).

AcHieVed resuLts

The implementation of the work programme in the first 12 months achieved the stakeholder analysis and assessment of the user and pol-icy requirements in both Cameroon and the Central African Republic. Furthermore, the advances in the R & D so far give adequate inputs for the mapping in the countries, which is planned for 2012. This section focuses on summarising the main sci-entific and technical results for defor-estation, degradation and direct EO biomass assessment.

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Deforestation assessment

The production of the forest cover maps is based on high resolution satellite data which are suited for mapping at mini-mum mapping units (mmu) from 0.5 to 1 ha. Available historical Landsat data (1990, 2000) as well as current SPOT or RapidEye data (2010) are being used for the mapping. The forest cover maps are then used to produce forest cover change maps and to assess the forest area change. In order to improve the usa-bility of multi-sensoral data, robust radi-ometric calibration techniques are being developed. Additionally, atmospheric cor-rection models and dehazing approaches as well as the optimisation of a com-bined spectral-geometric approach for cloud and cloud shadow detection have been developed and tested.

To optimise the use of optical satel-lite data a method was developed which radiometrically enhances areas covered by cloud shadows and, thus, makes these areas usable for fur-ther processing. The method is based on morphological techniques in order to take into consideration the diffuse intersection area between a cloud shadow and its surrounding. The radi-ometric correction is performed by histogram matching to the surround-ing area. These technical steps facil-itate the overall pre-processing of optical data in the production process.

In addition to optical data it is also important to assess the utility of radar data in cloudy areas as a means to opti-mise the forest cover and change map-ping. Forest cover change maps were derived from L-band SAR data (ALOS Palsar) using different polarisations.

A processing chain was developed and implemented considering, both,

pre-processing and thematic classi-fication. The first land cover classifi-cation (based on IPCC classes) led to validation accuracies between 76 % (mean class accuracy) and 95 % (overall accuracy). In order to give a final recommendation on using SAR as alternative input data, the results will be further compared to the accuracies derived from optical satellite data.

Degradation assessment

The complex issue of degradation mapping in tropical forest areas has been addressed by developing a con-cept based on selective logging. For this purpose an improved spectral mixture analysis (SMA) method (Asner et al., 2002) was developed which integrates multi-temporal regen-eration signals. This method will be tested in a concession area in south-eastern Cameroon, where recent deg-radation activities have occurred.

The approach for developing further EO methods for degradation mapping started with an investigation on the options for 3D mapping of forest can-opy disturbances. The work comprised InSAR processing, radargrammetric processing and the extraction of degra-dation areas from digital surface mod-els. Figure 1 illustrates the possible detection of features such as logging roads from a COSMO SkyMed image. The methods developed for the detec-tion of forest gaps from 3D imagery have yet to be tested and validated.

Direct EO biomass assessment

The activities related to direct bio-mass assessment with SAR data aim to provide a transferrable methodol-ogy to deliver a mapping product that contains gridded and geocoded values

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Figure 1. Degradation mapping using 3D information (COSMO SkyMed coherence image)

of above-ground biomass (AGB). The approach focuses on improving exist-ing image processing and biomass inversion methods to fully exploit the potential of the currently available data (ALOS Palsar-L-band). The work is based on testing existing meth-ods using in situ biomass data from Cameroon. The study site has been selected in the Adamawa region, which is one of the demonstration sites of the Group on Earth Observation- Forest Carbon Tracking (GEO FCT). Over this site, 38 ALOS Palsar datasets (28 FBD scenes and 10 PLR) have been made available by JAXA. In situ reference plots of 1 ha have been identified and biomass field measurements for each plot will be made during the field mis-sion from January to March 2012.

The improvement of the methods beyond the state of the art in biomass mapping (in particular in Cameroon, as reported by Mitchard et al., 2011) include several aspects: improve-ments of the spatial resolution of the biomass map, based on an optimised use of multi-temporal and polarimet-ric data, reduction of the uncertainties in biomass for biomass values beyond 100–150 ton/ha by taking into account the perturbing effects which mask the sensitivity of the backscatter to bio-mass (e.g. topographic and temporal variation effects). A Bayesian inver-sion method is also used to improve the retrieval performance. Changes in biomass will be observed in more detail with ALOS Palsar data in four years: 2007, 2008, 2009 and 2010.

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Figure 2 presents the preliminary bio-mass map of the study area. The map is derived from ALOS Palsar 2007 data using an inversion model devel-oped for L-band SAR data (Le Toan et al., 2004) and recently tested in Vietnam and in French Guiana. In situ data from the Cameroon test area will be used for calibration of the model and verifying the results. In particular, in situ data will also be used for rel-ative radiometric calibration between tracks and between data acquired at different dates. The validated process-ing chain will be further tested in the Central African Republic

The map in Figure 2 highlights the dense humid forests (Mbam and Djerem National Park) with biomass > 150 ton/ha, and the gallery for-ests in the savanna, with biomass lower than 100 ton/ha. It should be noted that large areas of gallery for-ests and transitional forests (with bio-mass reaching 60–80 ton/ha) contain a large amount of carbon stocks, which is often neglected in carbon estimates.

The preliminary results will be updated and assessed based on the in situ data. The transition between forest and savanna and the changes in biomass from 2007 to 2010 will be analysed.

Figure 2. Preliminary biomass map of the region of Adamawa (about 120 km × 130 km), central Cameroon. The biomass value for each 25 m pixel is in ton/ha and has a resolution of 25 m. It is derived from 4 FBD ALOS-Palsar data, acquired on 26 July 2007 (east track) and 12 August 2007 (west track).

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CONCLUSIONS

The REDDAF project has achieved tech-nical results in the use of optical and SAR EO data which will now facilitate product development for the dem-onstration sites in Cameroon and the Central African Republic. For the SAR data, most of the processing steps are achieved using free software so that the method can be easily transferred to users. Extensive field-based surveys for calibration of the research results in these tropical forests have proven to be challenging to implement, due to logistical and budgetary reasons. However, a confined field mission in Cameroon is being undertaken in the first quarter of 2012 to collect spe-cific ground truth data for calibration of the direct biomass maps. Overall, the experience gained in this study will be used for future SAR missions dedi-cated to measuring above-ground bio-mass such as the P-band SAR Biomass mission (Le Toan et al., 2011).

Important achievements in the REDDAF project have been the formalisation of the partnerships with national insti-tutions such as University of Bangui and GTG of Cameroon, which ensures the uptake of REDDAF methods and products in the relevant countries. Additionally, capacity building modules were prepared based on the stakeholder analysis and some training has already been implemented. These activities will raise national awareness on the REDD+ process as well as address the technol-ogy transfer that is required. The overall impact on the beneficiaries is therefore to expand the knowledge base of the users, which will further enhance their participation in the REDD process.

The REDDAF project is contribut-ing to the scientific and conceptual

understanding of the technical chal-lenges, whilst taking note of the most recent developments in the scientific and policy communities.

REFERENCES

   Asner, G. P., Keller, M., Pereira, R., Zweede, J. C., ‘Remote sensing of selective logging in Amazonia assessing limitations based on detailed field observations, Landsat ETM+, and textural analysis’, Remote Sensing of Environment, 80(3), 2002, pp. 483–496.

   GOFC-GOLD, (2011): Reducing greenhouse gas emissions from deforestation and degradation in developing countries — A sourcebook of methods and procedures for monitoring, measuring and reporting, GOFC-GOLD Report Version COP16, GOFC-GOLD Project Office, Natural Resources Canada, Alberta, Canada, 2011.

   Haeusler, T., Gomez, S., Seifert-Granzin, J., Amougou, J. A., ‘REDD pilot projects in Cameroon and Bolivia’, contribution to the UNFCCC post-Kyoto Protocol process, 33rd ISRSE Symposium, Proceedings of 33rd ISRSE Symposium, Stressa, Italy, 2009.

   Hirschmugl, M., Maier, A., Haas, S., Siwe, R., Schardt, M. and Amougou, J., ‘REDD pilot project in Cameroon — Monitoring forest cover change with EO data’, Proceedings of AARSE 2008 International Remote Sensing Conference, 2008.

   IPCC, 2006 IPCC guidelines for national greenhouse gas inventories, prepared by the National Greenhouse

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Gas Inventories Programme, S. Eggleston, L. Buendia, K. Miwa, T. Ngara and K. Tanabe (eds), published by IGES, Japan, 2006.

   Le Toan, T., Quegan, S., Davidson, M., Balzter, H., Paillou, P., Papathanassiou, K., Plummer S., Rocca, F., Saatchi, S., Shugart, H. and Ulander, L., ‘The Biomass mission: Mapping global forest biomass to better understand the terrestrial carbon cycle’, Remote Sensing of Environment, 15(11), 15 November 2011.

   Le Toan, T., Quegan, S., Woodward, I., Lomas, M., Delbart, N. and Picard, G., ‘Relating radar remote sensing of biomass to modelling of forest carbon budgets’, J. of Climatic Change, 67(2–3), December 2004, pp. 379–402.

   Mitchard, E. T. A, Saatchi, S. S., Lewis, S. L., Feldpausch, T. R., Woodhouse, I. H., Sonke, B., Rowland, C. and Meir, P., ‘Measuring biomass changes due to woody encroachment and deforestation/degradation in a forest-savanna boundary region of central Africa using multi-temporal L-band radar backscatter’, Remote Sensing of Environment, 15(11), 2011.

    Mermoz, S., Le Toan, T., Villard, L. and Lasne, Y., ‘Biomass assessment in an African forest–savanna region using ALOS-Palsar data’, submitted to International Geoscience and Remote Sensing Symposium (IGARSS 2012), 2012.

CHAPTER 10 REDDiness — Support EO-driven forest and carbon monitoring in central Africa for REDD

Authors: Nathalie Stephenne, Cindy Delloye, Benoit Mertens, Anton Vrieling

consortium members: Eurosense, Wemmel, Belgium; Institut de recherche pour le développement, France; Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, the Netherlands

AbSTRACT

International agreements on reduc-ing greenhouse gas (GHG) emissions from deforestation and forest deg-radation — REDD — must rely on operational national forest monitor-ing systems that accurately measure, map, report and verify (MRV) the evolu-tion of their forest resources and asso-ciated emissions removals. REDDiness supports Gabon and the Republic of the Congo in improving their ability to participate in potential carbon pay-ment schemes. This paper presents the first results of the REDDiness project, based on a state-of-the-art analysis and an extensive survey carried out in both countries. This survey aimed to identify which EO products are con-sidered of highest importance by local institutions. A contextual analysis revealed that other national, regional initiatives and projects are already developing forest change and carbon

stock estimation products. Therefore, REDDiness proposes to focus on EO techniques for developing the third product, namely forest degradation monitoring. This focus is challenging, given the small spatial size of expected change and the persistent cloud cover in these countries.

introduction

Besides being a global treasure of bio-diversity, the central African forests are also an important carbon sink. Preserving the African forests contrib-utes to international efforts in global cli-mate change mitigation. International agreements on reducing emissions from deforestation and forest degra-dation (REDD) must rely on operational national forest monitoring systems that accurately measure, map, report and verify (MRV) timely changes in forest state and carbon emission. Up-to-date Earth observation (EO) techniques are recognised as essential tools for these MRV systems. REDDiness aims to sup-port two African countries — Gabon and the Republic of the Congo — in devel-oping relevant techniques for their MRV systems. This paper presents the first results of this ongoing project.

The REDDiness project responds to the European Commission’s call for increased collaboration between African

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and European partners through spe-cific international cooperation actions (SICA). REDDiness is led by Eurosense in Belgium. The project relies on two European partners (the Faculty of Geo-Information Science and Earth Observation of the University of Twente, in the Netherlands, and the Institut de recherche pour le développement, in France) and one central African regional actor OSFAC (Observatoire Satellital des Forêts d’Afrique Centrale) to assist Gabon and the Republic of Congo in improving their ability to participate in potential carbon payment schemes. Our local partners in the two countries are the Centre National d’Inventaire et d’Aménagement des Ressources Forestières et Fauniques (CNIAF) in the Republic of the Congo, and the Ministère des Eaux et Forêts (MEF) in Gabon. Both local partners are key players in their countries for setting up a REDD MRV system.

Countries aiming to participate in REDD negotiations must defend their rights in the agreements and develop methods for forest cover monitoring. REDDiness aims to support development of EO techniques and to transfer expertise in forest monitoring. EO monitoring tech-niques have still to be adapted to the specific REDD and central African con-texts and REDDiness wants to work in that direction. Based on a contextual and scientific state-of-the-art analysis carried out in the initial phase of the project, REDDiness will assist the two countries in developing EO forest mon-itoring services and building national capacity with respect to the require-ments identified in this in-depth analy-sis of existing and needed expertise in Congo and Gabon.

This paper is divided into two sec-tions. The first reports on the results

of REDDiness’ user requirements sur-vey based on two approaches: (i) a lit-erature and contextual review of REDD MRV methods, projects and initiatives in central Africa; (ii) a quantitative sur-vey carried out through a questionnaire (multiple choice questions). The sec-ond section presents the results of the REDDiness progress meeting, which took place in Kinshasa in October 2011. At this meeting, the participants (part-ners and scientific advisors) reviewed the state-of-the-art analysis of current EO capabilities for REDD MRV and the results of the user requirements sur-vey to further decide on the specific EO monitoring and capacity building objec-tives that REDDiness should focus on.

USER REqUIREMENTS ANALySIS

Before performing the user require-ments analysis, an analysis of interna-tional and regional agreements, actors and ongoing projects in relation to REDD was performed to identify potentially relevant interactions for REDDiness. This analysis refers specifically to the current status of negotiations, actors and pilot projects in both countries of interest. These existing methods, data and pro-jects which can be related to REDDiness are described in a number of reports delivered to the EC Research Executive Agency (REA). After approval by the European Commission (EC) administra-tion, these reports will be publicly avail-able on the REDDiness website (http://www.reddiness.eu).

Subsequently, REDDiness conducted a quantitative survey with two major objectives: (i) to assess the level of knowledge regarding REDD and EO techniques of relevant stakeholders; (ii) to understand what local users

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perceive as their main needs in terms of MRV. This survey first confirmed that REDD negotiations are still at an initial stage in the considered countries. Both countries have limited technical and human resources to develop a forest monitoring system meeting UNFCCC requirements. The set-up of the survey and the main results are described in the following four sections: (i) question-naire structure and survey implemen-tation; (ii) presentation of participants; (iii) methodology used for analysis; (iv) results.

Questionnaire structure

To analyse and compare stakehold-ers’ responses in an objective way, REDDiness conducted a quantita-tive survey. In addition, the survey contained several open questions to gather general information about the survey participants and their involve-ment in REDD initiatives or projects. The questionnaire’s body includes mul-tiple choice questions about geomat-ics (data used, expertise, hardware and software resources) and the par-ticipants’ knowledge regarding the REDD mechanism (political and scien-tific knowledge, interesting products and definitions or parameters which

are useful in setting up a MRV). A total of 26 questionnaires were returned, corresponding to a 59 % response rate. The involvement of the local and regional project partners (CNIAF, MEF, OSFAC) was key in obtaining this satis-factory response rate.

Participant institutions

The majority of the responding insti-tutions have a national status (54 %) and to a lesser extent an international one (27 %) (Figure 1a). They mainly represent research and administration (58 %) in the fields of natural resource management, forestry or environment (Figure 1b). Only 32 % of the insti-tutes are involved in REDD projects and a mere 13 % report having a good knowledge of the REDD process.

In the REDD MRV context, the survey questions particularly focused on the types of spatial data and tools used by REDD stakeholders. Nearly all institu-tions (91 %) produce and use thematic maps. A majority of participants make direct use of optical satellite imagery (70 %) and aerial photographs (61 %) while radar imagery (including satel-lite radar) is used by only 39 %. LIDAR data acquired by satellite or aircraft

(a) (b)

Figure 1. (a) Management level of the 26 institutions surveyed in REDDiness. (b) Domain of application.

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is relatively unknown (4 % and 9 %). This survey also provides informa-tion on existing software and technical expertise. ArcGIS/ArcView and MapInfo, the most well-known GIS/mapping soft-ware programs, are available in most institutions (87 % and 65 % respec-tively). Remote sensing software (e.g. ENVI and Erdas Imagine) is available in 26 % of the institutions. Concerning technical expertise, most institutions are able to create geo-referenced data-bases (70 %), but less than 50 % are able to perform basic image process-ing, such as unsupervised classifica-tions (48 %). Hence, although a large part of the organisations report a direct use of satellite imagery, in many cases software (and knowledge) for advanced analysis of this data seems unavailable.

The understanding of questions was not the same among participants. Unanswered or incomplete answers demonstrate a limited level of knowl-edge about REDD and MRV imple-mentation. This confirms the need for capacity building on REDD/REDD+ and forest monitoring in the coun-tries involved (Herold, 2009). REDD projects have a role in strengthening the dissemination of information on the objectives and implementation of REDD, in Africa in general, and in the Congo Basin in particular.

Methodology

The number of questionnaires allow only for a limited statistical analy-sis. For the quantitative analysis, we selected the surveys containing the most comprehensive responses. These included the potentially relevant part-ners for REDDiness in the implemen-tation of these MRV systems in Congo and Gabon. Three selection crite-ria, presented in Figure 2, were used:

(i) knowledge of REDD; (ii) complete-ness of responses; (iii) consistency of responses evaluated by two sub-cri-teria — compliance with instructions and logical link between two spe-cific responses. A threshold of 79 % in the sum of these criteria identifies eight institutions, four per country, for which the quantitative responses on REDDiness products and data were analysed in detail (Figure 2).

For Congo, we selected four REDD actors, which include a government body — CNIAF, a non-governmen-tal organisation — OCDH, a research centre — Cergec, and a private actor — CIB. For Gabon, this quantitative analysis includes two governmental services: DG-Aqua and DG-Wood and two research centres: IRSH–CNDIO and IRET. In addition to these institutions, our local partner in Gabon (MEF) identi-fied a number of other potential stake-holders, such as Lagrac (Laboratoire de Graphique et Cartographie of geo-graphic department of the University Omar Bongo) and DG-Forests. For those institutions, filled questionnaires were received, but did not meet our selection criteria for the quantitative analysis.

Survey results

This survey assisted in defining needs of EO data and products to be devel-oped in both countries. Regarding the perceived need in the framework of REDD monitoring, there is no clear con-sensus between the participants on EO data types to be used. However, most of them point out high-resolution sat-ellite imagery (Landsat) as their first choice (five out of eight). There was more consensus regarding the rele-vance of potential EO products to be developed (Figure 3): forest change estimation (rate of deforestation and

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Figure 2. Selection criteria and selected institutions.

Figure 3. Order of importance in the three most useful products for REDD strategy and forest monitoring.

degradation) and biomass estimation. Spatially explicit forest degradation

monitoring is seen as the third impor-tant element to be addressed by the

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national REDD strategy. The contex-tual analysis indicated that other pro-jects such as the two first pilot projects led by the Congolese National REDD Coordination in collaboration with GAF and WRI (CN-REDD, 2011) should develop the first two products.. To avoid overlap and increase the signif-icance of this project, REDDiness pro-poses to focus on EO techniques for the third product, i.e. spatially explicit forest degradation monitoring.

EO MONITORING SOLUTION

Many issues need to be addressed and EO techniques need to be tai-lored to local conditions before effec-tive implementation of MRV systems in both countries. The user survey and the knowledge acquired on other pro-jects in the region clearly pointed to a topical focus for REDDiness, i.e. for-est degradation assessment and mon-itoring. This priority is an outcome of the project progress meeting that took place in Kinshasa in October 2011. At this occasion, project partners and sci-entific advisors discussed the results of the user requirements study and set directions for the way forward. A con-sensus was achieved between the par-ticipants on the main objective of the EO development part of REDDiness. To support the meeting decisions, several technical and methodological choices faced by REDD projects (or participat-ing country) were identified, i.e. princi-pal theme (deforestation/degradation/carbon), study zone and sampling, and the spatial and temporal reso-lution to be used. Figure 4 shows the different options that were discussed for REDDiness. Several options in this figure are related: for example it was agreed that assessing forest degra-dation is impossible with low spatial

resolution infrequent observations, especially for the Congo Basin.

The agreed research and development objective for REDDiness is to evalu-ate the effectiveness of different types of satellite imagery in detecting and monitoring forest degradation. Such an evaluation is urgently needed given: (1) the importance of forest degrada-tion in REDD, which is currently not addressed in detail especially in cen-tral Africa; (2) the difficulty in assess-ing forest degradation due to spatial size and pattern of the process — in the Congo Basin forest degradation is often characterised by small-scale changes in forest cover; (3) the limited time frame in which to detect degra-dation given the potential quick regen-eration of vegetation; (4) the frequent cloud cover in both countries limiting optical image acquisition. The defined priority objective is supported by the EC. In order to avoid overlap with other existing projects the EC requested to use EC resources optimally. Because REDDiness is a research project, the EC encourages the testing of new options and techniques regarding REDD+. The project intends to evaluate a variety of satellite image types, including optical and radar data of high (30 m) to very high (< 1 m) resolution. Given the short duration of the project, use of existing archive data will be an essential ele-ment of the analysis, but a number of new acquisitions are also foreseen. The focus will be on two study areas of limited extent, one in Congo and one in Gabon.

CONCLUSIONS

This paper described the decision pro-cess carried out in REDDiness to focus on one niche of EO monitoring in the frame of REDD. A strong point of our

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Figure 4. Selection of REDDiness focus by surveying four main questions within the consortium.

project is the extensive analysis of user requirements and existing initia-tives. In addition we have summarised key choices to be made in any planned REDD Earth observation activity. In our view, these activities could highly ben-efit other REDD projects within and also outside the central African region. The consortium decided to focus on an evaluation of monitoring options for the assessment of forest degra-dation by using optical and radar data at high and very high resolution (0.5–30 m). This decision relies partly on the user requirements analysis. The qual-ity level of responses in the quanti-tative survey reveals differences not only in the level of knowledge of REDD, but also in the degree of understand-ing of MRV implementation. Hence, knowledge regarding REDD/REDD+ and forest monitoring can certainly be improved in both countries. REDD pro-jects need to strengthen the dissemi-nation and sharing of information on the objectives and implementation of REDD, in Africa in general, and in the Congo Basin in particular. In addition, the technical knowledge of forest map-ping including remote sensing software

as well as hardware resources seems currently insufficient to implement a national MRV system fully based on national expertise. Integration and cooperation between EU partners and local institutions clearly does improve the understanding of forest processes. In this context, REDDiness proposes for the remainder of the project (end date January 2013) to: (1) provide options for satellite-based forest degradation monitoring; (2) raise national capaci-ties in the field of GIS, remote sensing and field analysis.

REFERENCES

   Herold, M., ‘An assessment of national forest monitoring capabilities in tropical non-Annex I countries: Recommendations for capacity building’, GOFC-GOLD Land Cover Project Office, Friedrich Schiller University Jena, 2009.

   CN-REDD, ‘Proposition pour la préparation à la REDD+ (RPP) — République du Congo’, Coordination National REDD, 2011.

CHAPTER 11

Authors: Tim Pearson, Rob Verhoeven, Eric van Valkengoed, Dirk Hoekman, Jonas Franke, Vasco van Roosmalen, Jacqueline Sunderland-Groves, Almeida Sitoe

consortium members: Remote Sensing Applications Consultants Ltd, United Kingdom; SarVision BV, the Netherlands; TerraSphere Imaging & GIS BV, the Netherlands; Wageningen University, the Netherlands; Remote Sensing Solutions GmbH, Germany; Amazon Conservation Team (Equipe de Conservação da Amazônia), Brazil; Borneo Orang-utan Survival Foundation, Indonesia; Universidade Eduardo Mondlane, Mozambique

AbSTRACT

The REDD fast logging assessment and monitoring environment (REDD-FLAME) project will design and imple-ment a system capable of monitoring tropical and sub-tropical forests using high resolution radar (and optical) imagery acquired by Earth observation satellites. By focusing on early detec-tion of logging activities, the system will provide the means to quickly iden-tify the first signs of deforestation and thus act as a tool to control resource use and sustainable development within these fragile and valuable envi-ronments. The system will form a high

resolution add-on for existing (semi-)operational low to mid-resolution sys-tems, providing hot-spot monitoring for areas at highest risk of deforesta-tion. As such, it could be integrated into national or regional forest monitoring centres and provide inputs for large-scale carbon emission assessments in the context of the UN-REDD (reducing emissions from deforestation and for-est degradation) programme.

The system is being developed in col-laboration with investigators from developing countries on three con-tinents in an effort to build lasting partnerships and transfer European expertise. Test sites in Indonesia, Brazil and Mozambique have been chosen to represent a variety of forest types and deforestation issues, and thus to prove the system’s versatility.

This article describes the work carried out in the first 6 months of the project in preparation for technical devel-opment and implementation later in 2012.

ObjECTIVES

The REDD-FLAME project focuses on monitoring tropical and sub-tropi-cal forest areas with high and very high resolution Earth observation sat-ellites. The aim is to detect logging

REDD-FLAME — REDD fast logging assessment and monitoring environment

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activities at an early stage and pro-vide this information rapidly after sat-ellite observation. The system will form a high resolution add-on for existing (semi-)operational low to mid-resolu-tion systems covering entire countries or regions (wall-to-wall mapping), pro-viding hot-spot monitoring for areas at highest risk of deforestation.

The system will be designed primarily to use synthetic aperture radar (SAR) data, but as part of the project, an approach using optical remote sensing data will be implemented in parallel so that the relative merits of each type of data can be assessed.

The system will eventually be imple-mented and evaluated in three coun-tries to determine its potential as part of a national forest monitoring centre. The results and experiences from each of the countries involved will be pre-sented at final workshops, which will be organised at the end of the project in each country to showcase the sys-tem and make recommendations for its operational implementation.

FORESEEN PARTNERSHIPS And coLLABorAtions

The real drivers of the REDD-FLAME project are the partners in the test site countries, who have detailed knowledge of the forest ecosystems that the sys-tem seeks to protect. In Indonesia, the Borneo Orangutan Survival Foundation is dedicated to protecting endangered forest environments and developing REDD projects in Kalimantan. In Brazil, the Amazon Conservation Team has links to the many and diverse indig-enous groups living in the Amazon Basin, with whom it is already working to introduce 21st century solutions. In

Mozambique, the Faculty of Agronomy and Forestry at the Eduardo Mondlane University works very closely with the Ministry of Agriculture (Forest Service) and the Ministry of the Environment on guidelines for natural forest manage-ment and the implementation of natu-ral forest concessions.

From an early stage in the project, con-tact has been made with local stake-holders in the forest environments of the three test site countries, including representatives of national ministries (of forestry, environment), international organisations (UN, EU), NGOs (WWF) and the scientific community (local universities), to help determine system requirements and pave the way for the procurement of feedback on the sys-tem design and implementation.

The system will be prototyped at test sites in established REDD or GEO loca-tions with ample verification datasets, and partners will work closely with the participants of these programmes to ensure optimum use of existing data and maximise the impact of new prod-ucts. Furthermore, links will be estab-lished with other concurrent FP7 space projects concerning forest monitoring in relation to GMES and UN-REDD, to exchange knowledge, share resources and ultimately produce a joint White Paper.

SERVICE CONCEPT

The REDD-FLAME service concept is guided by user requirements. Its princi-ple, depicted in Figure 1, involves users (above the dotted line), the REDD-FLAME system (below the dotted line), and a number of interactions between the two. For each dedicated implemen-tation of REDD-FLAME, the service will

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be tailored through the selection by users of choices or options in each ele-ment of the system.

A wide range of users has been identi-fied, including local communities, for-est managers, enforcement agencies, policy-makers, monitoring and report-ing agencies and logging and mining enterprises. Broadly, these users fall into two distinct categories:

1. those who need information on potential changes in the forest as soon as possible after the event to enable direct action to be taken; and

2. those whose interest is in track-ing deforestation and forest deg-radation over long time periods for reporting purposes and statistics; they require cumulative updates of deforestation extent every 3 months to 3 years (REDD).

The requirements of these users deter-mine the selection of service options in the first box of Figure 1 and hence the definition of the rest of the system. Events information comprises change map products that will show the loca-tion of suspected deforestation phe-nomena which have occurred during a specific period, usually the most recent interval between acquired images. This information satisfies the needs of for-est managers and enforcement agen-cies, who seek to catch transgressors ‘in the act’ (user group 1 above), and constitutes the core service offered by REDD-FLAME. Trends information com-prises change map products that will show patterns of cumulative land cover change over extended periods and sat-isfy the needs of policy-makers and monitoring authorities who require val-idated results but have more relaxed time constraints (user group 2 above). The latter service is possible as a con-sequence of repeatedly acquiring data

Figure 1. REDD-FLAME organisational model © REDD-FLAME Consortium 2011.

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for the former service over a particu-lar site, and also represents a refine-ment of the earlier ‘preliminary’ information. Coverage options repre-sent the trade-offs between data res-olution, areal extent and cost. Choice of frequency is dependent on the tem-poral nature of the phenomena to be detected.

Ultimately, results will be disseminated to users for use as required for inter-vention purposes. They may inform pol-icy-makers, provide input to monitoring programmes, facilitate law enforce-ment efforts or provide local communi-ties with evidence with which to protect their lands from illegal encroachment.

Through their application of outputs, users will also contribute to evaluation of the service and provide feedback for further development of the system.

tecHnicAL deVeLoPMent

REDD-FLAME will typically exploit time series monitoring using high resolu-tion SAR data, to be complemented by mapping at a very high resolution, using SAR and/or optical data, where required at sites of particular interest.

Appropriate satellite data will be selected for each implementation according to the monitoring require-ments; TerraSAR-X and Cosmo-SkyMed for VHR SAR data, Envisat ASAR for HR SAR data and RapidEye for VHR opti-cal data are the principal sources to be considered during the project. New algorithms to process these data and to detect and characterise the first signs of deforestation are now being developed and these will eventually be implemented in end-to-end systems tailored for three test sites.

Once input data are properly calibrated and co-registered, change detection processing can proceed in one of three ways, according to needs and availa-ble data:

• long, regular SAR time series pro-cessing over large areas;

• change detection using a few SAR images with variable temporal resolution;

• change detection using a few very high resolution optical images with variable temporal resolution.

So-called hot spots, to be monitored in greatest detail, will be selected in the following ways:

• using intelligence or circumstantial evidence acquired in cooperation with local partners and other users;

• detection of indicators (such as camps, new roads) through routine high resolution monitoring or lower resolution national or regional wall-to-wall monitoring systems

The end products of the REDD-FLAME data processing chain will, in general, be forest change maps. However, the nature of such maps will be tailored according to user requirements, and methods to extract information from them for dissemination by non-graphic means (e.g. coordinates of change fea-tures as text files) will be developed.

The mode of results dissemination will depend on the user’s preferences and the nature of the change map products required. It follows that different prod-uct formats and data resolutions need to be established to suit these different dissemination modes. Dissemination

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Figure 2. Example of a change map product: map of selective logging activities and logging trails derived from very high resolution TerraSAR-X data to assist the assessment of logging impact. Small logging roads can be detected even when the tree canopy overarches the road almost completely. Map and picture © SarVision 2009.

modes that will be considered include e-mail, physical media by post and downloads from a website (or FTP site). Maps designed to be visualised with web mapping applications, a WebGIS or Google Earth could be served across the Internet. Alternatively, a Google Earth API could be implemented on a dedicated website. Information in short text form representing the coordinates of change features could be sent to a mobile phone by SMS. The use of DevCoCast will also be investigated.

TEST SITES

In the second year of the project, REDD-FLAME will be implemented and evalu-ated in three countries to determine its potential as part of a national forest

monitoring centre. Test sites have been chosen by local partners and users because of their particular vulnerabil-ity to deforestation.

In Indonesia (Mawas, Central Kalimantan), peat swamp forests are important carbon sinks, yet fires and drainage of the land for conversion to agriculture are resulting in large quantities of carbon being released to the atmosphere. In Brazil (Sete de Setembro Indigenous Land in Rondonia, Cacoal City and Mato Grosso), gold min-ing and smuggling activities threaten vast swathes of lowland rainforest. In Mozambique (Mecuburi Forest Reserve, Nampula Province), agricultural con-version and the harvesting of fuelwood result in damaging degradation of the sub-tropical Miombo forests.

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The sizes of these areas (around 5 000 km2) are typical of the regions that REDD-FLAME is intended to moni-tor, i.e. forest reserves, logging conces-sions, threatened areas in the proximity of population centres. They are too big for frequent monitoring using very high resolution satellite data, so an approach whereby high resolution monitoring and local intelligence are used to identify hot spots for investigation in greater detail is therefore essential.

PROjECT STATUS

The project began in 2011 with an in-depth review of applicable interna-tional policy and user requirements in each of the test site countries, to hone the requirements for a forest monitor-ing system. This involved an analysis of international conventions, policies and programmes (REDD, GEO, GOFC-GOLD, etc.), and consultation on a country-by-country basis with politi-cal actors and stakeholders to gain an understanding of local monitor-ing needs and national responsibilities and initiatives. The requirements were compared, discussed and synthesised in a user requirements document.

Based on these findings, an appropri-ate service concept and high-level sys-tem design were elaborated, based on existing capacities for change detection. Technical development is now focusing on new methodologi-cal insights and the latest sources of high resolution imagery, research and development of new algorithms for detection of change in forest state and generation of new products.

At the end of the first year of the pro-ject, a technical development work-shop will be organised where members

of the consortium and invited speakers will present status reports, findings of research and feedback on deforesta-tion initiatives relevant to the tropical forest ecosystem.

Later in 2012, REDD-FLAME will be implemented and evaluated at test sites in three countries to determine its potential as part of a national for-est monitoring centre. The results and experiences from each of the coun-tries involved will be presented at final workshops, which will be organised at the end of the project in each coun-try to showcase the system and make recommendations for its wider imple-mentation. These workshops will also include an element of training and hence facilitate knowledge transfer to local groups.

eXPected AcHieVeMents

REDD-FLAME will bring benefits to a wide range of parties concerned with deforestation in tropical and sub-tropi-cal environments, including indigenous people, environmentalists, research scientists, national governments and international policy-makers.

During the course of the project, the information required for mapping and monitoring deforestation, forest type and land cover will be determined, and appropriate techniques developed to implement a near-real time forest monitoring system capable of deliv-ering it, using data from multiple sat-ellite SAR sensors operating in C- and X-band wavelength ranges, multiple polarisations and various spatial and temporal resolutions.

By developing a component appropri-ate for integration into national forest

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monitoring centres, REDD-FLAME will build capacity in the host countries for managing forest resources and carbon balances.

By implementing a dedicated version of REDD-FLAME for each participat-ing host country, results targeted at their specific monitoring requirements, based on the strategies and policies for deforestation in place, will be provided to give a clear overview of forest state.

CONCLUSIONS

The REDD-FLAME project supports the global effort to combat deforestation,

under the auspices of the UN-REDD programme, by developing a system to quickly identify the first signs of illegal logging and thus allow earlier intervention by the authorities and bet-ter management of these fragile and valuable forest ecosystems to prevent lasting damage. Using very high reso-lution data from SAR satellite systems, the project will add value to existing forest satellite monitoring systems that use lower resolution imagery. Implementing the enhanced system, REDD-FLAME will monitor logging hot spots on three continents and help to build capacity for managing forest resources and carbon balances on a national scale.

CHAPTER 12

Authors: Caren Jarmain, Remco Dost, Ellen De Bruijn, Fanie Ferreira, Onno Schaap, Wim Bastiaanssen, Frans Bastiaanssen, Ivo van Haren, Toine Wayers, Daniel Ribeiro

consortium members: University of KwaZulu-Natal, South Africa; WaterWatch, the Netherlands; WEConsult, Mozambique; GeoTerraImage, South Africa; Hydrosoph, Portugal; Basfood, the Netherlands; Prezent, the Netherlands; Hidrosoph, Portugal

AbSTRACT

The WATPLAN project provides a spa-tial earth observation monitoring system for water resources assess-ment, planning and allocation in the international Incomati Basin shared between South Africa, Swaziland and Mozambique. WATPLAN uses a com-bination of high resolution (30 m) sat-ellite data and in situ collected data to derive water management indica-tors on a weekly basis which can assist both the Tripartite Permanent Technical Committee (TPTC) and the Inkomati Catchment Management Agency (ICMA) in objective and sound water resources management. Data products used in

WATPLAN include the FEWS-NET rain-fall data product and data products derived from a combination of DMC and MODIS satellite data used in the SEBALtm modeling. Following engage-ment with important stakeholders in the Incomati catchment, a data dissem-ination portal (http://www.watplan.com) was developed and land use and hydrol-ogy-related data products are currently disseminated weekly for various land use classes and sub-catchment of the Incomati catchment. Data dissemina-tion via this portal started in February 2012 and dates back to November 2011. Data dissemination will continue for 12 months. Refinements to the var-ious data products provided and accu-racy assessment thereof are under way. The integration of the data products into stakeholders’ existing system and networks are currently investigated to ensure that the WATPLAN data products can contribute to equitable and efficient water allocation and water use monitor-ing across various sectors represented in the Incomati Basin.

introduction

Equitable and efficient water allo-cation, especially across countries’

WATPLAN — Spatial Earth observation monitoring for planning and water allocation in the international Incomati Basin — Managing water from catchment down to field scale

149WATPLAN — SPATIAL EARTH OBSERVATION MONITORING FOR PLANNING AND WATER ALLOCATION IN THE INTERNATIONAL INCOMATI BASIN

boundaries, necessitates information on water resource use and availabil-ity in space and over time. However, well maintained monitoring systems that can provide objective information to all relevant decision makers are often lacking. The use of remote sens-ing technologies to derive information related to water resources holds great potential, since data that is objective can be generated at frequent inter-vals and over extensive areas and be presented for different users or stakeholders.

The Incomati catchment is an exam-ple of a trans-boundary basin that can benefit from objective infor-mation on water resources use and availability as it changes in time and space. The Incomati Basin covers a total of 46 800 km2 and is shared by South Africa (61 %), Swaziland (5 %) and Mozambique (32 %) (Figure 1). The Incomati catchment extends over

several parallel river catchments to form the Incomati River which dis-charges into the Indian Ocean just north of Maputo. Water resources management in the Incomati Basin is facilitated by the Tripartite Permanent Technical Committee (TPTC), which was established in 1983 to assist the three countries in sharing informa-tion related to water allocation and to use, monitor and ensure adherence to the agreement on water delivery to downstream users. In South Africa, the Inkomati Catchment Management Agency (ICMA), as required through the National Water Act declared in 1998, is developing a strategy for allocat-ing water diversions from the river in a political manner that meets the requirements of the act. In general though, within the Incomati Basin, a sparse hydrological ground observa-tion network exists and is currently informing decision-making related to water allocation.

Figure 1. Outline of important catchments in Southern Africa including the trans-boundary Incomati Basin

150WATPLAN — SPATIAL EARTH OBSERVATION MONITORING FOR PLANNING AND WATER ALLOCATION IN THE INTERNATIONAL INCOMATI BASIN

The principle objective of WATPLAN ‘Spatial Earth observation monitor-ing for planning and water allocation in the international Incomati Basin’ is to (a) develop and then (b) imple-ment an operational Earth observa-tion-based monitoring system that uses a combination of high resolution (30 m) satellite data and data from the ground observation network to provide objective information related to land use and hydrology. WATPLAN will provide information at a frequent (weekly) interval from field to entire basin scale and should assist differ-ent stakeholders (farmers to govern-ments) in managing water resources better. The data sets will be dissem-inated to the different stakeholders for evaluation through a web portal (http://www.watplan.com).

RESULTS

WATPLAN was initiated from the gen-eral need for objective information that can be used to improve water resources management in the internationally shared Incomati Basin. Information is required for the entire basin and sub-catchments; it needs to be updated fre-quently, should assist in water resources management at different spatial scale (field to catchment) and for different stakeholders, and also be objective.

During the first multi-stakeholder plat-form (MSP) meetings held in September 2011 in the three countries, stakehold-ers confirmed this need for objective information in the Incomati Basin. The 28 different stakeholders that attended the meetings represented government departments, water users’ associations/irrigation boards, private sector organi-sations and researchers. Although their specific needs differed slightly, it was

mainly concerned with the need for land use-related information — infor-mation at high resolution (space and time) that can be integrated into exist-ing management systems. The feed-back obtained from the MSP meetings were used in the development of the web portal (http://www.watplan.com) through which the different data prod-ucts (parameter maps) related to land use and hydrology are displayed in space and time at catchment level and for different land use classes.

Land use and hydrology-related data products displayed on the www.watplan.com data portal are derived from differ-ent data sources. Figure 2 summarises the data flows within WATPLAN, includ-ing the different data sources, the prin-ciple algorithm used, the data products displayed for the various categories and also the link (validation and calibration) between ground and remotely sensed data. WATPLAN focuses on quantifying the principle components of the water balance — rainfall and evapotranspira-tion — i.e. how much water is available (rainfall) and used (evapotranspira-tion) and how does this change over space and in time. At present the rain-fall maps presented are extracted from the US Agency for International Development (USAID) Famine Early Warning Systems Network (FEWS-NET). This precipitation product com-bines TRMM rainfall and infrared data sets to provide a 5-day data product at a 0.05o resolution. In the execution of WATPLAN, the accuracy of this rain-fall data product across the Incomati catchment will be evaluated using the existing and newly established rainfall observation network. Improvements to this data product through auto-cal-ibration and integration with alterna-tive — e.g. radar data — sources will be investigated.

151WATPLAN — SPATIAL EARTH OBSERVATION MONITORING FOR PLANNING AND WATER ALLOCATION IN THE INTERNATIONAL INCOMATI BASIN

Figure 2. Summary of important data sets and algorithm used and data flows that occur to generate the different data products for different categories/sectors as part of WATPLAN

Other data products, e.g. evapotran-spiration, biomass production and the evapotranspiration (ET) deficit, are esti-mated using the Surface Energy Balance Algorithm for Land (SEBALtm) model. DMC and MODIS (Terra and/or Aqua) satellite data and spatially extrapolated weather data is combined in the SEBAL model (Figure 2), first published by Bastiaanssen et al. (1998). SEBAL is a physically based model that calculates the actual ET from the energy balance and not as the residual from the water balance. The SEBAL model has been applied widely and evaluated and vali-dated in many studies conducted inter-nationally. However, to demonstrate the accuracy of the ET estimates to stake-holders, the SEBAL-ET estimates will be compared to ground observations thereof for different land uses (natural veld, sugar cane, macadamia nuts, cit-rus) found in the Incomati Basin.

Although a land use map is not needed in the SEBAL modeling or to produce the different land use and hydrology-related data products, an accurate and updated map is needed for the accu-rate extraction and display of data for the different land use classes. The generation of a new, updated land use map for the Incomati Basin is currently under way. DMC data is used for this purpose.

The five hydrology and land use-related data products disseminated through the webportal are presented to all end-users for free for a mini-mum of 1 year to evaluate. So far, for the period November 2011 to March 2012, 11 weeks’ data have been pro-cessed and published on www.watplan.com. On average, one set of satellite images is used to produce one weekof data products.

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The data products currently displayed on the www.watplan.com data por-tal can be used in land use and water resources management at field, farm, sub-catchment and international basin scale. The quantitative data is dis-played in both graph and map format. It shows water resources distribution (availability and use) as its variation in space and change over time. Figure 3 shows an example of the data products (rainfall and evapotranspiration) as it differs over Basin 13 and in time. For example, in mid-January 2012, heavy and widespread rainfall occurred uni-formly across Basin 13, located in South Africa (Figure 3). The rainfall that occurred across Basin 13 during the following week was substantially lower and showed a less uniform distribu-tion over the catchment (Figure 3). The land use (crop) response to the rainfall can be observed in the ET data during

these 2 weeks. In mid-January 2012, as a result of substantial and catch-ment-wide rainfall and hence reduced solar radiation, the ET was substan-tially lower than the following week, at which time the crops responded to the available water through increased ET. These data products can therefore be used to quantify the water resources, specifically rainfall and ET, but spatial variation thereof can be assessed at different scales — e.g. sugar cane field to catchment — as shown in Figure 3.

Many other applications of the data products, relevant for different stake-holders, do exist and are explored in WATPLAN. For example, at field scale, another data product, ET deficit, can be used to assess where, in a field, water shortages exist and irrigation applica-tions are required. However, to deter-mine the actual irrigation amount to be

Figure 3. Screen print of data products posted on the www.watplan.com site, specifically rainfall and evapotranspiration (both in mm/week). The data shown here is for Basin 13, which contains large areas of sugar cane. Data maps are for the second and fourth week of January 2012.

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applied, the current spatial data prod-ucts need to be integrated with other in situ data sets. Also, combining the biomass production and ET data, the efficiency with which water is used can be determined and used to set benchmarking standards for pro-duction of different crops and areas across catchments. This will all lead to improved water use and water resources management.

CONCLUSION

Equitable and efficient water alloca-tion to meet international obligations can only be measured by and achieved through objective and regular monitor-ing across a shared basin. Within the trans-boundary Incomati Basin with a sparse in situ hydrological monitor-ing network, remote sensing technol-ogies investigated in WATPLAN hold great potential in providing informa-tion related to land use and water resources management. These data sets can be provided at frequent inter-vals and across a large area, whilst providing field-scale details. A number

of challenges remain: (a) providing sat-ellite-derived data products timeously; (b) integrating new spatial data prod-ucts into existing databases (e.g. from the ICMA); (c) illustrating the bene-fits of satellite-derived land use and hydrology data sets over conventional data products in all three countries; (d) motivating different stakehold-ers, dependent on the same water resource, to use the same set of objec-tive data products.

REFERENCES

  Bastiaanssen, W. G. M., Menenti, M., Feddes, R. A. and Holtslag, A. A. M., ‘A remote sensing surface energy balance algorithm for land (SEBAL): Part 1. Formulation’, Journal of Hydrology, 212/213, 1998, pp. 198–212.

  Carmo Vas, A. and Van der Zaag, P., ‘Sharing the Incomati Waters: cooperation and competition in the balance’, Unesco, IHP-VI, Technical Documents in Hydrology, PCCP series, No 14, 2003.

CHAPTER 13 GMES4Regions and local authorities — Bridging the gap between European local and regional authorities and GMES

Authors: Volker Schumacher, Arnault Contet

consortium members: For DORIS_Net: CEON GmbH, Germany; Fundación Adeuropa, Spain; Asociación Madrid Plataforma Aeronáutica y del Espacio (MPAE), Spain; Association Pôle Mer Bretagne, France; Tecnologie per le Osservazioni della Terra ed i Rischi Naturali, Italy; University of Leicester, United Kingdom; Consiglio Nazionale delle Ricerche, Italy; Forum Luft- und Raumfahrt Baden-Württemberg eV, Germany; Centre d’Études Techniques de l’équipement du Sud Ouest, France; Association Guyane Technopole, France; Secretaria Regional da Ciência, Tecnologia e Equipamentos, Spain; Capital High Tech SARL, France; Instytut Geodezji i Kartografii, Poland For GRAAL: SpaceTec Partners, Belgium; Planetek, Italy; Starlab, Spain; FDC, France; Deutsches Zentrum für Luft- und Raumfahrt eV (DLR), Germany; Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), Italy; European Regions Research and Innovation Network (ERRIN), international; Paris Lodron University, Austria; GISAT, Czech Republic; Specto Natura, United Kingdom

AbSTRACT

GMES4Regions is a unique banner under which two FP7-funded projects

act, i.e. DORIS_Net and GRAAL. Both projects aim at raising the atten-tion of European local and regional authorities on the European GMES programme. In fact, GMES can bring various benefits to the local actors and can represent a driver of innova-tion by fostering the creation of GMES services at local level. One major achievement of GMES4Regions is its web portal with its various sections linked to the interests and purposes of different stakeholders. It is described in this contribution, with a brief out-look on the expected results.

GMes ProGrAMMe And tHe LocAL And reGionAL diMension

The Global Monitoring for Environment and Security (GMES) programme of the European Commission and the European Space Agency aims at achieving an autonomous and oper-ational Earth observation capacity. GMES rationalises and federates data collected in situ or with satellites in order to provide access to informa-tion in relation to the environment and security. Decision-makers and public authorities at the European, national and local levels are the major users of GMES.

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Two FP7-funded projects have joined forces to help GMES move closer to European local and regional authori-ties (LRAs) through the GMES4Regions (G4R) initiative. It is no secret that cit-ies, provinces and regions are among the most important potential end-users of GMES downstream services1, yet the link between LRAs and GMES needs to be strengthened. The industrial, eco-nomic and social structures that exist at the local level in the European Union (EU) can strongly benefit from GMES tailor-made services, which ultimately

address decision-makers, technical end-users and European citizens.

Bringing GMES closer to LRAs will not be achieved by scientific work but rather by a combination of commu-nication activities and the implemen-tation and development of dedicated GMES contact offices throughout European regions implemented in the frame of the G4R initiative.

Finally, the G4R initiative will also mate-rialise thanks to the GMES4Regions.eu

Figure 1. GMES can be of great use to improve urban and rural planning. Credit: Dr David Otway

1

1 The GMES downstream services are those services that will not be funded by the European Commission or the Member States.

158GMES4REGIONS AND LOCAL AUTHORITIES — BRIDGING THE GAP BETWEEN EUROPEAN LOCAL AND REGIONAL AUTHORITIES AND GMES

(http://www.gmes4regions.eu/) portal that will contain resources and mate-rial aimed at helping to enlarge the user base of GMES among LRAs.

THE ROOTS OF GMES4REGIONSIn 2009, the FP7 space work pro-gramme included a topic entitled ‘Fostering GMES downstream services and link with regions’. Two projects were selected for funding: DORIS_Net and GRAAL.

The two projects complemented each other and, as a result, the European Commission requested that they work in a coordinated manner and, when-ever possible, communicate under a single banner: GMES4Regions (or G4R, in its short version). The main objective of this G4R single identity is to ensure consistency in the communication and awareness activities.

As for the complementarities of the projects: on the one hand, the DORIS_Net consortium is composed of public entities that are members of Nereus (Network of European Regions using Space Technologies) while GRAAL brings together SMEs and the ERRIN network (European Regions for Research and Innovation) as mem-bers of the consortium. The funda-mental synergy in the approach of the two projects to meet their objective is that DORIS_Net’s approach is cen-trifugal, whereas GRAAL’s is centrip-etal. DORIS_Net starts from Nereus regions to expand towards other regions that have not yet emerged as users of space applications, whereas GRAAL focuses on cities and regions that are supposed to have limited knowledge of the use of GMES down-stream applications.

THE IMPORTANCE OF LRAS FOR GMES

Although the initial topic of the FP7 space work programme of 2009 stressed the need to reinforce the link between the downstream sector of GMES and regions specifically, G4R has decided to also engage with cities and provinces.

There are several reasons for this choice. First of all, the EU is heteroge-neous when it comes to administra-tive organisation. For instance, unlike Germany or France, some Member States do not have intermediate levels between local government and national government (Malta is an example of this). Yet, local governments in these countries may become end-users of GMES downstream applications and services. As a matter of fact, it would be a mistake not to engage local gov-ernments just because the topic of the call only mentioned regions. Secondly, overall there are about 1 600 regions or provinces and more than 120 000 communes and municipalities in the EU. Depending on their administrative attributions, they can all be potential users of GMES downstream services and, therefore, customers for service providers.

In summary, the market exists but its potential will only be fully reached when the largest possible number of LRAs become aware of and under-stand the benefits GMES downstream services can offer them. G4R will not be able to reach all of them and it is certainly not the overall objec-tive that was entrusted to DORIS_Net and GRAAL. However, as the projects advance, some specific activities and products are being developed and implemented to provide a solid basis

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for future actions towards local and regional public authorities in the EU.

The following sections describe a major achieved result of GMES4Regions, i.e. its portal and its sections, while the last section is focused on the expected activities.

THE GMES4REGIONS.EU PORTAL

The GMES4Regions.eu portal brings together the joint work produced by DORIS_Net and GRAAL and is one of the entry points to the list of GMES Regional Contact Offices (RCO) set up by DORIS_Net. In this sense, regional stakehold-ers themselves define and implement a methodology to coordinate and fos-ter the European GMES downstream service sector at a regional level and so for the first time the users are in the driving seat. Based on the strong sup-port from the Nereus network, currently

comprising 26 European regions, DORIS_Net sets the foundation for a sustainable approach connecting the network of RCOs. With this important keystone, significant economic benefits can be created with positive impacts on the economies of the European regions, as well as public benefits to European citizens if the implementation of GMES services can be boosted in such a way.

Communication is a key aspect of the GMES4Regions initiative. G4R pro-duces several communication tools such as the Window on GMES publi-cation or a multimedia presentation showcasing the benefits of GMES for LRAs. All communication tools and products will be available on the por-tal in five languages (English, French, German, Italian and Spanish). Overall, the GMES4Regions.eu portal will be home to a large scope of communica-tion material aimed at raising aware-ness on the substantial benefits that GMES can provide for LRAs in the EU.

Figure 2. Homepage of the GMES4Regions.eu portal. Figure 3. View of the categories of GMES products displayed in the multimedia presentation.

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Figure 4. View of the network of regional contact offices entry page.

eXPAndinG tHe GMES COMMUNITy

Reaching out to the largest possible number of LRAs can only be achieved through efficient relays. Nereus and ERRIN represent two important relays towards LRAs. Additionally, G4R can also rely on the strong involvement of the Committee of the Regions, whose Secretary General, Mr Gerhard Stahl, chairs the G4R Advisory Board in which major networks are also represented. G4R therefore provides a unique plat-form for GMES downstream projects to ensure that the products or services they offer that are relevant to LRAs reach a large number of potential clients.

However, fostering downstream services cannot be achieved simply by spread-ing the ‘GMES word’ across potential public users in the EU. GMES is the end product of research activities that have spanned over a decade and the political drive of the founding fathers of GMES. The academic and R & D worlds, along with SMEs and service providers, have been at the very heart of the devel-opment of GMES and remain today important stakeholders in ensuring the sustainable development of the down-stream component of GMES. Therefore the GMES4Regions.eu portal hosts two specific sections devoted to academic and research centres and also to ser-vice providers and SMEs.

161GMES4REGIONS AND LOCAL AUTHORITIES — BRIDGING THE GAP BETWEEN EUROPEAN LOCAL AND REGIONAL AUTHORITIES AND GMES

The G4R initiative involves two key uni-versities as far as GMES is concerned — the University of Leicester (G-STEP — a DORIS_Net partner) and the Paris Lodron University of Salzburg (Z_GIS — a GRAAL partner). The research compo-nent of the GMES4Regions.eu portal is gathered in the section corresponding to the Virtual GMES Academy (VGA). Its aim is to link GMES research and devel-opment with potential users of infor-mation services. The VGA also hosts a job and internship section allow-ing companies and students to post or seek job and internship opportunities.

The business stakeholders are addressed through the ‘Entrepreneurs and SMEs’ section that targets public or private organisations looking for a service provider as well as providers looking for partners to develop new products or services, and private com-panies looking for funding or new busi-ness development opportunities. This section will provide information on the various funding opportunities available at the European level for entrepreneurs and SMEs. It also offers a directory of service providers identified in the EU.

eXPected finAL resuLts

The overall objective of G4R is to pro-mote GMES downstream services among the largest possible number of local and regional authorities. There are many reasons for which involving

the regions as active partners from the very beginning is vital: as both the users and beneficiaries of the services, they will become committed to a use-ful and sustainable result if they can be convinced of the benefits. In that regard, the G4R team works as an amplifier not only to ensure that LRAs have a better understanding of GMES but also to assist in raising aware-ness of the existing downstream pro-jects. Together with the network of regional contact offices, Window on GMES and the GMES4regions.eu por-tal, GMES4Regions offers a platform to help downstream projects to increase their visibility. In that sense, several downstream projects are already col-laborating with G4R by contributing content to Window on GMES.

By the conclusion of the project, G4R will also produce recommendations on how to continue fostering the link between GMES downstream ser-vices and European local and regional authorities. These recommendations will, for instance, assess the various barriers that are faced when promot-ing GMES and Earth observation ser-vices and applications among LRAs.

However, this promotion needs to be pursued on many levels and is a long-term process; therefore, it is important to work towards ensuring the future sustainability of the various tools and products developed by DORIS_Net and GRAAL.

CHAPTER 14 ZAPÁS: Assessment and monitoring of forest resources in the framework of EU–Russia space dialogue

Authors: Christian Hüttich, Christiane Schmullius, Christian Thiel, Carsten Pathe, Sergey Bartalev, Kirill Emelyanov, Mikhail Korets, Anatoly Shvidenko, Dmitry Schepaschenko

consortium members: Department for Earth Observation, Institute of Geography, Friedrich-Schiller-University Jena, Germany; Space Research Institute, Russian Academy of Sciences, Moscow, Russia; Joint Stock Company ‘Russian Space Systems’, Moscow, Russia; Sukachev Institute of Forest, Russian Academy of Sciences, Krasnoyarsk, Russia; International Institute for Applied System Analysis, Laxenburg, Austria

AbSTRACT

ZAPÁS (Rus.: Запaс) was chosen as the project acronym since this Russian word is used in forest terminology for growing stock volume, or forest stock, which is one of the envisaged products of this project. Addressing the important issue of assessing for-est resources in the boreal zone, par-ticularly in Siberia, the ZAPÁS project is aiming to actively support the EU–Russian space dialogue. ZAPÁS delivers innovative procedures and new prod-ucts for forest resource assessment and monitoring using jointly ESA and Roscosmos satellite data.

The geographical focus of research and development within the ZAPÁS project is central Siberia, which con-tains two administrative districts of Russia, namely Krasnoyarsk Kray and Irkutsk Oblast. The project team aims to develop Earth observation prod-ucts at two geographical scales. First, improved regional-scale land cover and biomass maps will be developed for central Siberia to (a) improve exist-ing coarse-scale land cover databases, (b) link them with biomass informa-tion from medium resolution Radar imagery, and (c) use this up-to-date land cover and forest resource geo-information as input for full carbon accounting (Nilsson et al., 2000). The results of the terrestrial ecosystem full carbon accounting will be addressed to the Federal Forest Agency at federal instance. Second, high resolution bio-mass and change maps for selected local sites will be developed to sup-port the UN FAO Forest Resources Assessment as well as the require-ments of the local forest inventories. The team consists of a balanced distri-bution of leading experts from Europe and Russia in the field of Earth obser-vation for forestry applications and includes Russian stakeholders, e.g. the Sukachev Forest Institute, who them-selves apply remote sensing tech-niques. The Russian partners come from two geographically different fed-eral regions: the city of Moscow and the

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Krasnoyarsk Kray. An external review board, the ZAPÀS Advisory Board (ZAB) has been installed to involve represent-atives of the Russian Space Agency and of the Federal Forest Agency and connect ZAPÁS to the United Nations Forest Resource Assessment 2010 (FRA 2010) and further international programmes.

FOREST MONITORING IN THE frAMeWorK of eu–RUSSIA sPAce diALoGue

Russia, the European Union’s larg-est neighbour, is considered by the European Parliament as a key player in its efforts to protect the global climate and environment. The strengthening of genuine stra-tegic partnerships founded on com-mon interests and shared values are strongly supported. The ZAPÁS pro-ject represents such a strategic part-nership between well acknowledged Russian and European scientists in the field of Earth observation with the support, direct involvement and con-tribution of the Russian and European Space Agencies. The bilateral basis for EU relations with Russia is the PCA (PCA) signed in December 1997. The provisions of the current partner-ship and cooperation agreement cover a wide range of policy areas includ-ing science and technology, education and training, and environment. A new basis for EU–Russian environmen-tal cooperation was the signing of a major agreement in Helsinki (2006) in order to intensify the collaboration on environmental protection and nature conservation. The three main themes considered were climate change, pres-ervation of biodiversity, and the links between economic development and the environment.

A further important international agreement is the Kyoto Protocol of the UN Framework Convention on Climate Change, providing mecha-nisms to reduce greenhouse gases and tackle global warming. It entered into force in February 2005 after Russian ratification. In the case of climate change, the need for com-mon efforts and transnational coop-eration to close existing knowledge gaps have been pointed out by the IPPC Working Group III in the report Climate change 2007 — Mitigation (IPCC 2007). The intensification of col-laboration between the EU and Russia on environmental issues is a welcome step forward in bringing ecological sustainability and social responsibil-ity more to the forefront in economic dealings. Such responsibility is vital in all kinds of industrial investments, in cooperation on energy issues, and in the farming, forestry and fisheries sectors. This makes the harmonisation of European and Russian environmen-tal policies and legislation particularly important. The collaborative develop-ment of advanced methods and the exchange of Earth observation data is fully compliant with the cooperation policy established between the EU and Russia. ZAPÁS relies on the ESA-Roscosmos Data Exchange Agreement from 11 March 2009.

The ZAPÁS network is involved in inter-national programmes such as GEO FCT (Group on Earth Observation — Forest Carbon Tracking), GOFC–GOLD (Global Observation of Forest Cover and Land Dynamics) and NEESPI (Northern Eurasian Environmental Science Partnership Initiative), through which support to international conven-tions related to the global environmen-tal issues, such as UNCBD, UNFCCC and its Kyoto Protocol, is ensured.

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Multi-scale assessment and validation of central Siberian forest maps

Looking at the large-sale distribution of the Siberian Taiga, the systematic monitoring of forest dynamics is still challenging. Satellite Earth observation is the only alternative for a frequent monitoring of biomass-decreasing pro-cesses such as clear cutting, selective logging, fire, insect infestation, but also afforestation and forest succession processes (White et al., 2005; Yatabe et al., 1995; Kasischke et al., 1992).

ZAPÁS investigates and cross-val-idates methodologies using both Russian and European Earth observa-tion data to foster the development of a worldwide observation system. The methodologies include state-of-the-art optical and radar retrieval algo-rithms and their improvement as well as investigation of innovative syner-gistic approaches (Thiel et al. 2009). Products include biomass maps and

biomass change for the years 2007–10 on a local scale, a biomass and improved land cover map on a regional scale, and a 1 km-scale land cover map as input to a carbon account-ing model. These products serve the inventory community (e.g. FAO Forest Resource Assessment) as well as the Kyoto Protocol implementation bod-ies., Land cover change dynamics, specifically forest regrowth and land abandonment, will be investigated in specified regions.

One of the key perspective goals of the ZAPÁS initiative is to overcome still existing uncertainties in carbon accounting. Since the synergistic bio-mass — land cover product will be one new parameter of the full ecosys-tem carbon accounting, some general future improvements will be consid-ered for carbon accounting, such as in situ and multi-scale Earth observation synergies and combining regional land cover mapping and biomass products.

Figure 1. Integrated concept for forest resource assessment and forest geo-information cross validation to be implemented by the ZAPÁS project. The graph exemplarily indicates the range of data specifications in terms of spatial and thematic detail in relation to the effort of frequent update (adapted from Herold et al., 2008).

167ZAPÁS : ASSESSMENT AND MONITOR ING OF FOREST RESOURCES IN THE FRAMEWORK OF EU–RUSS IA SPACE D IALOGUE

AcHieVed resuLts

Synergistic ESA–Roscosmos satellite database

Optical and SAR imagery are acquired in WP2 basically from ESA and Roscosmos archives (including the ESA third-party missions of NASA and JAXA) and used in a synergistic manner by (1) enhancing the data acquisition by involving the national space agency contacts and (2) combining optical and SAR high VHR imagery with time series for local and regional-scale biomass, forest cover and forest disturbance mapping. An overview of the sensor specifications is given in Table 1.

Optical MERIS and MODIS time series data are used for the generation of an improved central Siberian land cover database (WP3). As indicated in Figure 2, hyper-temporal ASAR imagery is used for regional-scale biomass mapping by applying the Biomasar algorithm (Santoro et al., 2010) (WP4). By involv-ing recently updated forest inventory data (e.g. growing stock volume, species composition on forest stand level) the SAR data is being used for high reso-lution biomass mapping. Additionally, optical high resolution imagery is used for forest cover and disturbance map-ping and validation purposes (WP8).

Sensor sensor characteristics Purpose

ALOS-Palsar Imaging microwave radar: Fine beam modes (FBS/FBD): 7 –44 m; ScanSAR mode: 100 m, L-band; polarisation modes: VV, HH, VV/HH, HV/HH or VH/VV

Local-scale mapping of biomass, forest cover and disturbances (fire, clear cuts)

Envisat ASAR Imaging microwave radar: image, wave and alternating polarisation modes: app. 30 m; wide swath mode: app. 150 m; global monitoring mode: app. 1 000 m, C-band; polarisation modes: VV, HH, VV/HH, HV/HH or VH/VV

Regional-scale biomass mapping for central Siberia

Resurs DK-1 Imaging multispectral radiometer: spectral resolution: pan: 0.58– 0.8 µm; green: 0.5–0.6 µm; red: 0.6–0.7 µm; NIR: 0.7–0.8 µm; spatial resolution: panc. 1 m, multispectral 2–3 m

Local-scale forest cover and change mapping (fire, clear cuts)

Monitor-E PSA Panchromatic camera (PSA): spectral resolution: pan: 0.51–0.85 µm, 8 m spatial resolution

Ground truth reference data for forest land dynamics (cover change due to logging and fire)

Envisat MERIS Imaging multispectral radiometer: spectral resolution: VIS-NIR: 15 bands selectable across range: 390 nm to 1 040 nm; spatial resolution: 300 m

Regional-scale land cover mapping for central Siberia

TERRA MODIS Imaging multispectral radiometer: spectral resolution: VIS-SWIR: 7 bands selectable across range: 620 nm to 2 155 nm; spatial resolution: 250– 500 m

Regional-scale land cover mapping for central Siberia

Table 1. Joint ESA–Roscosmos satellite data base used in the ZAPÁS project.

168ZAPÁS : ASSESSMENT AND MONITOR ING OF FOREST RESOURCES IN THE FRAMEWORK OF EU–RUSS IA SPACE D IALOGUE

Figure. 2. Combining in situ and multi-scale optical and SAR Earth observation synergies for forest resource assessment in central Siberia. The exemplary maps are generated within the ZAPÁS project and indicate the spatial and thematic data characteristics from inventory to local-scale and regional level.

Regional and local biomass and forest cover mapping

The local-scale biomass and forest cover mapping aims at the actualisa-tion of forest resources by delivering up-to-date biomass and forest cover maps. The maps are generated at local and regional-scales and should assist the future forest inventory update by the local forest agencies. As an ini-tial step within the bottom-up forest resource assessment, local-scale bio-mass maps (25 m spatial resolution) are being generated by training linear regression models using Palsar back-scatter and interferometric coherence imagery. Ground reference data (grow-ing stock volume (m³/ha)) are used for map validation. Figure 3 shows the first results of the local-scale bio-mass and forest disturbance map-ping in the Kazachinskoe test site in Krasnoyarsk Kray. Linear regression models were applied on one winter

coherence (28 December 2006, 12 February 2007) and three HV back-scatter images covering the summer period 2007/08 (15 August 2007, 30 September 2008, 17 August 2008). The GSV map was generated by aver-aging the summer backscatter and winter coherence modelling results. Using independent inventory data, an RMSE of 15 % was derived. One of the key perspective goals of the ZAPÁS ini-tiative is to deepen the understanding of land cover and biomass assessment in the boreal zone on different scales. As a next step, the biomass and land cover mapping will be conducted using the above-listed medium resolution optical and SAR imagery to be inte-grated in a cross-validation process.

CONCLUSIONS

The ZAPÁS project represents and fosters the future collaboration between Russian

169ZAPÁS : ASSESSMENT AND MONITOR ING OF FOREST RESOURCES IN THE FRAMEWORK OF EU–RUSS IA SPACE D IALOGUE

and European scientists in the field of Earth observation of forest resources by actively involving ESA and Roscosmos.

The overall goal of the ZAPÁS initiative is to overcome still existing uncertainties in carbon accounting of the boreal zone, particularly for Russia, based on (1) in situ and multi-scale Earth observation synergies and (2) combining regional land cover mapping and biomass prod-ucts. As described in this paper, in situ and local site forest resource assess-ment is being realised in the first phase of the project. Future activities will focus on the integration of these results for

generating a synergy map on regional scale including land cover and biomass classes as a novel parameter set for full ecosystem carbon accounting. The key methodological objectives of ZAPÁS are briefly summarised below.

• Joint exploitation of new (optical and radar) EO data: Earth observa-tion data synergies are one of the key challenges towards the implementa-tion of multi-source earth observa-tion data in trans-boundary forest monitoring systems. There is little practical knowledge about the syn-ergistic use of ESA and Roscosmos

Figure 3. Advanced processing and value-adding of multi-temporal high resolution SAR data (ALOS-Palsar) for forest cover and disturbance mapping in a local-scale test in central Siberia. Summer backscatter and winter coherence images are used for biomass modelling. Using this information, knowledge- and segment-based classification is further used to delineate the forest cover and forest disturbance maps. The example shows the map of the Kazachinskoe test site.

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data (including ESA third-party mis-sions). ZAPÁS presents the poten-tial based on first ALOS-Palsar and Resurs-DK1 data acquisitions of the Krasnoyarsk and Irkutsk test sites.

•Analysis of upscaling and down-scaling effects of integrated data sets and products: Land cover and biomass are becoming more and more available for the Boreal eco-systems. However, the comparability and possibility of combining these products is still lacking. Within the project, related spatial scaling and thematic integration effects (con-straints, potential and limitations) are systematically assessed.

• realisation of cross-validation approaches: Local and regional bio-mass maps are being developed by a number of projects and programmes. Validation of biomass maps is limited by the availability of inventory and in situ data in general or strong tempo-ral mismatches of the data takes. The project presents first results of using up-to-date inventory data surveyed by local forest agencies to be used for validating EO-based biomass maps at local and regional scales.

The results being achieved during the project are presented and disseminated through the bilingual ZAPÁS web portal (http://zapas.uni-jena.de). Acting as the main communication platform of the EU and Russian scientific and stakeholder community on forest resource assess-ment, the ZAPAS web portal will deliver recent reports and scientific outcomes. The abovementioned geo-information products on forest biomass distribution and dynamics are being disseminated through the Siberian Earth System Science Cluster (Sib-ESS-C) available at http://www.sibessc.uni-jena.de.

REFERENCES

  Herold, M., Woodcock, C. E., Loveland, T. R., Townshend, J., Brady, M., Steenmans, C. and Schmullius, C., ‘Land-cover observations as part of a Global Earth Observation System of Systems (GEOSS): Progress, activities, and prospects’, IEEE Systems Journal, 2(3), 2008, pp. 414–423.

  IPCC, B. Metz, O. R. Davidson, P. R. Bosch, R. Dave and L. A. Meyer (eds), Climate change 2007 — Mitigation, Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge UK and New York N, 2007, x, 851 pp. (retrieved June).

  Kasischke, E. S. et al., ‘Initial observations on using SAR to monitor wildfire scars in boreal forests’, International Journal of Remote Sensing, 13(18), 1992, pp. 3495–3501.

  Nilsson, S., Shvidenko, A., Stolbovoi, V., Gluck, M., Jonas, M. and Obersteiner, M., ‘Full carbon account for Russia’, IIASA Interim Report, IR-00-021, 2000.

  Santoro, M., Beer, C., Cartus, O., Schmullius, C., Shvidenko, A., McCallum, I., Wegmüller, U. et al., ‘Retrieval of growing stock volume in boreal forest using hyper-temporal series of Envisat ASAR ScanSAR backscatter measurements’, Remote Sensing of Environment, 115(2), 2010, pp. 490–507.

  Thiel, C., et al., ‘Analysis of multi-temporal land observation at

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C-band’, International Geoscience and Remote Sensing Symposium (IGARSS’09), Cape Town, South Africa, 2009.

  White, J. C. et al., ‘Detection of red attack stage mountain pine beetle infestation with high spatial resolution satellite imagery’, Remote

Sensing of Environment, 96, 2005, pp. 340–351.

  Yatabe, S. M. and Leckie D. G., ‘Clearcut and forest-type discrimination in satellite SAR imagery’, Canadian Journal of Remote Sensing, 21(4), 1995, pp. 456–467.

CHAPTER xx Marine monitoring

CHAPTER 15 AquaMar: Towards sustainable marine and coastal space-based services in support of European water quality… legislation

Authors: Stephane Pierotti, Anna Ruescas, Odile Hembise Fanton d’Andon, Andrey Kurekin, Giulio Ceriola

consortium members: Thales Alenia Space France, France; ACRI-ST SAS, France; Brockmann Consult, Germany; Planetek Italia SRL, Italy; DHI Institut for vand og miljo forening, Denmark; Institut Royal des Sciences Naturelles de Belgique, Belgium; Finnish Environment Institute SYKE/TK/GEO, Finland; Plymouth Marine Laboratory, United Kingdom; Starlab, Spain; Nansen Environmental and Remote Sensing Center, Norway; Danish Meteorological Institute, Denmark; Deutsches Zentrum für Luft- und Raumfahrt eV, Germany; Satellite Oceanographic Consultants Ltd, United Kingdom; Argans, United Kingdom; Water Insight, the Netherlands; Ilmatieteen Laitos, Finland

AbSTRACT

Water quality is one focus of monitor-ing agencies and the public, and it is subject of several European directives: the water framework directive (WFD), the bathing water directive, the marine strategy framework directive (MSFD); as well as regional conventions: OSPAR, Helcom, etc. Yet in order to be effective, the implementation of such legislation

needs to be rigorously monitored. In this respect, and in the context of the GMES initiative, AquaMar aims at pro-viding sustainable space-based down-stream services. The goal is to foster the development of a European capac-ity to provide validated information products, in a standardised and har-monised way, and to support the wide range of service providers involved since a long time in that development.

Remote sensing techniques applied to data images obtained from sen-sors operating in the visible range pro-vide measurements of apparent optical properties of water (e.g. the water leav-ing reflectances). In turn these can be converted into inherent optical proper-ties directly linked to basic biological and physical parameters (transparency, chlo-rophyll-a concentration, suspended mat-ter concentration) and furthermore into higher level indicators (e.g. Percentile 90) through statistical analysis and inte-gration with in situ measurements.

After 2 years of activity, AquaMar is demonstrating concrete progress and interesting scientific results in an area of considerable policy interest.

Among these results, the quality of sat-ellite data products near the coast has been improved in order to provide better

175AQUAMAR: TOWARDS SUSTAINABLE MARINE AND COASTAL SPACE-BASED SERVICES IN SUPPORT OF EUROPEAN WATER QUALITY…

products to support monitoring require-ments of the WFD. Improvements on the pre-processing of coastal water ocean colour data have been achieved; the validation on chlorophyll concen-tration with in situ data has been per-formed and established; a front product has been validated with a potential use for marine protected area monitoring for detection and follow-up of thermal/chl_a fronts and a harmful algal bloom (HAB)-risk classifier has been trained to discriminate certain species of algae that cause problems in some areas. In complement to the development of ser-vices, cross-cutting activities provided generic tools such as a daily chl-a analy-sis at 4 km resolution, considered as the first global chl-a analysis in the world, relevant for climate change studies; high frequency monitoring for coastal areas; a time series tool for service pro-viders and an interface tool providing MyOcean products to all AquaMar ser-vice providers in an automatic way and in a suitable format.

AcHieVed resuLts

The AquaMar project has focused since April 2010 on downstream services turn-ing marine core services products into water quality end-user services. While the current MarCoast 2 project (marine and coastal environmental information services) — funded by the ESA under the GMES services Element programme — does not include any R & D activi-ties, AquaMar aims at developing new service lines that could potentially be included into operational services.

Water quality is one focus of monitor-ing agencies and the public, and it is subject of several European directives: the water framework directive (WFD), the bathing water directive, the marine

strategy framework directive (MSFD), the environmental impact assess-ment (EIA) directive; as well as regional conventions: the Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR), the Helsinki Convention (Helcom), Barcelona Commission (Barcom). Marine water quality is indicated by the physical, chemical and biological characteristics of water in relationship to a set of standards. Water quality standards vary significantly due to dif-ferent environmental conditions, eco-systems and intended human uses. Some measurements can be made on site (temperature, pH, dissolved oxygen, conductivity), in direct con-tact with the water source in question. More complex measurements require a water sample to be collected and pre-served, then analysed in the laboratory. Taking these complex measurements can be expensive. In the past, remote sensing has been proven to provide a contribution to water quality meas-urements limited in terms of number of measurable parameters but signif-icant in terms of spatial span of the observed parameters and in terms of cost–benefit.

Users have expressed their need for products and services which go beyond what has been achieved so far. The basic products delivered from optical remote sensing only partially serve their requirements. The near coastal area, which is the main focus of the WFD, is not properly addressed. The MSFD and WFD require integrated param-eters and indicators which are closer to the assessment criteria. In addi-tion to the WFD and MSFD, remotely sensed products will be made usable for other directives, such as the bath-ing water directive, and for monitoring offshore activities (like aquaculture or

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large infrastructure building). The users require a reliable, long-term assured service instead of timely limited R & D projects.

AquaMar, as the R & D branch of MarCoast, is developing five new services:

• support to the water framework directive (WFD),

• detection of harmful algal blooms (HAB),

• compliance monitoring for large infrastructure projects,

• bathing waters monitoring,

• precision farming aquaculture.

After 2 years of activity, the project is demonstrating concrete progress and interesting scientific results in an area of considerable policy interest.

Support to the water framework directive (WFD)

This activity is improving the quality of satellite data products near the coast

(within 1 nautical mile) in order to provide better products to support monitoring requirements of the WFD. Four activities demonstrated significant results.

• Improvements on the pre-process-ing of coastal water ocean colour data have been achieved: cloud detection has been refined; new flags for differentiating mixed pixels and floating vegetation have been added; a more accurate land–water mask has been achieved.

• The validation on chlorophyll concen-tration with in situ data as well as error estimation of P90 calculation has been performed and validated. An indicator built on the P90 has been developed following the Belgian implementation of the WFD, and time series of chlorophyll_a are also being used as an indicator (searching for algal bloom characteristics like start-ing date, duration, etc.).

•A front product has been validated qualitatively and quantitatively with very good results, with a potential use for marine protected area moni-toring for detection and follow-up of thermal/chl_a fronts.

Figure 1. (a) Original image; (b) standard land/water mask; (c) new land/water mask; (d) Difference L1b standard mask/new water mask (source: Brockmann Consult)

(a)

(c)

(b)

(d)

177AQUAMAR: TOWARDS SUSTAINABLE MARINE AND COASTAL SPACE-BASED SERVICES IN SUPPORT OF EUROPEAN WATER QUALITY…

• Finally, research on the improvement of the chlorophyll detection is carried out by the implementation of the OC5 algorithm and the use of vicari-ous calibration approaches.

Detection of harmful algal blooms (HAB)

Several institutions are involved and are developing algorithms to identify certain species of algae that cause problems in different regions. There are some optical differences between

species identified in the laboratory but, in general, satellite imagery is only able to give results for high concentra-tions of certain species. Classification techniques are also being investigated as an alternative approach. Within each method being studied there is a requirement for in situ measurements to support the detection of the algae and for the validation of algorithms.

A HAB-risk classifier (Kurekin et al. 2011) has been trained to discriminate Karenia mikimotoi HAB in the western

Figure 2. Example of the chlorophyll P90 products as stated in the Belgian law used to monitor the eutrophication state of the Belgian part of the North Sea. The chlorophyll P90 values are classified according to the stated requirements for the 6-year period 2006–11.

178AQUAMAR: TOWARDS SUSTAINABLE MARINE AND COASTAL SPACE-BASED SERVICES IN SUPPORT OF EUROPEAN WATER QUALITY…

(a) (b)

Figure 3. PML weekly HAB risk maps of (a) Karenia mikimotoi algal bloom in the western English Channel in summer 2010 and (b) Phaeocystis globosa bloom in the southern North Sea in spring 2003

English Channel and Phaeocystis glo-bosa HAB in the southern North Sea regions and it has been extended to the use of MERIS (medium resolu-tion imaging spectrometer) products. The methodology has been devel-oped to merge MODIS (moderate res-olution imaging spectroradiometer) and MERIS HAB risk maps and gener-ate a more accurate merged product. Validation of the developed HAB clas-sifier is carried out for the Phaeocystis globosa species and demonstrated good agreement with in situ measure-ments of HAB cell concentration.

Bathing waters monitoring: assessing potential proliferation of cyanobacteria

Cyanobacteria, also called blue-green algae, are photosynthetic micro-organ-isms. They can be found as unicellular individuals (Microcystis, Woronichinia, oelosphaerium, Aphanocapsa,

Merismopedia, Snowella) or colonies (like filamentous Aphanizomenon, Anabaena, Planktothrix, Oscillatoria, Limnothrix, Phormidium). These spe-cies develop in inland waters or fresh, brackish or saline waters with poor renewal, producing bright green, yel-low-brown and red blooms. Three methods have been evaluated to detect cyanobacteria in coastal waters showing that the study of the reflec-tance at 620 nm is probably the most suitable (cyanobacteria characteristic pigments show peeks of absorption at 550 nm (PE) and at 620 nm (PC)). An operational algorithm has been devel-oped that makes use of this absorp-tion band (available on MERIS). Figure 4 shows for the Baltic Sea the compari-son between ACRI-ST method with the model outputs provided by the SMHI on the Baltic Sea (which is used here as a reference). The brown area on the top image indicates anomaly in absorption

179AQUAMAR: TOWARDS SUSTAINABLE MARINE AND COASTAL SPACE-BASED SERVICES IN SUPPORT OF EUROPEAN WATER QUALITY…

of Phycocyanin (APC). It corresponds rather well to zoning performed by using the SMHI algorithm (based on a threshold detection which has been tuned on Baltic waters). The method developed and validated in AquaMar could then be directly used to other marine and continental waters.

A daily chl-a analysis at 4 km resolution

A daily chl-a analysis at 4 km resolution, i.e. cloudless daily fields of chl-a has been developed. The method is based on geostatistical interpolation and clus-ter analysis to basically use the best algorithm for a specific water type (oli-gotrophic, chl-a dominated waters and coastal waters). The final purpose is to provide to the user community cloudless continuous fields of chl-a. The method will be published soon and the resulting product is the first global, multi-sensors

and multi-algorithms, chl-a analysis in the world. The following hot topics in science should benefit from time series of the chl-a analysis:

• climate change studies: the estimated trends from the analysis are less biased than trends estimated from the monthly means usually used;

• high frequency monitoring for coastal areas for the WFD directives: the analysed data is directly com-parable in term of frequency to the buoy measurements; the continuous distribution in time of the chl-a fields ensures an unbiased estimation of the P90 of the chl-a used to esti-mate the eutrophication status;

• direct comparison with bio-geo-chemical model outputs for valida-tion (or for assimilation as forcing condition).

Figure 4. (a) ACRI-ST zoning of positive phycocyanin absorption; (b) threshold classification (SMHI)

The Figure 5 shows a comparison between the daily simple chl-a merge of MODIS–MERIS for the 20040420 and the corresponding chl-a analysis. Fifteen MODIS images and 15 MERIS images are used to estimate the daily chl-a analysis. The increase of cover-age is from about 25 % for the sim-ple merge of MERIS and MODIS to

97% of the water pixels for the chl-a analysis.

Cross-cutting activities

As support of the development of AquaMar and MarCoast services, sev-eral software tools have been devel-oped and are hosted on a web platform

(b)(a)

180AQUAMAR: TOWARDS SUSTAINABLE MARINE AND COASTAL SPACE-BASED SERVICES IN SUPPORT OF EUROPEAN WATER QUALITY…

Figure 5. Comparison between the daily merge of chl-a (MODIS & MERIS) and the analysis for the 20080420 (© ACRI-ST).

developed by the project, and mainly based on open source solutions. This AquaMar information system platform provides specific functions for service providers and end-users, such as:

• a service provider tool: a techni-cal tool allowing to directly fetch MyOcean data for further processing;

• service validation tools: to assist the validation bureau in analysing the validation reports, and to provide users with validation assessments;

• a metadata editor: allowing service providers to define their service’s metadata in a standardised way;

• a service and product catalogue: to retrieve products in a harmonised and standardised way

•A time series tool has been also developed as a graphical extension to BEAM VISAT. Its purpose is to foster validation and quality improvement by making it possible to investigate time series for specific EO variables. The time series tool allows the user to load and display series of satellite data of different dates for analys-ing the behaviour of several EO var-iables (e.g. total suspended matter,

chlorophyll_a) along a timeline. It also allows the user to import in situ data for comparing them with the satellite data for validation purposes.

• To facilitate access to MyOcean, pro-viding an unprecedented opportunity to access a series of core products required to deploy AquaMar services, an interface layer has been devel-oped, providing MyOcean products to all AquaMar service providers in an automatic way in a suitable for-mat and based on relevant delivery requirements.

• Finally, the process for the valida-tion of AquaMar services has been defined within the ESA MarCoast pro-ject. Service providers can now val-idate their services by comparison with in situ data and finally compile a validation report. Users and a ded-icated validation bureau review and assess the services based on these reports as well as on users’ experi-ences during service delivery. At the end of the process, a comprehensive validation report is compiled com-prising: ‘Service provider validation reports’, ‘User assessments, valida-tion bureau reviews’ and ‘Summary and conclusions’ compiled by the validation bureau.

181AQUAMAR: TOWARDS SUSTAINABLE MARINE AND COASTAL SPACE-BASED SERVICES IN SUPPORT OF EUROPEAN WATER QUALITY…

Figure 6. AquaMar/MarCoast information system portal

CONCLUSIONS

After 2 years of activity, the project is demonstrating concrete progress and interesting scientific results in an area of considerable policy interest.

To support the service validation process, initially defined within the MarCoast project, the validation meth-odology has been improved and imple-mented in the AquaMar information system. This will allow in the future that the users and a dedicated valida-tion bureau will be able to review and assess the services, based on valida-tion reports as well as on users’ expe-riences during service delivery.

The first multi-sensors and multi-algo-rithms daily Chl-a analysis at global scale will be distributed to the end-users using the AquaMar/MarCoast facilities, providing a real improvement of spatio-temporal coverage to the users.

Developments related to the support of WFD demonstrated significant results, in particular through the improvements on the pre-processing of coastal water ocean colour data, the validation on chlorophyll concentration with in situ data, and the creation of an indicator build on the P90 following the Belgian implementation of the WFD. A front product showed very good results with a potential use for marine protected area monitoring for detection and fol-low-up of thermal/chl_a fronts.

A new algorithm for detecting the potential proliferation of cyanobac-teria in a coastal area has been vali-dated and shall be applied to support the implementation of the bathing water directive — for marine and fresh waters.

As one of the main users of MyOcean services, AquaMar is also contributing to the marine core service improvement

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thanks to feedback received from the AquaMar service providers testing and validating downstream services with end-users all over Europe.

Cooperation with several other FP7 marine projects1 has been established, giving access to AquaMar tools and validation processes with the objective of strengthening and sharing relevant R & D results.

REFERENCES

  Ruddick, K., Park, Y. and Nechad, B., ‘MERIS imagery of Belgian coastal waters: Mapping of suspended particulate matter and chlorophyll-A’, in H. Lacoste (ed.), Proceedings of MERIS User Workshop (ESA SP-549), ESA-ESRIN, Frascati, Italy, 10–13 November 2003 (published on CD-ROM), p. 32.1.

1 MarCoast, CoBios, OSS2015, SeaU, ASIMUTH. The close collaboration with MarCoast is offering AquaMar a wide range of European end-users benefiting at the end of AquaMar developments and promising results, expected in particular from the use of future GMES Sentinel satellites in 2014.

  Saulquin, B., Gohin, F. and Garrello, R., ‘Regional objective analysis for merging high-resolution MERIS, MODIS/Aqua, and SeaWiFS chlorophyll-a data from 1998 to 2008 on the European Atlantic Shelf’, IEEE Transactions on Geoscience and Remote Sensing, 49(1), 2011, pp. 143–154. Publisher’s official version: http://dx.doi.org/10.1109/TGRS.2010.2052813, Open Access version: http://archimer.ifremer.fr/doc/00029/14063/.

  Van der Zande, D., Lacroix, G., Desmit, X. and Ruddick, K., 2012. ‘Impact of irregular sampling by MERIS on eutrophication monitoring products for WFD and MSFD applications’, Proceedings of the sixth EuroGOOS Conference on Sustainable Operational Oceanography, 4–6 October, Sopot, Poland, 2012 (submitted).

CHAPTER 16

Authors: Marcos Mateus, Julie Maguire, Hilda de Pablo, Kieran Lyons, Manuel Ruiz Villarreal, Caroline Cusack, Keith Davidson

consortium Members: Daithi O’Murchu Marine Research Station, Ireland; Marine Institute, Ireland; Institut français de recherche pour l’exploitation de la mer, France; Instituto Español de Oceanografía, Spain; Scottish Association for Marine Science, United Kingdom; Instituto Superior Técnico, Portugal; Instituto Nacional de Recursos Biológicos/Instituto de Investigação das Pescas e do Mar, Portugal; Hocer, France; Nowcasting International Ltd, Ireland; Starlab, Spain; Numerics Warehouse Ltd, Ireland

AbSTRACT

The nature of the problem of harmful algal blooms (HABs) has changed sig-nificantly over recent decades, with a substantial increase in the number of occurrences, the types of resources affected and the resulting economic losses (Hallegraeff, 1993). These blooms are triggered and controlled by a complex interplay of physical, bio-logical, geological and chemical pro-cesses. ASIMUTH (http://www.asimuth.

eu) aims to develop forecasting capa-bilities based on mathematical mod-els to warn of impending HABs, thus providing an operational tool for those responsible for the management of coastal resources.

The main objectives of ASIMUTH include: (1) identification of key past HAB events for reanalysis and for training of the modelling system; (2) incorporation of the GMES marine core services with the above selected events to tune the system and move towards an opera-tional model for forecasting events; (3) design of regional model systems and delivery of nowcasts for specific HABs, using location information and remotely sensed data; (4) population of an HAB-distributed decision support system (HAB-specific thematic assembly cen-tre) from relevant data; (5) provision of expert interpretation of the availa-ble data by way of a web portal on a periodic basis and, depending on risk, issuing this assessment via a warning system to end users.

The main outcomes expected for this project are: (1) demonstration through pilot tests based both on modelled data and on real events when possible; (2) a financially self-sustainable fore-casting system for HABs; (3) provision

ASIMUTH: applied simulations and integrated modelling for the understanding of toxic and harmful algal blooms

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of a business model for the opera-tional supply of the product, contrib-uting directly to the sustainability and competitiveness of European value-adding services; (4) examination of the impact of this service in a socio-economic context, particularly in finan-cially depressed peripheral regions where aquaculture has frequently cre-ated employment and where jobs have historically been lost due to mech-anisation of agriculture and fisher-ies; (5) demonstration of the mutual dependency of technology, organisa-tional dynamics and societal issues as well as related legal/economic aspects in different sectors; (6) establishment of close collaboration with represent-ative user communities throughout Europe (oceanographers, modellers, HAB expert biologists, fish/shellfish farmers, processors, consumers and regulators).

AcHieVed resuLts

Phytoplankton form the base of the aquatic food chain. In marine waters, there are approximately 4 000 spe-cies of phytoplankton, most of which are benign. However, some species are ‘harmful’, and may impact on human health through the production of a range of potent natural biotoxins, or damage the economy through their negative impact on fish or shellfish farming or other human use of ecosys-tem services. Generally, but not exclu-sively, human health is threatened by low biomass HABs (≈ few hundred to thousands of cells L-1), the biotoxins produced by these species being con-centrated by filter feeding shellfish and other organisms that may be sub-sequently ingested by humans. High biomass HABs can result in oxygen depletion when the bloom sinks and is

decomposed by bacteria in the bottom water. Farmed fish may also be killed by smothering of the gills due to phy-toplankton mucus production or gill abrasion by phytoplankton spines.

HABs therefore pose serious con-straints to the sustainable develop-ment of coastal areas. Despite being difficult to quantify, the estimated total welfare cost in Europe (public health, commercial fishery, recreation and tourism, monitoring and man-agement) of HAB-related events each year is > EUR 800 million (Lorentzen and Pettersson, 2005). The economic cost of the Karenia blooms of 2005 and 2006 which resulted in mass mor-talities of caged fish in the shelf seas of the north-east Atlantic remains to be quantified but has forced the clo-sure of some marine finfish farms (Silke et al., 2005; Davidson et al., 2009). The presence of diarrhetic shellfish poisoning (DSP) toxins from Dinophysis spp. routinely cause pro-longed shellfish closures that can last for months in Portugal, Spain, France and Ireland (Escalera et al., 2006; Trainer et al., 2010). Autumn blooms of Gymnodinium catenatum (para-lytic shellfish poisoning toxins) can be devastating to mussel aquaculture and natural shellfish banks production in north-west Iberia. For example, in 2005, closures lasted several months including through the winter shellfish harvest season. A substantial part of local famers’ annual income depends on these winter markets (Escalera et al., 2010). Such incidents are sporadic, largely unpredictable and may seri-ously disrupt production plans of fish and shellfish farms.

The importance of the European aqua-culture industry to peripheral regions in Europe cannot be overstated. Since the

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European industry is more heavily reg-ulated than most of their competitors, it is essential that production schedules are maintained to secure profitability. HAB-generated biotoxins result in tem-porary closures of shellfish harvesting areas, with subsequent loss of income. More sustained closures can result in complete production losses, as fully grown shellfish (particularly mussels) can become too heavy for their grow-ing structures and will eventually fall off particularly during winter storms. If an early warning system were avail-able production schedules could be adapted to suit each HAB situation.

A difficulty in HAB forecasting is the enigmatic nature of bloom initiation. Nevertheless, predicting and monitor-ing HAB is central to developing pro-active strategies to ameliorate their

impact on human health and the eco-nomics of coastal communities. In many regions, particularly in Europe, at the moment there is no warning when a bloom will occur.

The main outcome of ASIMUTH is the development of forecasting capa-bilities to warn of impending HABs (Figure 1). HABs can be generated by a very diverse range of causative organ-isms, with different bloom dynam-ics and type of impacts, so their study calls for a coordinated scientific and management approach. The steps to achieve this include a series of scien-tific and technical objectives which will enable the modelling of physical–bio-logical interactions leading to the fore-casting of toxin events, fish mortalities or ecological disruption associated with HAB.

Figure 1. Diagram of ASIMUTH main methodologies and outcomes. See the text for more details on the complementary characteristic of the methodologies and their contribution to the project’s main outcome, namely the warning system for coastal resource managers, fishermen, aquaculture operators and public health officials.

189ASIMUTH: APPLIED SIMULATIONS AND INTEGRATED MODELLING FOR THE UNDERSTANDING OF TOXIC AND HARMFUL ALGAL BLOOMS

Combining methodologies

Our understanding of the biological, chemical and physical processes that result in HABs in the ocean depends on the scope and scale of our obser-vations. When adequate observational coverage in time and space is lack-ing, we can supplement our knowledge through mathematical models that simulate the oceanographic conditions and their impact on the ecosystem.

Monitoring programmes for HABs are typically reactive, safeguarding human health through the closure of aqua-culture areas once harmful species or their toxins are detected, but usu-ally without means for advance warn-ing of these events. Given this, the development of algal forecasting sys-tems would be of great use in guid-ing traditional monitoring programmes and providing a proactive means for responding to HABs.

Forecasting systems require near real-time observational capabilities and hydrodynamic/biological mod-els designed to run in forecast mode. ASIMUTH is therefore designed to make use of the outputs (satellite, in-situ and model products) from the GMES marine core services (MCS) for launching a downstream service in HAB forecast. The ASIMUTH expert system will pro-duce HAB bulletins at various sites along Europe’s Atlantic coast based on model forecasts, satellite imagery and in situ networks that the MCS and intermedi-ate users (the ASIMUTH consortium) will provide, combined with an array of bio-logical samples collected and the knowl-edge provided by HAB biology experts. The combination of these methodolo-gies has previously been shown to pro-vide an effective means to predict HABs (Stumpf et al., 2009).

Remote sensing

Since the early days of ocean model-ling, remotely sensed data has always played a fundamental role in the val-idation of model results. Today, more than ever, this link between satellite imagery and model predictions is still valid (Figure 2) and is at the core of the ASIMUTH modelling approach.

Remote sensing for the detection of surface pigments or temperature sig-natures has been utilised for HAB detec-tion over the past 30 years. During this period there has been much discussion of satellites being able to track surface algal blooms, resulting in the produc-tion of some services that purport to be HAB nowcasts and forecasts. Near surface high chlorophyll a (Chla) zones, frequently associated with HABs like the Karenia spp. blooms, can be eas-ily detected and tracked by aircraft and satellite remote sensing techniques. However, subsurface HAB blooms like the Dinophysis spp. blooms can-not be detected directly with satellite remote sensing. Such blooms can per-sist in the water for weeks unnoticed and appear as sudden events without early warning. Understanding the driv-ers behind these biological phenomena in the ocean therefore requires a more complex approach than simple remote sensing, though there is some merit in using satellite-derived Chla images to delineate high-biomass, near-surface algal blooms.

Ocean colour satellites provide large synoptic sampling, impossible to col-lect with standard in situ techniques. However, persistent cloud cover can potentially cause data gaps in passive, remotely sensed data. Nevertheless, advances in optical instrumentation may provide rapid spatial coverage for

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HABs and, coupled with data-assim-ilative modelling, will provide the

necessary components for building an HAB detection and forecasting system.

Figure 2. Comparison of remote sensing data with model results. Example of a validation report of a MOHID forecast model for the Iberia domain.

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Model applications

Decades of laboratory and field research has significantly increased our knowledge on the ecological inter-relationships of HAB communities. This enables the identification of some basic bloom triggers and contributes to the construction of bloom models that eventually will lead to the forecast of bloom initiation.

HAB forecasts need to factor in changes in both water column struc-ture (including likely areas where HAB species will be retained) and transport pathways in order for such a forecast to be realistic. The forecast should also include all available biotoxin, phy-toplankton count and bioassay data to support the model forecast and sat-ellite imagery of a bloom. Current bloom locations, future bloom loca-tions and areas of impacts are critical components of these forecasts. From a management perspective, a major concern is also the ability to predict where a bloom is likely to be trans-ported over a few days from its last known location.

A stepwise approach will be followed to achieve the desired HAB forecast capa-bility in ASIMUTH model simulations. The ability to forecast where a feature is likely to be transported is a critical step towards developing an ecological forecasting system. Even a rudimen-tary forecast system can be useful and could be used as a baseline for future improvements (Velo-Suárez et al., 2010; Wynne et al., 2011). Once a fea-ture or algal bloom has been identified in imagery, it is now possible to track bloom position, thus compensating for missing imagery, and creating a now-cast and forecast for potential impacted areas (see the example in Figure 3).

The assessment of skill of the opera-tional forecasts depends on the ability of the model to forecast conditions at an appropriate resolution, within the constraints of the available valida-tion data. Coupling of a hydrodynamic model and routine satellite imagery will allow visualisation of forecast bloom movement and, at the same time, validate the model or provide insightful clues to tune the modelling system.

The outcome

There is now scope to provide a worth-while HAB forecasting downstream service to the aquaculture industry using the combined model forecasts, satellite imagery and in situ net-works that the MCS and intermediate users will provide, combined with an the array of biological samples col-lected in monitoring programmes and the expertise provided by HAB biol-ogy experts. Through ASIMUTH, sci-entists and industry in five European countries will roll out the first realistic HAB forecasting capability as a GMES downstream service to users, in this case the European aquaculture indus-try along Europe’s Atlantic margin. The early warning of severe blooms will allow fish farmers and shellfish farmers to adapt their culture and harvesting practices in time, in order to reduce potential losses and in turn increase their productivity.

For the model results to be useful in a management context, they need to be run in near real time and have a mechanism in place for rapid dissem-ination of forecasts and nowcasts. A forecast could become available to the research and management com-munity in the form of a weekly or biweekly report.

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Figure 3. Model forecast (MOHID–PCOMS) for potential impacted areas by the tracking of bloom position. Simulation made in a preliminary stage of ASIMUTH for the first record of Ostreopsis proliferations in the continental Portuguese coast. The forecast was used for the decision-making process that led to the closure of several beaches in a major tourist spot in Portugal (panel in the lower-right side; image retrieved from a national newspaper)

CONCLUSIONS

Reasons for the emergent inter-est in HABs are abundant, includ-ing concerns associated with human health, adverse effects on biological resources, economic losses attributed to recreation, tourism and seafood-related industries, and the cost of maintaining public advisory services and monitoring programmes for shell-fish toxins and water quality.

In the current economic climate, it is imperative that the activities in this domain are not wasteful or a repeti-tion of previous efforts. New insights need to be gained in the study of HAB

formation and impact on human activ-ities, and the new approaches need to bring added value in terms of meth-odologies and results.

ASIMUTH is the first step to develop short-term HAB alert systems for Atlantic Europe. This will be achieved using information on the most cur-rent marine condition (weather, water characteristics, toxicity, harmful algal presence, etc.) combined with high res-olution local numerical predictions.

This integrated, multidisciplinary, trans-boundary approach to the study of HAB developed during ASIMUTH will lead to a better understanding of the

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physical, chemical and ecological fac-tors controlling these blooms, as well as their impact on human activities. The outcome will be an appropriate alert system for an effective manage-ment of areas that are usually associ-ated with HAB events and where these episodes may have a more significant negative impact on human activities.

Specifically for the aquaculture indus-try, the information provided will enable farmers to adapt their work-ing practices in time to prevent mor-talities in finfish farms and/or manage their shellfish harvest more effec-tively. This will lead to the ‘improve-ment of European competitiveness and sustainable development’ in this area.

REFERENCES

Davidson, K., Miller, P. I., Wilding, T., Shutler, J., Bresnan, E., Kennington, K. and Swan, S., ‘A large and prolonged bloom of Karenia mikimotoi in Scottish waters in 2006’, Harmful Algae 8, 2009, pp. 349–361.

Escalera, L., Reguera, B., Moita, T., Pazos, Y., Cerejo, M., Cabanas, J. M. and Ruiz-Villarreal, M., ‘Bloom dynamics of Dinophysis acuta in an upwelling system: in situ growth versus transport’, Harmful Algae, 9(3), 2010, pp. 312–322.

Escalera, L., Reguera, B., Pazos, Y., Morono, A. and Cabanas, J. M., ‘Are different species of Dinophysis selected by climatological conditions?’, African Journal of Marine Science, 28(2), 2006, pp. 283–288.

Hallegraeff, G. M., ‘A review of harmful algae blooms and their apparent global increase’, Phycologia, 32, 1993, pp. 79–99.

Lorentzen, T. and Pettersson L. H., How to estimate costs of harmful algal blooms — Economic impacts on wild fisheries, aquaculture and commercial tourism, 2005, Report Deliverable D.10, SNF Report No 26/05, Project No 5305: HABILE online at: http://brage.bibsys.no/nhh/bitstream/URN:NBN:no-bibsys_brage_24469/1/R26_05.pdf

Silke, J., O’Beirn, F. and Cronin, M., ‘Karenia mikimotoi: an exceptional dinoflagellate bloom in western Irish waters, summer 2005’, Marine Environment and Health Series, 21, 2005, Marine Institute, Galway, Ireland, 2005, 44 pp., online at http://www.marine.ie.

Stumpf, R. P., Tomlinson, M. C., Calkins, J. A., Kirkpatrick, B., Fisher, K., Nierenberg, K., Currier, R. and Wynne T. T., ‘Skill assessment for an operational algal bloom forecast system’, Journal of Marine Systems, 76(1–2), 2009, pp. 151–161.

Trainer, V. L., Pitcher, G. C., Reguera, B. and Smayda, T. J., ‘The distribution and impacts of harmful algal bloom species in eastern boundary upwelling systems’, Progress in Oceanography, 85(1–2), 2010, pp. 33–52.

Velo-Suárez, L., Reguera, B., González-Gil, S., Lunven, M., Lazure, P., Nézan, E. and Gentien, P., ‘Application of a 3D Lagrangian model to explain the decline of a Dinophysis acuminata bloom in the

194ASIMUTH: APPLIED SIMULATIONS AND INTEGRATED MODELLING FOR THE UNDERSTANDING OF TOXIC AND HARMFUL ALGAL BLOOMS

Bay of Biscay’, Journal of Marine Systems, 83, 2010, pp. 242–252.

Wynne, T. T., Stumpf, R. P., Tomlinson, M. C., Schwab, D. J., Watabayashi, G. Y. and

Christensen, J. D., ‘Estimating cyanobacterial bloom transport by coupling remotely sensed imagery and a hydrodynamic model’, Ecological Applications, 21(7), 2011, pp. 2709–2721.

CHAPTER 17

Author: Gerard Margarit

consortium members: GMV Arerospace and Defence SA, Spain; eOsphere Limited, United Kingdom; Aratos Technologies SA, Greece; Joint Research Centre, the European Union; Universitat Politèctica de Catalunya, Spain; ZRC SAZU, Slovenia; GMVIS Skysoft, Portugal; TNO, the Netherlands; NURC, International; Thales Communications SA, France; Fraunhofer FKIE, Germany; ACS SpA, Italy; Guardia Civil, Spain; Active Space Technologies, Germany; Aerospace Innovation, Germany

AbSTRACT

This paper details the techniques and technologies adopted by NEREIDS to tackle the scientific challenges that maritime surveillance is currently fac-ing. Far from being constrained to the scientific world, the need to find an operational solution will force the consortium to evolve the ideas up to the practical level. NEREIDS is con-ceived to provide an integrated vision of maritime policy and maritime sur-veillance by designing a system of systems capable of handling heter-ogeneous maritime domains. These domains are illegal trafficking, illegal immigration, fisheries control, border surveillance and traffic monitoring.

The NEREIDS objective is completely aligned with the aims of the Eurosur programme: ‘Awareness in the mari-time domain requires monitoring the compliance of all activities, detecting with the help of surveillance and ship reporting system anomalies that may signal illegal (security threats) acts and generating intelligence that ena-bles law enforcement authorities to stop unlawful entry into the EU area’. The benefits for users are significant as the same platform can be used to perform diverse applications (coastal monitoring, target tracking, buffer monitoring …). The key scientific ele-ments tackled in NEREIDS are:

— to define an open architecture simplifying the process of defining, implementing, testing new Earth observation-based capabilities for maritime surveillance; ICT analysis will be added in spite of ensuring the proper security, reliability and resources of such type of system;

— to investigate new SAR and opti-cal satellite automatic processing capabilities; a particular empha-sis will be placed on improving the reliability of detecting small vessels;

— new collaborative and non-col-laborative data fusion techniques with route tracking and reckoning;

NEREIDS: New service capabilities for integrated and advanced maritime surveillance

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— to better understand maritime operational activities by analysing maritime anomalies;

— to exploit the enhanced capa-bilities (resolution, polarisation) of new sensors such as COSMO-SkyMed, TerraSAR, and Radarsat2;

— advanced displaying of results with a 4D approach.

AcHieVed resuLts

Requirements analysis

The design of a maritime surveillance system, which in the case of NEREIDS is ambitious, shall be linked to an engi-neering analysis task of user require-ments. As the user community is very complex and the nature and strategic approaches of each entity is diverse, requirement gathering becomes a challenging task. While there are users covering intensive surveillance cam-paigns focused on short durations of time, there are others with continuous monitoring mandates that force unin-terruptible control activities.

Nowadays, the picture of maritime sur-veillance and monitoring at European level is becoming less complex as the strategy of a joint exploitation of the available resources and the deploy-ment of interoperable nets is being embraced. This idea has been crystal-lised in the so-called integrated mari-time policy (IMP) (BS-CONOPS, 2011), which fixes the way that Member States have to face maritime surveil-lance. The need to work together has forced the ruling of European initia-tives (Eurosur, PTMARSUR) and agen-cies (Frontex, EMSA, EUSC).

In the framework of NEREIDS, a con-sultation process with different user communities has resulted in the fol-lowing list of requirements:

— delivery time: nominal < 3 h, rapid response < 1 h.

— lead time: nominal ~ 1 day, rapid response < 17 h.

— spatial resolution: nominal 3 m (1 m shall be needed for detecting targets ~ 5 m).

— coverage: nominal 100 × 100 km2, 10 × 10 km2 when VHR data is needed.

Note that these numbers provide a nominal value, which can be modified in specific scenarios.

Service architecture

In order to meet user requirements, NEREIDS has conceived an architecture based on the service-oriented architec-ture (SOA) paradigm (due to the lim-ited space, the figure is not attached, please see (NEREIDS project, 2011). It permits managing distributed capa-bilities that may be under the control of different ownership domains and implemented using various technology stacks. For NEREIDS, the SOA-based architecture will provide:

— rapid and independent ingestion of diverse data streams, as this step can be migrated to the data pro-vider side, plus some basic pro-cessing functions; thus, the data reaching the system is preformat-ted into a common standard;

— a secure and customisable user interface with own visualisation

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skills and service publishing to interconnect with other opera-tional services (EMSA’s CSN and SSN, Eurosur);

— large flexibility for transparently adding external functions and plug-ins; they will be focused to develop added-value func-tionalities (data fusion, decision making …);

— a system that can be operated as a geographically distributed ser-vice provider network where each provider will join the network with its own resources. So, part of the system components will not be centralised in the same location. Management (SOA Service Bus, security and management serv-ers …), data repository and visuali-sation will be the main elements initially envisaged for building the system kernel. The algorithms run at the data provider side will be invisible to the system and only the results will be managed.

Advanced EO image processing

A key element of the NEREIDS system iconcerns the algorithms tackling image processing. As Earth observation (EO) imagery will be one of the most impor-tant supports, much attention must be paid to this issue. Right now, the state of the art shows mature procedures that can detect most of the metallic targets on the high seas (Crisp, 2004). But prob-lems arise when the targets of interest are small, wood-made and sailing close to the coast. In addition, atmospheric influence is also important with regard to optical imagery.

NEREIDS gathers the know-how and enough experience to tackle the main

limitations in ship detection. The con-sortium has developed algorithms based on wavelet processing, polari-metric and/or interferometric analy-sis, super-resolution techniques and image segmentation. The first three are suited to work with SAR images while the latter work with optical ones. Wavelet processing works with the concept of scene texture. The infor-mation texture for ships, sea and land in SAR images is different and, then, a proper mathematical manipulation permits a clear isolation of the targets in the scene (Margarit et al., 2009). Eosphere has developed a new detec-tion methodology that makes novel use of the polarimetric representation of targets. The algorithm is based on a perturbation analysis in the target space that was originally developed for land targets. In its current form the algorithm can be considered as a negative filter focused on the sea. Single-pass interferometry can also be useful to detect small targets on the sea by overlapping intensity and coherence maps. Another alternative recently presented proposes the use of spectral estimators (Capon, 1969) to locate punctual complex targets in SAR images. The idea consists of applying azimuth defocusing to refo-cus the image based on the spectral estimation theory.

Regarding optical image process-ing, segmentation is the most suit-able current option. There are two options: (1) segmentation based on morphological operators (Soille, 2004); (2) segmentation based on region-growing (Corbane et al., 2008). Both can adopt geodesic active con-tours (Caselles et al., 1997) to bet-ter delimitate object boundaries RD. Some examples of ship detection are depicted in Figure 1.

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Figure 1. Examples of ship detection for the algorithms adopted in NEREIDS. Left corresponds to wavelet processing where a small less-reflective target is detected. Right correspond to image segmentation based on morphological operators (source: GMV).

Figure 2. Examples of ship categorisation for the algorithms adopted in NEREIDS. This corresponds to the e-cognition based solution (source: Active Space, NEREIDS Consortium).

Ship classification is also a matter of interest and the NEREIDS consortium addresses this with different options for both SAR and optical images. In the SAR world, methodologies exploit-ing single- and multi-channel SAR images are adopted. GMV has pro-posed a SAR classification algorithm that uses histogram-based segmen-tation and fuzzy-logic based deci-sion rules (Margarit and Tabasco, 2011). In the past, UPC proposed a methodology exploiting single-pass

polarimetric and interferometric SAR data (Margarit, 2007). In the opti-cal side, object-oriented categorisa-tion is gaining significant popularity. E-cognition solutions are appearing as a very promising option. Exampless are illustrated in Figure 2.

Added-value processing

The processing applied to images can be complemented with added-value capabilities. Examples are data fusion

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with collaborative sensors, track delineation and reckoning (estimation) based on ancillary information, anom-aly detection and decision support.

For the first topic, the NEREIDS con-sortium has extensive experience in data fusion, not only from the theo-retical perspective, but also from the practical point of view. Probably the most relevant result is the implica-tion of GMV in the development of the data fusion module that EMSA will use in its MarSurv system. The main fea-tures are (Margarit, 2011):

— independence from the sce-nario conditions (density of data streams, geographical location, targets to track, formats of data sources, timeline…);

— track delineation and reckoning features;

— correlation features (SAR and collaborative);

— data filtering and consistency checker to build realistic tracks;

First tests have been conducted with Frontex and Eunavfor with positive feedback. An improvement phase is currently underway with the aim of enhancing processing time and added-value features. One of these consists of including ancillary information in track reckoning, such as coastlines, bathyme-try and corridor lanes. The idea is based on the assumption that these ancillary items are constraints that drive how the track is built and reckoned. Figure 3 shows an example of the output that DFM provides. Large volumes of data are consistently consolidated into tracks with specific macro-scale features (speed, route …).

Regarding anomaly detection, TNO has developed studies aimed at evaluat-ing the behaviour of vessels in specific areas of interest. The results are maps of most probable corridors where the vessels can cruise into. This would be the base for introducing intelligence into data fusion and decision-making sys-tems. Certainly, this information would allow more accurate track estimations as well as more accurate tactical and strategic operations conducted at sea.

Figure 3. Example of Data Fusion of SAR + AIS + LRIT streams (up) and of track reckoning taking corridor lanes into account (down) (source: GMV).

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CONCLUSIONS

The members of the NEREIDS consor-tium have competitive knowledge and experience for properly covering the main goals of the project. Theoretical studies conducted in the past assure the success in developing the scien-tific challenges that maritime surveil-lance is constantly faced with. Detection of small targets with low reflectivity, detection with adverse meteorological conditions, robust target categorisation, advanced data fusion with added-value features or anomaly detection and analysis are examples of issues that must be resolved during project lifetime. One of the key challenges is to trans-late the diverse theoretical algorithms into an operational solution. To this end, suitable system architecture is defined. Among the different options, the SOA-based solution appears to be efficient for working with geographically distributed and heterogeneous resources. This is the case of maritime surveillance where data providers have their own systems that can develop basic data pre-pro-cessing and can arrange the opportu-nity and acquisition plan of the different EO assets. In addition, different entities collaborate with their know-how to per-form specific applications and features. With SOA architectures, the integration of such external plug-ins is straightfor-ward and only needs the adoption of specific libraries to reach the resources managed by the system.

In NEREIDS, the main plug-ins would be devoted to:

— target detection in SAR (wave-let, polarimetry, interferometry, spectral estimators) and optical images (segmentation, geodesic active contours);

— target categorisation in SAR (fuzzy logic, polarimetry, interferometry) and optical images (object-ori-ented segmentation);

— data fusion with independent and non-independent data streams;

— target delineation and reckoning subjected to constraints (coastline, bathymetry, corridor lanes …);

— anomaly detection and analysis to support decision making tools;

— advanced visualisation with open-source standards for publishing and disseminating the layers of information. The concept of multi-tier with OGC, WFS, WMS and CSW standards is adopted. The advan-tages of the new specifications contained within the new HTML 5 standard will be analysed. They foresee the usage of a type of OpenGL libraries for web brows-ers that permit handling each element within a GIS (ship icon, track …) as an independent object. This makes refreshing easier with one object being independent from the others. Certainly, the whole view does not have to be refreshed when a single icon is updated.

It should be noted that goals set in NEREIDS are ambitious, but needed to make an important step forward in the usage of EO resources for maritime surveillance. This would improve mis-sion exploitation, increase the social impact of such missions and lead to the proposal of new missions with more advanced capabilities.

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REFERENCES

  BS-CONOPS, Application of surveillance tools to border surveillance ‘Concept of Operations’, BS-CONOPS_V1.4.0.07_ 2011, 09-2011.

  Capon, J., ‘High-resolution frequency-wavenumber spectrum analysis’, Proceedings of the IEEE Transactions on Image Processing, 57(8), 1969, pp. 1408–1418.

  Caselles, V., Kimmel, R. and Sapiro, G., ‘On geodesic active contours’, Int. J. Comput. Vis., 22(1), 1997, pp. 61–79.

  Corbane, C., Marre, F. and Petit, M., ‘Using SPOT-5 HRG data in panchromatic mode for operational detection of small ships in tropical area’, Sensors, 8, 2008, pp. 2959–2973.

  Crisp, D. J., ‘‘The state-of-the-art in ship detection in synthetic aperture radar imagery’, Australian Government, Department of Defence, Intelligence, Surveillance and Reconnaissance Division, DSTO–RR–0272, 2004.

  Margarit, G., ‘Maritime applications of SAR polarimetry’, PhD dissertation, UPC, 2007.

  Margarit, G., ‘GMV data fusion’, 1st C-SIGMA ESA workshop, June 2011, Frascatti, Italy.

  Margarit, G., Barba, J. A. and Tabasco, A., ‘Operational ship monitoring system based on synthetic aperture radar processing’, Special issue on microwave remote sensing, Remote sensors, 1(3), 2009, pp. 375–392.

  Margarit, G. and Tabasco, A., ‘Ship classification in single-pol SAR images based on fuzzy logic’, IEEE Transactions on Geoscience and Remote Sensing, 49(8), 2011, pp. 3129–3138.

  NEREIDS project, NEREIDS architecture D-120, Deliverable NEREIDS project, 09-2011.

  Soille, P., Morphological image analysis —Principles and applications, Springer-Verlag, Berlin, 2004.

CHAPTER 18

Authors: Fulvia Verzegnassi, Sergio Barbarossa, Federico Letterio, Eric Barz, John Loizou, Manuele Barbieri, Patrizio Nini

consortium members: Thales Alenia Space Italia, Italy; DIIET, Italy; Deimos Space, Spain; Universitat Politècnica de Catalunya, Spain; VEGA Space Ltd, UK; D’Appolonia, Italy; Sistematica SpA, Italy

AbSTRACT

In the maritime security domain sev-eral GMES project efforts have striven to identify and demonstrate space-based services for certain appointed authorities — at both national and regional level — by relying on the existing satellite and in situ capabili-ties. A general concern has been raised by the user community: how can users rely on GMES services if their perfor-mance is hardly assessed against oper-ational scenarios? The critical nature of the information needs required by the users — e.g. early warning capabilities for implementing an effective response to illegal actions at sea such as ille-gal migration, asymmetric terrorism threats and piracy attacks — does not allow a clear answer. In the last 5 to 10 years the number of demonstrated space-based services for maritime sur-veillance has already achieved suffi-cient maturity for drawing conclusions. One of the latest LIMES demonstration trials has recorded an astonishing num-ber of missed space data acquisitions

during the ship’s route in the Somali area. Neglecting the contextual causes for the recorded service quality level (data acquisition conflicts, space data quality, processing bugs or low ser-vice priority), it is straightforward to admit that space-based capabilities are requested to rapidly evolve and adapt in order to comply with maritime security users’ needs. In such dem-onstration conditions the user-driven assessment of GMES services might lead to erroneous conclusions. A two-fold evolutionary road can be easily identified, which urges European indus-tries, academic researchers and mari-time stakeholders to focus their effort in operative integration of intelligence and decision support systems in the service chains, and in the development of assessment tools to examine next-generation space techniques and tech-nologies — coming from the ESA or national space agencies. A reply to the abovementioned issues can be derived by relying on modelling and simula-tion (M & S) techniques. A model is the computer-based representation of the addressed application composed by (i) threats scenario, (ii) background, (iii) sensing systems and (iv) information management chain. In recent years an innovative capability has been dis-cussed in the scientific and industrial community and it emerged as the most promising added-value solution for security-related services from space: the ground moving target indication (GMTI) capability. The establishment of space-based GMTI capabilities from

SIMTISYS: Simulator for MTI system

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space requires ad hoc space assets in terms of techniques and technolo-gies which have been studied in the EC NEWA (New European Watcher) support action in FP7 second call. Moreover, recent studies performed by the Joint Task Force ESA, EDA, EC have highlighted some urgent actions to be taken into account in the identification of the implementing technologies dur-ing the FP7 studies. The expected out-put of these parallel developments should be implemented into the final results.

The model to be developed in this pro-ject will cover all the aspects that have a role in determining the overall ser-vice quality level (the observation geometry, the communication channel, the sea state, the processing approach, the sensors that can be useful for the detection from space, etc.). Simulation should focus on complex threat sce-narios, which are the ones that require the user capabilities improvement the community is searching for, and the sensors evaluated in SIMTISYS will be radar. The design approach will be modular and standard so the improve-ment of the capabilities of the sim-ulator to add different sensors and processing algorithms or different scenarios and mission models will be assured. The basic goal of SIMTISYS is to define and develop a system simu-lator able to emulate different realistic scenarios, as defined by the end users, and alternative data collection mecha-nisms from formation-flying and con-stellation satellites.

concePts And oBJectiVes

As outlined above the GMTI tech-nique can be a useful support for the most challenging issue of maritime

surveillance. Model and simulation techniques are a key issue to evaluate GMTI capability considering complex threat scenarios together with a com-bination of emerging technologies and techniques. The US Air Force Research Laboratory (Jones, 2004) has been performing research activities in the field of ground moving target tracking and exploitation performance meas-ures by means of ‘operator in the loop experimentation’. The US Department of Aeronautics and Astronautics (Cerutti-Maori, 2006) has developed a model to assess radar performance capabilities of sparse aperture space-based GMTI radar system. In particu-lar, a design study based on GMTI radar reference mission for the airforce’s TechSat 21 programme was conducted to identify viable system design config-urations that verify specific radar per-formance requirements. The SIMTISYS models and simulator will act as a set of instruments to support stakehold-ers to study European capabilities for moving object detection within present and future Earth observation missions and evaluate space qualification and readiness level of critical technologies for moving object detection and track-ing capabilities, in view of utilisation of commercially available technolo-gies. The SIMTISYS models and simu-lator will reproduce the behaviour of GMTI systems and services from the performance point of view, identifying and characterising the key parameters which affect the feasibility, capabilities, quality of service, effectiveness and reliability of such kind of systems and services. The simulator will be com-posed of the following components:

• an environmental scenario gen-erator and animator which allows the user to create and simulate the behaviour of entities (e.g. ship’s

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position, kinematics, trajectory) and the evolution of environmental con-ditions (e.g. sea state, weather) in a particular geographic area;

• a satellite constellation model which allows the user to compose and simulate the behaviour of a satellite constellation taking into account access, coverage and con-stellation constraints;

• sensors models which reproduce the key performance parameters of SAR sensors such as resolution and measurement errors;

• processing algorithms models which reproduce the key perfor-mance parameters of SAR process-ing and MTI techniques. In this way the performance of the SAR GMTI processing techniques will be evalu-ated analytically or numerically using low complexity raw data. The signa-ture from the targets of interest will be modelled as the superposition of echoes from a set of dominant scatterers, while the echo from the sea will be generated as a stochas-tic process having predefined sta-tistical properties. The performance evaluation of a SAR-GMTI simula-tor for complex scenarios will be obtained by analysing the (spatially-variant) SAR transfer function. The performance results will be given in terms of target detection probability, motion parameter estimation and preliminary classification, for a vari-ety of sea clutter states;

• a human–computer interface which provides instrument to display simu-lation data. An interface bus, which provides the input/output HMI to the users and the workflow management of the simulated data of the SIMTISYS

models and simulator, will be based on the following key concepts:

° level of simulation: the possibil-ity to have different levels in the reproduction of the real compo-nent/algorithms (i.e. different level of simplification in the model parameters with respect to the real component);

° modularity in the simulator out-comes: the possibility to have different levels of details in the results depending on the type of request, simulation time, etc. For example the simulator could consider a first level of simula-tion which identifies if a target is detectable or not and a second level of simulation which provides more detailed information on the quality of the detection results;

° modularity in the composition: the possibility in the future to add new sensor models without changing the core of the simulator;

° interoperability and use of stand-ards: use of standards in the rep-resentation of the simulation results in order to interoperate with external simulation tools and techniques (e.g. use of DIS or GML).

The model to be developed in this pro-ject will cover all relevant aspects that have a role in determining the overall service quality level (the observation geometry, the radar sensor, the com-munication channel, the sea state, the processing approach, etc.). Simulation should focus on complex threat sce-narios, which are the ones that require the user capabilities improvement the community is searching for.

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Figure 1. Simulator main components.

Figure 2. Logic flow of the activities.

consortiuM And ORGANISATION

The SIMTISYS project development will follow the guidelines of the logic flow laid out in Figure 2.

During the whole development life cycle, quality control activities will be performed in order to ensure the respect of defined standards and procedures. After the system design phase, the detailed design of the com-ponent capabilities, taking into account

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the system design decision, will be based on an agreed approach avoid-ing a possible design incompatibility. Intermediate releases of the software (SW) modules will be delivered in order to start the integration phase at an early stage of the project and perform tests at simulator level even with mod-ules having a subset of functionalities already implemented. In this way the development–integration and valida-tion phases will be an iterative pro-cess. During this process SW bugs will be recorded by simulator test and inte-gration engineers and notified to the development team.

To avoid any integration and design risks, strict control and a very high cooperation within the activities of the partners is assured by a plan of meet-ings and reviews. The cooperation and the continuous exchange of informa-tion within the team are of fundamen-tal importance to meet the prefixed results.

The overall duration of the project is 30 months and the due dates of the above reported meetings are chosen in order to allow the Commission to share the outcomes of the develop-ment’s steps with other related pro-jects that can benefit from SIMTISYS results (Dolphin, NEREIDS).

The consortium is composed of accu-rate chosen companies and research entities to optimise the activities in terms of performances and costs:

TASI coordinates the project and is responsible for the simulator architec-ture and its validation. A training ses-sion for the users is also foreseen.

diiet is responsible for the evalua-tion of the system performance, the

evaluation of the implementation of MIMO techniques and of the best measurement techniques.

deimos space is responsible for the development of the SW model of the mission and satellite constellation.

UPC is responsible for the implemen-tation of the modelling of the SAR pro-cessor and the development of MTI algorithms, which will be validated using simulated data.

VEGA Space Ltd is responsible for the development of the SW model of the simulation of operational scenarios that will be implemented within the simulator.

d’Appolonia is responsible for the con-nection with other European projects and the identification of the quantised simulator requirements. Moreover, the build-up of a website is also foreseen.

sistematica is responsible for the implementation of the connecting SW infrastructure and for the integration of all the SW models on it.

eXPected scientific And TECHNOLOGICAL RESULTS.

The main approach to model develop-ment is described in the sections below.

Identification of operational scenario

The provision of a properly modelled set of scenarios for the subsequent simulation and evaluation of differ-ent GMTI architectures is a critical step in the overall development pro-cess for SIMTISYS. The approach pro-posed is based upon elements of the ‘Combined Operational Effectiveness

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and Investment Appraisal’ (COEIA) methodology. COEIA is widely used for the evaluation of technical sys-tems through simulation and model-ling for procurement by the UK Ministry of Defence. It is an integral part of through-life capability management (TLCM) and represents a formal way of presenting an analysis of user needs and operational scenarios in a rigor-ous way. It can be independently chal-lenged, tested and compared with other models proposed to meet the objectives of the GMES maritime secu-rity service. For SIMTISYS purposes it will be extracting the core components from the methodology related to the definition of the individual components of an operational scenario (known as ‘vignettes’), their modelling using an appropriate technology, and the setting of appropriate measures of effective-ness (MoE). The starting point for the vignette definition is the set of data and documentation which currently specifies the proposed GMES maritime surveillance service, supplemented specifically by the outputs of the New European Watcher (NEWA) project. The scenarios will be also compared with the scenarios coming from other European programmes both in space and in security themes. Once the sce-narios and their constituent vignettes have been defined and agreed, the next critical step is to have them faithfully modelled and simulated. For this activ-ity elements from the Presagis suite of simulation software will be used. The data format for the GMTI data that must be transported is expected to be STANAG 4607.

Satellite constellation

The detection of small ships from space is typically a difficult problem because of the very small target to clutter and

noise ratio. Different approaches could be employed in order to enhance the capabilities of detection:

• using a cluster of microsatellites fly-ing in close formation, each equipped with a transmit/receive module;

• using different sensors embarked on cooperative missions.

The advantages of using a constella-tion of microsatellites in comparison to a large satellite with the same over-all antenna aperture area are numer-ous as, for example, the scalability and fault tolerance and the usage of differ-ent sensors embarked on cooperative missions. The present simulator will be based on the simulation of actual present or planned missions in order to better exploit and justify data from these missions and to identify possi-ble gaps in the present and planned EU constellations missions. The constella-tion module will simulate a complete GMES constellation (including Sentinels and other cooperative missions), ena-bling zone/target coverage analyses and ground station contact as well as timeliness analysis, to be used as input for the determination of the capabili-ties of the GMES system. The constel-lation module will be composed of at least five main modules:

• constellation definition (e.g. number of satellites, satellite orbit definition);

• satellite orbits propagation;

• coverage performance assessment (swath and coverage analyses) for the set of space sensors on board the satellites considered;

• target coverage analysis (for ‘What if’ analyses);

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• ground station contact analysis (including data timeliness prelimi-nary assessment).

Typical examples of visualisations for coverage analyses are reported in

Figures 3 and 4. The typical elements of these analyses are represented, namely an area of interest, the satel-lite’s orbit and ground track, the swath and instantaneous field of view of its sensors.

Figure 3. Coverage analysis scenario.

Figure 4. Coverage example.

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Processing algorithm techniques

Multiaperture signal reception. One of the earliest techniques for detect-ing moving targets from space-borne radars is the use of displaced phase centre antennas (DPCA). This implies stringent requirements on the SAR PRF, which can be in conflict with the timing diagram and may exclude the opportu-nity to increase the PRF improving azi-muth ambiguity suppression.

Time-frequency processing. One of the distinguishing features of the echoes from slow moving targets, as exposed to clutter echoes, is their instantane-ous frequency. Even if the echo from a slow moving target, moving parallel to the spacecraft, could be fully embedded within the clutter spectrum, it is still pos-sible to discriminate the two signals by resorting to a joint time–frequency rep-resentation of the signals, like a Wigner-Ville distribution (WVD) (Barbarossa and Farina, 1992) or a pseudo-smoothed WVD. An interesting extension of this approach consists of combining the echoes received from a set of spatially separated antennas, to further increase the differences between targets and clutter (Barbarossa and Farina, 1992). In SIMTISYS, this joint space–time fre-quency processing will be carried out under realistic clutter and signal echo models (Barbarossa and Farina, 1994; 1992).

Digital beam forming. One of the major dilemmas in space borne radars is how to combine high along-track resolution with wide swaths. Having a wide swath is in fact useful to reduce the revisit time, while high resolution is instrumental to better detect and possibly classify the object of interest, moving on the ground. A promising option for improving the resolution/

swath tradeoff consists of using dig-ital beam forming (DBF) on receive, by splitting the receive array antenna into multiple sub-apertures. This amounts to separately down-convert and digitise the signals received from each sub-aperture and then combine the resulting samples in order to form a set of multiple beams with adap-tive shapes. Digital beam forming on receive can increase the performance by suppressing ambiguous signals, or increase the antenna’s gain by sup-pressing localised interferences. DBF is certainly well motivated in a SAR system mounted onboard a space-craft, where the sub-apertures are controlled by a common signal gener-ation system.

MIMO-GMTI. Specific attention will be devoted to the so-called multiple-input multiple-output (MIMO) ground mov-ing target indication (GMTI) system. It is a rather novel system approach that is particularly very appropriate for the detection and tracking of slow mov-ing targets, like ships at sea, embed-ded in a strong clutter environment, as observed from a formation-flying satel-lite cluster. MIMO-GMTI applies to both the microsatellite dedicated to GMTI in flying formation and to different coop-erative missions. This technique entails the presence of multiple transmit-ters, placed onboard different satel-lites, with multiple receivers. The most important aspect in MIMO-GMTI is that the system does not require a phase synchronisation between the wave-forms transmitted from different sat-ellites, which could be rather difficult to implement and maintain; from the pro-cessing of the signals, MIMO technique can be approximated to N instruments flying in train formation and the signals can be combined in order to increase the overall performance.

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MIMO radar virtual aperture. An inter-esting aspect of MIMO radar signal processing is the formation of a virtual aperture. It is in fact known that the set of signals collected after matched filtering at each receiver with a filter-bank composed of M filters, each one matched to one transmitted waveform, is equivalent to collect data from a vir-tual array, whose configuration is given by the convolution between the topolo-gies of the transmit and receive arrays (Forsythe et al., 2004; Barbarossa and Farina, 1994).

Ships and sea clutter radar model-ling. Traditional approaches to predict the RCS return are based on subwave-length discretisation of targets and electromagnetic matrix computations based on methods of moments, finite elements, etc. and are only suitable to sizes up to the order of 100 wave-lengths. Even a small ship has a size several orders of magnitude above the matricial methods feasibility range and

other approximated modelling alter-natives must be used. Physical optics (PO) is a sound approximated method valid for large metallic structures and has been applied for multiple electro-magnetic problems including antenna design and radar modelling. The usage of efficient graphic hardware and related software has allowed a sub-stantial breakthrough in radar mod-elling obtaining successful results for mid-size ships and aeroplanes vali-dated with experimental measure-ments. The PO limitations has been now overcome with more sophisti-cated approximations and complemen-tary algorithms, based on the Physical Theory of Diffraction (PTD), detection of multiple reflections, full polarimetric prediction (VV, HH, VH, HV) very relevant since present and coming sensors are dual polarisation, like COSMO SkyMed, or fully polarimetric, like Radarsat 2. For computational load reasons, exist-ing public results of ship radar cross-section analysis (Margarit et al., 2006;

Figure 5. Radar scattering map of a fishing vessel.

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Margarit et al., 2007) (see for exam-ple Figure 5) will be used to propose simplified ship models based on appro-priate distributions of dominant scat-tering centres.

Sensors models

The SAR-MTI processing module of the simulator transforms the radar raw data captured by a multichannel simu-lated radar into high resolution images including associated spatial informa-tion of interest: detection and imaging of moving targets with appropriate clut-ter rejection, targets’ speed information. Processing algorithm models will take into account the following aspects:

• simple raw data generation for algo-rithm testing purposes,

• SAR raw data decoding and expan-sion from compressed formats,

• antenna phase centres trajectory determination from satellite precise orbital data,

• SAR focusing/beam forming algo-rithms adapted to the selected imag-ing modes,

• MTI algorithms and innovative MTI techniques,

• SAR processing and MTI evaluation.

Processing algorithm models and architecture and human–computer interface

The simulator will be based on the implementation of several modular SW tools which will be integrated on a common platform. Particular atten-tion will be devoted to the human–computer interfaces which will take

into account both the plug-in and the self standing simulator approach. This means that the simulator can be used directly by the end users or service pro-viders as a stand-alone tool, but also can be inserted into a complex auto-matic chain to simulate the maritime surveillance contribution from space components. The architectural design process will follow different steps that will take into account the exigency of user interfaces and an expandable and flexible architecture.

CONCLUSIONS

The present project will contribute with a real and practical tool to the evalu-ation of reachable performance and results of an MTI system. The interac-tions and the impacts of this project with parallel activities within the EC programmes apply to several themes in the work project of the third call, from space to security.

The proposed project will contribute to identify those EU technology areas in which improvements can be effec-tively made, by giving the comparison between the present efficiency and the reachable performance. The validation of sensor technology and the integra-tion data methodology will evidence the vulnerability of space-based sys-tems and services. As a consequence of implementing the MTI simulator as a common tool in pre-operational service, SIMTISYS will contribute to the analysis of competitiveness of European space industries through individuation of gaps in reachable per-formances, directly connected to sen-sor technology, and in evidencing of missions or constellations that could be incremented through additional collaborative satellites (GMES-S). It

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is important to notice that due to the usefulness of the SIMTISYS tool, the project outcomes can be easily phased with other programmes within the same framework. The outcomes of SIMTISYS can easily support activities already foreseen in parallel projects and can offer a quick validation tool for pre-operational service.

REFERENCES

  Barbarossa, S. and Farina, A., ‘Detection and imaging of moving objects with synthetic aperture radar — 2. Joint time-frequency analysis by Wigner-Ville distribution’, IEE Proceedings Radar and Signal Processing, February 1992, pp. 79–87.

  Barbarossa, S. and Farina, A., ‘Space–time–frequency processing of synthetic aperture radar signals’, IEEE Transactions on Aerospace and Electronic Systems, April 1994, pp. 341–358.

  Bliss, D. W., Forsythe, K. W., Davis, S. K., Fawcett, G. S., Rabideau, D. J., Horowitz, L. L. and Kraut, S., ‘GMTI MIMO Radar’, 2009 Int. Waveform Diversity and Design Conference, 2009.

  Cerutti-Maori, D., ‘Performance analysis of space-based GMTI — From monostatic to multistatic systems’, EUSAR 2006, European Conference on Synthetic Aperture Radar, Dresden, Germany, May 2006.

  Chiu, S., 2002, ‘Computer simulations of Canada’s RADARSAT2 GMTI’, EUSAR 2002, European Conference on Synthetic Aperture Radar, Germany, May 2002.

  Forsythe, K. W., Bliss, D. W. and Fawcett, G. S., ‘Multiple-input multiple-output (MIMO) radar: performance issues’, Thirty-eighth Asilomar Conference on Signals, Systems and Computers, 7–10 November 2004, pp. 310–315.

  Gierull, C. H., ‘SAR-GMTI concept for Radarsat-2’, in R. Klemm (ed.), Applications of space–time adaptive processing, IEE Publisher, London, 2005.

  Hacker, T. L., 1998, ‘Performance analysis of a spaced based GMTI radar system using spacecraft interferometry’, USA, 1998.

  Herpel, H. J., ‘Modelling and simulation of satellite based systems’, Germany.

  Jones, J., 2004, ‘Ground moving target tracking and exploitation performance measures’, March 2004

  Krieger, G., Gebert, N. and Moreira, A., ‘Multidimensional waveform encoding: a new digital beamforming technique for synthetic aperture radar remote sensing’, IEEE Transactions on Geoscience and Remote Sensing, January 2008, pp. 31–46.

  Lipps, R., ‘Advanced SAR GMTI techniques’, Proceedings of the IEEE Radar Conference, 26–29 April 2004.

  Margarit, G., Mallorqui, J. J., Rius, J. M. and Sanz Marcos, J., ‘On the usage of Grecosar, an orbital polarimetric SAR simulator of complex targets, to vessel classification studies,’ IEEE Transactions on Geoscience and Remote Sensing, 44(12), December 2006, pp. 3517–3526.

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  Margarit, G., Mallorqui, J. and Fàbregas X., ‘Single-pass polarimetric SAR interferometry for vessel classification’, IEEE Transactions on Geoscience and Remote Sensing, November 2007, pp. 3494–3502.

  ‘New European Watcher — European Space-borne moving object detection system for security’.

  Rabideau, D. J., ‘Non-adaptive multiple-input, multiple-output radar techniques for reducing clutter’, IET Radar Sonar Navig., 4, 2009, pp. 304–313.

  Seventh framework programme, ‘Development and pre-operational validation of upgraded GMES marine

core services and capabilities (Myocean)’ research project.

  Seventh framework programme, ‘GMES services for management of operations, situation awareness and intelligence for regional crises (G-Mosaic)’ research project.

  Sixth framework programme, ‘Land and sea integrated monitoring for European security (LIMES)’ research project..

  Zhang, Huansheng, et al., ‘Real extended scene and moving target multi-channel SAR raw signal simulation’, Journal of Electronics (China), March 2008.

CHAPTER xx Emergency response

CHAPTER 19

Authors: Fabrizio Ferrucci and Steve Tait

consortium members: Institut de Physique du Globe de Paris, France; Institut d’Aéronomie Spatiale de Belgique, Beglium; Booz & Co. Italia, Italy; NERC — British Geological Survey, United Kingdom; OHB — Compagnia Generale per lo Spazio, Italy; Deutsches Zentrum für Luft- und Raumfahrt, Germany; Koninklijk Nederlands Meteorologisch Institut, the Netherlands; Intelligence for Environment and Security — IES Consulting, Science [&] Technology, Italy; Tele-Rilevamento Europa, Italy; TerraSphere Imaging & GIS, the Netherlands; Université libre de Bruxelles, Belgium; Università degli Studi di Roma ‘La Sapienza’ — CRPSM, Italy

AbSTRACT

EVOSS (European Volcano Observatory Space Services) is centred on the development and the integration into a real-time browsable operational system, of a blend of advanced pro-cessing techniques for detecting and simultaneously analysing high-tem-perature features, syn-eruptive ground deformation, volcanic gases and vol-canic ash at erupting, or severely unresting, volcanoes in Europe, Africa, the ocean islands and the Antilles. Due for completion late in February 2013, EVOSS was designed to act in situations ranging from sustained unrest up to events of outstanding

areal impact, that may even lead to withdraw personnel from the field or to evacuate the volcano observatory. This requires adaptive task scaling up to possible handing over the sur-veillance to space-borne observation during extreme events. The EVOSS concept is voluntarily restricted to EU, Africa and the eastern Caribbean, but through R & D done during the project the system can readily be extended to global scale by exploiting the com-bined potential of geostationary and polar orbiting satellite platforms, hosting infrared, ultraviolet and radar instruments. In two years of R & D and tune-up operations, before the start of the full scale demonstration in spring 2012, EVOSS has already allowed monitoring in delayed time or in real time of as many as 28 eruptions at nine volcanoes in seven nations.

ACHIEVEMENTS

EVOSS (European Volcano Observatory Space Services) stem from the unique ensemble of phenomena, parameters and precursors involved in volcanic eruptions, and the inherent need for responses scaled to the vastly vari-able intensities, durations and extent of possible eruptive activity. It has capitalised on achievements of the European Commission’s fourth and fifth framework programme projects in the so-called ‘European laboratory volcanoes’ theme, as well as from

EVOSS: European Volcano Observatory Space Services

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later Earth observation projects by the European Space Agency, the seventh framework programme and GMES.

The decision to propose developing an end-to-end service uniquely devoted to the operational monitoring of major volcanic hazards on ground and in the atmosphere was taken by a group of nine major institutional stakehold-ers from the EU, the Caribbean and

Africa, managing six volcano observa-tories and having direct early-warning and forecast responsibility in 11 vol-canoes worldwide, some of which are in remote areas and subject to com-plex operational conditions.

Spanning from Iceland to the Indian Ocean, and from the Mediterranean to the eastern Caribbean, EVOSS was designed to act in supra-regional

Figure 1. The ‘full disk’ imaged by the geostationary satellite Meteosat Second Generation of the European Organisation for the Exploitation of Meteorological Satellites (Eumetsat) is the test site of EVOSS. Nineteen active and erupting volcanoes, monitored at refresh rates ranging from 96 times daily for volcanic thermal features to two to four times monthly for ground deformation, are included in the four large circles. The whole disk is the theatre for volcanic ash and gas (mostly sulphur dioxide — SO2) detection and tracking. Any dormant volcano springing back to life within the disk is automatically included in the list of monitored volcanoes once thermal activity is detected on it.

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operations theatres, thus able to encompass at once several, spatially scattered, long-lasting crises (months to years). To satisfy the monitor-ing needs and to assist in the remote management of critical situations, pri-ority was given to measuring physical parameters from space at very-high temporal resolution as opposed to the option of infrequent observation of the same parameters at high spa-tial resolution. This methodological breakthrough was attempted target-ing multi-parametric, near real-time information support to emergency decisions, and also an economically sustainable solution thanks to the thorough exploitation of the new gen-eration of meteorological satellites.

However, there are about 1 500 poten-tially active volcanoes worldwide, and a high proportion of these are barely monitored or not monitored at all. As individual volcanoes may show infrequent activity of different dura-tion and type, spanning very different energy scales, monitoring at ground level is costly and frequently unfeasi-ble. This means that, even at the 40 to 50 best-monitored sites in the world (Europe, North America and Alaska, Japan), there are circumstances in which the ability to observe and fore-cast eruptions at ground level is lim-ited as eruptive activity may exceed the response capacity of the person-nel based there, and, for example, it may become dangerous or impossible to service equipment.

Furthermore, the volcano may be located in unstable areas in which ground equipment cannot be safely

installed, run and serviced, as could be the case in some parts of Africa, Asia and the Americas: and unforeseen sit-uations may develop, such as reawak-ening of volcanoes which had been dormant for hundreds or even thou-sands years.

Monitoring volcanic activity using multi-parametric observation with satellite payloads removes many of these obstacles. EVOSS, which entered its 1-year operational demonstration phase in March 2012, develops along three main research-and-technol-ogy lines: two of them focus on the markers of the volcano dynamics on ground (high-temperature features and ground deformations) and one in the atmosphere (volcanic ash and gases, mainly the sulphur dioxide). The key is that, with the exception of seismicity, all parameters can be effi-ciently measured from space by one or more satellites, at various levels of spatial resolution (how detailed the picture) or temporal resolution (how frequently), without involving the presence of instruments or operators on the ground. Internet-based deliv-ery of information products empow-ers a system user, who should be the mandated organisation responsible for providing scientific advice to crisis management authorities. The follow-ing table depicts the eruptions dealt with for which at least half of the geo-physical parameters were available at once (instant thermal power and mass eruption rates, ground defor-mation and digital elevation models, SO2 detection, SO2 concentration and mass estimate, volcanic ash detection and mass loading measurement).

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VOLCANO EVENT dAte(s)

Nyamuragira (Congo) Eruption January 2 - 29, 2010

Nyiragongo (Congo) permanent Lava Lake

Soufriere Hills (Montserrat) Pyroclastic flow February 11, 2010

Eyjafjallajökull (Iceland) Eruption March 20 – May 9, 2010

Manda Hararo (Ethiopia) Eruption March 21, 2010

Piton de la Fournaise (Reunion) Eruptions October 14 – 22, 2010

December 9, 2010

Etna (Italy) Eruptions January 12, 2011

April 9, 2011

May 11, 2011

July 9, 19, 25, 30, 2011

August 5, 12, 20, 29, 2011

September 8, 19, 29, 2011

October 8, 23, 2011

November 15, 2011

January 3, 2012

February 6, 2012

Nabro (Eritrea) Eruption June, 12 – July 17, 2011

Nyamuragira (Congo) Eruption November 6, 2011 – March 30, 2012

Table 1. Twenty-eight eruptions at nine volcanoes in seven nations were successfully followed by EVOSS during the R & D phase which finished in February 2012. Two 2011 eruptions (El Hierro, Canary Islands, and Jebel Zubair, Red Sea) could not be detected directly as both were submarine, poorly explosive and of limited strength overall.

The three technological components of EVOSS are listed below.

1. High-temperature volcanic features

These are dealt with by space-borne instruments operating in the InfraRed portion of the electromagnetic spec-trum, which are able to capture tem-peratures of molten lavas as high as close to 1 200 °C (e.g.at Piton de la Fournaise, Réunion Island) and as low as

about 600 °C (e.g. at Ol Doinyo Lengai, Tanzania). Such thermal effects are directly associated to the main phases of eruptions, the monitoring of which constitutes the central goal of EVOSS. The key instrument suiting the pro-ject’s requirements in this component is the geostationary Meteosat Second Generation (MSG), whose radiometer Seviri supplies an exceptional frequency of imaging: one multi-channel infrared image every 15 minutes, for an out-standing daily total of 96 images. This

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is the principal reason why, as shown earlier (Figure 1), the EVOSS playground corresponds to the ‘full disk’ of MSG. EVOSS is the first project, and the first complete system to exploit in depth MSG for the systematic, real-time moni-toring of instant thermal power released and the corresponding rate of eruption of lavas, simultaneously at all volca-noes in such huge area which includes more than 150 volcanoes that erupt, or have been erupting at least once in the last 12 000 years (the Holocene geo-logical epoch).

2. Ground deformation and digital elevation models

Because of a combination of techni-cal needs (number and characteristics of images required) and of the varia-ble frequency of overpasses (depend-ing on satellites and constellations) of Radar satellites, this component is not real time or near rea time as are ther-mal and gas products. Indeed, removal of the effects of the troposphere on images acquired in standard, mid-lat-itude areas, is usually feasible with 12–15 images minimum. On account of the cost of modern, X-band, 3 cm wavelength radar images (EVOSS has used data acquired by the Cosmo-SkyMed constellation), this makes the technique nonaffordable for the standard follow-up of unresting areas. However, as EVOSS acts at the scale of one third of the planet, where the need for accurate digital elevation models is acute, the blend of advanced interfero-metric techniques developed within the EVOSS consortium was used to reach top accuracy and hitherto unachieved vertical and horizontal resolutions in DEM building on five areas: Nyiragongo and Nyamuragira (Congo), Karthala (Comoros), Soufriere Hills (Montserrat) and Piton de la Fournaise.

3. Volcanic ‘aerosols’ so2 and ash

Sulphur dioxide is reliably retrieved from satellite measurements; it is often used as a proxy for the presence of ash. However, some eruptions either emit amounts of SO2 that are barely detectable (e.g. the 2010 eruption of Eyjafjallajökull, Iceland) or SO2 and ash are emitted at different altitudes and therefore are transported in differ-ent directions (e.g. the 2011 eruption of Grímsvötn, Iceland). In contrast to SO2, remote satellite detection of ash is hampered by the absence of narrow absorption bands in the spectral signa-ture of ash. The latter displays broad shape absorption.

Several quantitative ash algorithms exist relying on assumptions about the altitude of the plume and micro-physical aerosol properties. As these parameters are rarely available at the time of measurement, most of the available algorithms for the rou-tine detection of ash, provide only qualitative information for the pres-ence of ash in the atmosphere. The EVOSS system uses the data from four polar orbiting satellites for SO2 detection and measurement: three operating in ultraviolet (in daylight: OMI onboard NASA’s AURA, Sciamachy onboard ESA’s Envisat, GOME-2 on board Eumetsat’s MetOP-A) and one in infrared (IASI).

As far as the detection of ash is con-cerned, the EVOSS system has incorpo-rated SEVIRI (MSG), aimed to maximise the frequency of observation and opti-mise the results through a quantitative (analytical) merge of high-tempera-ture thermal analysis and ash detec-tion, aimed to improve the constraints on height to be modelled for ash early warning to air navigation.

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The pattern shown in Figure 3 integrates the SO2 emissions and losses during the first three-and-a-half days of the Nabro

eruption. The SO2 plume reached trop-opause altitudes (~ 15 km at these latitudes), and fast easterly jet winds

Figure 2. Thanks to the outstanding image refreshment rate of 15 minutes of geostationary satellites MSG of the Eumetsat consortium for spaceborne meteorology, the onset of the reawakening of dormant (since about 5 000 years) Eritrean volcano Nabro could be precisely detected. Left: the thermal signal (‘hot spot’ or HS) allows setting the onset of the eruption at 20:30 UTC precisely on 12 June 2011, prior to development of the ash plume (expanding black spot) and the inherent spoiling of ground features. Right: geolocation of the centroids of the two Seviri hot-spot pixels (HS), on a high-resolution satellite image acquired 2o years earlier. (© 2011 Eumetsat)

Figure 3. Because of wind patterns at the top of the troposphere, the SO2 plume originated from Nabro (Eritrea) had stretched along more than 6 000 km on 16 June 2011, about 4 days after the eruption onset. The colour scale highlights the SO2 concentration (DU).

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spread the plume towards south-east Asia. All UV and IR sensors could still measure significant SO2 concentra-tions several weeks after the onset of

the eruption, which finished (from the remote-sensing standpoint) on 17 July. Total SO2 masses of ~ 1.5 Mt are reported by Clarisse et al. (2011).

Figure 4. Nabro volcano (Eritrea): Satellite borne measurements of Radiant flux (instant thermal power expressed in GigaWatt — red scale) and of sulphur dioxide concentrations (expressed in Dobson Units — blue scale) measured in slightly delayed time at Nabro during the 2011 eruption. Radiant fluxes were measured at the typical refresh rate of 15 minutes by one geostationary satellite, whereas SO2 concentrations arise from daily overpasses of four sensors in polar orbit. The peak of SO2 (313 DU) was measured on 16 June at 07:39 UTC, whereas the peak of Radiant flux (75 GW) at 18:15 UTC, 13 hours later. Dashed line and arrows encompass the duration of the eruption.

CONCLUSIONS

Thanks to the faultless development of some crucial project elements (novel remote-sensing techniques in thermal analysis, inter-satellite SO2 data homogenisation and high-preci-sion digital elevation model construc-tion) and the successful adaptation of detection and computing tech-niques from one satellite to another, EVOSS has been able to monitor as many as 28 eruptions at nine volca-noes — many of them simultane-ously, as Nyiragongo, Etna and Nabro in July 2011 — even before comple-tion of the integrated system, which entered the demonstration phase in Spring 2012.

At that moment, the volcanoes simul-taneously monitored by EVOSS were: Stromboli and Etna (Italy), Hierro (Spain), Jebel-al-Tair and Jebel Zubair (Red Sea, Yemen), Manda Hararo, Dalafilla, Dabbahu, Erta Ale (Ethiopia) and Nabro (Eritrea), Mt Cameroon (Cameroon), Nyiragongo and Nyamuragira (Congo), Ol Doinyo Lengai (Tanzania), Karthala (Comoros), Piton de la Fournaise (Reunion Isl., France), Soufriere Hills (Montserrat, BWI), Eyjafjallajökull and Grimsvotn (Iceland).

The thematic maps (example in Figure 3) and data series (example in Figure 4) can be browsed by end users in real time, knowing that the data

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stream is continuous and in real-time for thermal, SO2 and ash, whereas there is no real-time component for the ground deformation component.

Overall, achievements are fully in line with expectations; nevertheless, an ongoing effort is required for the adap-tation/porting of algorithms and proce-dures to new satellites in replacement of others as they become obsolete or whose real life cycle has gone too far beyond the design life cycle.

There are two potent reasons why a space-borne, real-time, multi-param-eter observing system such as EVOSS can be of great use. First, there are massive differences in the local on-ground observational capacity at dif-ferent volcanoes. This varies from ‘everything’ at a few state-of-the-art observatories worldwide, to ‘noth-ing’ in others. The stark reality is that most potentially dangerous volcanoes are not monitored, and it is not realis-tic to imagine this situation otherwise. Clearly in the case where no volcano observatory or instrumental network exists, by definition, almost any vol-canic event overwhelms the local observational capacity. However, as volcanic events of an unusually violent nature ramp up instrumental capacity can be destroyed and even advanced observatories become progressively ‘blind’ or even in exceptional cases themselves menaced.

Between these extremes there is a whole spectrum of levels of on-site observing capacity which can never be designed to cope with all possibilities. Hence, the problem of how to handle events that overwhelm that capac-ity is clearly posed. This held true for Nabro, where no monitoring system of any type existed or does exist, and

held true also for the Congo eruptions at Nyamuragira and the permanent molten lava lake of Nyiragongo, which is monitored by a volcano observatory which may easily be cut off from effec-tively following unrest because of the huge extent of the area to observe and a generalised weakness of telecom-munication networks, and/or the objec-tive complexity of anthropic/political and terrain components.

The second constraint for structure and usefulness of a satellite observ-ing system is that it is notoriously dif-ficult to measure eruption fluxes from ground observing systems despite the crucial importance of this parame-ter. Instrumental networks run by vol-canic observatories are understandably designed primarily to identify precur-sor signals. These enable changes in the system to be identified that, even in the absence of a clearly adequate theoreti-cal framework, can be used empirically to track changes until the onset of an event. Indeed, once lava and gas and/or ash begin to erupt at the surface, one of the key variables that can give access to how an event is evolving is the erup-tive fluxes of those different materials. However, because neither the precise site of an eruption nor its impending magnitude can be known accurately in advance, no reliable or sufficiently flexible on-site solution has yet been devised to cope with the problem of monitoring all types of eruption fluxes.

The natural convergence of EVOSS’ results shown above, synergistically obtained with as many as four differ-ent satellites for SO2 detection and measurement (currently still released by the project SACS 1 in form of con-centration) and with Seviri-MODIS for

1 http://sacs.aeronomie.be/index.php

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radiance-driven estimates and ‘run-ning’ validation of mass discharge rates, is conclusive and more than promising. The results open an impor-tant new prospect: the feasibility of systematically integrating in real-time lava and gas fluxes measured indepen-dently from each other by multiple sen-sors, using the thermal emission from cooling erupted material as a proxy for the amount of mass (essentially liquid magma) that is being erupted, and the flux information on SO2 as a proxy for the overall amount of magmatic gases that have been erupted during the crit-ical phases of major volcanic events anywhere on Earth.

REFERENCES

  Clarisse, L., Prata, F., Lacour, J.-L., Hurtmans, D., Clerbaux, C. and Coheur, P.-F., ‘A correlation method for volcanic ash detection using hyperspectral infrared measurements’, Geophys. Res. Lett., 37, 2010, L19806; doi:10.1029/2010GL044828.

  Clarisse, L., R’Honi, Y., Coheur, P.-F., Hurtmans, D. and Clerbaux, C., ‘Thermal infrared nadir observations of 24 atmospheric gases’, Geophys. Res. Lett., 38, 2011, L10802, doi:10.1029/2011GL047271.

  Clerbaux, C., Boynard, A., Clarisse, L., George, M., Hadji-Lazaro, J., Herbin, H., Hurtmans, D., Pommier, M., Razavi, A., Turquety, S., Wespes, C. and Coheur, P.-F., ‘Monitoring of atmospheric composition using the thermal infrared IASI/MetOp sounder’, Atmos. Chem. Phys., 9, 2009, pp. 6041–6054.

  Hirn, B. R., Di Bartola, C. and F. Ferrucci, ‘Spaceborne monitoring 2000–2005 of the Pu’u’O’o-Kupaianaha (Hawaii) eruption by synergetic merge of multispectral payloads ASTER and MODIS’, IEEE Trans. Geosc. Rem. Sens., 46, 2008, pp. 2848–2856.

  Hirn, B. R., Di Bartola, C. and Ferrucci, F., ‘Combined use of Seviri and MODIS for detecting, measuring and monitoring active lava flows at erupting volcanoes’, IEEE Trans. Geosc. Rem. Sens., 47(8) , 2009, pp. 2923–2930.

  Kaminski, E., Tait, S., Ferrucci, F., Martet, M., Hirn, B. and Husson, P., ‘Estimation of ash injection in the atmosphere by basaltic volcanic plumes: The case of the Eyjafjallajökull 2010 eruption’, J. Geophys. Res., 116, 2011, B00C02; doi:10.1029/2011JB008297.

  Puglisi, G., Bonforte, A., Ferretti, A., Guglielmino, F., Palano, M. and Prati, C., ‘Dynamics of Mount Etna before, during, and after the July–August 2001 eruption inferred from GPS and differential synthetic aperture radar interferometry data’, J. Geophys. Res., 113, 2008, B06405; doi:10.1029/2006JB004811.

  Rix, M., Valks, P., Hao, N., Loyola, D. G., Schlager, H., Huntrieser, H. H., Flemming, J., Koehler, U., Schumann, U. and Inness, A., ‘Volcanic SO2, BrO and plume height estimations using GOME-2 satellite measurements during the eruption of Eyjafjallajökull in May 2010’, J. Geophys. Res., 116, B00C02; doi:10.1029/2011JD016718.

CHAPTER 20

Authors: Ides Bauwens, Jonas Franke, Michael Gebreslasie, Sabelo Dlamini, Fethi Ahmed, Penelope Vounatsou

consortium members: Eurosense Belfotop NV, Belgium; South African Medical Research Council, South Africa; Ministry of Health, Swaziland; Remote Sensing Solutions GmbH, Germany; University of Kwazulu-Natal, South Africa; Swiss Tropical and Public Health Institute, Switzerland

AbSTRACT

The World Malaria Report 2011 (World Health Organisation, WHO) estimated 216 million malaria cases world-wide, of which approximately 81 % or 174 million cases were reported in the African region. There were an estimated 655 000 deaths caused by malaria, of which 91 % were in Africa. Around 86 % of malaria deaths were children under 5 years of age. In 2008, the Roll Back Malaria (RBM) partnership prepared a global malaria action plan (GMAP) in line with the 2010 targets of the UN Secretary-General. A global strategy outlined the goal to have a substantial and sustained reduction in the burden of malaria in the near and mid-term (2015), and the eventual global erad-ication of malaria in the long term. Geographic information systems (GIS), Earth observation (EO), global position-ing systems (GPS) and spatial statistics

play a crucial role to plan malaria vec-tor control. MALAREO aims to develop and implement EO products and capac-ities within malaria vector control and management programmes in southern Africa, including South Africa, Swaziland and Mozambique. End-user surveys conducted in MALAREO have shown high interest for linking EO with epi-demiology as well as for EO products directly supporting the malaria control programmes (MCPs) in their daily work. MALAREO is a mixed European–African consortium that is building local capac-ity in GIS, EO and advanced spatial sta-tistics on the one hand and is developing user-driven EO monitoring solutions on the other hand. Remote sensing derived meteorological information is combined with NDVI and land cover information (MODIS) to map malaria prevalence and incidence. High resolution satel-lite data (RapidEye) are used to extract water bodies and map vector breeding sites. Household maps differentiating different types of housing are classified from very high resolution data using an object-oriented approach.

introduction

Geographical information systems (GIS), Earth observation (EO), spatial modelling and statistical analysis are increasingly being recognised as val-uable tools for effective management and planning of malaria vector con-trol programmes. Previous research

MALAREO: Earth observation in malaria vector control and management

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activities already related EO data to vector-borne diseases, mainly for epi-demiological studies. Indeed, Earth observation can be used for the sur-veillance, monitoring and early warn-ing of vector-borne diseases. Remotely sensed images indicating environmen-tal conditions are powerful predictors of vector distribution patterns and of average transmission levels of malaria parasites by the malaria vectors. They can be used to generate malaria distri-bution maps, supporting malaria con-trol programmes to effectively orient efforts and resources (Rogers et al. 2002; Curran et al. 2000).

Remote sensing has been used to asso-ciate land use and land cover types with vector habitats based on simple classification techniques, as well as complex statistical models that link satellite-derived multi-temporal mete-orological and Earth observations with vector biology and abundance (Kalluri et al. 2007). In 1998, NASA’s Center for Health Applications of Aerospace Related Technologies (CHAART) already evaluated the range of sat-ellite systems for their potential to support epidemiological and entomo-logical research (Beck et al. 2000). The authors concluded that system perfor-mance, data costs and long turnaround times for products of sensors available in 1998 hampered the use of EO data for epidemiology. They point to the range of new sensors, in the meantime most of them are already operational, which should extend remote sensing into operational disease surveillance and control. According to Kalluri et al. (2007), a combination of high spa-tial resolution data for land use and land cover classification and frequent coarse resolution environmental satel-lite data for monitoring environmental variability would be ideal for studying

surface climate conditions for mod-elling vector populations. Ceccato et al. (2005) reviewed the capabilities of remote sensing to support oper-ational malaria early warning sys-tems and stated that ‘The time is ripe for the wealth of research knowledge and products from developed coun-tries to be made available to the deci-sion-makers in malarious regions of the globe where this information is urgently needed’ (Ceccato et al., 2005).

The aim of MALAREO is to stimulate and implement the use of EO data by decision-makers and to contribute to the control of malaria in southern African countries, including South Africa, Swaziland and Mozambique. MALAREO addresses two different applications of Earth observation, i.e. EO applications to support malaria epidemiological studies and EO applications to directly support malaria vector control. Epidemiological EO applications mainly address param-eters that are suitable to predict the environmental conditions for the vec-tors. These parameters are used to pro-duce malaria incidence and prevalence maps. EO applications that directly sup-port malaria control aim at providing rel-evant geo-data that optimise planned vector control measures, which is a new field for EO applications. For more than 30 years, research has aimed at creating capabilities to control malaria using remote sensing technologies but an integration of these tools into opera-tional disease control management has rarely taken place (Ceccato et al. 2005, Beck et al. 2000).

study AreA

MALAREO is focusing on the cross-bor-der region of southern Mozambique, eastern Swaziland and north-eastern

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South Africa. The region is largely undeveloped, this being exacerbated by the fact that it falls within a malaria area. Increased anti-malarial drug resistance and the lack of a malaria control programme in the past (mainly in southern Mozambique) have contrib-uted to this impeded development. The three countries in the MALAREO study area are in different stages of malaria control, which causes different condi-tions for the use EO products.

South Africa

South Africa is at the southern-most fringe of malaria transmission in Africa. The malarious regions in the country are the eastern part of Limpopo and Mpumalanga provinces and the north-eastern parts of KwaZulu-Natal. Malaria transmission in South Africa is unstable and seasonal, with transmission limited to the warm and rainy summer months and peaking in late summer to autumn (March–May). The average seasonal pattern in malaria incidence follows the periodicity in rainfall and temperature with a 3 to 4 month lag. Anopheles ara-biensis is currently the only mosquito vector in South Africa. Yearly indoor residual spraying (IRS) is one of the main pillars of the malaria vector con-trol programmes. South Africa is cur-rently in the pre-elimination stage of malaria control.

Swaziland

The majority of Swaziland has his-torically had low malaria transmis-sion. However, in the lowveld ecological zone in the east, transmission has been persistent and at times high, record-ing 114 cases per 1 000 population at risk in 1996 (Swaziland Ministry of Health report, 1999). Swaziland has greatly reduced the national burden

of malaria; between 1999 and 2009 laboratory confirmed cases declined from 3.9 to 0.07 cases per 1 000 population (Kunene et al., 2011). This decrease has been attributed to a scale up of vector control activities in Swaziland’s at-risk region and border-ing areas associated with the cross-border collaboration with Mozambique and South Africa. With malaria control achieved through national and cross-border efforts, Swaziland has exceeded Roll Back Malaria’s Abuja target (Roll Back Malaria plan of action 2011) and the millennium development goal on malaria (Ministry of Economic Planning and Development, 2010)). Recognising Swaziland’s success, the Southern African Development Community (SADC) and the African Union ear-marked Swaziland for elimination by 2015 (Africa Union, Africa Malaria Elimination Campaign 2007) and is currently in the elimination stage of malaria control. The backbone of Swaziland’s malaria control strategy is selective residual spraying of dwelling houses. The IRS is complemented by the distribution of long-lasting insecti-cide-treated nets (LLIN).

Mozambique

In Mozambique, estimated prevalence in children of the age group 2 to 9 years old varies from 40 % to 80 %, with 90 % of children under 5 years old infected by malaria parasites in some areas. According to the Permanent Secretary in the Ministry of Health, Joge Tomo, the number of cases of malaria diagnosed in Mozambique fell from 6 million in 2007 to 4 mil-lion in 2009. Malaria is endemic and climate favours its transmission throughout the year in many areas. In Mozambique, transmission peaks after the rainy season (from December to

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April). Mozambique is currently in the control stage of malaria control. In the last decade the malaria control programme has evolved to a point of implementing large scale IRS pro-grammes in several areas of 42 dis-tricts (unpublished documents of NMCP of Mozambique, 2006). IRS was also the major component of the Lubombo Spatial Development Initiative (LSDI). A significant reduc-tion in parasite prevalence among the human population, vector density and sporozoite positivity rates in An. Arabiensis and An. Funetus have been documented following the launch of the comprehensive malaria control programme (Sharp et al. 2007).

MetHodoLoGy

In a first phase, a user survey was conducted to gather information on the current capacity needs and user requirements from malaria research-ers and malaria control programmes in the MALAREO study area. Existing capacity and user requirements were analysed and compared with state-of-the-art requirements. A capacity gap analysis identified and prioritised

required capacities. Figure 1 shows the MALAREO project scheme with the aim of increasing GIS and EO capacity dur-ing the project lifetime also through research and development of EO applications.

Capacity building

The skills of staff were interrogated against the state-of-the-art of EO applications and statistical modelling for malaria vector control. The exist-ing capacity of the surveyed institutions were assessed and categorised into dif-ferent skills groups. The results showed divergent training needs, but clearly indicate the need to start with introduc-tory training themes. GIS, remote sens-ing and spatial statistical modelling courses will be given at increasing level, focusing on a stable group of trainees following a series of courses going from introductory to advanced level.

EO monitoring solutions

Based on user requirements and state-of-the-art EO applications for malaria, the products to be developed will be cate-gorised into two fields of EO applications,

Figure 1. Scheme of the MALAREO project approach.

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i.e. EO applications for epidemiology and EO applications for supporting the MCPs. The EO epidemiology applica-tions are focused on the application of Bayesian statistics on malaria cases and remote sensing derived data for producing malaria incidence and preva-lence maps. EO products for epidemiol-ogy are in the first place intermediate inputs for the modelling of malaria risk. EO products designed for the MCPs are final outputs that will be directly deliv-ered to the MCPs’ management (Figure 2). There is a thematic overlap between these two applications, whereby some products will be used as input for the epidemiological modelling as well as for the direct support of the national malaria control programmes.

EO datasets

All currently available as well as planned EO sensor systems were ana-lysed for their potential use for malaria research. Since for land cover and veg-etation-type mapping only data with high (HR) or very high (VHR) spatial resolution are used in MALAREO, only sensor systems which provide data with a higher or equal to 30 m spatial

resolution were taken into account. RapidEye data was chosen for high res-olution land cover, population and water body mapping as well as for vegetation indices calculation, whereas very high resolution data from GeoEye-1 and Ikonos-2 are used for household map-ping. Lower resolution MODIS data indi-cating climatic conditions and ASTER Global Elevation data are also used for modelling malaria risk. Meteorological data will be used from the US Famine Early Warning Systems Network (FEWS NET) Africa data portal i.e. the rainfall estimate (RFE) product (source: NOAA-CPC, temporal resolution: 10-day (dec-adal), spatial resolution: 8 km).

About 25 000 km2 RapidEye data were provided via the EC/ESA GMES Space Component Data Access (GSC-DA) cov-ering the MALAREO study area in South Africa, Swaziland and Mozambique (Figure 3). The data was acquired at five different dates between 18 July 2011 and 10 November 2011 with a total cloud cover of less than 1 %. In addition, very high resolution data (VHR) was acquired from GeoEye and IKONOS for three demonstration areas, also provided via the GSC-DA.

Figure 2. General MALAREO overview of parameters derived from remote sensing for the two EO applications: epidemiology and malaria control management.

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Figure 3. On the left, the data order sites of the first data order for the HR data (yellow area with about 25 000 km2) and the three VHR sites (red areas with 850 km2 in total). Background: ESRI World Imagery. Right: Example of a true colour RapidEye subset.

HR land cover mapping

The 25 000 km2 high resolution RapidEye data will be classified accord-ing to malaria-relevant land covers using an object-oriented approach. The following classification scheme will be used: forest/woodland, bush/shrubland, grassland/savannah, wetland, large-scale agriculture, bare soil/rock, building/settlement/infrastructure, roads/tracks, standing open water, flowing open water.

Malaria risk modelling

In order to model the spatial and temporal malaria risk, environmen-tal parameters are used as input for the Bayesian modelling of malaria

incidence that can partly be derived from satellite remote sensing data. The main environmental parameters that are used for Bayesian modelling are distance to water, land surface temperature, vegetation indices (NDVI/EVI), rainfall estimates, digital ele-vation model (DEM) and land cover information.

It is the aim of MALAREO to improve Bayesian modelling results through providing improved input data. The above-listed environmental data will still be used if no better data is avail-able, which is the case for land sur-face temperature and rainfall data. However, major improvements can be achieved by using high resolution data

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for land cover classification (identifi-cation of potential vector habitats), identification of water bodies (even small water bodies can be detected that could be potential vector breed-ing sites), calculating vegetation indi-ces (small-scale differences can be considered) as well as for elevation (most detailed DEM can be used). This will be achieved by the use of high resolution RapidEye data and by the use of the ASTER Global Digital Elevation Model with 30 m spatial res-olution, which is derived from stereo image pairs.

Table 1 summarises the intended improvements of MALAREO in model-ling malaria risk and malaria area to be achieved by the use of innovative sensor data with improved spatial and temporal resolution.

Household mapping

In addition to the epidemiological application, detailed household maps derived from VHR EO data are required to support NMCPs when preparing their control measures. An approach for an automated house/hut detection based on VHR data is being developed and tested by the use of object-based

image information and/or textural parameters of panchromatic and mul-tispectral bands.

Water body mapping

Even small water bodies are playing an important role as larval breeding sites for malaria vectors. The identifica-tion of water bodies are thus a direct indicator for malaria risk and the dis-tance to water is a major determinant for Bayesian modelling of malaria inci-dence. Remote sensing can be used to identify water bodies over large rural areas. The higher the resolution of the data, the more small water bodies can be detected. The NMCP of Swaziland has used a digitised water body layer of Swaziland (based on Google Earth) and sampled water bodies by larval sam-pling to identify breeding sites of the Anopheles. Therewith, a reference data set is available to validate the HR water body map generated in MALAREO.

Mapping of potential breeding sites

The reference data set of vector breed-ing sites from Swaziland and the water body map will be combined with the HR land cover map to generate probabil-ity maps of the presence of breeding

environmental parameter

Sensor source spatial resolution Improvement

Distance to water/land cover

RapidEye 5m yes

Min and Max Temperature

MODIS 1000m no

Vegetation Indices RapidEye 5m yes

Rainfall Estimates NOAA-CPC 8000m no

Elevation Aster 30m yes

Table 1. EO-derived environmental parameters used for modelling malaria incidence and prevalence with their data source, spatial resolution and aimed data improvements of MALAREO

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sites in larger areas, using the Maxent software. Kulkarni et al. (2010) used maximum entropy to model the spatial distributions of three dominant vec-tor species (An. funetus, arabiensis and gambiae) in a 94 000 km² region of East Africa (Tanzania) based on land cover data and other environmen-tal factors. Results showed that the land cover information was required in each of the three vectors’ niche model. Inclusion of the derived vector habitat information significantly improved the precision and accuracy of the malaria prevalence conditions (r² = 0.83 includ-ing vector habitat, r² = 0.50 without vector habitat).

PRELIMINARy RESULTS And concLusions

At the time of publication, the produc-tion of the HR land cover layer had just started (see example in Figure 6) together with the development of automated VHR household mapping. Preliminary results are very promising due to the high level of spatial and the-matic detail of the maps. In February 2012, a meeting with end users from the southern African national malaria control programmes and the MALAREO project team took place in Durban, South Africa, where the RapidEye imagery and the preliminary

Figure 4. Preliminary results of HR classification following an object-oriented approach

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results have been presented. The end users emphasised the benefit of these EO products for malaria control, since these products will greatly improve planning of malaria control measures and will complement the followed approach of linking environmental and epidemiological data, which is a first step towards an early warning system for malaria.

The end-user meeting was part of a 1-week course on GIS and was the first part of three courses building GIS and EO capacity from basic to advanced level. The course was organised at the University of KwaZulu-Natal (UKZN) and targeted participants working operation-ally with spatial data that could benefit directly from the use of GIS and EO prod-ucts. In total, there were 13 participants, coming from different provincial MCPs in South Africa, NMCP from Madagascar and Botswana and the African Center of Meteorological Applications in Niger.

A large number of research questions are being addressed in MALAREO. In terms of modelling malaria incidence and prevalence, the best environ-mental predictors will be investigated incorporating all EO-derived param-eters, and their influence on the mod-elling results will be assessed. Another research question addresses the lag time of each predictor for malaria inci-dence. Possible relationships between incidence and prevalence in areas of very low transmission will be analysed to reveal whether they are comparable, which would mean that intensive preva-lence surveys are no longer necessary. The relation of imported to local cases at household level will be investigated, including HR land cover and an over-view will be given of prevalence and incidence across the different areas in southern Africa. MALAREO will hopefully

contribute to a better integration and awareness of EO solutions in local and national MCPs, and build on the fun-daments of an EO monitoring cell that supports the MCPs in their fight against malaria.

REFERENCES

  Beck, L. R., Bradley, M. L. and Wood, B. L., ‘Remote sensing and human health: new sensors and new opportunities’, Emerging Infectious Diseases, 6(3), 2000, pp. 217–266.

  Ceccato, P., Connor, P. J., Jeanne, I. and Thomson, M. C., ‘Application of geographical information systems and remote sensing technologies for assessing and monitoring malaria risk’, Parassitologia, 47, 2005, pp. 81–96.

  Curran, P. J., Atkinson, P. M., Foody, G. M. and Milton, E. J., ‘Linking remote sensing, land cover and disease’, in S. I. Hay, S. E. Randolph, D. J. Rogers, J. R. Baker, R. Muller and D. Rollinson (eds), Advances in parasitology — Remote sensing and geographical information systems in epidemiology, Academic Press, Oxford, 2000.

  Kalluri, S., Gilruth, P., Rogers, D. and Szczur, M., ‘Surveillance of arthropod vector-borne infectious diseases using remote sensing techniques: a review’, PLoS Pathogens, 3(10), 2007, pp. 1361–1371.

  Kulkarni, M. A., Desrochers, R. E. and Kerr, J. T., ‘High resolution niche models of malaria vectors in northern Tanzania: a new capacity to predict malaria risk?’, PLoS ONE, 5(2), 2010, e9396.

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  Rogers, D. J., Randolph, S. E., Snow, R. W. and Hay, S. I., ‘Satellite imagery in the study and forecast of malaria’, Nature, 415, 2002, pp. 710–715.

  Sharp, B. L., Kleinschmidt, I., Streat, E., Maharaj, R., Barnes, K. I., Durrheim, D. N., Ridel, F. C., Morris, N., Seocharan, I., Kunene, S., La Grange, J. P., Mthembu, J. D., Maartens, F., Martin, C. L. and Barreto, A., ‘Seven years of regional malaria control collaboration — Mozambique, South Africa, and Swaziland’, Am J Trop Med Hyg, 76, 2007, pp. 42–47.

  Kunene, S., Phillips, A. A., Gosling, R. D., Kandula, D. and Novotny, J. M, ‘A national policy for malaria

elimination in Swaziland: a first for sub-Saharan Africa’, Malaria Journal, 10, 2011, p. 313.

  Ministry of Economic Planning and Development, Swaziland millennium development goals progress report — Swaziland on the road to development, 2010.

  Swaziland Ministry of Health and Social Welfare and the National Malaria Control Programme: Malaria control in Swaziland Mbabane, Swaziland 1999 and 2010.

  World Health Organisation, WorldMalaria Report 2011, online: http://www.who.int/malaria/world_malaria_report_2011/en/

CHAPTER 21

Author: Ren Capes

consortium members: Fugro NPA Ltd, United Kingdom; Natural Environment Research Council (British Geological Survey), United Kingdom; Landmark Information Group, the United Kingdom; Nederlandse Organisatie Voor Toegepast Natuurwetenschappelijk Onderzoek (TNO), the Netherlands; Systèmes d’Information à Référence Spatiale (SIRS), France; Consorci Institut de Geomatica (Institute of Geomatics), Spain; Bureau de Recherches Géologiques at Minières (BRGM), France; EuroGeoSurveys, pan-European; Fédération Européenne des Géologues, EU; AB Consulting, United Kingdom; Tele-Rilevamento Europa, Italy; Gamma Remote Sensing, Switzerland; Altamira Information, Spain; Geologische Bundesanstalt, Austria; Institut Royal des Sciences Naturelles de Belgique, Belgium; Ministry of Environment and Water, Bulgaria; Ministry of Agriculture, Natural Resources and Environment of Cyprus, Cyprus; Česká Geologická Služba, Czech Republic; Geological Survey of Denmark and Greenland, Denmark; Eesti Geoloogiakeskus OU, Estonia; Geologian tutkimuskeskus, Finland; Bundesanstalt für Geowissenschaften und Rohstoffe, Germany; Instituto Geologikon Kai Metalleytikon Ereynon, Greece; Magyar Állami Földtani Intézet, Hungary; Department of Communications, Energy and Natural Resources, Ireland; Istituto Superiore per la Protezione e la Ricerca Ambientale, Italy; Latvijas Universitāte, Latvia; Lietuvos

geologijos tarnyba prie Aplinkos ministerijos, Lithuania; Administration des Ponts et Chaussees — Direction, Luxembourg; Malta Resources Authority, Malta; Państwowy Instytut Geologiczny, Poland; Laboratório Nacional de Energia e Geologia, Portugal; Institutul Geologic al Rômaniei, Romania; Štátny geologický ústav Dionýza Štúra, Slovakia; Geološkega zavoda Slovenije, Slovenia; Instituto Geológico y Minero de España, Spain; Sveriges geologiska undersökning, Sweden

AbSTRACT

PanGeo is a 3-year FP7 GMES down-stream services collaborative project that started on 1 February 2011 with the objective of enabling free and open access to geohazard information in support of GMES. This will be achieved by providing an Inspire-compliant, free, online geohazard information service for the two largest towns in each EU country (Cyprus and Luxembourg only one) — 52 towns in total (~ 13 % of the EU population). Products will be made by the EU-27 national geolog-ical surveys by integrating terrain-motion data from Persistent Scatterer InSAR (PSI), their own geological data, and then further integrated on the fly within a portal using the exposure data inherent in the EU’s Urban Atlas land

PanGeo: Enabling access to geological infomation in support of GMES

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cover data set. At the time of writing, after one year of project duration, the overall design of the service has been confirmed. Two key deliverables at this time are the Service specification and the Production manual — the latter representing the definitive instruction to the geological surveys on how to make the products.

introduction

Geohazards in the built environment can be dangerous and costly, yet infor-mation about these phenomena and their effects can be difficult if not impossible to obtain. PanGeo is about generating information on urban geo-hazards and then making this informa-tion freely available and accessible to all, online.

Geohazards in PanGeo are natural and man-made phenomena that have the potential to make the ground unsta-ble. These geohazards include: earth-quakes, landslides, mineral workings, groundwater abstraction and recharge, shrink and swell clays, soluble rocks, compressible ground, collapsible deposits and landfill (many of these geohazards manifest as subsidence).

PanGeo is a 3-year collaborative pro-ject that started on 1 February 2011, with the objective of enabling free and open access to geohazard infor-mation in support of GMES. This will be achieved by providing an Inspire-compliant, free, online geohazard information service for the two largest towns in each EU country (Cyprus and Luxembourg only one) — 52 towns in total (~ 13 % of the EU population).

The geohazard information will be served in a standard format by the

27 EU national geological surveys via a modified version of the ‘shared access’ infrastructure as devised for the DG Information Society and Media project ‘OneGeology-Europe’. The information to be served (a new geohazard data-layer and accompanying interpreta-tion) will be made by each survey, and will be compiled from integrations of:

• satellite Persistent Scatterer InSAR processing, providing measurements of terrain-motion;

• geological and geohazard informa-tion already held by national geolog-ical surveys;

• the land cover and land use data contained within the GMES land theme’s Urban Atlas.

Upon user enquiry, a PanGeo web por-tal will automatically integrate the geohazard data with the Urban Atlas to highlight the land cover polygons influenced. Mousing over polygons will hyperlink to interpretative text. User input to design will be facilitated by the surveys contracted into the pro-ject and initiation of a Local Authority Feedback Group (LAFG). The ‘LAFG’ was established in the first 6 months of the project and comprises representa-tives from geographically spread local authorities from six of the 52 towns to be processed. By both face-to-face interviews and online surveys, the LAFG is providing direct input to the overall design of the PanGeo products and service.

It is exptected that sustainability of PanGeo will be achieved by attracting a proportion of the remaining 253 Urban Atlas towns to procure the PanGeo ser-vice for their towns. The service that will already be provided in their country

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will form the basis of the required pro-motional activity.

Target users of the PanGeo service

PanGeo is quite specifically targeted at four key user groups:

• government local authority planners and regulators who are concerned with managing development control and risk;

• national geological surveys and geo-science institutes who collect and disseminate geohazard data for pub-lic benefit;

• policy-makers concerned with assessing and comparing pan-Euro-pean geological risk;

• the public, for general empowerment.

Service mechanics

The first year of the project has seen intense work in designing the service. Figure 1 shows the overall concept.

All 27 EU national geological surveys are producing two key products: A ‘ground stability layer’ and a ‘geohaz-ard summary’. Four InSAR providers are providing the geological surveys with terrain-motion data for each of the 52 towns involved in the service (note that 27 of the PSI datasets have already been produced in the European Space

Agency GMES service element project ‘Terrafirma’, leaving 25 datasets to be produced from within PanGeo). The sur-veys use these data, in conjunction with their own geological data and expertise, to produce a new ground stability layer. This 2D vector layer comprises polygons surrounding discrete areas of common geohazard, both observed and potential. Each polygon then relates to interpreta-tive text within a newly compiled geo-hazard summary document.

Production of PanGeo products by the geological surveys splits into three key stages:

• Psi data reception and integration:

— various compliancy checks,

— optional interpolation,

— integration of PSI data with geo-logical data;

• interpretation and production of the ground stability layer:

— confirming coverage options,

— polygonising discrete areas of geohazard,

— assigning interpretative attributes,

— preparation of a geohazard summary containing polygon interpretation;

Figure 1. Conceptual mechanics of PanGeo product generation.

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• Preparation of products for delivery:

— compiling web-mapping and web-feature services,

— preparation of a geohazard sum-mary for the portal,

— server-hosting to allow remote portal harvesting.

deriving coverage extents: Decisions need to be made by the interpreter relating to the extents of the ground stability layer. Figure 2 helps explain this: on top of the Open Street Map background there are three layers. In order of size, these are: the Urban Atlas ‘larger urban zone’ (which is very large indeed), a red box indicating the extent of the PSI data coverage and, finally, solid-filled polygons representing inner

London administration boundaries. Due to the large extent of some larger urban zones vs the PSI coverage, a decision has been made for the ground stabil-ity layer to confirm with the contiguous urban fabric of the inner London admin-istration boundaries.

Polygonising geohazards: Figure 3 shows prototype polygonisation of geohazards in London, UK. Note that the overall 20 geohazard types used in PanGeo are compressed into six group-classes to aid visualisation. It is important to stress that the geohazard polygons are not based solely upon PSI, but on all data, including PSI, at the dis-posal of the interpreter. Background ori-entation mapping is ‘Open Street Map’ (free geographic data as supported by the OpenStreetMap Foundation — www.osmfoundation.org).

Figure 2. Deriving the extents of the ground stability layer.

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Figure 3. Prototype polygonisation of part of London, United Kingdom.

When the geological survey has com-pleted the ground stability layer, it is submitted to an automated valida-tion tool which checks geometry, e.g. that all polygons are closed, as well as collecting base statistics facilitat-ing the production of ‘global’ statis-tics, e.g. how many square kilometres of all towns are affected by geohaz-ard type x.

User access

Users will access the informa-tion provided by PanGeo through a ‘PanGeo portal’ — a derivative of the OneGeology-Europe geoportal upon which the PanGeo service is built. Upon a user enquiry for a given town, the portal will automatically coincide with the ground stability layer described above with corresponding data from the EU’s Urban Atlas, which com-prises 27 land cover classes at 2.5 m

resolution (~ 1:10 000). Urban Atlas polygons that intersect with the ground stability layer polygons will be high-lighted indicating that they are influ-enced by a geohazard(s). Mousing over these areas will pop-up a brief descrip-tion of the hazard. A mouse-click will link the user directly to a full explana-tion within the geohazard summary document. The concept for user access is shown in Figure 4.

Figure 5 is a prototype visualisation of what a user will see when first clicking on a town. The image shows the extent of the ground stability layer coverage, as well as geohazard polygons in sum-mary form.

The user then has an option to inte-grate the Urban Atlas data for the area. When this is done, the Urban Atlas is highlighted where it coincides with geohazard polygons (see Figure 6).

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Figure 4. Concept for user access.

Figure 5. Initial (prototype) visualisation.

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Figure 6. Prototype visualisation showing the Urban Atlas land cover data highlighted where it coincides with geohazard polygons. In this example, the polygon geohazard type is depicted by the polygon line-style.

The integration of the ground stability layer with the Urban Atlas allows the derivation of various data, such as the type of land cover exposed to a par-ticular hazard, or even populations affected by hazard-type. Examples of what can be done with PanGeo prod-ucts will be available from the PanGeo website. All PanGeo products (geo-coded Urban Atlas, ground stability layer and the geohazard summary as a standalone PDF) will be downloadable to enable use within a users’ own geo-graphic information system.

The 52 towns currently included in the service

The following table shows the 52 towns currently included within the PanGeo ser-vice. Note that Cyprus and Luxembourg only have one town each as these coun-tries only have one Urban Atlas data set available, as the threshold for inclusion in the Urban Atlas is a minimum pop-ulation of 100 000. In most cases the towns chosen are simply the two largest in the country. The final decision is made by the geological survey.

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CHAPTER 22

Authors: Valerio Tramutoli, Carolina Filizzola, Sedat Inan, Norbert Jakowski, Sergey Pulinets, Alexey Romanov, Irk Shagimuratov, Nicola Pergola, Nicola Genzano, Mariano Lisi, Erhan Alparslan, Semih Ergintav, Claudia Borries, Volker Wilken, Kostantin Tsybulia, Eugeny Ginzburg, Igor Cherny, Alexander Romanov, Irina Coviello, Rossana Paciello, Irina Zakharenkova, Yuri Cherniak, Marianna Balasco, Giuseppe Mazzeo

consortium members: University of Basilicata, Italy; Geospazio Italia srl, Italy; TÜBİTAK Marmara Research Center, Turkey; Deutsches Zentrum für Luft- und Raumfahrt eV, Germany; Fedorov Institute of Applied Geophysics, Russia; JSC Russian Space Systems, Russia; West Department of NV Pushkov IZMIRAN RAS, Russia; Institute of Methodologies for Environmental Analysis of the National Research Council, Italy

AbSTRACT

The scientific objective of Pre-Earthquakes is to demonstrate how far the systematic integration of measures of different physical and chemical parameters may improve our present ability to forecast strong earthquakes in the short term.

Observations are collected from 18 different satellite systems and more than 100 ground stations will be used to study the anomalous variations of surface and atmospheric parameters (up to the ionosphere) that have long been proposed as possible precursors of strong earthquakes. The Sakhalin peninsula in eastern Russia, Turkey and Italy have been selected as initial testing areas where observation inte-gration will be particularly intensified up to a period of real-time monitoring at the end of the project, expected for December 2012.

After only 1 year of activity, automatic data-product generation chains were fully implemented for seven moni-tored parameters, using 20 independ-ent observing technologies (including both satellite systems and ground sta-tions), 11 different data analysis algo-rithms for (more than) three testing areas and 24 different testing periods. A Pre-Earthquakes Geoportal (PEG), is now ready to operate, serving prod-uct integration, cross-validation and scientific interpretation not only for project partners but also for network-ing members (presently more than 20) asking to join the project in the framework of the EQuOS (Earthquake Observation System) initiative. In this paper project rationale, scientific

Pre-Earthquakes: Processing Russian and European Earth observations for earthquake precursors studies

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approach and achieved results to date are briefly presented.

AcHieVed resuLts

Nowadays a large amount of scien-tific documentation is available about the occurrence of anomalous transient patterns of geophysical parameters in seismic areas, attributed to stress and strain changes preceding earthquakes (e.g. Chu et al., 1996; Johnston, 1997). Recent studies pointed out that sig-nals related to tectonic processes in the Earth’s crust can be revealed by means of geo-chemical pathfinders, often connected to electro kinetic phe-nomena. Total electronic content (TEC), as measured by dense global position system (GPS) networks, is expected to exhibit a temporary increase of the electrons number as a consequence of acoustic gravity waves generated by a strong earthquake (Melbourne et al., 1997). The migration of fluid and/or gases triggered by tectonic activity, in particular, can produce shallow geo-chemical anomalies (CO2, radon and other ionic concentrations) and related electromagnetic signals (self-poten-tial anomalies, resistivity changes, ULF electromagnetic emissions, e.g. Revil and Glover, 1997).

It is widely recognised that areas of CO2 discharge globally coincide with the most seismically active regions (Irwin and Barnes, 1980) and that CO2 emissions may increase pore pres-sures within fault zones (Lewicki and Brantley, 2000). Transient physical phenomena, affecting crustal struc-tures involved in seismogenic pro-cesses, may influence the circulation of deep-seated underground fluids and gases as well as physical char-acteristics of hosting rocks. In par-ticular, observational evidences and

theoretical arguments have been pro-posed to associate abrupt changes in greenhouse gases (particularly CH4 and CO2) emissions with earthquakes’ preparatory phases (e.g. Scholz et al., 1973).

Several authors (e.g. Tronin, 1996; Qiang et al., 1997) have ascribed those abrupt changes in atmospheric greenhouse gases to the anomalous variations of Earth thermally emit-ted radiation, observed by TIR (ther-mal infrared) satellite surveys some weeks before a number of earth-quakes occurred in Asia (e.g. Qiang et al. 1997; Tronin 1996, 2000; Tramutoli et al., 2005). Other contributions to the increase of TIR emissions can be expected from concurrent phenom-ena (like deep ground water resurfac-ing and/or convective transport of the heat produced by friction along active faults) described by several authors (e.g. Hayakawa et al. 2001; Dragoni et al.,1996; Tronin, 1996; Qiang et al., 1997)

More recently, a unique, more com-plex, physical model (Pulinets, 2009) has been proposed (named LAIC — Lithosphere Atmosphere Ionosphere Coupling) linking, in the same chain of physical processes, thermal and atmospheric with seismo-ionospheric anomalies. In the same model, anom-alous transients in the measure-ment of several different parameters (geochemical emissions, ground sur-face thermal anomalies, surface air temperature and relative humid-ity, anomalous fluxes of latent heat, earthquake clouds, anomalous OLR emission and ionospheric anomalies) can be explained as a consequence of the physical processes associated with the preparation phases of an earthquake.

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The observational and theoretical arguments proposed for the relations between greenhouse gas (and partic-ularly CO2) discharges and seismo-genic zones distribution (e.g. Irwin and Barnes, 1980) — as well as among earthquakes’ preparatory phenom-ena and their occurrence (Scholz et al., 1973) — have received wide sup-port. This is not the case for the pro-posed observational methodologies for earthquake prediction. In general, no one single observational strategy, appears suitable to predict impending earthquakes with the level of accu-racy (in terms of time, place and mag-nitude) required, for example, by an operational early warning system (see for example Geller et al., 1997, and Evans, 1997).

The claimed relations between anom-alous signal transients and seismic activity have for a long time, and with good reason, been considered with some caution by the scientific com-munity. Mainly because of the insuffi-ciency of the validation data sets and the relevance of other potential causes (e.g. meteorological) that could be responsible for the signal anomalies, rather than seismic activity. Probably for this reason no specific funds have been, before now, specifically allocated by the European Commission to the study of earthquake precursors.

The specific scientific objective of Pre-Earthquakes is to investigate and demonstrate to which extent a systematic integration of independ-ent observations can improve (pos-sibly up to a pre-operational level of precision and reliability) our capabil-ities of short-term earthquake pre-dictions, which are presently based mostly on single parameter/observa-tion methods.

The project strategy is based on the following three mainstreams:

• to coordinate and implement sys-tematic data acquisition of earth-quake precursors’ candidates (from lithosphere to ionosphere) organised in predefined (standardised) output formats;

• to define and implement a common integration platform, where hetero-geneous data inputs can be ingested, organised, shared and compared;

• to validate and disseminate data analysis and integration meth-ods/tools, making them available and open to the contribution of the worldwide scientific community, in order to further extend the number of contemporary monitored param-eters and to improve the quality of data analysis methods.

According to Pre-Earthquakes’ ration-ale and objectives, both ground- and satellite-based observations, different data analysis methodologies, different measured parameters (Table 1) have been collected already and are going to be rigorously compared and integrated, in order to move the research in this field beyond its present frontiers. For this purpose, 80 radon measurement stations and a number of independent observations from 18 different satel-lite systems — particularly those from the European Space Agency (ESA) and Russian Agency (Roskosmos) — are used to study the anomalous variations of surface and atmospheric parame-ters (up to the ionosphere) that have been, for a long time, proposed as pos-sible precursors of strong earthquakes.

In particular, parameters from litho-sphere to ionosphere (near-surface

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thermal anomalies, total electron content, radon concentration, etc.), independently measured by several observing technologies are analysed by well-established data analy-sis methodologies, following a rigor-ous validation/confutation approach, for selected testing areas and study cases. In more detail, earthquakes that occurred in recent years in Italy

(Mw 6.3 Abruzzo EQ, April 2009), Sakhalin (Mw 6.2 Nevelsk EQ, August 2007) and Turkey (Mw 6.1 Elazig EQ, March 2010) have been used as Pre-Earthquakes’ initial test cases (Figure 1). Additional events, like the recently occurred earthquakes of Tōhoku (Japan) and Van (Turkey), have also been included among the project study cases.

Instruments Source Methodology - Partner Products

Meteor-M/GGAK ROSKOSMOS

Correlation Algorithm [Pulinets, S. A., et al., NHESS, 2004; Pulinets, S. A. and Boyarchuk K. A., Spring., 2005; Pulinets, S. A., et al.,

ASR, 2007] -FIAG

Maps of space plasma and ionospheric

anomalies (TEC)

GPS

IGS ESA RSSDifferential algorithm

[Pulinets, S. A., et al., ASR, 2007] -WD IZMIRAN

IGS EUREFAlgorithm for GPS TEC

[Jakowski, N., et al., ASR, 1998] – DLR

IGS EUREF RSS

Algorithm for vertical TEC reconstructions; Algorithm of

TEC maps creation; Algorithm of differential mapping; Algorithm of GEC calculation [Afraimovich E.L., et al., IRI, 2006]; Algorithm of wave-like disturbances calculations [Krankowski

A., et al., ActaG, 2005]; Numerical modelling

– WD IZMIRAN

GLONASS ROSKOSMOS

GALILEO and EGNOS ESA

FORMOSAT-3/COSMIC UCARAlgorithm of COSMIC profiles analysis

– WD IZMIRAN

Vertical profile of the ionospheric electron density

CHAMP GFZ PotsdamRadio Occultation technique

[Jakowski, N., et al., GRL, 2002, Jakowski, N., et al., ASR, 2005, Jakowski, N., GPS Solut 2005]

– DLRGRACE

NASA

GFZ Potsdam

COSMOS 2407

ROSKOSMOS

The ionosphere electron concentration vertical distribution

reconstruction technology [Romanov, A.A., et al., PICES Scientific

Report, 2007] – RSS

COSMOS 2414

COSMOS 2429

COSMOS 2454

METEOR-M/MSU-MR ROSKOSMOSCloud detection algorithms.

Visual inspection - RSS

Identified anomalous cloud

shapes

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METEOR-M/MSU-MR ROSKOSMOSCloud detection algorithms.

Visual inspection - RSS

Identified anomalous cloud

shapes

METEOR-M/MTVZA ROSKOSMOS Standard inversion procedures – FIAG Temperature and humidity profiles

MSG/SEVIRI ESA RST Technique

[Tramutoli, V., SPIE, 1998; Tramutoli, V., Multitemp, 2007, Tramutoli, V., et

al., RSE, 2005]

- UNIBAS

Maps of TIR anomalies by RETIRA index

EOS/MODIS NASA

NOAA/AVHRR NOAA NESDIS

RESOURS-DK/GEOTON-1

ROSKOSMOSVisual interpretation, supervised and unsupervised classification – UNIBAS

Land cover maps

RADON STATIONSTUBITAK MAM-EMSI

NETWORK

Time series data analysis

[İnan, S., et al., EOS Transactions, 2007]

– TUBITAK MAM

Punctual anomalies of radon

concentration

Permanent stationUNIBAS

IMAA-CNR

Time series data analysis

[Balasco, M., et al., AG, 2008]

- UNIBAS

Electrical resistivity profiles 0-10km

Table 1. Pre-Earthquakes’ observations (European systems in blue, Russian in red) and methodologies.

In summary, at the time of writing, prod-uct generation was fully implemented for seven monitored parameters, using 20 independent observing technolo-gies (including both satellite systems and ground stations), 11 data analysis methodologies, for three testing areas and 24 different testing periods.

The Pre-Earthquakes Geoportal (PEG), intended as an integration platform where independent observations and new data analysis methodologies can be shared, compared and cross-val-idated, is fully designed in terms of its architecture and functions, and developed in terms of its (server/cli-ent) components. Product integration, cross-validation and scientific interpre-tation is presently in progress.

Moreover, Pre-Earthquakes’ research and activities have been widely dis-seminated and promoted through

intensive dissemination actions, including the organisation of a dedi-cated workshop, several project pres-entations in relevant international scientific conferences, a number of meetings with representatives of con-nected projects to enhance the Pre-Earthquakes’ impact, and through enlarged cooperation. In this regard, Pre-Earthquakes has envisaged a strategy to open new partnerships, with a view to augment its research capacity by extending the consortium’s Earth observation capabilities and to promote and build up the EQuOS (Earthquake Observation System) Network as a dedicated component of GEOSS (Global Earth Observation System of Systems). To this aim, a rigorous process to involve ‘network members’, intended as external mem-bers interested in collaborating with the consortium and in sharing their data/observations/products relevant

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for the project, has been implemented. To date, about 20 requests from potential ‘network members’ have been already received, confirming the wide interest of the scientific commu-nity on these topics and, in particular,

on the Pre-Earthquakes’ rationale and scientific approach. Pre-Earthquakes begins to be present in the rele-vant scientific literature, with several already published papers quoting the project in international journals.

Figure 1. Present Pre-Earthquakes’ observation capabilities. Connection lines represent from the left to the right: (a) partners contributing to observations related to lithosphere, low atmosphere, ionosphere; (b) specific data-products generated by each partner (double lines means that the same product is generated by using multiple observation technologies, algorithms, stations); (c) data-products made available for each main testing area.

CONCLUSIONS

The appearance of anomalous space–time patterns of geophysical param-eters measured from days to weeks before the occurrence of earthquakes have been reported by several authors in the past years.

However, up to now no single meas-urable parameter, nor a single obser-vational methodology have been demonstrated to be sufficiently reli-able and effective for the implemen-tation of an operational earthquake prediction system. The claimed rela-tion between observed parameter

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variations and earthquake occurrence is still lacking a rigorous scientific approach, with often insufficient vali-dation analyses. On the other hand, a general consensus exists, in the sci-entific community, on the description of phenomena related to earthquake preparation and evolution as well as on the main parameters to be measured in order to confirm or reject theoreti-cal models. Pre-Earthquakes intends to restore the scientific method in the matter, improving available data anal-ysis methodology and to coordinate and realise a systematic collection and analysis of earthquake precursors observations.

To this aim, the combined use of differ-ent observations/parameters together with the refinement of data analysis methods, are expected to give major improvements, reducing false alarm rates and improving reliability and precision (in the space–time domain) of predictions. After the first year of activity it seems that Pre-Earthquakes was actually able to commit European and Russian researchers to start to integrate a wide variety of observa-tional data and to improve, by cross-validating their methodologies, and, moreover:

• to substantially improve our knowl-edge of preparatory phases of earthquakes and their possible precursors;

• to promote a worldwide Earthquake Observation System (EQuOS) as a dedicated component of GEOSS (Global Earth Observation System of Systems);

• to develop and offer to the inter-national scientific community the PEG integration platform where

independent observations and new data analysis methodologies devoted to the research on/of earth-quake precursors can be collected and cross-validated.

REFERENCES

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  Balasco, M., Lapenna, V., Romano, G., Siniscalchi, A. and Telesca, L., ‘A new magnetotelluric monitoring network operating in Agri Valley (Southern Italy): study of stability of apparent resistivity estimates’, Annals of Geophysics, 51(1), 2008.

  Baran, L. W., Shagimuratov, I. I. and Tepenitzina, N. J., ‘The use of GPS for ionospheric studies’, Artifical Satellites, 32, 1997, pp. 49–60.

  Chu, J. J., Gui, X., Dai, J., Marone, C., Spiegelman, M. W., Seeber, L. and Armbruster, J. G., (1996): ‘Geoelectric signals in China and the earthquake generation process’, Journal of Geophysical Research, 101(B6), 1996, pp 869–882.

  Dragoni, M., Doglioni, C., Mongelli, F. and Zito, G., ‘Evaluation of stresses in two geodynamically different areas; stable foreland and extensional backarc’, Pure and Applied Geophysics, 146(2), 1996, pp. 319–341.

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in the lithosphere, atmosphere and ionosphere’, Final Report, Univ. Electro-Comms., 2001, 228 pp.

  İnan, S., Ergintav, S., Saatçılar, R., Tüzel, B. and İravul, Y., ‘Turkey makes major investments in earthquake research’, EOS Transactions, 88, 2007, pp. 333–334.

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  Jakowski, N., Sardon, E. and Schlueter, S., ‘GPS-based TEC observations in comparison with IRI95 and the European TEC Model NTCM2’, Adv. in Space Res., 22(6), 1998, pp. 803–806.

  Jakowski, N., Wehrenpfennig, A., Heise, S., Reigber, C. and Lühr, H., ‘GPS radio occultation measurements of the ionosphere on CHAMP: early results’, Geophys. Res. Lett., 29(10), 2002, doi:10.1029/2001GL014364.

  Jakowski, N., Stankov, S. M., Schlueter, S. and Klaehn, D., ‘On developing a new ionospheric perturbation index for space weather operations’, Adv. Space Res., 2005, doi:10.1016/j.asr.2005.07.043.

  Jakowski, N., ‘Ionospheric GPS radio occultation measurements on board CHAMP’, GPS Solutions, 9(2), 2005, pp. 88–95, doi:10.1007/s10291-005-0137-7.

  Johnston, M. J. S., ‘Review of electric and magnetic fields accompanying seismic and volcanic activity’, Surveys in Geophysics, 18, Springer

Netherlands, 1997, pp. 441–475, ISSN: 0169-3298

  Krankowski, A., Shagimuratov, I. I., Baran, L. W. and Ephishov, I. I., ‘Study of TEC fluctuations in Antarctic ionosphere during storm using GPS observations’, Acta Geophys. Polonica, 53(2), 2005, pp. 205–218.

  Lewicki, J. L. and Brantley, S. L., ‘CO2 degassing along the San Andreas fault, Parkfield, California’, Geophysical Research Letters, 27, 2000, pp. 5–8.

  Melbourne, T., Carmichael, I., DeMets, C., Hudnut, K., Sanchez, O., Stock, J., Suarez, G. and Webb, F., ‘The geodetic signature of the M8.0 Oct. 9, 1995, Jalisco subduction earthquake’, Geophysical Research Letters, 24(6), 1997, pp. 715–718.

  Pulinets, S. A., Gaivoronska, T. B., Leyva Contreras, A. and Ciraolo L., ‘Correlation analysis technique revealing ionospheric precursors of earthquakes’, Natural Hazards and Earth System Sciences, 4, 2004, pp. 697–702.

  Pulinets, S. A. and Boyarchuk, K. A., Ionospheric precursors of earthquakes, Springer, Berlin, Germany, 2004, 315 pp.

  Pulinets, S. A., Kotsarenko, A. N., Ciraolo, L. and Pulinets, I. A., ‘Special case of ionospheric day-to-day variability associated with earthquake preparation’, Adv. Space Res., 39(5), 2007, pp. 970–977.

  Pulinets, S. A., ‘Lithosphere–Atmosphere–Ionosphere Coupling (LAIC) model’, Electromagnetic phenomena associated with

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earthquakes, Chapter 9, Research Signpost, Japan, 2009, pp. 235–253.

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  Romanov, A. A., Urlichich, U. M., Pulinets, S. A., Romanov, A. A. and Selin, V. A., ‘A pilot project on the comprehensive diagnosis of earthquake precursors on Sakhalin Island: Experiment results from 2007’, PICES Scientific Report, 36, 2009, pp. 208–214

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  Tramutoli, V., Cuomo, V., Filizzola, C., Pergola, N. and Pietrapertosa, C., ‘Assessing the potential of thermal infrared satellite surveys for monitoring seismically active areas: The case of Kocaeli (İzmit) earthquake, August 17, 1999’, Remote Sens. Environ., 96, 2005, pp. 409–426.

  Tronin, A. A., ‘Satellite thermal survey — A new tool for the study of seismoactive regions’, Int. Journal Remote Sensing, 17(8), 1996, pp. 1439–1455.

  Tronin, A. A., ‘Thermal IR satellite sensor data application for earthquake research in China’, Int. Journal Remote Sensing, 21(16), 2000, pp. 3169–3177.

CHAPTER 23

Authors: Simon Walker, Michael Balikhin, Oleg Pokhotelov, Michel Parrot, Alexander Rozhnoi, Maria Solovieva, David Shklyar, Valeri Afonin, Boris Levin, Leonid Bolomogolov

consortium members: University of Sheffield, United Kingdom; LPC2E Orleans, France; Institute of Physics of the Earth, Russia; Space Research Institute, Russia; Institute of Marine Geology and Geophysics, Russia

AbSTRACT

SEMEP, the ‘Search for electro-mag-netic earthquake precursors’, is an EU FP7-funded project to investi-gate the changes observed in ground-based radio transmissions as well as perturbations of the ionosphere that may occur due to seismic activ-ity. Preliminary results show that the signals from VLF/LF terrestrial trans-mitters are modified in both ampli-tude and phase if their propagation path passes in the vicinity over seis-mically active zones. Examples of these changes, in the form of both a case and statistical study are pre-sented. Changes in the ULF wave envi-ronment within the lower ionosphere are also investigated, showing an increase in the overall wave power at low frequencies.

introduction

Earthquakes pose a naturally occur-ring hazard to our way of life in cer-tain regions of the planet. They can result in large numbers of fatalities and destroy the infrastructure we rely on to lead our everyday lives. Recent examples include the M9 event off Japan in March 2011, the M6.3 event in L’Aquila, Italy, in April 2009, and the M7.9 quake in Sichuan, China, in May 2008. The occurrence of such events has been associated with the obser-vation of various electromagnetic phenomena such as perturbations of the ionospheric particle and plasma wave environments and anomalies in VLF/LF transmitter signals observed both from the ground and space. The main goal of SEMEP is to investigate electromagnetic phenomena in the global lithosphere–atmosphere–iono-sphere system that may be generated during periods of increased seismic activity as a prelude to a major earth-quake by employing both space-based and ground-based observations to produce a scenario for the changes observed in the electromagnetic envi-ronment associated with the occur-rence of large earthquakes.

This paper outlines some of the initial results of this project.

SEMEP: Search for electro-magnetic earthquake precursors

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deMeter oBserVAtions of Ground-BAsed TRANSMITTER SIGNALS

Case study

Simultaneous analysis of ground-based and satellite VLF/LF transmit-ter signal have been made for the Simushir earthquake (15 November 2006). Data from the VLF/LF station in Petropavlovsk-Kamchatsky and the ICE receiver on board Demeter were used for the analysis, using data col-lected between 1 October 2006 and January 2007. The satellite observa-tions focused on the signal from the

Australian NWC transmitter (19.8 kHz), whilst ground-based observations also include signals from two Japanese transmitters, JJI (22.2 kHz) and JJY (40 kHz). The NWC transmitter signal is the most powerful in the VLF range, enabling the analysis of signals from a large area. Signals from Japanese transmitters are local and can only be used for satellite analysis if the epicen-tres of earthquakes are located within the maximum signal zone.

A comparison of the results from sat-ellite and ground observations is pre-sented in Figure 1. Here we use the differences averaged over night time

Figure 1. Comparison of ground and satellite observations during October 2006 to January 2007 (from Rozhnoi et al., 2012a).

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for the ground reception and differences averaged along the section of the sat-ellite orbit as it traversed the seismic area. We notice an evident decrease in the amplitude of VLF/LF signals both in the ground and in the satel-lite data in association with seismicity. Amplitude anomalies are always neg-ative both for magnetic storms and seismic activity due to loss of signal caused by ionosphere irregularities during propagation. Phase anomalies can be both positive and negative. It depends on the length of the path. In the present case, the anomalies in the phase of the JJY signal are positive (Rozhnoi et al., 2012a).

Statistics of the electric field recorded by Demeter in the VLF range

The availability of almost 6.5 years of measurements provides a good opportunity to analyse a unique data set with global coverage and perform a statistical study of the intensity of VLF electromagnetic waves observed in the upper ionosphere. This analy-sis is based on survey mode VLF data from Demeter and a list of earthquakes from the USGS earthquake catalogue

(http://earthquake.usgs.gov). Altogether, about 9 000 earthquakes with magni-tude M >= 5.0 and depth D <= 40 km were included in the study.

Figure 2 shows the frequency–time dependence of the normalised prob-abilistic intensity obtained for dis-tances less than 440 km from the epicentre. One can see that the main observed feature is a decrease of the normalised probabilistic intensity at the frequency of about 1.7 kHz shortly (0–4 hours) before the time of the main shocks (Píša et al., 2012).

The frequency of 1.7 kHz at which the decrease is observed corresponds approximately to the cut-off frequency of the first TM mode (i.e. transverse magnetic mode; electromagnetic wave lacks magnetic field compo-nent in the direction of propagation) of the Earth–ionosphere waveguide during the night time. An increase of this cut-off frequency would there-fore necessarily lead to the decrease of the power spectral density of electric field fluctuations observed by Demeter in the appropriate fre-quency range. Such an increase of the cut-off frequency would correspond

Figure 2. Frequency-time dependance of the normalised probabilistic intensity (see text) obtained from the night-time electric field.

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to a decrease of the height of the ion-osphere. Our results could therefore indicate that the height of the iono-sphere is statistically lower above the epicentres of imminent earthquakes.

deMeter uLf oBserVAtions PRIOR TO THE SICHUAN EARTHqUAKE

In contrast to the VLF measurements shown above, the wave power at ULF frequencies has been observed to increase prior to the occurrence of a large earthquake. This increase is most obvious at low frequencies. The results shown here were measured in the vicinity of the Sichuan earthquake epicentre and concentrate on the period of around 20 days preceding the earthquake. An examination of the spectra for these data periods reveals that bursts of wave noise occur typ-ically at frequencies f < 0.5 Hz.

Figure 3 shows the wave power meas-ured below 0.5 Hz as a function of time averaged for a 30-second period centred on the time when Demeter is geographically closest to the epi-centre (blue), closest to the conju-gate point (red) or closest to the north (green) and south (magenta) conju-gate points at the satellite altitude. This plot indicates that for a number of days before the onset of the earth-quake there is an increase in the wave power below 0.5 Hz. This increase in wave energy probably results from the changes of the electrical properties of either the Earth’s crust due to the for-mation cracks and voids that will rap-idly fill with gases and liquids ahead of the magma front causing a step-like change in the electrical conduc-tivity in the thin layer changes in the lower atmosphere due to out-gassing. These changes are large enough to create internal gravity waves that may propagate through the atmosphere,

Figure 3. Variation of wave power

at frequencies f < 0.5 Hz

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transporting energy into the iono-sphere resulting in perturbations and instabilities in the plasma population and the growth of plasma waves.

ModificAtions to tHe SIGNALS OF TERRESTRIAL trAnsMitters oBserVed By deMeterThe amplitude of a ground-based VLF transmitter signal observed by Demeter in the region magneti-cally conjugate to its source depends strongly on whether the transmitter frequency is above or below the max-imum lower hybrid resonance (LHR) frequency above the satellite. This maximum is known to be very sensitive to small variations in the ion content of the ionosphere. Such variations are thought to be generated above regions increased seismic activity prior to an earthquake. Thus these measurements suggest an indirect way of monitor-ing ionospheric variations by means of monitoring the amplitude variations of ground-based VLF transmitter signals at frequencies close to the LHR maxi-mum. This methodology for monitoring ionospheric plasma variations is much easier and cheaper than direct plasma composition measurements. To inves-tigate the implementation of such a method, global maps of LHR frequency for various seasons and diurnal periods (day and night) have been constructed based upon Demeter measurements. Combining these maps with meas-urements of VLF signals from the Russian system of navigation trans-mitters (Alpha), we have experimen-tally demonstrated the dependence of signal amplitude on the relation between its frequency and LHR fre-quency. We have found several cases clearly showing that an increase in the

signal amplitude occurs in response to a decrease of LHR maximum. A com-prehensive study of the variations of LHR frequency before earthquakes, the correlations between background LHR frequency over seismically active regions and the variations of LHR fre-quency before earthquakes has been undertaken. A detailed account of the results will be presented in the first deliverable, which is due in May 2012.

Variations in the plasma particle dis-tribution and/or wave spectral fea-tures in the ionosphere have been suggested by many authors as pos-sible precursors of an earthquake. Comparing two corresponding types of measurements, i.e. particles and fields, the latter seem to be easier to trace on a regular basis. We sug-gest the monitoring of man-made VLF signals whose frequencies f lie close to the maximum of the lower hybrid resonance (LHR) frequency (fLH)max in the hemisphere opposite to that of the VLF transmitter. Since signal propagation close to (fLH)max may be qualitatively different for f > (fLH)max and f < (fLH)max, and since (fLH)max is very sensitive to the plasma particle distribution at the ‘base level’ of the ionosphere, the measurement of unexpected transmitter signal vari-ations can indicate unexpected varia-tions in plasma distribution above the receiver. These variations may serve as a warning of anomalous processes in the ionosphere, possibly related to a gathering earthquake. Figure 4 shows the maximum LHR frequency above the satellite (green line) calcu-lated from the lower frequency cut-off of LHR noise in the Demeter VLF spec-trograms measured in the burst mode.

A sharp decrease of both local (blue line) and maximum (green line) LHR

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frequency a few days before the earth-quake is clearly seen. This is accom-panied by a corresponding increase of spectral intensity at a frequency of 11.9 kHz, i.e. one (the lowest) of the working frequencies of ground-based VLF Alpha transmitters.

MULTISTATION ANALySIS OF VLF SIGNALS

Figure 5 shows an example of the multistation analysis. Signals from a transmitter in Iceland are received in three locations — Bari (Italy), Graz (Austria) and Moscow (Russia) — as shown in the top panel. The lower left panel shows the propagation paths of the three received signals and the lower right panel shows the spec-trum of these signals. The results

show that the signals received in Graz and Moscow (red and blue) are simi-lar whilst that from Bari exhibits large amplitude changes and also a noisier spectrum. This difference appears to be related to the fact that the propagation path to Bari lies very close to the epi-centre of the L’Aquila earthquake.

Statistical analysis

For the purpose of determining the sensitivity threshold of the LF signal to the magnitude of an earthquake and unearthing probable periods of observation of anomalies caused by seismic activity, a statistical analy-sis has been made using 7 years of observations of the wave path JJY–Petropavlovsk–Kamchatsky. A previous analysis was made using only 2 years of observations.

Figure 4. Variations of the LHR frequency and wave spectral intensity measured by Demeter at the time of the New Zealand earthquake on 15 July 2009.

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Figure 5. Example of multistation analysis.

Figure 6. Dependance of amplitude anomalies of the LF signal on M of EQs for the interval from 10 days before to 10 days after EQ times.

Figure 6 shows histograms of the average residual amplitude as a func-tion of time taken 10 days either side of the earthquake for four dif-ferent earthquake magnitude ranges. We find that the sensitivity of the LF signal to seismic processes becomes apparent mainly for M ≥ 5.5. The most

probable times of anomalies are 6–7 and 3 days before an earthquake and 6–7 days after it. Statistically, signif-icant analysis (made for 80 events) shows that anomalies of LF signal are observed in 25–30 % ofcases for earthquakes with М = 5.5–6.5.

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Spectral analysis

We examined changes in the spectral composition of the LF sub-ionospheric signal from the NRK transmitter (37.5 kHz) in Iceland that was received in Bari (Italy) around the time of the earthquake that occurred in L’Aquila on 6 April 2009. The strongest anoma-lies in the signal were observed in the NRK–Bari propagation path during the period 5–6 days before the earthquake as well as during the series of after-shocks (Rozhnoi et al., 2012b).

These anomalies are similar to the anomalies during strong magnetic activity. Although the characteristics of the waveform of the NRK signal anomalies appear identical during the L’Aquila earthquake and for periods of strong geomagnetic activity, their resulting spectra are different.

We have applied spectral analy-sis to signals recorded on quiet days and compared them to similar results for days on which geomagnetic- and

seismo-induced anomalies were observed. For the analysis we have used the night-time amplitudes of the NRK signal filtered in the frequency band 0.28–15 mHz which corresponds to wave periods in the range T from 1 to 60 minutes. Figure 7 shows the spec-tra of the filtered LF signal received at the Bari, Graz and Moscow stations for quiet days long before the earthquake (top row), for possible seismo-induced anomalous days in NRK–Bari wave path just before the earthquake (mid-dle row), and for days after main after-shocks (bottom row). Note that for the last period we had data only from the Bari station.

The spectra are very similar for all three stations during quiet periods. This con-trasts with the differences seen in the spectra of seismo-disturbed days. Only the spectra of the signal propagating along the NRK–Bari path exhibits wave activity with periods of the order 10–20 minutes. These periods are absent from the spectra of the undisturbed signals, those used as control paths.

Figure 7. Spectra of the filtered (0.28-15 mHz) amplitude of the NRK signal (from Rozhnoi et al, 2012b).

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Similar spectral changes were also observed in the LF (40 kHz) signal from the JJY transmitter in Japan measured in Petropavlovsk-Kamchatsky (Russia) for strong earthquakes (M = 6.1–8.3) which occurred in the sensitivity zone of this wave path in November 2004, November 2005 and November 2006.

QuAsi-Periodicity of SEISMIC EVENTS

The seismicity of the territory of the Far East (north-west region of the Pacific Basin) was analysed with the use of the data from the local seismic networks (southern part of Sakhalin island, South Kuriles, Kamchatka) as well as the pri-mary operative data of the National Earthquake Information Center (NEIC/USGS) (Tikhonov and Lomtev, 2011).

The mega-earthquake Sendai (Toho ku), occurred on 11 March 2011 at 05.46 GMT (14.46 LT) to the east of Honshu island (Japan). About 160 shocks

with M = 4.6–7.9 were recorded during the first day after the mega-earthquake (22 of them had M ≥ 6.0). The strongest aftershock, occurring after 39 minutes after the main event, had a magnitude of 7.9.

Quasi-periodicities in the flow of strong seismic events were found, implying that the occurrences of powerful earth-quakes in different seismically active zones of the Far East are synchronised. This aspect forms another essential tool for detection of alarm periods related to the sequence of earthquakes. The time intervals (quiescence and alarm windows) characterising the periods of decreased and increased occurrence probability of earthquakes with M ≥ 7.7 were calculated based on observation data for covering 100 years. A periodic-ity of T = 780 days appears to exist for earthquakes with M ≥ 7.7, situated in three active zones (to the east of Honshu and Hokkaido islands, Kamchatka and the South Kuriles). A diagram show-ing their alarm and quiescence periods

Figure 8. Mapping of clusters of strong (M ≥ 7.7) shallow earthquakes in sub-regions of Kamchatka, the South Kuriles and Japan (from Tikhonov and Lomtev, 2011).

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is shown in Figure 8. The largest cir-cle denotes the occurrence of the Great Japan Earthquake of 11 March 2011. It occurred at the end of an alarmwin-dow spanning 24 December 2009 to 20 March 2011); i.e., it obeys the gen-eral regularity observable over the last 100 years.

CONCLUSIONS

The objective of the SEMEP project is to investigate perturbations in the lower ionosphere using electromag-netic techniques and their possible relationship to increased seismic activ-ity. The preliminary results show that ground-based transmitter signals can be affected if their propagation path passes close to a seismically active region. This may lead to a methodology that can provide input to the prediction of the occurrence of large earthquakes.

REFERENCES

  Píša, D., Němec, F., Parrot, M. and Santolik, O., ‘Attenuation of

electromagnetic waves at the frequency ~ 1.7 kHz observed in the upper ionosphere by the Demeter satellite in the vicinity of earthquakes’, 2012, accepted for publication in Annales Geophysicae.

  Rozhnoi, A., Solovieva, M., Parrot, M. Hayakawa, M., Biagi, P.-F. and Schwingenschuh K., ‘Ionospheric turbulence from ground-based and satellite VLF/LF transmitter signal observations for the Simushir earthquake (November 15, 2006)’, 2012a, accepted for publication in Annales Geophysicae.

  Rozhnoi, A., Solovieva, M., Biagi, P.-F., Schwingenschuh, K. and Hayakawa, M., ‘LF signal spectrum analysis for strong earthquakes’, 2012b, accepted for publication in Annales Geophysicae.

  Tikhonov, I. N. and Lomtev, V. L., ‘Great Japan earthquake of March 11, 2011: Tectonic and seismological aspects’, Izvestiya, Atmospheric and Oceanic Physics, 46, 2011, pp. 978–991.

Space science . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277

Space propulsion and transportation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301

Space data exploitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341

Space technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377

Space weather . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 473

Space debris . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 505

Part II Strengthening Space Foundations

CHAPTER xx Space science

CHAPTER 24

Authors: Audrey Berthier, Natalie Leys, Rob Van Houdt, Alexander Tikhomirov, Natalia Novikova, Vacheslav Ilyin, Ilpo Kulmala, Matti Lehtimäki, Eero Kokkonen, Pertti Pasanen, Hafid Abaibou

consortium members: MEDES Institute for Space Physiology and Medicine, France; SCK•CEN Belgian Nuclear Research Centre, Belgium; Institute of Biophysics of the Siberian Branch of the Russian Academy of Sciences (IBP), Russia; Institute of Biomedical Problems of the Russian Academy of Sciences (IBMP), Russia; VTT Technical Research Centre of Finland, Finland; University of Eastern Finland (UEF), Finland

AbSTRACT

On Earth, nowadays, people spend more than 90 % of their time indoors or in vehicles. Biocontamination in these closed areas can have significant health impacts (Franchi et al., 2004).

When humans go into space, so also do bacteria. On manned space-craft, there is a need for effective biocontamination control measures. Biocontamination in spacecraft may indeed result both in a risk for the health of the crew and for the on-board equipment.

BIOSMHARS is the first phase of a joint EU–Russia research effort to develop the scientific and technical tools for a comprehensive approach to the chal-lenging issue of biocontamination inside manned spacecraft. The pro-ject intends to develop, to calibrate and to validate a mathematical model to predict the transportation of bio-aerosols in a closed environment and the concurrent spread of biocontami-nation, first on the ground, without human activities. The long-term objec-tive is to produce a versatile and robust modelling tool for predicting airborne microbial contaminant dispersion and concentration distribution in a space-craft. In addition to the normal airflow fields and temperature distribution predictions, the objective is that the model also takes into consideration the different types of human bioaero-sol emissions. It will be a 3D compu-tational fluid dynamics (CFD) model. Experiments will be required to check the validity of simplifying assumptions as well as to find out the accuracy, the limitations and the development needs of the model. The model will be refined as required, based on the results of the experiments. The initial calibration will be realised in a special test room at VTT using non-viable particles gener-ated by conventional aerosol genera-tors. The model will then be validated with non-viable particles in a BIOS-3 facility, which is a closed ecosystem

BIOSMHARS: Biocontamination specific modelling in habitats related to space

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used to conduct confinement studies. Finally, the model will be calibrated (at VTT) and validated (in BIOS-3) with biological particles using bacterial and fungal aerosols. The aim will be to ensure that the model provides a reli-able picture of bioaerosol behaviour. The project started in June 2011 and will last 2 years and will, in addition, develop a scientific and technical road-map to plan further phases.

AcHieVed resuLts

Review of current issues and procedures (SCK•CEN, IBMP, UEF with support of BioMérieux)

The project started with a review of the current issues and procedures related to biocontamination in spacecraft. Partners of the consortium have summarised this review in a scientific paper called ‘The space microbiome: ecology and implications’, currently under evaluation for publication in a scientific journal.

Space stations offer an environment that protects the astronauts/cosmo-nauts from the extreme space environ-ment. Next to humans, microorganisms are inevitable co-inhabitants in space

stations; and microorganisms found in space stations are both from human and environmental origins. Most of these microorganisms do not present severe hazards for healthy people. However, microbial contamination can be a threat to the health of astronauts/cosmonauts with reduced immune response (Aponte et al., 2006). In addition, bacteria and fungi found on interior construction materials and hardware can deterio-rate polymers and mediate corrosion of metals (Gu, 2007). An adequate control of the total load and microbial diver-sity in manned spacecrafts and moni-toring of specific parameters influencing their persistence, survival and growth in these habitats is thus essential. Figure 1 summarises the microbial risks in spaceflight.

To ensure the indoor environmen-tal quality in the ISS, the maximal amounts of bacteria and fungi in the air, on surfaces and in water permit-ted in the living and working areas of the ISS were internationally defined and agreed upon, and included in the ISS Medical Operations Requirements Document (ISS MORD, 2009). These standards are similar to the thresholds defined for health offices and homes on Earth.

Microbial risks in manned spaceflight

Health Technical

AutoinfectionAutoinfection

SPACE MICROBIOME

Dysbiosis BiodegradationBiodegradation

BiocorrossionBiocorrossion

Water and food quality deteriorationWater and food quality deterioration

Cross-infectionCross-infection

HypersensitivityHypersensitivity

Microbial risks in manned spaceflight

Health Technical

AutoinfectionAutoinfection

SPACE MICROBIOME

DysbiosisDysbiosis BiodegradationBiodegradation

BiocorrossionBiocorrossion

Water and food quality deteriorationWater and food quality deterioration

Cross-infectionCross-infection

HypersensitivityHypersensitivity

Figure 1. The microbial risks in a long-term manned space mission.

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To meet these quality standards, sev-eral prevention, monitoring and mit-igation measures are implemented by the space agencies to control con-tamination in manned space sta-tions. Partners offer in the scientific paper also a review of these meas-ures and a review of microbial popu-lation observed aboard space stations. The collected data of microbiological contamination from different environ-mental sources indicates that the ISS is a microbiologically safe working and living habitat. However, the facts that astronauts have a weakened immune system and that occasional contami-nation hazards are reported indicate that the current strategies for preven-tion and monitoring are a minimum. Fluctuations in microbial concentration and contamination events suggest the need for continued diligence and eval-uation as well as further improvements in engineering systems. Significant improvements could be achieved if a reliable model to predict bioaerosol dispersion in closed habitats would be available to be used to validate hab-itat design and to develop adequate prevention and monitoring procedures for airborne microbial contamination. BIOSMHARS should contribute in devel-oping such a model.

Requirements for the modelling approach (VTT, UEF, SCK•CEN with support of BioMérieux)

The consortium defined in paral-lel the requirements for the modelling approach.

Human exposure to airborne biocon-taminants is mainly affected by the generation and dispersion of bioaero-sols and their transport and dilution due to ventilation airflows (Li et al., 2007). Thus the control of bioaerosols is

essential in indoor air quality manage-ment. The partners have reviewed the current knowledge gained from relevant studies in this wide and multidisciplinary area of bioaerosol dispersion modelling and biological indoor air quality control, taking into consideration the specific conditions in space. This review has been synthesised in a scientific paper called ‘Modelling of airborne microbial contamination in space stations’, cur-rently under evaluation.

Microorganisms in indoor air specifically associated to human activity originate from two main sources: (i) droplets expelled during respiratory activities; (ii) skin flakes or scales, which are par-ticles shed from the skin surface due to the continuous renewal of the epi-dermal cell layer. Characterisations of these two sources have also been reviewed in the paper under evalu-ation. The complex phenomena of microbial dispersion through air and deposition onto surfaces in a confined environment are a topic of interest in numerous areas such as hospitals, aer-oplanes and the food industry (Chao et al., 2008; Wan, 2009). Reliable simu-lation tools, mathematical models, are urgently needed to correctly describe the biocontamination phenomena.

Methodology for the modelling (VTT)

The partners identified five phases that should be included in a comprehensive modelling of indoor biocontamination, specifically the description of: (i) the airflow field in enclosed space, (ii) the microbial contaminant generation (source description), (iii) the microbial contaminant dispersion, (iv) the micro-bial contaminant deposition on sur-faces; (v) the microbial growth (biofilm formation) on surfaces. The latter will

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not be modelled within the current BIOSMHARS project. The model will be developed step by step following this methodology. It will be validated after each step and further refined as needed before including the next step of modelling. The partner in charge of the modelling is VTT.

The development of the model will start by the construction of its basis, i.e. by modelling the geometry and of the airflow inlets and outlets, with realistic boundary conditions. Modelling will then include the description of the contamina-tion sources, taking into account in particular the contaminant size distributions and injection prop-erties (amount, location/volume, velocity/momen-tum, etc.). Modelling of contaminant dispersion will consist in particle tracking in terms of airflow and particle dynamics. Finally, modelling of the deposi-tion of particles should include the settling, impac-tion on surfaces, turbulent eddies and electrostatic, thermophoresis and other possible effects.

The model will be a 3D CFD model. The calcula-tions will be made first assuming normal gravity but the model will allow the gravity vector to be adjusted in the future to reflect microgravity condi-tions. First, the model will be calibrated, i.e. tested at each step, and further refined at VTT’s test labo-ratory. It will then be validated in a BIOS-3 facility. The calibration and the validation will be realised in two steps: first through a physical validation with non-biological particles and then through a biological validation, i.e. with aerosols containing microbes. The modelling is just starting.

Bioaerosol calibration (UEF with the support of IBMP, SCK•CEN and BioMérieux)

The biological calibration and validation of the model, i.e. with aerosols containing biological par-ticles, requires the generation of well calibrated aerosols (calibrated in terms of expected size dis-tributions of the particles, number of particles, etc.). One of the objectives of the project is thus also to set up and develop bioaerosol generation systems for selected micro-organisms. The microorgan-isms that have been selected for the project are: Penicillium expansum, Staphylococcus auricularis

and Bacillus subtilis. The tested strains have been isolated from samples retrieved from the ISS (by IBMP). They have been selected because they are well representative of the microbial flora found on the International Space Station. The bioaerosol will be generated and tested by UEF, with the support in particular of IBMP, SCK•CEN and BioMérieux.

The performance of the bioaerosols will be tested with characterisation of stability, source strength, size distributions of the generated aerosols, examination of the agglomeration stage and the purity of the generated aerosol. The system set-up will then be realised for model calibration and validation at VTT (by UEF) and at IBP in BIOS-3 for the validation experiments (by IBMP). Bacteria will be generated as wet and fungi as dry.

The bioaerosol generation step is just starting.

Upgrade of a BIOS-3 facility for experiments on biocontamination (IBP with the support of other partners for definition of the requirements)

For the validation of the model, the objective was to carry out experiments in a facility similar to a spacecraft environment. The facility was expected to meet the following life support requirements: to be a pressurised volume comparable in size with the ISS living module; to provide environmental parameters’ control (airflow rates, temperature, humidity, artificial illumination, etc.) within suf-ficiently broad limits including those optimal for human life support; to be suitable for humans’ long-term autonomous stay via mass exchange closure. At present the BIOS-3 facility owned by the IBP SB RAS (Krasnoyarsk, Russia) meets the abovementioned requirements. Of all the man-made life support systems so far devised, BIOS-3 is the only one that has kept a crew of two to three alive for 4 to 6 months by almost 100 % closure of the cycle in terms of gas and water and more than 50 % in terms of food (Salisbury et al, 1997; Gitelson et al, 2003). Extensive experience of microbiological investigations during the long-term experiments in BIOS-3 (including a human crew) is available (Rerberg et al, 1977; Gitelson et al, 1981; Kochetova et al, 1988).

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Figure 2. View of BIOS-3

compartments.

Therefore, the BIOS facility has been con-sidered adequate for validation experi-ments planned within BIOSMHARS. IBP, operating the BIOS-3 facility will be in charge both of the upgrade of the facil-ity and of providing the engineering and technical support for the realisation of the experiments within BIOS-3. Upgrade of the facility will include, in particular, the upgrading of the required sensors to perform the experiment and the imple-mentation of a telecommunication sys-tem that will allow the remote following of the measurements. IBP will then be responsible to set up the airflow gener-ation system within the compartment, according to the requirements defined by VTT and with the support of VTT.

Experiment design (IBMP with the support of other partners)

The experiment design for the physical validation is currently under definition. At this stage, the biological validation

is envisaged as follows: it would con-sist of four experimental sessions with the same conditions, i.e. bacteria and fungi, at the same time. Each session as a whole (with preparation time) would last about 1 week: 5 days for the experiment duration within BIOS after the introduction of the bioaerosol. Disinfection of the compartment before and after the experiment would be real-ised by wiping and spraying with 3 % hydrogen peroxide. This design might evolve during the coming months.

Dissemination

The partners have submitted the results of their work ‘Review of current issues and procedures’ and ‘Definition of the requirements for the modelling’ in two scientific papers currently under evaluation.

For more information about the project, please visit the project website (http://www.biosmhars.eu).

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CONCLUSION

BIOSMHARS should deliver a preliminary calibrated predictive model for biocon-tamination, validated in a facility repre-sentative of a spacecraft – BIOS — both with non-biological and biological aero-sols. The model intends to describe and to predict the airborne microbial con-tamination dispersion profile in a con-fined habitat. This preliminary predictive model should contribute to improving the tools to support ‘risk assessment’ of microbial contamination for long dura-tion missions in space. Future evolutions of this model could be used to define an improved strategy to deal with bio-contamination in spacecraft or for appli-cations for confined environments on Earth (confined area such as subma-rines, hospitals, etc.). The model will be calibrated with a real bioaerosol. The procedure for producing a calibrated bio-aerosol should be, as such, a progress in the general area of biocontamination. In addition, BIOSMHARS should charac-terise the dissemination and survival of microorganisms in a real confined envi-ronment after introduction via aerosol. This should bring new information on the survival and growth mechanisms, in the air and on surfaces, of living envi-ronments of microbes travelling through the air. Besides, BIOSMHARS will enable the adaptation of BIOS for future stud-ies on the issue of biocontamination in space and, more generally, in close hab-itats. Finally, BIOSMHARS will develop a European–Russian strategy to deal with biocontamination in spacecraft and will contribute to the preparation of a road-map defining the detailed scientific and technical achievements required to solve this issue.

The project has, up to now, not met any major problem. The review of the background confirms the need for a

predicting model such as that planned in BIOSMHARS, with both applications for space and Earth. The definition of the requirements for the modelling has been completed. The model develop-ment is now starting, in parallel with the definition of the procedure to gener-ate calibrated bioaerosols, the upgrade of the BIOS facility and the prelimi-nary design of the biological validation experiments. The next main milestones will be the physical calibration of the model at VTT. This will be followed by a refinement of the model and then by the experiment for physical validation within BIOS-3 before starting the bio-logical calibration and validation.

REFERENCES

  Aponte, V. M., Finch, D. S. and Klaus, D. M., ‘Considerations for non-invasive in-flight monitoring of astronaut immune status with potential use of MEMS and NEMS devices’, Life Sci., 79, 2006, pp. 1317–1333.

  Chao, C., Wan, M. and Sze To, G., ‘Transport and removal of expiratory droplets in hospital ward environment, Aerosol Science and Technology, 42, 2008, pp. 377–394.

  Franchi, M., Carrer, P., Kotzias, D., Rameckers, E. M. A. L, Seppänen, O., van Bronswijk, J. E. M. H. and Viegi, G., Towards healthy air in dwellings in Europe — The THADE report, EFA Central Office, Brussels, 2004.

  Gitelson, J. I, Lisovsky, G. M. and MacElroy, R., Manmade closed ecological systems, Taylor & Francis, 2003, 400 pp.

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  Gu, J.-D., ‘Microbial colonization of polymeric materials for space applications and mechanisms of biodeterioration: A review’, International Biodeterioration & Biodegradation, 59, 2007, pp. 170–179.

  Ilyin, V. K., Volozhin, A. I. and Vikha, G. V., Colonial resistance of organism in modified environment, Nauka, Moscow, 2005, 275 pp.

  ISS MORD, SSP 50260, ISS Medical Operations Requirement Document, 2009.

  Leys, N., Baatout, S., Rosier, C., Dams, A., s’Heeren, C., Wattiez, R. and Mergeay, M., ‘The response of Cupriavidus metallidurans CH34 to spaceflight in the International Space Station’, Antonie Van Leeuwenhoek, 96, 2009, pp. 227–245.

  Li, Y., Leung, G. M., Tang, J. W., Yang, X., Chao, C. Y., Lin, J. Z, Lu, J. W., Nielsen, P. V., Niu, J., Qian. H, Sleigh, A. C., Su, H. J., Sundell, J., Wong, T. W. and Yuen, P. L., ‘Role of ventilation in airborne transmission of infectious agents in the built environment — a multidisciplinary systematic review’, Indoor Air, 17, 2007, pp. 2–18.

  Mastroleo, F., Van Houdt, R., Leroy, B., Benotmane, M. A., Janssen, A., Mergeay, M., Vanhavere, F., Hendrickx, L., Wattiez, R., Leys, N.,

‘Experimental design and environmental parameters affect Rhodospirillum rubrum S1H response to space flight’, ISME J, 2009.

  Novikova, N. D., ‘Review of the knowledge of microbial contamination of the Russian manned spacecraft, Microbial Ecology, 47(2), 2004, pp. 127–132.

  Novikova, N. D., ‘Microbiological safety maintenance of the mission’, in A. S. Koroteev (ed.), Manned mission to Mars, Russian Academy of Cosmonautics named after K. E. Tsiolkovsky, 2006, pp. 277–283.

  Novikova, N. D., De Boever, P., Poddubko, S., Deshevaya, E., Polikarpov, N., Rakova, N., Coninx, I. and Mergeay, Max, ‘Survey of environmental biocontamination aboard the International Space Station’, Research in Microbiology, 157(1), 2006, pp 5–12.

  Salisbury, F., Gitelson J. I. and Lisovsky, G. M., ‘BIOS-3: Siberian experiments in bioregenerative life support’, BioScience, 47, 1997, pp. 575–585,.

  Wan, M., Sze To, G., Chao, C., Fang, L. and Melikov, A., ‘Modeling the fate of expiratory aerosols and the associated infection risk in an aircraft cabin environment’, Aerosol Science and Technology, 43(4), 2009, pp. 322–343.

CHAPTER 25

Authors: William Thuillot, Valéry Lainey, Véronique Dehant, Jean-Pierre De Cuyper, Jean-Eudes Arlot, Leonid Gurvits, Hauke Hussmann, Juergen Oberst, Pascal Rosenblatt, Jean-Charles Marty, Bert Vermeersen, Vincent Robert, Dominic Dirkx, Maria Kudryashova, Sébastien Le Maistre

consortium members: Institut de mécanique céleste et de calcul des éphémérides (IMCCE), France; Royal Observatory of Belgium (ROB), Belgium; Joint Institute for VLBI in Europe (JIVE), the Netherlands; Deutsches Zentrum für Luft- und Raumfahrt (DLR), Germany; Technical University of Berlin (TUB), Germany; Observatoire Midi-Pyrénées/Centre National d’Études Spatiales (CNES), France; Delft University of Technology (TUD), the Netherlands

AbSTRACT

This article describes the activ-ity of ESPaCE, the European Satellite Partnership for Computing Ephemerides, and the first results obtained. This new EC-FP7 project aims at strengthen-ing the collaborative activities in the domain of the development of ephe-merides and reference systems for nat-ural satellites and spacecraft. Teams from seven European institutions par-ticipate in the project: IMCCE, ROB, TUB,

JIVE, DLR, CNES and TUD. All these institutes convened to benefit from their mutual expertise in order to reach a better knowledge of the dynam-ics and physics of natural satellites and of spacecraft motions. The project started in June 2011 for a 4-year dura-tion. Twelve workpackages have been defined in order to ensure the good development of the work and must ensure the evolution toward new highly accurate ephemerides of Martian, Jovian, Saturnian and Uranian satellites by combining the fit of new dynami-cal models to ground-based and space data. Besides, this programme will also permit to provide new planetary maps, reference systems, gravity models and rotation models, and to estimate the performance of the new position-ing techniques, VLBI (very long base-line interferometry) and laser ranging. All the results and documents will be made available using standard for-mats (VO — Virtual Observatory stand-ard, SPICE kernels) for use by space agencies, planetary scientists or the public. This article describes the first results, already obtained in the domain of spacecraft orbits determination by radioscience, digitising of photographic plates for astrometry of natural satel-lites, estimate of performance of laser ranging and VLBI. These results will be extended and exploited during the remaining period in order to reach our goals.

ESPaCE: European Satellite Partnership for Computing Ephemerides

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AcHieVed resuLts

ESPaCE, the European Satellite Partnership for Computing Ephemerides, is a new EC-FP7 project which aims at strengthening the collaborative activi-ties in the domain of the development of ephemerides and reference sys-tems for natural satellites and space-craft. This project started in June 2011 for a 4-year duration. Teams from seven European institutions convened to benefit from their mutual exper-tises: Institut de mécanique céleste et de calcul des éphémérides (IMCCE-Paris observatory, France), the Royal Observatory of Belgium (ROB, Belgium), the Technical University of Berlin (TUB, Germany), the Joint Institute for VLBI in Europe (JIVE, the Netherlands), the German Space Agency (DLR, Germany), the Centre National d’Études Spatiales (CNES, France) and the Delft University of Technology (TUD, the Netherlands). Our goal is to reach a better knowledge of the dynamics and physics of natural satellites and of spacecraft motions.

For these goals, this consortium deals with the extraction and analysis of astrometric data from observations by spacecraft not yet applied to dynamic solutions. Such data will be combined with ground-based astrometry in order to improve constraints on the dynamics and the physics of the objects. Improved ephemerides for natural satellites and spacecraft and characterisation of rota-tion properties of selected satellites will be provided. The consortium intends also to investigate new technologies, in particular VLBI and laser ranging (LR) techniques. Another important part of the project will consist in merging (for the first time in Europe) natural satellite astrometry data and spacecraft data in a global inversion. All the results and documents will be made available using

standard formats (VO standard, SPICE kernels) for the use by space agencies, planetary scientists or the public.

In practice we intend to deliver several useful data sets and reports concern-ing: performances of the laser track-ing and VLBI technology, digitised images of USNO (United States Naval Observatory) planetary photographic plates and astrometric analysis for Mars, Jupiter, Saturn, Uranus satellites, accurate ephemerides of these sat-ellites and orbits of the space probes which gave space images of these satellites, rotation data of Phobos, icy satellites control point networks, shapes and coordinate systems. The main expected scientific results of the ESPaCE project will be new dynami-cal models of several natural satellites and new orbits of spacecraft derived from the natural satellite space obser-vation analysis. By combining space- and ground-based observations, we will be able to compute accurate eph-emerides. Where several natural sat-ellite systems are concerned (Mars, Jupiter, Saturn, Uranus) we can expect that this work will also allow us to improve our knowledge of the interior of the celestial bodies. More generally, the ESPaCE network will allow Europe (for the first time) to consider and use spacecraft and natural satellite data in a simultaneous process. Such expertise is very valuable for prospective plan-etary missions such as BepiColombo, ExoMars, JUICE/Laplace and others.

At the present date we can already describe the first results achieved in the following domains.

Radioscience

The WP2 is dedicated to the improve-ment of the determination of the

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orbital motion of spacecraft which have orbited or are orbiting planets targeted by the ESPaCE project. These space-craft provide measurements which are used for the determination of the moon ephemeris (through images taken by cameras onboard these spacecraft) and of the moon physical parameters (through the radio-tracking data of these spacecraft). In both cases a pre-cise determination of the position and velocity of the spacecraft needs to be achieved (e.g. Rosenblatt et al., 2008). The navigation orbits, which are usually released for each spacecraft mission, are designed for operation purposes and not for precise orbit determination (POD). Therefore, we plan to provide precise orbits of spacecraft for which tracking data are available.

The POD process requires fitting a model of the motion of the spacecraft to the radio-tracking data performed by Earth-based tracking stations. These tracking data are Doppler shift measurements of the carrier frequency of the radio signal established between these stations and the spacecraft as well as ranging meas-urements (round-trip time delay) of this radio-signal. The model of the space-craft motion takes into account, as pre-cisely as possible, all the forces acting on the spacecraft. The fit to the tracking data allows for adjustments of some parameters of this force model, and to obtain improved positions and veloci-ties of the spacecraft along its orbit. In turn, the precise orbit of the spacecraft can be used to further reduce astro-metric measurements (thus, improving moon ephemeris determination) and to improve the determination of physical parameters of moons like for instance their gravity fields.

These precise spacecraft orbits will be released as SPICE kernels. A first release

is foreseen for the Mars Express (MEX) spacecraft for the period February 2004 to July 2008 as successive data-arcs (each several days long). These ker-nels are foreseen to be maintained and updated (if needed) all along the ESPaCE project, depending on the release of the tracking data by the MEX project. The SPICE kernels will be found on the SPICE-NAIF website (http://naif.jpl.nasa.gov/naif).

In parallel, specific kernels will be pro-duced, especially for the WP8 (arc-splitting method) aiming to improve spacecraft position determination at the epoch of astrometric measurements.

VLBI (very long baseline interferometry)

The VLBI workpackage of ESPaCE exploits a well established synergy between radio astronomy and explo-ration of space which goes back to the early days of the space era more than half a century ago. At present, the advanced technology of VLBI observa-tions of natural celestial sources ena-bles astronomers to ‘zoom’ into their radio images with a breathtaking angu-lar resolution (‘sharpness’) reaching fractions of a milliarcsecond. Moreover, this technique provides the most accu-rate astrometric data on the position of celestial radio sources with the accu-racy reaching microarcseconds. This accuracy corresponds to the angular size of a one euro cent coin on the sur-face of the Moon as seen from Earth. But the VLBI technique can be applied not only to natural celestial radio sources but to human-made too. These are deep space science missions which can be treated in VLBI observations as point-like sources. The technique of interplanetary spacecraft VLBI tracking has been successfully demonstrated by European radio astronomers, for

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example, for the ESA’s Huygens Probe during its descent in the atmosphere of Titan in January 2005 (Lebreton et al. 2005). Recently the ESPaCE-led collaboration demonstrated the lat-est more accurate modification of the VLBI-tracking algorithms in observa-tions of the ESA’s Venus Express (VEX) orbiter. These observations were con-ducted with radio telescopes in Finland, Sweden, Italy, Germany and Russia and processed at the Joint Institute for VLBI in Europe (JIVE) in the Netherlands. They resulted in the estimates of the VEX state vector with the accuracy of several tens of metres. The technique is now undergoing preparation for pro-spective planetary and space science missions and aims to provide multidis-ciplinary scientific support to a broad variety of applications ranging from gravimetry to celestial mechanics and planetology to fundamental physics.

Laser ranging

The performances of the laser rang-ing technique are described in the first ESPaCE deliverable. Interplanetary spacecraft tracking provides impor-tant data for the creation of precise planetary ephemerides. Current tech-niques used for this tracking all uti-lise radio frequencies, which suffer from a number of effects, such as their sensitivity to tropospheric, ion-ospheric and solar plasma influence, introducing uncertainties in the meas-urements. Additionally, large antennas are required for establishing a radio link to distant spacecraft. Tracking at optical wavelengths, which are insen-sitive to ionospheric and solar plasma influence and which can be per-formed using a much smaller ground station, is done routinely for Earth-orbiting spacecraft, as well as the Moon, by measuring the round-trip

time-of-light of a laser pulse reflected off retro-reflectors. The inverse-quar-tic relation between distance and sig-nal strength makes this technology infeasible for interplanetary track-ing. This report is concerned with the evaluation of models required for the analysis of an extension of laser tracking to interplanetary distances. Instead of using a space-based reflec-tor, active laser systems both on Earth and the deep space target are used. Estimates for the attainable accu-racy in range of 1 mm are reported in literature. Detailed link, mission and data analyses are required to ascer-tain the realism of this value, though. The concepts and models presented in this report for the delay, signal attenuation and noise term will be used in the continuation of this work to develop interplanetary laser rang-ing simulation software. A number of critical issues have been identified for extending the technology to inter-planetary distances. One is stray light, which limits the attainable sun inci-dence angle. This causes link outages at conjunctions, makes robust links at outer planets challenging and limits the measurable gravitational effects. Depending on the type of technique used, the deep-space clock will limit the attainable accuracy of the meas-urements. Pointing, acquisition and tracking of a laser link at interplan-etary distances has not been dem-onstrated, but has been researched quite extensively for the field of laser communications. The modeling of uplink turbulence in all turbulence and link conditions will require additional development on scintillation models. Despite these challenges, laser rang-ing has the potential for providing an order of magnitude improvement in the attainable range accuracy at inter-planetary distances in the near future.

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Digitised images

Observational constraints are neces-sary in order to fit the dynamical mod-els. The goal of this project is to use a large amount of accurate observa-tional data from different origins. In this context, the use of rather ancient observations such as photographic plates of planetary systems done with long focus instruments can ensure an improvement of the accuracy of the dynamical models. Thanks to a part-nership with the United States Naval Observatory (USNO, Washington DC), ESPaCE benefits from such a large collection of photographic plates that have been taken between 1926 and 1998. In particular, it contains hun-dreds of observations of Martian plates and Saturnian plates, two major targets of the nowadays space pro-grammes. Recently, one of the part-ners of ESPaCE, ROB, has acquired a high accurate scanning digitiser, which can scan photographic plates within 10 minutes and with an unprece-dented accuracy. Within the ESPaCE project we have performed the digiti-sation and the reduction of such pho-tographic plates. The data will be used jointly with space mission data to pro-vide new ephemeris kernels.

Astrometry

Plates which were digitised at ROB were reduced at IMCCE. Preliminary results have been obtained for the Galilean satellites. The reduction will continue for Saturnian plates. The pro-cedure of reduction is being adapted to the future plates to be digit-ised. The observations of the mutual events were made in 2007–2008–2009. Mutual events of the Uranian

and Saturnian moons are reduced and are under publication. Observations of the mutual events of the Galilean sat-ellites were very numerous and are still under reduction. The observations of the Cassini space probes are under the astrometric reduction process.

CONCLUSION

The goal of the ESPaCE project is to strengthen the European collaborative activities in the domain of the devel-opment of ephemerides and refer-ence systems for natural satellites and spacecraft. This project is centred on the exploitation of astrometric data not already used for the dynamical mod-eling, and on the investigation of new technologies for planetary positioning and spacecraft tracking. The ESPaCE consortium is the first in this domain in Europe and the workplan will allow it to deliver original tools and reports. By establishing this project, all the part-ners of this consortium have decided to join their efforts to initiate sustainable activities in this domain. The project aims at initiating a European network of experts and at providing useful tools, data and services in particular for the space organisations. The ESPaCE pro-ject started on 1 June 2011 and first results are already obtained. Among the foreseen activities, several are already strongly engaged: the devel-opment of methods for radioscience exploitation for spacecraft orbit deter-mination, the estimate of performances of the VLBI and the laser ranging tech-niques for astrometric measurements, the digitisation of photographic plates of planetary systems, their astrometric measurements and their exploitation for improved ephemerides.

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REFERENCES

  Lebreton, J.-P. et al. 2005, Nature, 438, p. 758.

  Rosenblatt, P., Lainey, V, Le Maistre, S., Marty, J. C., Dehant, V., Pätzold, M., Van Hoolst, T. and Häusler, B., ‘Accurate Mars Express orbits to improve the determination of the mass and ephemeris of

the Martian moons’, Planet Space Sci., 56, 2008; doi:10.1016/j.pss.2008.02.004.

  Thuillot, W., Dehant, V., Oberst, J., Gurvits, L., Marty, J.-C., Hussmann, H. and Vermeersen, B. 2010, proposal ‘European Partnership for Computing Ephemerides’ (FP7-ESPaCE), Tech. Rep. SPA.2010.2.1-03/263466, European Space Agency.

CHAPTER 26 EU-UNAWE: EU universe awareness

Authors: Pedro Russo, Sarah Reed, George Miley

consortium members: Universiteit Leiden, the Netherlands; Ruprecht-Karls-Universität Heidelberg, Germany; Universitat Politècnica de Catalunya, Spain; Istituto Nazionale di Astrofisica/INAF, Florence, Italy; National Research Foundation/SAAO, South Africa; Armagh Observatory and Planetarium, United Kingdom

AbSTRACT

A child’s early years are widely regarded to be the most important for their development and the formation of their value systems (see article: ‘Too young to learn?’1). The idea behind the Unesco- and IAU-endorsed education programme ‘EU universe awareness’ (EU-UNAWE) is to use astronomy and space sciences to inspire children aged 4–10 years — especially those from underprivileged communities. The goals are twofold: to encourage children to develop an interest in science and tech-nology and to help broaden their minds, thereby stimulating a sense of global citizenship and tolerance.

EU-UNAWE is a 3-year programme that was launched in January 2011. It was officially presented during a public event held at the European Parliament in

1 Too young to learn? (http://www.unawe.org/about/audience/).

Brussels, Belgium, on 24 May 2011. Six countries were chosen to build national EU-UNAWE programmes: Germany, Italy, the Netherlands, the United Kingdom, South Africa and Spain.

The EU-UNAWE national project manag-ers (NPMs) for each of these countries were tasked with running workshops that would give primary school educa-tors the ideas, resources and confidence that they need to bring astronomy and space science topics into the classroom. Currently, more than 200 teachers have attended EU-UNAWE workshops in five countries. Furthermore, the NPMs are developing innovative new educational resources for engaging young chil-dren in astronomy and space sciences. Several of these resources are already being used in classrooms across Europe.

While these resources are developed within the FP7 Consortium, an impor-tant goal of EU-UNAWE is to create an international network that will provide a platform for sharing ideas, best prac-tices and resources between educators from around the world. The EU-UNAWE website, which was launched in June 2011, is the central hub for the inter-national network and it hosts all of the programme’s educational resources.

AcHieVed resuLts

Create an international network

The EU-UNAWE website was launched in June 2011 and it is the central hub for

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all of the programme’s news and edu-cational resources. Since it launched, the website has seen a steady 30 % increase in visitors each month, and it is currently attracting about 3 000 vis-its per month. In addition to hosting all of the EU-UNAWE educational mate-rials (currently 53 items), a stream of regular news updates (about four items per week) give educators a reason to return to the website. Furthermore, the news updates demonstrate to educa-tors that EU-UNAWE is an active pro-ject, while also inspiring them with ideas for new educational activities.

Meanwhile, the early achievements of the EU-UNAWE Consortium are attract-ing more countries to join the interna-tional network. In the past 12 months, national ‘Universe awareness’ (UNAWE) programmes have been established in Nepal, Nigeria, Canada and the Philippines, bringing the total number of countries in the network to 38.

At the end of March 2012, the EU-UNAWE International Office, based in Leiden University in the Netherlands, will hold its first workshop for mem-bers from its international network. The aim of this workshop is to share ideas and best practices of educators from around the world.

Organise teacher training sessions

Teacher training workshops have already been held in five of the coun-tries in the EU-UNAWE Consortium. This is a great achievement, consid-ering that some of the national pro-ject managers (NPMs) were only appointed in September 2011. By February 2012, a workshop will be held in South Africa — the only mem-ber of the EU-UNAWE Consortium yet to organise teacher training sessions.

From these teacher training work-shops, EU-UNAWE has already reached

Figure 1. EU-UNAWE teacher training workshop in Groningen, the Netherlands, in June 2011. Credit: EU-UNAWE, the Netherlands.

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203 educators. Given the multiplier effect that teachers have, it is estimated that more than 5 000 children have already benefited from EU-UNAWE’s teacher training workshops.

Develop educational resources

Many educational resources have already been developed by the NPMs in the EU-UNAWE Consortium. These materials include: a Spanish astron-omy book aimed at 9- to 11-year-old children; a German activity book that describes numerous astronomy-based activities; a weekly astronomy-based

experiment published in the highbrow Dutch newspaper NRC; and a series of lesson plans designed for UK primary schools. Furthermore, many events for children have been organised, such as astronomy drawing workshops, with more than 800 children in attendance.

Meanwhile, the EU-UNAWE International Office has pioneered an astronomy news service for children aged 8+, called Space Scoop. The idea behind Space Scoop is to change the way that astronomy and space sciences are presented to young children, to move away from teaching it like an historical

Figure 2. EU-UNAWE activity during the ESA Space Camp 2011 in Italy. Credit: EU-UNAWE, Italy.

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subject and to show children the excit-ing new discoveries that are still being made today.

Since February 2011, EU-UNAWE has published around 50 Space Scoops based on press releases produced by the European Southern Observatory, NASA Chandra X-ray Observatory and Europlanet. Each Space Scoop is pub-lished on the EU-UNAWE website so that it is available to the international network and can be translated into other languages. Currently, members of the international network translate Space Scoop from English into eight languages (including three languages of the European Union: Portuguese, Romanian and Slovenian).

Furthermore, in collaboration with our Space Scoop partner, Europlanet, EU-UNAWE organised a week-long Space Scoop Camp ’11 dur-ing the EPSC-DPS 2011 Joint Meeting in Nantes, France, in October 2011. During this event, daily Space Scoops brought the breaking news from this important planetary science meeting into the classroom.

Finally, The EU-UNAWE International Office has also collaborated with the British-based magazine Anorak, a quarterly publication aimed at 6- to 12-year-old children. This is a gen-eral magazine, which offers an excel-lent opportunity to reach children who haven’t yet been inspired to develop an interest in science. For example, the theme of the Summer 2011 issue of Anorak was ‘Vikings and pirates’ and it featured an EU-UNAWE article

about navigating by the stars. This col-laboration will continue, with the next EU-UNAWE article appearing in the Spring 2012 issue.

CONCLUSIONS

EU-UNAWE is nearing the end of its first year and can celebrate many achieve-ments in all three of the programme’s goals. The FP7 grant has already pro-vided training workshops for 203 teachers in five countries. Furthermore, the international network means that the impact of the programme has reached beyond the FP7 Consortium, which is demonstrated by the estab-lishment this year of new national pro-grammes in Nepal, Nigeria, Canada and the Philippines.

The early successes of the programme are even more impressive given the delay in hiring some of the NPMs, with some members of the team joining as late as September 2011. One of the most important tasks for the NPMs in early 2012 is to complete the develop-ment of the national websites for the EU-UNAWE Consortium. It had been hoped that the national websites would be online by the end of 2011, but the delay in recruiting some of the NPMs, and in developing the EU-UNAWE inter-national website, has pushed this pro-ject 1 month behind schedule.

With a full team now in place, EU-UNAWE is in a strong position to build on its first year and to deliver many more educational materials and teacher training workshops.

CHAPTER xx Space propulsion and transportation

CHAPTER 27 E-SAIL: Electric solar wind sail technology

Author: Pekka Janhunen

consortium members: Helsinki University, Finland; Jyväskylä University, Finland;

Uppsala University, Sweden; Nanospace AB, Sweden; Tartu Observatory, Estonia; DLR Bremen, Germany; Pisa University, Italy; Alta SpA, Italy

Figure 1. Schematic view of the E-sail. Long tethers are kept positively charged by shooting out electrons from the spacecraft. In full-scale mission the tethers are up to 20 km long and they are connected by auxiliary tethers from the tips for mechanical stability. Figure © Pekka Janhunen, Finnish Meteorological Institute.

AbSTRACT

The electric solar wind sail (electric sail or E-sail for short) is a proposed novel technique for moving payloads in the solar system without consum-ing any propellant and potentially capable of revolutionarily high total impulse versus mass ratio. The E-sail (Figure 1) consists of a number of centrifugally stretched, long, thin and

conducting tethers which are artifi-cially kept charged to a high positive voltage (20 kV) by an onboard solar-powered electron gun which constantly ejects out negative electrons from the system. In a full-scale mission, a 1 N thrust at 1 AU would be produced by a 2 000 km total tether length, consist-ing e.g. of 100 tethers, each of which is 20 km long. The E-sail thrust scales as 1/r, where r is the solar distance. This 1/r scaling is due to plasma Debye

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length effects and is more favoura-ble than the 1/r² scaling of solar pho-ton sails and solar electric propulsion. The E-sail is more easily manoeuvra-ble than the photon sail because the E-sail thrust direction and thrust mag-nitude can be controlled independently by inclining the sail and throttling the electron gun, respectively.

A full-scale 1 N E-sail could be used for a variety of ambitious tasks such as multi-asteroid touring, flight out of the solar system at over 50 km/s speed, Earth or Sun observing missions in non-Keplerian orbits, to mo ving 500–2 000 kg payloads in the solar system.

The goal of the E-sail project is to build and test laboratory prototypes of the key components of the E-sail at tech-nical readiness level (TRL) 4–5. For the E-sail ‘remote unit’, a new butane cold gas thruster and a new ionic liquid field effect electric propulsion (FEEP) thruster are developed. These new thrusters

may also find uses in CubeSat and other satellites. Additionally, a mechan-ics simulator modelling the dynami-cal behaviour of the E-sail in real solar wind, specific E-sail designs and uses of those designs in concrete space mis-sions are targeted by the E-sail project.

AcHieVed resuLts

We describe the main results and mile-stones achieved during the first year of the 3-year E-sail project.

Main tethers

The main tethers are the key hard-ware of the E-sail. The main teth-ers are made of bonding together thin 25–50 µm aluminium wires at a few centimetre intervals to produce a redundantly micrometeoroid-resistant and electrically conducting tether whose mass and outer surface area are small. The thin aluminium wires are a com-mercial bulk product, but the process

Figure 2. (Clockwise from upper left) Automatic tether factory, schematic drawing of four-wire micrometeoroid-resistant Heytether geometry, scanning electron microscope image of a single ultrasonically made wire-to-wire bond between 25 and 50 µm wires, piece of produced 100 m-long two-wire tether. Figure © Henri Seppänen, University of Helsinki.

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of bonding them together with ultra-sonic wire-to-wire bonding is nontriv-ial. Ultrasonic bonding of a wire to a metallic platform is a widespread tech-nique throughout electronics industry, but bonding two thin wires together ultrasonically is currently a unique speciality of the Electronic Research Laboratory of the University of Helsinki. The ultrasonic bonding tech-nique is used because it produces min-imal damage and structural weakening to the bonded wires and because it works at room temperature with a tab-letop device.

The automatic bonding factory (Figure 2) was successfully designed, built and used during the first year. The factory was used to produce alto-gether 250 m of two-wire tether and 23 m of four-wire tether. The longest continuous two-wire tether was 110 m and the longest four-wire tether was 11 m. The fraction of failed bonds in two-wire tether production was below 1 % and about 4 % in four-wire tether production. The milestone of produc-ing a 100 m continuous piece during the first year was therefore reached. The final goal of the E-sail project is to produce a 1 km-long sample of

continuous four-wire tether with less than 0.1 % of failed bonds, verified by automatic online contact resist-ance measurement and laser-ultra-sonic pulse propagation based quality control methods. The development of these quality control methods has started. A 100 % bond success rate is not needed because micrometeoroids will break the individual wires anyway in space. The essential requirement is that the number of failed bonds does not disturb correct unreeling of the tether.

Reeling demonstration

A test of reeling in and out of 10 m of two-wire tether was successfully carried out at DLR Bremen in sum-mer 2011. No symptoms of the tether getting stuck when unreeling were observed with any of the used reel geometries. In November 2011, some more tests with 30 m-long two-wire tether and 10 m-long four-wire tether were carried out at the University of Helsinki. Also in these tests, no prob-lems were encountered even when the tether was wound on the reel in a deliberately uncontrolled and ran-domised way.

Figure 3. Perforated 3 cm-wide kapton tape auxiliary tether at rest (left) and under tension (right). Notice the micrometeoroid-resistant 3 D shape that forms when the tether is stretched. Figure © Jouni Polkko, Finnish Meteorological Institute.

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Auxiliary tethers

Auxiliary tethers are non-conducting tethers whose purpose is to connect together the tips of the main tethers. Their role in the flying E-sail is to keep the main tethers away from each other without a need for active control. The auxtethers are deployed from reels placed in the remote units. Our base-line solution for the auxtether is a per-forated (punched) 3 cm-wide, 12.6 µm thin polyimide tape (Figure 3). Thinner polyimide also exists and would pro-vide some mass savings, but was not considered in this project because it is ITAR-regulated. Perforation is used to give the auxtether an elastic constant (strain versus stress) which gives the E-sail good dynamical flight properties and a good ability to dampen oscilla-tions caused by solar wind variations. Polyimide (kapton) is plastic material which has excellent tolerance for vac-uum, temperature changes and space radiation. Our perforated tape assumes a micrometeoroid-resistant 3-D

U-shaped form when slightly stretched after deployment. Polyimide also has relatively large damping, coeffi-cient loss modulus, which contributes to damping oscillations in the E-sail tether rig. We showed experimentally that it is possible to create an auxtether with wanted mechanical properties by suitable perforation. Laser perfora-tion technique is possible by adapting to a roll-to-roll process through mod-est investments made by the company which does the perforation.

The remote unit

The remote unit (RU) is a small device located at the tip of each main tether, marked by small dots in Figure 1. The RU (Figure 4) hosts the motorised reels from which the auxiliary teth-ers connecting the main tether tips are deployed and it hosts a small thruster which is used to spin up the tether rig during deployment and potentially for spinrate modification during flight. The baseline auxiliary tethers are made

Figure 4. The remote unit. Figure © Greger Thornell, Ångström Space Technology Centre, Uppsala University.

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of thin kapton tapes (12.6 µm thick-ness, 3 cm width) that are patterned with holes to obtain an elastic con-stant (tension force versus elonga-tion), giving optimal tether dynamics for the target E-sail size. For increased robustness against reel failures, each auxtether that connects two RUs is deployed from both ends, so that each RU contains two auxtether reels.

Two thruster options are considered and progressed in parallel: a butane cold gas thruster (Nanospace) and ionic liq-uid FEEP thruster (Alta). The cold gas thruster is more lightweight and pro-duces enough total impulse to deploy the E-sail, but does not leave much pro-pellant for later flight-time spin rate adjustments. On the other hand the FEEP thruster is heavier, but its total impulse capability is much larger. Two cold gas thrusters are used per RU, one for accelerating and one for decelerat-ing the spin. In case of FEEP, the base-line idea is that each RU contains one FEEP which is mounted oppositely in every other unit so that every other RU can accelerate the spin and every other can decelerate it. The RU thrusters are not single-point failure points because thrusters on different RUs act as back-ups of each other.

Besides containing the motorised aux-tether reels and the thrusters, the RU also contains a bidirectional low bitrate telemetry capability, with the main spacecraft receiving commands and sending housekeeping data, a mechanism to jettison (cut) the main tether in case a main tether has to be ‘amputated’, due to it being bro-ken, and an optical blinking beacon which can be imaged from the main spacecraft to find out the instantane-ous position of the RU. The RU is pow-ered by a solar panel mounted on a

sunshield (sun shines from below in Figure 3).

The RU auxtether reels are only needed during E-sail deployment, which takes place soon after the start of the mis-sion at 1 AU. During deployment the RU thrusters are fired to produce the initial E-sail spin. During E-sail flight the RU is needed for three reasons: for tracking the RU trajectory from the main space-craft by the optical beacon, for pos-sibly adjusting the E-sail spin rate by the thrusters, if needed, and for possi-bly jettisoning the main tether in case of main tether breakage. The specifi-cation adopted for the E-sail project is that propulsive E-sail flight is possible in the solar distance range 0.9–4 AU. This means that the RU reels need to work only at 1 AU for a few weeks, but the other RU functionalities should work for 5 years in the range 0.9–4 AU. The thruster function may not be com-pletely necessary near 4 AU, though.

The rather wide 0.9–4 AU operational range makes the thermal design of the RU somewhat challenging. We solve this problem by utilising the fact that the same side of the RU always faces the sun (although it can be inclined by up to 60º) and having a sunshield where the solar panels are mounted (Figure 3). The main parts of the RU are contained in a thermally controlled box which is behind the sunshield. The thermal box is covered by MLI from all sides and it is attached to the sunshield by well insulating thermal spacers made of Vespel. The idea is to keep the thermal box always in dark-ness to ensure a naturally cold bias. A suitable internal temperature for elec-tronics and thrusters is then reached by dissipating electric power (some combination of functional power and heating resistor power depending on

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the mission phase). The MLI insula-tion ensures that the needed amount of dissipated power is small, which is important at 4 AU, where only small amounts of solar power is gathered by the solar panels. Components dissipat-ing significant power (reel motors) are placed within the reel axes outside of the thermal box. Extra power produced by the solar panels is dissipated by a hot space-facing radiator. The internal temperature of the RU thermal box is maintained by electrical means, with-out louvres or other moving parts.

The remote unit design was nearly completed during the first year.

CONCLUSIONS

The goal of the E-sail project is to pro-duce TRL 4–5 prototypes of the key components of the electric solar wind sail, scalable up to 1 N thrust with 100 kg own mass. After the first year of work we are well under way towards satisfying these ambitious goals. The overall mass goal of 100 kg is a chal-lenge, however, and it may be that we have to loosen it somewhat. However, at least for use in conventional mis-sions the overall performance (payload fraction for given specific accelera-tion) is rather insensitive to the E-sail system’s own mass. For example the 1 N E-sail could be used to move a 1 000 kg total mass in the solar sys-tem relatively freely. In that case, if the E-sail would weigh 150 kg instead of the goal 100 kg, it would only decrease the payload from 900 kg to 850 kg.

The challenges that we encountered thus far were not fundamental but of more mundane character. For exam-ple, it was necessary to develop some kind of reeling capability also in the

University of Helsinki and not only in DLR Bremen, because the tether must be stored on some reel during pro-duction. Also the auxiliary tether reel of the remote unit is quite an inte-gral part of the RU and the fact that it was designed in a different place (DLR Bremen) than the rest of the RU (Uppsala) created some challenges. At one point the RU concept mass was well over 1 kg, but after putting a cou-ple more months into designing the RU and paying strong attention to ration-alising the use of structural mass, we were able to push the mass down nearer the goal of 0.5 kg.

REFERENCES

   Janhunen, P., ‘Electric sail for spacecraft propulsion’, J. Prop. Power, 20, 2004, pp. 763–764.

   Janhunen, P. and Sandroos, A., ‘Simulation study of solar wind push on a charged wire: basis of solar wind electric sail propulsion’, Ann. Geophys., 25, 2007, pp. 755–767.

   Mengali, G., Quarta, A. and Janhunen, P., ‘Electric sail perfromance analysis’, J. Spacecr. Rockets, 45, 2008, pp. 122–129.

   Janhunen, P., ‘The electric sail — a new propulsion method which may enable fast missions to the outer solar system’, J. British Interpl. Soc., 61( 8), 2008, pp. 322–325.

   Mengali, G., Quarta, A. and Janhunen, P., ‘Considerations of electric sail trajectory design’, J. British Interpl. Soc., 61(8), 2008, pp. 326–329.

   Mengali, G. and Quarta, A., ‘Non-Keplerian orbits for electric sails’,

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Cel. Mech. Dyn. Astron., 105, 2009, pp. 179–195 (doi:10.1007/s10569-009-9200-y).

   Janhunen, P., ‘On the feasibility of a negative polarity electric sail’, Ann. Geophys., 27, 2009, pp. 1439–1447.

   Toivanen, P. K. and Janhunen, P., ‘Electric sailing under observed solar wind conditions’, Astrophys. Space Sci. Trans., 5, 2009, pp. 61–69.

   Janhunen, P., ‘Increased electric sail thrust through removal of trapped shielding electrons by orbit chaotisation due to spacecraft body’, Ann. Geophys., 27, 2009, pp. 3089–3100.

   Janhunen, P., ‘Electrostatic plasma brake for deorbiting a satellite’, J. Prop. Power, 26, 2010, pp. 370–372.

   Quarta, A. A. and Mengali, G., ‘Electric sail mission analysis for outer solar system exploration’, J. Guid. Contr. Dyn., 33, 2010, pp. 740–755.

   Quarta, A. A. and Mengali, G., ‘Electric sail missions to potentially hazardous asteroids’, Acta Astronaut., 66, 2010, pp. 1506–1519.

   Quarta, A. A., Mengali, G. and Janhunen, P., ‘Optimal interplanetary rendezvous combining electric sail and high thrust propulsion system’, Acta Astronaut., 2010 (doi:10.1016/j.actaastro.2010.01.024).

   Janhunen, P., Toivanen, P. K., Polkko, J., Merikallio, S., Salminen, P., Haeggström, E., Seppänen, H., Kurppa, R., Ukkonen, J., Kiprich, S., Thornell, G., Kratz, H., Richter, L., Krömer, O., Rosta, R., Noorma, M., Envall, J., Lätt, S., Mengali, G., Quarta, A. A., Koivisto, H., Tarvainen, O., Kalvas, T., Kauppinen, J., Nuottajärvi, A. and Obraztsov, A. ‘Electric solar wind sail: Towards test missions’ (invited article), Rev. Sci. Instrum., 81, 2010, 111301.

   Merikallio, S. and Janhunen, P., ‘Moving and asteroid with electric solar wind sail’, Astrophys. Space Sci. Trans., 6, 2010, pp. 41–48.

   Seppänen, H., Kiprich, S., Kurppa, R., Janhunen, P. and Haeggström, E., ‘Wire-to-wire bonding of µm-diameter aluminum wires for the electric solar wind sail’, Microelectronic Engineering, 88, 2011, pp. 3267–3269.

CHAPTER 28

Authors: Daniele Pavarin, Francesca Ferri, Denis Packan, Filippo Graziani, Mario Pessana, Angelo A. Tuccillo, Andrey Loyan, Edoardo Ahedo, Fabrizio Piergentili, Michael Ovchinnikov, Gennady Markelov, Loig Allain, Klaus Grue, Patrick van Put, Antonio Selmo, Kostantinos Katsonis

consortium members: Dipartimento di Ingegneria Industriale, Centro Interdipartimentale Studi e Attività Spaziali, CISAS ‘G.Colombo’, Università degli Studi di Padova, Italy; Office National d’études et de recherches aérospatiales (ONERA), France; Università degli Studi di Roma ‘La Sapienza’, (Uniroma1), Italy; Thales Alenia Space Italia SpA (TAS-I), Italy; Agenzia Nazionale per le Nuove Tecnologie, l’Energia e lo Sviluppo Economico Sostenibile (ENEA), Italy; National Aerospace University, Kharkiv Aviation Institute (KhAI), Ukraine; Universidad Politécnica de Madrid (UPM), Spain; Alma Mater Studiorum, Università di Bologna (UNIBO), Italy; Keldysh Institute of Applied Mathematics, Russian Academy of Sciences (KIAM), Russia; Advanced Operations and Engineering Services Group BV (AOES), the Netherlands; LMS Imagine SA (Imagine), France; C; Bradford Engineering BV (Bradford), the Netherlands; Studio Progettazione e Realizzazione di Apparati Elettronici di Selmo Antonio (RESIA), Italy; Centre national de la recherche scientifique — Laboratoire de Physique des gaz et des plasmas (CNRS-LPGP), France

AbSTRACT

Current electric propulsion technol-ogy is based on families of thrusters able to cope efficiently with different mission profiles; however, they are not versatile enough to allow a unique propulsion system technology for the entire mission. Moreover current pro-pulsion options for mini- and micro-satellites below 100 W are limited.

Helicon-source-based plasma thrust-ers promise to be a very versatile fam-ily of systems, able to be adapted to very different mission scenarios with a substantial reduction in costs and increase in reliability. However, their development is mainly confined to the USA and Japan and, although helicon plasma sources have been proven to be very efficient, the underlying funda-mental physical mechanisms still need to be investigated.

The objective of the HPH.com research project is to significantly improve the knowledge on helicon-based plasma thrusters through numerical/theoret-ical investigation and an extensive experimental campaign. This is to lead to a better optimised design for a space plasma thruster. The thruster has been specifically conceived for a low-cost demonstration mission of attitude and position control of a micro-satel-lite. To further increase versatility of

HPH.com: Helicon plasma hydrazine.combined micro

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this system with respect to standard electric thrusters, a detailed feasibility study is also conducted, evaluating the possibility of using the plasma to heat and/or decompose a secondary pro-pellant, thereby providing a two-mode system, with a high-efficiency/low-thrust (plasma-thruster) mode and a low-efficiency/high-thrust (secondary-propellant-plasma enhanced) mode.

introduction

Recently, a strong interest in micro-propulsion has arisen within the space community: these devices are to pro-vide very low thrust values (millinew-tons and below) and low impulse, and should be characterised by masses and sizes smaller than those available from current propulsion technology. Interest in such devices is driven by the needs of advanced missions currently being studied within the scientific space communities. Because a large fraction of launch costs is associated with safety procedures surrounding the storage, handling and loading of toxic and/or carcinogenic propellants of established propulsion systems, additional cost savings can be realised by utilising environmentally safe pro-pellants, with better performance and/or storage characteristics than existing monopropellants.

These needs are for primary propul-sion and attitude control of micro-spacecraft having a total wet mass of a few kilogrammes, and precise posi-tioning control of the spacecraft con-stellation. Micro-propulsion systems require miniature feed system com-ponents, such as valves, pressure reg-ulators, flow controllers, tanks. Thus, development of new propulsion hard-ware has to make use of advanced

micro-fabrication techniques, such as MEMS technology. Spacecraft with a mass of less than 100 kg, but larger than a few tens of kilograms, may still be characterised to a large extent by subsystem architectures that follow traditional design approaches in both component design and integration. To enable an additional order of magni-tude reduction in spacecraft size, while retaining mission capabilities, further developments in propulsion technol-ogy are needed.

HELICON PROPULSION SySTEM

Helicon plasma thrusters

Helicon plasma thrusters are based on plasma sources specifically designed to provide high plasma-exhaust velocities. A helicon source is com-posed of few physical elements: (i) a feeding system able to provide the required neutral gas flow, (ii) a glass tube where the plasma is generated, (iii) an antenna having a helix shape wrapped around the glass tube, (iv) a system of coils placed coaxially with the glass tube to provide a magnetic field able to confine the plasma, and to increase power deposition of the antenna

The source is the main element of the helicon plasma thruster. The thrust is obtained by exhausting the plasma into vacuum, after driving it through a suitable magnetic field whose gra-dient is optimised to increase plasma velocity.

Despite the simple structure, a heli-con-based propulsion system exhibits a very complicated physical behav-iour, which needs to be understood.

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The main expected advantages of the helicon technology with respect to cur-rent propulsion systems are:

(i) very long operative life: helicon thrusters don’t rely on critical components sensitive to erosion, such as grids and cathodes;

(ii) suitability to many different gas propellants: helicon systems can

operate in principle with many different types of gases, also reactive ones;

(iii) throttability: a helic on thruster is in principle a throttable sys-tem, thus allowing a wide range of operations;

(iv) high power density: a helicon sys-tem scales very well with power.

Figure 1. Scheme of HPH.com helicon thruster.

HPH.COM RESEARCH PROGRAMME

HPH.com has the following objectives: (i) to better understand the physics involved in a helicon plasma thruster, (ii) to apply the acquired knowledge to the development of a thruster, (iii) to verify the possibility of devel-oping a two-mode propulsion sys-tem through plasma interaction with a secondary propellant, (iv) to verify the possibility of performing a space

qualification mission onboard a dedi-cated mini-satellite.

The overall logic of the study can be summarised by the following main steps.

(i) thruster modelling: Suitable codes need to be developed to model and design the thruster and to optimise it. A different type of codes is developed for this purpose.

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(ii) experimental set-up: Three exper-imental set-ups are developed to allow code validation to perform detailed investigation of thruster behaviour and to support thruster design and development.

(iii) thruster design and development: Three prototypes are designed combining numerical analysis and detailed numerical investigations: one laboratory model, one engi-neering model and one qualification model,. These have to be manu-factured, tested and optimised for thruster performance

(iv) coMBi analysis and design: The combined thruster options are evaluated in detail to assess their feasibility and to identify expected performance.

(v) compatibility with mini-satel-lite mission: A detailed analysis is conducted, critical components are developed, and a micro-satellite mock-up is built for the HPH.com space application for attitude and position control.

(vi) exploitation and dissemination: Future thruster applications are identified to exploit the developed technology.

The applied methodology combines the-oretical and numerical physics investi-gations with experimental analysis, with the main phases of the project being presented in the following sections.

Thruster modelling (WP2)

This section of the research pro-gramme is focused on investigat-ing the physical behaviour of plasma generation, heating and acceleration

into vacuum, and the set-up of suit-able simulation tools. The complexity of the system is due to the superposi-tion of several phenomena, each play-ing a fundamental role: (i) propagation of electromagnetic waves generated by the antenna, (ii) electron dynamics, (iii) ion dynamics, (iv) neutral dynamics, (v) time-dependent evolution during ionisation, (vi) magnetic confinement.

To face these complex tasks, several innovative simulation codes have been implemented combining plasma-trans-port with electromagnetic wave propa-gation. Among these, one of the most remarkable outcomes is the implemen-tation of a state-of-the-art simulation tool (F3MPIC) which is a three-dimen-sional plasma Particle-in-Cell code with an unstructured mesh of tetrahedra coupled with a 3D FEM electrostatic and electromagnetic solver in the time domain. This tool can manage geome-tries of arbitrary complexity thanks to the mesh of tetrahedra, with an arbi-trary number of plasma species, both charged and neutral. This complex code required a dedicated research effort and, thanks to its versatility, has proven to be a very powerful simulation tool. It allows aldetailed simulations of several types of different thrusters and plasma sources. For example, F3MPIC has been applied in the simulation of an ion source for particle accelerators in col-laboration with INFN (Italy).

The physics of plasma expansion into vacuum was explored in detail by UPM (Spain).

Experiment design and implementation (WP3)

The thruster development requires detailed experimental investigation. In order to reduce the development time

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Figure 2. Example of a simulation of HPH.com (left) and of an ion source for the particle accelerator (right) using F3MPIC code.

and to better exploit capabilities of all the partners, three different experi-mental set-ups have been developed at UPD-CISAS (Italy), KhAI (Ukraine), and ONERA (France). These are charac-terised by dedicated diagnostic equip-ment of very high versatility, allowing a wide range of physical investigations on many different aspects of the thruster. Moreover, this approach allowed paral-lel investigations of different physical features in different labs and cross-check of results. The test facilities have been used to study specific aspects of the ionisation and acceleration, investi-gation of the physical processes, code validation and to support thruster devel-opment through several dedicated con-figurations. The test facility developed at UPD-CISAS was supported by ENEA (Italy) for diagnostic design and imple-mentation, and Rovsing (Denmark) for automated equipment control during the test campaign. Spectral analyses have been performed by CNRS-LPGP.

Thruster design and development (WP4)

After the definition of requirements based on analysis of many different mission profiles, the helicon plasma thruster has been designed and devel-oped using the numerical tools and

the experimental set-ups developed in the previous working packages. Furthermore, specific analyses have been performed on spacecraft contami-nation by AOES and on plasma detach-ment from the magnetic field by ONERA.

Parallel research findings have been combined together into an engineering model and qualification model.

At UPD-CISAS (Italy) the activity has been focused on studying the plasma source and the feature of plasma expansion. A very innovative and effi-cient helicon-source called Helicon-S, has been developed by RESIA. It has been proven to be able to achieve very high ionisation efficiency (up to 90 %) even in the very low plasma regime (< 50 W). Key parameters such as length, magnetic field shape and topol-ogy, have been fully explored in sup-port of thruster development.

At KhAI (Ukraine) the activity was focused on studying different acceler-ation mechanisms and to combine all the information provided from different partners into a more efficient thruster design. Several laboratory prototypes had been designed and developed before developing the engineering and the qualification models.

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In the laboratory of ONERA (France), test campaigns have been conducted for cross-checking results from differ-ent experimental set-ups and to verify thruster performance.

Bradford Moog developed the mass flow control equipment for the qualifi-cation model.

The results of the tests on the quali-fication model at KhAI, which need to be confirmed at ONERA, indicate thrust and specific impulse in line with the target of the research programme (i.e. thrust between 1 and 1.5 mN, ISP between 1 000 and 1 500 s).

Feasibility study of combined secondary propellant-plasma thruster (WP5)

The main objective of this work pack-age of the research project is to ver-ify the possibility of decomposing a secondary propellant using plas-mas instead of the catalytic bed. The analysis of the combined stage, con-ducted by Thales Alenia Space (TAS-I), Imagine and AOES, has been focused on the possibility of having a two-operational-mode thruster, character-ised by a high ISP (specific impulse)/low-thrust plasma-only mode, and a low-ISP/high-thrust combined mode.

Figure 3. Helicon plasma source developed at UPD-CISAS (left) and ONERA (right) in operation. The plasma plume generated in the high density source and its expansion into vacuum is shown.

Figure 4. Testing of EM developed by KhAI at the ONERA facility (left) and Thruster laboratory model at CISAS (right).

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The combined mode considers the pos-sibility of using the plasma to ‘activate’ a selected propellant called ‘secondary propellant’ to avoid the use of a cat-alyser. Hydrazine has been considered as the main potential secondary pro-pellant, but work has been not limited only to it (e.g. green propellants).

A combined analysis of secondary-pro-pellant injection system and plasma-secondary-propellant interaction has been conducted to identify the most efficient strategy to activate the sec-ondary propellant without perturbing the plasma. The results of this analy-sis have been used to conduct a pre-liminary COMBI thruster design and to define a development plan.

Space application with mini-satellite (WP6)

A micro-satellite has been designed to prove that a low-cost qualification mis-sion is possible on board a Unisat class

satellite, and moreover that this spe-cific type of thruster is suitable to pro-vide maneuverability to a low power satellite. The satellite is developed and manufactured by Uniroma1–GAUSS group. The satellite and its subsystems have been designed to cope with the specific needs of this propulsion sys-tem in terms of electrical power, ther-mal environment and electro-eagnetic environment, and also diagnostic instru-mentation required to verify thruster performance in orbit. This has required a completely new design and research activity since previous satellites were not equipped with propulsion systems. This has led to an innovative assembly (for the micro-satellite class) character-ised by deployable solar panels.

The HPH.com thruster is to be assem-bled into the micro-satellite and will undergo a complete testing phase for space verification and qualification (e.g. system functional and environ-mental tests).

Figure 5. The HPH.com satellite developed by Uniroma1–GAUSS with deployed solar panels.

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Exploitation

This final part of the research pro-gramme is dedicated to the iden-tification of new opportunities of applications opened up by the HPH.com family of thrusters. As a first step, two investigations have been conducted based on the achievement of the pre-vious work-packages:

• analysis of power-scaling law in order to understand the application scenario of the helicon-thruster-family, both in case of lower power (in the micro-Newton range) and to higher power (in the Newton range), conducted by TAS-I and UPD-CISAS;

• identification of the attitude and position control strategies achiev-able with HPH.com, conducted by KIAM (Russia).

This activity has shown the device’s versatility to be suitable for many dif-ferent mission scenarios, from for-mation flight to observation missions, from space exploration to Earth obser-vation, introducing features such as atmospheric-breathing capability (e.g. the possibility of using planet atmos-phere gas as propellant). This last fea-ture may allow completely new mission scenarios in the future, such as space-craft able to fly endlessly refueling themselves around planets.

CONCLUSIONS

The HPH.com research programme made a big step in better understand-ing the physical features behind heli-con plasma source systems, especially when conceived for propulsion appli-cations. Moreover, it allowed for the development of powerful innovative

codes which can be applied to other propulsion systems, and to design-ing, developing and optimising plasma sources in many different fields of research (i.e particle accelerators) and industrial applications (solar panels, semiconductors, etc.). The HPH.com project has also led to the develop-ment of a new plasma source imple-menting the principle of ‘helicon systems’, with significant improve-ments achieving a very high efficiency both in the case of low power and for compact dimensions.

Thruster prototypes have been devel-oped and the preliminary results of the QM test campaign have shown that the achieved performance is in line with expectations.

Space application on a micro-satellite of the class of Unisat has been proven.

Finally, the identification of mission scenarios shows that this propulsion system will provide manoeuverability to mini- and micro-satellites, and may also introduce new remarkable fea-tures in almost all mission scenarios, ranging from commercial missions to space exploration.

REFERENCES

  Ahedo, E. and Merino, M., ‘Two-dimensional supersonic plasma acceleration in a magnetic nozzle’, Phys. Plasmas, 17, 2010, 073501.

  Elias, P.-Q. and Gueroult, R., ‘Investigation of plasma detachment mechanisms in a magnetic nozzle’, IO3B-6, 38th IEEE International Conference on Plasma Science (ICOPS), Chicago, USA, 26–30 June 2011.

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  Katsonis, K., Berenguer, C., Pavarin, D., Lucca Fabris, A., Trezzolani, F., Faenza, M., Tsekeris, P., Cohen, S. and Cornille, M., ‘Optical diagnostics of a low temperature argon thruster’, 32nd International Electric Propulsion Conference, 11–15 September 2011, Wiesbaden, Germany, IEPC-2011-169.

  Markelov, G., ‘Particle simulations of ion detachment in thruster magnetic nozzle’, 62nd International Astronautical Congress, Cape Town, South Africa, October 2011, IAC-11-C.4.4.4.

  Ovchinnikov, M., Smirnov, G., Trofimov, S., ‘Near-circular orbit correction and formation maintenance using single-input low thrust control’, Sixth International Workshop and Advanced School ‘Spaceflight dynamics and control’, UBI, Covilhã, Portugal, 28–30 March 2011, 1 p.

  Parissenti, G., Koch, N., Pavarin, D., Ahedo, E., Katsonis, K., Scortecci, F. and Pessana, M., ‘Non conventional propellants for electric propulsion applications’, Space Propulsion Conference 2010, San Sebastian, Spain, 3–6 May 2010, SP2010_1841086.

  Pavarin, D., Ferri, F., Manente, M., Curreli, D., Melazzi, D., Rondini, D. and Cardinali, A., ‘Development of plasma codes for the design of mini-helicon thrusters’, 32nd International Electric

Propulsion Conference, Wiesbaden, Germany,11–15 September 2011, IEPC-2011-240.

  Pavarin, D., Ferri, F., Manente, M., Lucca Fabris, A., Trezzolani, F., Faenza, M., Tasinato, L., Tudisco, O., De Angelis, R., Loyan, A., Protsan, Y., Tsaglov, A.., Selmo, A., Katsonis, K., Berenguer, C., Packan, D., Jarrige, J., Blanchard, C., Elias, P. Q. and Bonnet, J., ‘Thruster development set-up for helicon plasma hydrazine combined micro research project overview (HPH.com)’, 32nd International Electric Propulsion Conference, Wiesbaden, Germany, 11–15 September 2011, IEPC-2011-241.

  Piergentili, F., Battagliere, M. L., Piattoni, J., Pessana, M., Parissenti, G., Ferri, F., Pavarin, D., ‘Mini RF-helicon double layer plasma thruster requirements for new space missions’, 62nd International Astronautical Congress, Cape Town, South Africa, October 2011, IAC2011-10591.

  Tudisco, O., Lucca-Fabris, A., Falcetta, C., Accatino, L., De Angelis, R., Faenza, M., Ferri, F., Florean, M., Neri, C., Mazzotta, C., Pavarin, D., Pollastrone, F., Rocchi, G., Selmo, A., Tasinato, L., Trezzolani, F. and Tuccillo, A. A., ‘A microwave interferometer for small and tenuous plasma density measurements’, to be submitted to Review of Scientific Instruments, 2012.

CHAPTER 29

Author: Herbert Shea

consortium members: École Polytechnique Fédérale de Lausanne, Switzerland; Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek (TNO), the Netherlands; Queen Mary and Westfield College, University of London (QMUL), United Kingdom; NanoSpace, Sweden; SystematIC, the Netherlands

AbSTRACT

MicroThrust will provide a key com-ponent in facilitating new space exploration missions: a miniaturised propulsion technology that can sub-stantially reduce the cost of space exploration by enabling sub-100 kg spacecraft to perform large delta-V missions. The MicroThrust propulsion system will be the transportation ele-ment for taking nano/microsatellites to any location in the Earth–Moon system and will even allow missions to nearby planets and asteroids. New exploration mission concepts based on small spacecraft then become pos-sible which, thanks to their small size, can be developed within a fraction of the time and cost of conventional missions, thus providing more flight

opportunities for planetary scientists and planetary exploration.

The propulsion system is a MEMS-based colloid thruster, which has a high degree of subsystem integration and represents substantial progress towards a thruster-on-a-chip. The pro-pellant is an ionic liquid (zero vapour pressure) and is fed by capillary forces to arrays of microfabricated silicon capillaries, from the tip of which ions or droplets are extracted and expelled at high speeds (over 20 km/s).

In order to allow a quick develop-ment of a flight capable prototype, this 3-year project, which started in December 2010, will demonstrate a complete system in a laboratory envi-ronment and will aim to reach technol-ogy readiness level (TRL) 5, including miniaturised HV power supply, MEMS ion emitters, microfluidics for propel-lant handling, packaging and detailed mission analysis and experimentally validated operating points.

introduction

Space exploration has long been hin-dered by the prohibitively high cost and time required to qualify space-com-patible technologies. Small spacecraft,

MicroThrust: MEMS-based electric micropropulsion for small spacecraft to enable robotic space exploration and space science

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ranging from CubeSats to nanosat-ellites (10–100 kg mass) have the potential to greatly shrink this bar-rier by allowing fast and inexpensive access to space. In addition to provid-ing technological test beds, they could also enable low-cost scientific explora-tion missions to nearby celestial bod-ies. A key element currently limiting the use of small spacecraft, however, is the lack of a small and efficient pro-pulsion system. In December 2010, the MicroThrust consortium (http://www.microthrust.eu) was put in place as the European FP7 initiative to fill this gap.

The consortium aims to develop a key component in facilitating explora-tion missions: a technology that can substantially reduce the cost of sci-ence and Earth observation missions. Building on the framework of a suc-cessful ESA study, the MicroThrust team of leading academics, research institutions and space companies has developed a conceptual design of a very small, yet highly-perform-ing, electrical propulsion system. In order to allow a quick development of a flight-capable prototype, this project will demonstrate a complete system in a laboratory breadboard, includ-ing miniaturised 4 kV HV power sup-ply, arrayed MEMS ion emitters chips, microfluidics for ionic liquid handling based on capillary forces, packaging, a novel neutraliser approach, detailed mission analysis and experimentally validated operating points.

The MicroThrust team, composed of partners from academia, research institutions, SMEs and industry lead-ers from different European countries will allow a full European development and recurrent production of the tech-nology, thus generating European inde-pendence. The team consists of five

partners, all of which have strong expe-rience in micropropulsion systems for small spacecraft: École Polytechnique Fédérale de Lausanne (Switzerland), Queen Mary University of London (UK), TNO: the Netherlands Organisation for Applied Scientific Research (the Netherlands), NanoSpace (Sweden) and SystematIC (the Netherlands).

MicroThrust system design

The MicroThrust propulsion system is a highly modular system, allow-ing it to be readily adapted to a wide range of missions, with one or many units per spacecraft. We aim to enable small spacecraft — and an emphasis is put on simplicity and reliability. Desire thrust range for the mission we con-sider is 10 µN to 6 mN, with each mod-ule capable of generating up to 300 µN of thrust at an Isp of 3 000 s.

Unlike micro-propulsion systems for large scientific formation flying mis-sions (such as LISA) our aim is not extremely accurate thrust levels or low thrust noise, but rather for an extremely compact and low-mass high-Isp thruster. A major driver is therefore reducing the mass of all sys-tems, including the power supply. We aim for a thrust/power ratio above 0.05 µN/mW and a total impulse of 1 300 Ns. All designs are done so the dry mass of the MicroThrust propulsion system is below 10 % of the spacecraft launch mass.

The conceptual design of the thruster head is shown in Figure 1. Each MEMS thruster head consists of hundreds to thousands of individual microma-chined emitters, fed from a local tank of 50 ml volume. Figure 2 shows the con-ceptual MicroThrust propulsion system mounted in a CubeSat. The full system

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being developed includes: miniaturised regulated precision HV power supply to supply up to 4 kV to extract and accel-erate the ions, local and optimal (mis-sion dependent) central propellant tank, fluid handling, mechanical and electrical interfaces, and MEMS-based thruster head (Figure 1). Figure 3 shows an exploded view of the thruster head.

Several operation modes are possi-ble: emitting positive ions and using a neutraliser to ensure charge-neutrality of the spacecraft or, since both cations and anions can be extracted from the ionic liquids used as propellant, bipolar operation could eliminate the need for a neutraliser, as the overall emitted beam would be globally neutral.

Since current flight-rated high-voltage power supplies have a mass of sev-eral kilograms, an unacceptable mass for the MicroThrust system, new power supplies are being designed from the ground up, to be compact yet provide the performance and reliability needed for our application.

Operation principle of the colloid thrusters

The MicroThrust propulsion system operates by emitting ions or small charged droplets, which are electrically accelerated to provide thrust. It is based on a miniaturised electrospray system.

Electrosprays (also know as colloid thrusters) typically operate by trans-porting a conductive liquid (often an ionic liquid) to an extraction site placed below an annular electrode. When elec-trical potential between the conductive liquid and the extraction electrode is increased, the liquid deforms from a meniscus into a Taylor cone (Taylor, 1964) and eventually starts spray-ing droplets or, if the dimensions, liq-uid properties, and applied field are adequate, single ions (Romero-Sanz et al., 2003). By varying the poten-tial at which the device is operated, it is thus possible to change the spray composition, from droplet to purely ionic. The resulting variation in charge-over-mass ratio of the emitted species

Figure 1. Conceptual design of the thruster head. The full propulsion system also includes a miniaturised power supply and a larger optional central propellant tank.

Figure 2. Preliminary design of the complete propulsion system (thruster module, neutraliser, power supply) filling only a fraction of a CubeSat (a 1 kg nanosatellite).

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Figure 3. Exploded view of the highly integrated thruster module proposed in MicroThrust. The full propulsion system also includes a miniaturised power supply and optionally a larger propellant tank.

allows the fine-tuning of the specific-impulse (Isp) and thrust (T). Operating in purely ionic mode, electrospray thrusters outperform any other rival-ling thruster technology in terms of Isp, but have low thrust density. Microfabrication however allows the seamless manufacturing of arrays of emitters, combining high specific impulse with sizeable thrust (Krpoun et al., 2008; Krpoun and Shea, 2009). The resulting thruster is thus an extremely efficient (> 3 000 s Isp) ‘high’ thrust (≈ 100 µN, according to array size) system that can be fine-tuned according to mission require-ments. Transporting the liquid through capillary action further removes the need for active pumping and pro-vides significant reductions in system complexity.

Demonstrated electrosprays using capillary transport of propellant can be separated in three types: externally wetted (Lozano and Martínez-Sánchez, 2005), wetted through porous materi-als (Legge and Lozano, 2011; Courtney and Lozano, 2009) or internally wet-ted (Krpoun et al., 2008; Krpoun and Shea, 2009; Lenguito et al., 2010 and 2011; Dandavino, 2011). The MicroThrust consortium has focused on the last method, using microfab-ricated arrays of silicon capillaries. Microfabrication uses the same basic technologies used to make integrated circuits, but adapted to making µm or

sub-µm scale mechanical structures on silicon wafers: thousands of identical devices can be made on a wafer. We have to date integrated emitter and extractor, and are developing the fabri-cation process to integrate accelerator electrodes at the wafer level.

We have previously (Krpoun et al., 2009) described how the operation mode of the microfabricated emit-ters could be tailored from droplet to ion mode by tailoring emitter geom-etry. We have now developed a fab-rication technology to assemble the thruster at the wafer scale, as seen in MicroThrust_FIGURE 4

Figure 4 and Figure 5. Our emitter den-sity is currently 1 600 emitters/cm2.

Liquid feed is done purely by capillary forces, thus allowing for a much sim-pler system design, as fluid pumps are not required.

Mission analysis

MicroThrust aims to provide high Isp

electric propulsion for small satel-lites. In its smallest configuration, the MicroThrust system must be low-mass and compact in order to fit in a 3 kg spacecraft (3U CubeSat). Thanks to its modular design, the system is also designed for a range of nanos-atellites (1–10 kg) to microsatellites (10–100 kg).

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Figure 4. Cross-section view of the integrated thruster chip depicting the thruster operation principle. The ion beam emission is induced by the large potential difference applied between the conductive ionic liquid and the extractor.

Figure 5. SEM image of an array of 19 micromachined silicon ion emitters with an inner diameter of 10 µm and outer height of 70 µm.

The MicroThrust system is designed to cover the most likely destinations for nanosatellites. A range of destinations is considered, from a mission to the Moon, to a near-Earth asteroid, to Mars’ moons. Since this represents the most challenging mission sets, a change in velocity of 5 km/s was taken as the baseline mission, and optimum trajec-tories were determined for rendezvous with Asteroid 1996 FG3 (the Marco Polo mission target) and the Moon. Assuming an Isp of 3 000 s, about 500 g of propel-lant is required to move a 3U CubeSat from LEO to low lunar orbit.

The goal of the mission analysis is to establish mission-derived require-ments and propulsion system perfor-mance requirements, and to determine what missions are possible with the current MicroThust system. We thus ensure that real mission requirements are understood and implemented in the design of the MEMS propulsion system.

Testing

MicroThrust aims to reach TRL5 of all key components, validated by testing

of a laboratory breadboard. Two part-ners are equipped with beam analy-sis equipment for full plume analysis including I–V curves, time of flight mass spectrometry, beam shape determina-tion and retarding plate analysis.

The microfabricated thruster chips were successfully tested in a pumpless liquid delivery configuration. Figure 6 is an I–V curve of the bipolar-mode oper-ation of a single 5 µm inner diameter emitter and a 150 µm inner diame-ter extractor. in bi-polar mode, apply-ing positive and negative potentials at 0.5 Hz, as shown in Figure 6. The scaling of spray current from arrays of emit-ters and the tunability of the Isp (reach-ing over 3 000 s at under 1 kV with no accelerator) were also demonstrated.

CONCLUSIONS

MicroThrust will allow small satellites to accomplish missions that today are impossible due to the lack of miniatur-ised high-Isp propulsion. For example, with MicroThrust, a 3 kg satellite could go from low Earth orbit to low lunar

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Figure 6. (a) I-V curve for a single 5 µm inner diameter emitter with passive liquid delivery and power supply polarity alter-nating at 0.5 Hz. Stable bipolar emission is observed starting from 695 V. Between 560 V and 690 V, pulsation mode is observed.

orbit using only 0.5 kg of propellant. Such ability is truly enabling, as it can reduce the cost of space exploration missions by more than a factor of 10.

For example OLFAR (‘Orbiting low fre-quency antennas for radio-astronomy’) is a mission proposed by Dutch radio-astronomers consisting of a constel-lation of up to 50 5 kg nanosatellites in lunar orbit, taking data in the sub-30 MHz band when on the far side of the moon so as to be shielded from EM noise from the Earth. Such a mission is only affordable if it is based on nano-satellites that have the ability to make large orbital changes under their own power.

MicroThrust is highly modular. The complete unit (including all power supplies, fluid handling, data inter-faces and propellant) weighs under 160 grams and easily fits into a CubeSat. The MEMS chips size can be varied to provide different thrust lev-els and, for larger missions, multiple thrust heads can be clustered together and a central propellant tank added to increase total impulse.

We are currently 1 year into the project and have developed an initial system thruster concept, analysed candidate missions and derived system require-ments. We have microfabricated two generations of MEMS chips, designed a very low-mass 4 kV power supply, designed a novel fluidic handling sys-tem and demonstrated an Isp of over 4 000 s at 1 kV from the MEMS chips using an ionic liquid. Current work is focused on developing the breadboard, fabricating larger arrays of microma-chined silicon emitters, testing the integrated capillarity-based fluid feed systems, the compact HV power sup-plies, testing the operating points and investigating lifetime.

REFERENCES

  Courtney, D. G. and Lozano, P., ‘Development of ionic liquid electrospray thrusters using porous emitter substrates’, International Conference on Space Technology and Science, 1-6, 2009.

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  Dandavino, S., Ataman, C., Shea, H., Ryan, C. and Stark, J., ‘Microfabrication of capillary electrospray emitters and ToF characterization of the emitted beam’, 32nd International Electric Propulsion Conference, 1-10, 2011.

  Krpoun, R. and Shea, H. R., ‘Integrated out-of-plane nanoelectrospray thruster arrays for spacecraft propulsion’, Journal of Micromechanics and Microengineering 19(4), April 2009, 045019.

  Krpoun, R., Räber, M. and Shea, H. R., ‘Microfabrication and test of an integrated colloid thruster’, 21st International Conference on Micro Electro Mechanical Systems, 2008, pp. 964–967.

  Krpoun, R., Smith, K. L., Stark, J. P. W. and Shea, H. R., ‘Tailoring the hydraulic impedance of out-of-plane micromachined electrospray sources with integrated electrodes’, Applied Physics Letters, 94(16), 2009, 163502.

  Legge, R. S. and Lozano, P. C., ‘Electrospray propulsion based on emitters microfabricated in porous metals’, Journal of Propulsion and Power, 27(2), March 2011, pp. 485–495.

  Lenguito, G., Fernandez de la Mora, J. and Gomez, A., ‘Multiplexed electrospray for space propulsion applications’, 46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 1-11, 2010.

  Lenguito, G, Fernandez de la Mora, J. and Gomez, A., ‘Design and testing of multiplexed electrospray with post-acceleration for space propulsion applications’, 47th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 1-11, 2011.

  Lozano, P. C. and Martínez-Sánchez, M., ‘Ionic liquid ion sources: characterization of externally wetted emitters’, Journal of Colloid and Interface Science, 282(2), February 2005, pp. 415–421.

  Romero-Sanz, I., Bocanegra, R., Fernandez de la Mora, J. and Gamero-Castano, M., ‘Source of heavy molecular ions based on Taylor cones of ionic liquids operating in the pure ion evaporation regime’, Journal of Applied Physics, 94(5), 2003, pp. 3599–3605.

  Taylor, G., ‘Disintegration of water drops in an electric field’, Proceedings of the Royal Society of London, 280, No 1382, July 1964, pp. 383–397.

CHAPTER 30

Authors: Philippe Gautier, Olivier Orlandi, Stéphane Henry

consortium members: SME SA, France; Astrium SAS, France; ONERA, France; Astrium GmbH, Germany; DLR, Germany; Avio SpA, Italy; Università di Napoli Federico II (DIAS), Italy; Politecnico di Milano (SPLab), Italy; University Polytechnic of Bucharest (UPB), Romania; Thyia Tehnologije d.o.o., Slovenia

AbSTRACT

Nowadays, chemical propulsion is based on solid (launch applications like first-stage booster) or liquid technologies (primary stages, upper-stage engines). Complementary, hybrid propulsion technology, as defined in ORPHEE (‘Operational research project on hybrid engine in Europe’), appears as a new generation of advanced space transpor-tation systems. Engines based on this innovative propulsion concept can pro-vide advantages such as high thrust and specific impulse, throttling (thrust mod-ulation), versatility (easy adaptation to various configurations) and safety.

Beyond these technological advan-tages, it will help to consolidate the long-term sustainability and ensure the availability of a technology needed by the European propulsion space com-munity to remain competitive in the long term.

The hybrid propulsion principle is based on the injection of a liquid or gaseous oxidiser into the engine com-bustion chamber where it reacts with solid fuel to generate hot gases pro-viding the thrust. Enlarging the burn-ing surface is the currently favoured solution to reach the needed perfor-mance level. However, it dramatically increases the solid grain volume and the engine weight, limiting the appli-cations. Consequently, the increase of the regression rate, which is a key parameter to control the solid fuel grain design, is a very attrac-tive solution to improve the overall performance.

Based on this analysis, a European Consortium, co-funded by the sev-enth framework programme (FP7) and the partners, was established. The project, named ORPHEE (Operational research project on hybrid engine in Europe), relies on 10 partners from five European countries.

MetHodoLoGy

The main objectives of ORPHEE are to increase the versatility of space pro-pulsion systems, ensure a significant increase of hybrid engine performance, improve the solid fuel technologi-cal maturity from TRL 1 to 3, gather European skills on hybrid propulsion and invest in the future European access to space.

ORPHEE: Operational research project on hybrid engine in Europe

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In the near future, the availability of new hybrid engines will give access to new space transportation missions. By consolidating the knowledge on this innovative technology and by imple-menting solutions in upcoming space agency roadmaps, the European space propulsion community will strengthen its global position.

To achieve the overall objectives described above, numerous measurable objectives have been identified in terms of knowledge development and phys-ics understanding, but also in terms of technological planning development:

• performance requirements for two space transportation applications

¸ thrust modulation and stop/restart: lander engine and upper-stage engine

¸ high thrust: booster engine

• solid fuel formulation characterised by an increased regression rate

• test-firing at lab-scale

¸ test definition

¸ solid fuel formulation and supply

¸ grain manufacturing

• feasibility of models for mastering

¸ liquid oxidiser injection

¸ solid fuel regression

¸ combustion efficiency

¸ operating effect (chamber geom-etry, operating pressure …)

• demonstrator design for both appli-cations and test bench design for demonstrating advantages of hybrid engines.

The logic of the project is organised in four work packages and simply described in Figure 1.

ProJect stAtus And ACHIEVEMENTS

Mission analysis and requirements

Based on mission analysis, the most promising applications are identified:

• upper-stage for small/medium launcher,

•Mars or Moon landers,

• first stage of low-cost launcher.

Figure 1. ORPHEE logic (SME SA)

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Figure 2. Example of mission (Lunar descent and soft landing) ensured by a hybrid engine (Astrium SAS)

Solid fuel

Based on mission analysis, a trade-off study was performed to select the most interesting fuels and oxidisers. The potentially interesting fuels were for-mulated and tested at small scale by the SPLab. Both ballistics and mechan-ical aspects have been addressed and the characterisation work used two SPLab experimental set-ups:

• the SPLab radial burner (typical grain shape is 30 mm length, 20 mm in diameter and 10 to 16 mm diameter for the central bore);

• the SPLab 2D slab burner (sam-ples have a rectangular shape (15 × 22 × 4 mm).

The references used for the project are based on pure hydroxyl-terminated polybutadiene (HTPB) grain tests, and then a ballistic characteriSation of solid fuels based on HTPB loaded with magnesium hydride (MgH2), nano-sized aluminium powders (n-Al) or other additives is studied. Several wax-based solid fuels formulations added with n-Al and MgH2 powders were also tested.

The reported results suggest a more efficient entrainment effect displayed by SW-based formulations when com-pared to GW-based fuels, leading to higher regression rate.

A second step is devoted to the scal-ing up and manufacturing of larger grains whose weight can reach several kilograms. All formulations are based on HTPB fuels and a major motiva-tion is to study the effect of the scaling up on the measured regression rate. Firings were performed on the DIAS experimental facility (University of Naples Federico II). A firing matrix was defined in order to study the effect on the regression rate of additives (n-Al, MgH2, nano-Fe), the mass flux and diameter size.

Modelling

The aim of the modelling work is firstly to gain a better understanding of the physical phenomena involved in the operation of a hybrid engine. A one-dimensional tool was developed by Onera to study the fuel regression rate considering fuel pyrolysis and an analytical law for the aerodynam-ics. Astrium GmbH focused on oxidiser injection. Numerical calculations were performed with the code Rocflam II, which allows us to consider a PDF chemistry and a local description of the fuel regression rate.

A study of the turbulence effect on the combustion was studied by the University of Bucharest. Simulation of the development of the flame showed the formation of a variety of large tur-bulent structures right above the fuel

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Figure 3. Example of results obtained on regression rate increase for wax-based fuels (SPLab)

Figure 4. Results for lab-scale motor measured regression rate for HTPB-based fuels (DIAS)

Figure 5. Example of numerical simulation results on the effect of liquid oxidiser droplet size (Astrium GmbH)

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grain that transport energy, mass and momentum to the main flow. The development of a high vorticity mag-nitude patch above the fuel slab that extends towards the middle chan-nel can be observed. Based on these results, a 3D-LES calculation was per-formed and showed, in particular, the appearance of vortex filaments that spread the flame downstream in the crossflow direction.

A global one-dimensional tool was built by SME. This numerical code considers a complex chemistry and a local evolu-tion of the geometry that corresponds to the fuel regression rate. Injection of liquid oxidiser droplets is also availa-ble. Satisfactory results were obtained by comparing to experimental test fir-ing, and potential development can focus on a better representation of the fuel regression law to take into account the specific properties of the considered fuel.

In parallel to the modelling activity, a database was built with the aim of gathering published information on hybrid propulsion. The collected data are useful for model validation and the future development of numerical tools.

Preliminary design and roadmap

The demonstration of hybrid technol-ogies studied in the ORPHEE project will be an important step towards the future applications of this propulsion capability.

To achieve this, two technological subscale demonstrators have been designed for the two main applica-tions identified in the ORPHEE scope, namely booster and lander. The scale of these demonstrators is compatible with a test bench existing in DLR facili-ties with LOX oxidant.

As a main output of the ORPHEE pro-ject, DLR and SME have coordinated the construction of an updated roadmap of advanced hybrid propulsion, including the technical elements and analysis of all the ORPHEE partners. The objective of this roadmap is to define the techni-cal steps and planning logic, in order to reach TRL 6 for the two main applica-tions — the booster-stage engine and lander vehicle engine. The main tech-nical challenges are the performance targets of this roadmap, as summa-rised in Figure 7.

The final roadmap is a combination of the roadmaps established for each

Figure 6(a). Booster subscale demonstrator (TRL 4). Figure 6(b). Lander subscale demonstrator (TRL 4–5) (Astrium–-Avio–DLR–SME SA).

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key technology of main subassemblies (solid and liquid parts) or main issues of system architecture and design. This gives access to a very detailed descrip-tion of technical activities, which can

be synthesised at different levels. As an illustration, a broad summary is presented hereafter in order to outline the main roadmap steps for booster application.

Figure 7.

Figure 8.

CONCLUSIONS

ORPHEE contributes to increasing European knowledge and compe-tences in the area of hybrid propul-sion. With regard to fuel, and based on small-scale tests, different solutions to increase the regression rate have been identified. Thus, a scaling up (7 kg grain) of some selected fuels allowed us to perform lab tests on motors.

Based on a mission analysis, fuel stud-ies and modelling work, two preliminary demonstrators have been designed.

Finally, a roadmap for increasing the maturity of the hybrid propulsion is available including all the needed tech-nologies in Europe.

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REFERENCES

   Carmicino, C. et al., ‘Basic aspects of the hybrid engine operation’, 45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, Denver, Colorado, 2–5 August 2009.

   Frey, M. et al., ‘Modelling of combustion and flow in a hybrid thrust chamber’, EUCASS 2011, St Petersburg, 4–8 July 2011.

   Galfetti, L. and al, ‘Characterization of a family of paraffin based solid fuels’, EUCASS 2011, St Petersburg, 4–8 July 2011.

   Martin, F. et al., ‘Hybrid propulsion systems for future space applications’, AIAA JPC, July 2010.

   Orlandi O. et al., ‘Some challenging aspects of hybrid propulsion for space application’, EUCASS 2009, Versailles, 6–9 July 2009.

   Orlandi, O. et al., ‘Toward advanced solid fuels for hybrid propulsion’, Space Propulsion Conference 2010, San Sebastian, 3–6 May 2010.

   Orlandi, O. et al., ‘Advanced solid fuels for hybrid propulsion in

ORPHEE’, ISTS 2011, Okinawa, 5–12 June 2011.

   Orlandi, O. et al., ‘Scale factor and advanced solid fuels for hybrid propulsion in ORPHEE’, EUCASS 2011, St Petersburg, 4–8 July 2011.

   Soller, S. et al., ‘Development roadmap and design of demonstrators for hybrid rocket propulsion in Europe’, EUCASS 2011, St Petersburg, 4–8 July 2011.

   Prevost, M. et al., ‘Modelling of hybrid rocket motor: 1D regression rate prediction model’, EUCASS 2011, St Petersburg, 4–8 July 2011.

   Russo, A. et al., ‘Advanced solid fuels for hybrid propulsion: the research activity in Europe’, 47th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, San Diego, California, 31 July to 3 August 2011.

   Russo, A. et al., ‘Advanced solid fuels for hybrid propulsion: the research activity in Europe’, Eighth International Conference on Flow Dynamics, Sendai, 9–11 November 2011.

   The website: http://www.orphee-fp7-space.eu/

CHAPTER 31

Authors: Mario Pessana and Enrico Gaia

consortium members: Thales Alenia Space Italia SpA (TAS-I), Italy; Università degli Studi di Padova, Italy; Nammo Raufoss AS, Norway; Bradford Engineering BV, the Netherlands; Vysoké učeni technické v Brnĕ, Czech Republic; Politecnico di Milano, Italy; GMV Aerospace and Defence SA Unipersonal, Spain; Studiel, France

AbSTRACT

SPARTAN project aims at developing a throttable propulsion technology for planetary soft and precision landing by exploiting hybrid engine technol-ogy. The research is complementary to the ESA basic technology research pro-gramme (TRP).

This hybrid propulsion system includes two major parts: the engine itself, housing the fuel, and the oxidiser injection system. The research focuses on three major objectives:

— the engine design, specific for throt-tling functionality,

— the oxidiser throttable device development,

— the design of the landing case: test bench and testing procedures.

The development includes the estab-lishment of an advanced coding capa-bility, enabling the definition of fuel and throttling behaviour of the hybrid engine. The engine definition is sup-ported by a series of development tests: cold injection case, dedicated to the throttling device; hot firing on sub-scale model, merging the throttling device and a subscale engine; hot firing full-scale testing, both under static and dynamic test configurations. A landing test and associated landing model (fly-ing test bed) will be developed in the last year of the project, resulting in a proven landing model and landing test capabilities. The project, during its first 9 months, succeeded in achieving the definition of the driving system and in establishing the mission requirements together with performing the major technological selection:

— fuel and oxidiser selection,

— fuel characterisation,

— throttling concept and throttling device design,

— flight management design and functional architecture definition,

— structure and landing gears design.

The functional architecture has been designed integrating the GNC func-tions together with the monitoring and recovery systems functions, generating

SPARTAN: Space exploration research for throttable advanced engine

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a redundancy when the vehicle atti-tude and position control functions are concerned. This leads to have a double check and an independent capability of detecting any eventual failure of the system, triggering the recovery system if necessary. An intensive analysis of the mission profile has been carried out, to harmonise conflicting mission perfor-mance requirements, with the recovery parachute behaviour. In this harmonisa-tion a great role was played by the heli-copter wake effect that is impacting on the vehicle aerodynamics performances both during the nominal flight and dur-ing the parachute-assisted phase.

AcHieVed resuLts

During this initial period — the pro-ject started at the beginning of March 2011 — some important activities have been pursued intensively, produc-ing important achievements.

Starting from the preliminary system performance requirements, which have been established on the basis of those evaluated during the proposal phase, the initial fundamental technical selec-tions have been carried out in the key development domain:

— fuel and oxidiser, including fuel characterisation,

— throttling concept,

— throttling device design.

In addition to this, and in accordance with the established requirements, sys-tem-level major activities have been performed, covering the following topics:

— lander structural design and budgets,

— flight management and functional architecture,

— mission profile and its preliminary verification by test.

Technological achievements

Fuel and oxidiser

The preliminary selection included in the proposal was to use wax/N2O; despite this it has been decided to investi-gate the possibility of swapping this for HTPB/H2O2, exploiting the synergy with another ESA project, awarded to NAMMO, which uses exactly this cou-pling. H2O2 is indeed more costly, it has a limited lifetime and needs deeper care during ground handling, but it is greener even when compared with N2O.

The H2O2 that will be used in the 87.5 % concentration has a storage lifetime that is still compatible with the worst case Mars mission lifetime require-ment. The available data shows that the hydrogen peroxide has been tested for a 3-year flight time with appropriate tank material and passivation procedure (5 years expected). Storage lifetime is an important parameter, because it can be a showstopper for long mission dura-tion, like those to reach Mars. Hydrogen peroxide has recently been successfully used in space missions like those listed in Table 1.

The data in Table 1 have been compared with Mars mission lifetimes, computed and recorded during all previous Mars missions and it has been found that the Mars mission lifetime ranges from the 128 days of Mariner 7 (launched on 27 March 1969) and the 500 days of Dawn (launched on 27 September 2007), Rosetta excluded, because it was not devoted to a pure mission to Mars.

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Mission duration [days]

Soyuz 22 8

Progress OKD 74.81

Soyuz T SA 2.01

Progress M 337

Table 1.

It has also been verified that the use of the hydrogen peroxide will decrease by far the L/D engine ratio (one third of that defined by the use of N2O), leading to a more compact engine design, with the possibility of increas-ing the allowable total impulse or, vice versa, of making it easier to install it on the lander.

A second advantage produced by the hydrogen peroxide, as oxidiser, is its higher combustion efficiency. Finally,

the hydrogen peroxide is injected in its gaseous form, because it makes use of a catalyst upward the injec-tion system needing a much more simple injection technology. The nitro-gen oxide is, in fact, injected as liq-uid, which means that the throttling device must be embedded into the injector system, thus requiring one throttling device for each engine. In this way, only one throttling device is introduced along the oxidiser line, common to all the engines.

Fuel characterisation

To check if the fuel capability is able to withstand the throttling demand, labo-ratory tests have been carried out on small cylinder samples of the planned HTPB, at both static and variable condi-tions. The plots in Figure 1 summarise the results, comparing the actual fuel, with a reference one:

Figure 1. 2D-Radial Ballistics: Steady Regression @ 13 bar Figure 1. 2D-Radial Ballistics: Unsteady Regression

The tests concluded as follows.

No important differences between the two types of HTPB are observed in terms of quasi-steady regression rate and grain fragmentation. Data reduction under transient conditions

shows similar trends for the two formulations: a slight oscillation is observed during oxidiser mass flow decrease. It is planned to increase the number of samples to be tested, but already the present results are encouraging.

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Throttling concept

SPARTAN throttable hybrid rocket motor requires 10:1 thrust modu-lation. This specification has been translated into a 10:1 throttle ratio for the oxidiser flow using a 0-D sim-ulation code. Moreover, a value has been specified for the response time of the oxidiser flow control valve: the attitude control requires a 20 % thrust modulation in 0.1 seconds. This delay is the sum of the feed-line, FCV, catalyst and combustion cham-ber response. Using the unsteady 1-D simulation code developed by UniPD in the frame of SPARTAN, this value has been verified and the specifica-tion reformulated in ‘20 % thrust var-iation in 0.05 seconds’ to take into account also the combustion cham-ber delay (that appears to negligible) and adding a safety margin.

The four motors will be fed by a single oxidiser tank and the hydrogen perox-ide must be delivered in a controlled way to the motor combustion cham-bers. To achieve this, two architectures have been proposed: the first with an FCV for each motor and the second with an additional FCV added upstream. The first solution has been selected because it provides better regulation and reduced feed-line complexity.

Throttling device design

A technical trade-off has been carried out against three different regulating concepts:

concept 1 — on/off valve,

concept 2 — poppet valve,

concept 3 — cavitating venturi.

The cavitating venturi has been selected, because of its major advan-tage in terms of controllability: only dependent on upstream (controlled) conditions and the position of the pin-tle, therefore independent of tran-sient effects in the rocket engine. Additionally, the pintle can be used for mass flow measurement, eliminating need for a separate mass flow meter. Figure 2 shows the pintle device func-tional architecture:

Figure 2.

System technical design

Lander structural design and budgets

SPARTAN system configuration, compo-nents lay-out and budgets are defined.

Top view

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Side view

Figure 3.

Structure and landing gears design

Figure 4.

Flight management and functional architecture

The SPARTAN functional architecture harmonises two systems which are not fully redundant:

— guidance, navigation and control system,

— monitoring and recovery system.

The GNC is not one failure toler-ant via the MRS, but the MRS dupli-cates the control sensors in a way that can autonomously detect a fail-ure, shut down the propulsion system and trigger the parachute to recover the lander.

Missionprofileanditspreliminaryverificationbytest

The vehicle has to achieve 30 m/s (ver-tical velocity) before starting damp-ing the vertical velocity down to 2 m/s

that must be reached at touchdown, this is a typical requirement for a Mars landing mission. The mission profile is driven by the above requirement and its implementation depends on the selected solution to lift the SPARTAN lander and the performances of the recovery parachute.

To lift off the lander we have selected a helicopter and the major diffi-culty in designing the mission profile

(a) (b)

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is generated by the rotor wake that impacts on both the nominal and the recovery scenario. Many CFD simula-tions have been performed, considering also NASA test data on the wake effect, but we are somehow far from being in a safe and robust position and the mis-sion profile still has to be finalised.

To reach a decision, the following devel-opment test plan has been established.

— Rotor wake test, using an instru-mented fixed platform on the

ground, with the helicopter moving vertically over the target. This is to characterise the wake.

Parachute driven test, adopting a mis-sion profile that allows a safe para-chute deployment and fixing a virtual ground on air to assess the vehicle behaviour at touch down, in the recov-ery scenario. The scope of this test is the validation of wake impact analysis, recovery parachute performances and landing gears behaviour.

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Figure 5.

CONCLUSIONS

SPARTAN is a leading project in Europe, supporting future precise and soft plan-etary landing, adopting a fully European technology. After almost 1 year of development the project is achieving the planned target as expected. The oxi-diser and the fuel have been selected and the throttling device has been pre-liminarily designed and cold testing is in progress. One-D advanced code, to support the engine preliminary design, has been established and validated pro-viding precise results. The lander struc-ture has been designed and verified. A mock-up is being manufactured to sup-port flight verification tests.

To meet the major mission require-ments (damping the lander velocity from 30 m/s down to 2 m/s), without lateral constraints during the flight of the lander for the final test under the helicopter wake has been discovered to be challenging and may increase the complexity of the project, but it has

been deemed as necessary to reach the expected results.

REFERENCES

   Parissenti, G. et al., ‘Throttleable hybrid engine for planetary soft landing’, Fourth European Conference for Aerospace Sciences (EUCASS), Saint-Petersburg, 22 March 2011.

   DeLuca, L. T. et al., ‘Characterization of HTPB-based solid fuel formulations: performance, mechanical properties, and pollution’, Second Private Human Access Space, Arcachon, France, 30 May 2011.

   DeLuca, L. T. et. al., ‘An optical time-resolved technique of solid fuels burning for hybrid rocket propulsion’, 47th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, San Diego, 31 July to 3 August 2011.

CHAPTER xx Space data exploitation

CHAPTER 32

Author: Michele Piana

consortium members: Università di Genova, Italy; Fachhochschule Nortwestschweiz, Switzerland; University of Glasgow, United Kingdom; Universität Graz, Austria; Centre national de la recherche scientifique, France; University of California at Berkeley, United States of America

AbSTRACT

On 28 October 2003, the Earth experi-enced one of the most dramatic effects of solar eruptive events for many years. Following an intense flare, a halo coronal mass ejection was directed straight towards the Earth, with a velocity of 8 million km/hour. Nineteen hours after the explosion, strong geo-magnetically induced currents caused blackouts of the power distribution grid; the accuracy of satellite navi-gation systems was degraded; airlin-ers scheduled for trans-polar flights were rerouted to lower latitudes. This one event brought home the reality that modern technology-based socie-ties are becoming increasingly vulner-able to this type of natural threat. And it clearly demonstrated that under-standing the physics of these most powerful events is a necessary prereq-uisite to predict their occurrence and their potentially damaging effects in space and on the Earth.

It has been recognised since the early days of space investigation that high energy observations play a crucial role in understanding the basic mechanisms of solar eruptions. Unfortunately, the peculiar nature of this radiation makes it so difficult to extract useful infor-mation from it that nonconventional observational techniques together with complex data analysis procedures must be adopted. The rationale of the ‘High energy solar physics data in Europe’ (HESPE) project is to formulate and implement computational meth-ods for solar high energy data analysis, and to utilise sophisticated information and communication technology (ICT) tools for providing algorithms and sci-ence-ready products to the solar phys-ics community.

HESPE aims at becoming a home for state-of-the-art high energy solar data and science-ready products that help to initiate original, challenging solar, helio and space science. To accomplish this goal, HESPE utilises highly sophis-ticated computational and technologi-cal tools, whose conception is driven by theoretical models formulated within the framework of solar flare phys-ics. More specifically, HESPE wants to realise a computational corpus con-taining a notable amount of numerical algorithms for spectral fitting, spec-tral inversion, image reconstruction, edge detection, image segmentation, and spectral and image classification. Further, HESPE is defining and realising

HESPE: High energy solar physics data in Europe

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a database of optimised data prod-ucts that are interoperable with stand-ard data analysis software. HESPE is also setting up a standard catalogue of science-ready products that auto-matically allows fast searching and browsing. Finally, HESPE is integrating these products into e-infrastructures that are already active in the EU solar, helio and space weather communities.

AcHieVed resuLts

HESPE activity has three main scien-tific goals. First, we aim at designing a HESPE framework to allow for pipe-lined processing of high energy data. Second, we want to realise a nota-ble corpus of computational methods for the analysis of high energy data in the case of spectroscopy, imaging and imaging spectroscopy. Third, we want to construct a database of science-ready products. Although HESPE has just fin-ished its first year of activity, all these tasks have been addressed and some results have already been achieved.

Specifically, as far as the first goal is concerned, we have based the HESPE framework on the idea that data pro-cessing can be modelled as a sequential execution of processing routines. Every routine takes an input and returns val-ues (data structures, arrays, etc.), which themselves serve as input for the next processing step. The structure of this framework is represented in the pipe-lines in Figure 1. During this first year, HESPE scientists fully realised the first module of the pipeline, i.e. the interval selection step (red pipeline in Figure 1). More precisely, we have realised an automatic pipeline for the creation of a visibility database that, by means of an interval selection algorithm, trans-forms measured counts into optimised

visibility bags. In this specific case, the first step of the pipeline is data acqui-sition; the second step is background noise removal; the third step is interval selection and the last step is visibility creation. This pipeline can eventually be integrated in the SolarSoftWare (SSW) library, which is required for our IDL-based software to work.

We believe that this technological real-isation may have a notable impact on current and future solar phys-ics research. Just as an example, this pipeline will allow, for the first time, statistical analysis of high energy data according to a fully automatic man-ner: eruptive events can be classified according to different parameters (e.g. position on the solar disk, peak flux, dynamic phase) and optimised visibility datasets can be created for each class and reached by means of simple data-base queries.

As far as the second goal is concerned, we have based the approach to the computational activity on two comple-mentary strategies: the implementa-tion of brand new or newly optimised algorithms in spectroscopy, imaging and imaging spectroscopy; and the val-idation of existing methods in order to assess their reliability when applied to experimental measurements. HESPE has implemented new statistical meth-ods for best fitting the different param-eters of a hard X-ray spectrum and for reconstructing electron flux spec-tra from count data. It has also pro-duced a new, optimised version of the uv_smooth routine for image recon-struction from visibilities by means of interpolation/extrapolation procedures and has provided the SSW tree with a software package able to reconstruct maps of the flaring events whose pix-els are related to the electron flux

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spectrum in situ, at different electron energies. But the most notable concep-tual result obtained so far by HESPE in this context is the achieved conscious-ness that not all the imaging methods typically utilised in solar physics (and typically implemented in SSW) are reli-able for the reconstruction of images

of flaring events of all possible physical or geometrical properties.

Indeed, for the first time, a systematic validation of all the imaging methods existing in the Solar SoftWare tree is under construction. A group of HESPE researchers has set up the following complex and sophisticated test.

Figure 1. The HESPE framework and, in red, realisation of the interval selection pipeline.

1. Ten different configurations of the flaring region have been invented, characterised by very different topographical and physical prop-erties (size, position, number and distance of disconnected com-ponents, relative intensity of the components) (see Figure 2).

2. For each flaring configuration, three different synthetic vis-ibility sets have been realised,

characterised by three different levels of statistics (low, medium, high). This simulation has been performed utilising the proper-ties of the Reuven Ramaty High Energy Solar Spectroscope Imager (RHESSI) imaging system but an extension to any other hard X-ray device is straightforward.

3. Many different imaging algorithms have been applied to each visibility

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bag and a set of routines has been implemented, for the quantita-tive assessment of the algorithms’ performances. These routines compare the topographical and physical properties of the original configurations with those of the reconstructions.

4. Based on the results of this assessment, look-up tables are under construction, in which the reliability of each algorithm will be assessed with respect to the

recovery of different physical, geometrical and computational parameters.

This experiment is still under construc-tion (in particular, we are still process-ing the results in step 4 and collecting all the information obtained in a sys-tematic fashion). Its preliminary out-comes have been discussed at the 12th RHESSI Workshop (Nanjing, China, 16–21 October 2011) and will be soon put at disposal of the solar scientists working at high energy data analysis.

Figure 2. HESPE imaging test: the 10 flaring configurations utilised to produce the synthetic visibility sets.

HESPE spectroscopy, imaging and imaging spectroscopy algorithms are the crucial computational tools for the realisation of science products that may reveal the most intriguing and mysterious aspects of solar flare physics. As an example of this poten-tiality, inversion methods together with interpolation and extrapolation techniques can provide maps as the ones in Figure 3, left panel. The pecu-liar feature of these images is the fact that their pixel content is no longer a remote signature of the bremsstrahl-ung emission but is directly related to the averaged electron flux in situ. With

these maps at disposal many open issues in solar flare physics can be addressed.

• Local electron flux spectra can be directly extracted from specific regions of the electron maps and, from them, information can be easily inferred about, for example, the loca-tion of the acceleration region and on the local spectra indices.

• The size of the sources can be esti-mated as a function of energy in both the photon and the electron domain in order to predict the mechanisms

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with which the electron are injected into the emitting region.

• Parameters like the energy variation of escape and scattering times can be derived in order to constrain the characteristics of stochastic-acceler-ation models.

These applications can focus on spe-cific events characterised by interest-ing morphologies or can be utilised in a statistical analysis of lots of events, analysis that will be possible just thanks to the availability of the HESPE pipeline for the automatic creation of optimised sets of high energy solar data.

Figure 3. Imaging spectroscopy in the HESPE framework. The left panel shows the electron flux maps corresponding to four electron energy channels in the case of the 8 September 2002 event. The right panel describes the local electron flux spectra extracted from the north (solid), middle (dashed) and south (dotted) region.

CONCLUSIONS

HESPE has just finished its first year activity. During this short time, sig-nificant progress has been achieved towards the three main goals of the project: the HESPE computational framework; the corpus of computational methods; the database of science-ready products. We are also addressing public outreach, which is crucial for the realisation of our scientific goals. HESPE scientific results will be published on an interactive website specifically devoted to the younger generations of European students. Furthermore, 114 papers

authored by HESPE scientists have been published, accepted for publication or submitted to refereed international journals in astrophysics and computa-tional mathematics. Finally, the project team is presenting HESPE research at all the most important conferences and workshops concerning solar physics, heliophysics and space weather science; for instance, at the RHESSI workshops, at the American Geophysical Union (AGU) meetings, and even at the inter-nationally renowned Festival of Science in Genova, Italy, where the importance of this research in the framework of the European space activities has been pre-sented to a audience of non-specialists.

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We have developed the HESPE web-site (http://hespe.eu). The domain ‘hespe.eu’ is owned and maintained by the Fachhochschule Nordwestschweiz (FHNW), representing all other par-ticipating institutions. This website is a portal for the HESPE team, for sci-entists, EU officials and the public, serving as a platform for data and information exchange.

REFERENCES

   Allavena, S., Piana, M., Benvenuto, F. and Massone, A. M., ‘An interpolation/extrapolation approach to X-ray imaging of solar flares’, Inverse Problems and Imaging, 2011 (in press).

   Battaglia, M. and Kontar, E. P., ‘Height structure of X-ray, EUV, and white-light emission in a solar flare’, Astronomy and Astrophysics, 533(L2), 2011.

   Battaglia, M. and Kontar, E. P., ‘Hard X-ray footpoint sizes and positions as diagnostics of flare accelerated energetic electrons in the low solar atmosphere’, Astrophysical Journal, 735(42), 2011.

   Bian, N., Kontar, E. P. and MacKinnon, A., ‘Turbulent cross-field transport of non-thermal electrons in coronal loops: theory and observations’, Astronomy and Astrophysics, 535(A18), 2011.

   Fleishman, G. D., Kontar, E. P, Nita, G. M and Gary, D. E, ‘A cold, tenuous solar flare: acceleration without heating’, Astrophysical Journal Letters, 731, 2011, L19.

   Hudson, H. S., Fletcher, L., Fisher, G. H., Abbett, W. P. and Russell, A., ‘Momentum distribution in solar flare processes’, Solar Physics, 2011; doi:10.1007/s11207-011-9836-0.

   Hudson, H. S., Fletcher, L., MacKinnon, A. L. and Woods, T. N., ‘EVE limits on low-energy alpha particles in solar flares’, Solar Physics, 2011 (submitted).

   Hudson, H. S., Woods, T. N., Chamberlin, P. C., Fletcher, L., Del Zanna, G., Didkovsky, L., Labrosse, N. and Graham, D., ‘The EVE Doppler sensitivity and flare observations’, Solar Physics, 273(1), 2011, pp. 69–80.

   Joshi, B., Veronig, A. M., Lee, J., Bong, S. C., Tiwari, S. K. and Cho, K. S., ‘Pre-flare activity and magnetic reconnection during the evolutionary stages of energy release in a solar eruptive flare’, Astrophysical Journal, 743, 2011, 195.

   Kontar, E. P., Hannah, I. G. and Bian, N. H, ‘Acceleration, magnetic fluctuations, and cross-field transport of energetic electrons in a solar flare loop’, Astrophysical Journal Letters, 730, 2011, L22.

   Massone, A. M. and Piana, M., ‘The use of electron maps to constrain some physical properties of solar flares’, Solar Physics, 2011 (in press).

   Schwartz, R., Kontar, E. P., Jeffrey, N. and Massone, A. M., ‘Accounting for the albedo flux in RHESSI image reconstructions’, American Astronomical Society, Solar Physics Division, 2011 meeting, Las Cruces, New Mexico, USA, 12–16 June 2011.

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   Torre, G., Pinamonti, N., Emslie, A. G., Guo, J., Massone, A. M. and Piana, M., ‘Empirical determination of the energy loss rate of accelerated electrons in a well-observed solar flare’, Astrophysical Journal, 2012 (in press).

   Vilmer, N., ‘Solar flares and energetic particles’, Philosophical Transactions of the Royal Society, A, 2011 (submitted).

CHAPTER 33

Authors: Klaus Briess, Ludmil Bankov, François Crespon, Arnold Sterenharz, Csaba Ferencz, Hanna Rothkaehl, Valery Korepanov, Georgii Lizunov, Olena Piankova

consortium members: Technical University Berlin, Germany; Space and Solar-Terrestrial Research Institute BAS, Bulgaria; Noveltis SAS, France; Eötvös Loránd University, Hungary; Lviv Center of Institute for Space Research NASU–NSAU, Ukraine; Space Research Institute, NASU–NSAU, Ukraine; Space Research Centre PAS, Poland; ECM-Office, Germany

AbSTRACT

In recent years the use or more accu-rate ‘non-use’ of old data from already closed satellite missions has been widely discussed. Quite often, only a rel-atively small part of the data collected during the satellite in-orbit operation is used for scientific publishing while the rest of it remains ‘out of the way’. Throughout decades of the ‘space era’ a huge amount of data has been accumu-lated, and it may be expected that their further use with respect to various sci-entific studies is quite promising without launching new satellites. Taking account of the financial resources already spent for these missions in the past, every bit of obtained information becomes

‘golden’. Thus, further processing of the old data sets could be seen as an investment by our predecessors.

Common understanding on the above-mentioned problem by the scien-tific community appears in the annual space call launched every year under the European seventh framework pro-gramme (FP7). Individual calls may change their basic objectives, as part of ‘exploration of space science and explo-ration of data’, but priorities remain constant:

— The continuous necessity of old missions’ data mining;

— additional visualisation and data classification requirements, as it is common practice that even already processed data becomes accessible only through principal investigators of the space experi-ments — both, because of specific data formats or certain complexity in the accurate data interpretation;

— the general creation of the ‘inte-gral field’ of space observations obtained from different satellites and/or the ground-based measure-ments containing different physical parameters in various frequency bands, which is easy to combine and compare with solar-geophysi-cal data.

POPDAT: Problem-oriented data processing and ionospheric wave catalogues creation

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We would like to describe in this paper a new concept of data processing of the ionospheric satellite observations, which has been used as a basis of the FP7 collaborative ‘POPDAT’ project.

AcHieVed resuLts

We have introduced a conceptual design of the data analysis approach to the ionospheric satellite observa-tions, addressed to the topical process-ing of the experimental data archives, and creation of the data catalogues and related web-resources of iono-sphere wave-like phenomena.

The project is addresses the following main tasks.

1. problem-oriented analysis of the data archives from the past sat-ellite observations of ionosphere–atmosphere parameters;

2. the creation of the catalogues by the data processing of wave-like disturbances;

3. the accumulation of wave cata-logues in an information system — the Ionosphere Waves Service;

Application of the Ionosphere Waves Service in the specific scientific studies

Third-level data processing of experimental observations

Scientific information created by a space vehicle, before it becomes a sub-ject of scientific study, passes through several basic stages of processing. In the beginning, decomposition of raw data such as adjusting to uni-versal time the data flow from differ-ent instruments by the onboard clock

timer, removing data gaps, glitches and many other necessary but unseen procedures by the end user (scientist). Therefore, quick-look plots of output electrical signals permit an estimation of the instrument onboard operation and the quality of data flow. In such a way, the first level is formed, which is a subject of unique engineering software application specially designed for the different instruments and systems.

In the second stage, electrical signals are transformed in the physical param-eters. This is a special procedure using specific calibration algorithms, usually known only by the principal investiga-tors of the instruments. In this stage they create catalogues (archives) of experimental data. Usually, every record in the catalogue expresses equidistant consequent observations represent-ing the course of measuring param-eters along the satellite path (plasma density or electromagnetic field, etc.). In addition to the experimental data, in the catalogues some actual infor-mation necessary for the data inter-pretation is attached, such as current universal time, attitude information, and solar and geophysical conditions at the time of observations (the number of these parameters can reach a few tens of items depending on the specific needs of the experiment). In Figure 1 we show an example of the second-level processing result — a sample record of data in the catalogue of the NACS instrument (Neutral Atmosphere Composition Spectrometer) onboard Dynamics Explorer 2 (DE 2) satellite.

However, such a huge amount of pro-cessed data obtained through signifi-cant efforts of the number of people integrated in the space experiments becomes actual only if it is used for further scientific studies.

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Figure 1. Part of the record in the data catalogue from Dynamics Explorer 2 as used on the NASA website.

The main purpose of the problem-ori-ented third-level data processing is to reveal signatures of the physical phe-nomenon into already collected experi-mental data. In the case of ionosphere physics it could be a search of trav-elling ionospheric disturbances (TID) in the measured density or plasma ‘bubbles’ and ‘blobs’, in the magnetic field — Alfven wave structures, in the electric field — double layers, etc. Third-level processing itself is usually realised by the scientists as end users, principal investigators of the space experiment (see, for example, the ref-erences below).

The contemporary level of information technologies gives an opportunity for further data processing of already accu-mulated ‘second-level’ data archives by the efforts of competent scientists, not exactly associated with the certain space mission. Thus, ‘old’ and appar-ently ‘used’ resources of scientific infor-mation could be a source of new higher level usability through a widely open web service. These ‘third-level’ data have to be accessible to the wide num-ber of customers, who can use them for their own scientific and/or educational purposes, even including for scientific

tasks which were never planned by the authors of the space experiments.

Main purpose of the POPDAT project is to apply modern information technolo-gies to topical ‘third level’ processing of the open access data taken from already closed missions.

An illustration of the abovementioned could be the study of the ionospheric earthquake precursors — phenome-non not exactly confirmed, hypothetical, but inspiring significant interest in the context of the earthquake prediction problem. Catalogues of anomalous ion-ospheric behaviour, revealed by the ion-ospheric physicists, would be a subject of interest of the geophysicists’ society interested in the earthquake prediction studies based on valuable statistics.

Wave catalogues

Ionospheric wave catalogues do not exist like class of objects. In the lit-erature we find references, usually as single most relevant wave exam-ples, which do not characterise whole patterns of ionospheric wave activ-ity. Often more illustrative than rep-resentative, these examples do not

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reveal planetary distribution of wave-like disturbances, their characteristic parameters, variability, dependence on solar-geophysical conditions, etc.

During prolonged periods the authors of the POPDAT project perform satellite data processing; their main task is the registration and study of wave fields in the ionosphere as it is (more precisely, as it was at the time of observation). Thus, a statistical basis is created for the continuous study of the ionosphere dynamics.

Here, term ‘wave catalogue’ denotes a record of parameters of wave pro-cess along the satellite orbit. Wave catalogue and data catalogue, cre-ated from certain space experiment,s have quite similar record structures;

however, the principal difference comes from the level of data process-ing. Below, we illustrate the abovemen-tioned by an example of observational data from DE 2.

In Figure 2, lines 1 correspond to the [O] and [N2] atmospheric densities along DE 2 orbital track; these curves are direct visualisation of the data available on the website of the project (a piece of it was shown in Figure 1). We extract atmospheric gravity waves (AGW) from these data records by means of specially developed data processing codes; obtained wave forms are shown in Figure 2 by line 2. Thus, evaluated by third-level data process-ing and recorded, wave signatures form the wave catalogue — in the pre-sent case, the AGW catalogue.

Figure 2. Curves 1: orbital variations of the atomic oxygen (solid line) and molecular nitrogen (dashed line) as observed by NACS on DE 2. Curve 2: AGW waveforms derived by third-level processing.

Ionosphere Waves Service

The Ionospheric Waves Service (IWS) supports flexible and useful access to the wave catalogues stored on the

project web resource. This service is for the benefit of the project participants to fulfil and edit wave catalogues as well as for potential users for data mining.

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The structure of the IWS is shown in Figure 3. This structure includes restricted access (authors’) and open public access (users’) parts. The authors’ part covers database man-agement services by authorised mem-bers of the project, shown in Figure 3 as ‘Ionosphere Waves Service Manager’. This part of the service gives an oppor-tunity to:

— make data records, edit wave cat-alogues, establish interconnectiv-ity of the stored data;

— create new services for data con-trol and data analysis, etc.

The users’ part of the service is addressed to the external end users

via website opportunities for requested data mining in appropriate output file format. For example, it is necessary to:

— reveal AGW in the given space/time interval;

— as one more specific example, define the average amplitude of AGW over Europe for the given period of time, etc.

The core of this part of service is the data analysis block. At the present stage of the project the structure of some standard search/visualisation procedures over database are under development and in the near future we expect to enlarge them following the needs of the end users.

Figure 3. Structure of the Ionosphere Waves Service.

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CONCLUSIONS

At the first stage of the POPDAT pro-ject, AGW and ULF-VLF electromag-netic waves are the main objects of interest, which correspond to the area of interest of the project team.

Obviously, it is unrealistic to expect that the whole amount of existing sat-ellite data could be processed by the efforts of a single team. An important condition of the further development of the project is to enlarge the number of interested scientists involved in it.

Practical opportunities of the IWS sat-isfying the expectations of the soci-ety of potential end-users, however, depend on the decisions made at the present time. The most important of them could be summarised as

1. the creation of the valuable struc-ture of wave catalogues (including proper structure of the metadata and data files);

2. the flexible and additive structure of the web-based IWS, which ena-bles further enlargement of the system by newly created wave cat-alogues of different types and fre-quency bands.

The POPDAT team hopes that during dissemination actions, presentations at topical conferences and through direct contacts, it will get from the scientific community proper feedback that will help to improve the IWS as a popu-lar open public tool for science and education.

REFERENCES

  Bankov, L., Heelis, R., Parrot, M., Berthelier, J.-J., Marinov, P. and Vassileva, A., ‘WN4 effect on longitudinal distribution of different ion species in the topside ionosphere at low latitudes by means of Demeter, DMSP-F13 and DMSP-F15 data’, Ann. Geophys., 27, 2009, pp. 2893–2902.

  Fedorenko, A. K., Lizunov, G. V. and Rothkaehl, H., ‘Satellite observations of wavelike atmosphere perturbations caused by strong earthquakes’, Geomagnetizm and Aeronomy, 45(3), 2005, pp. 403–410.

  Korepanov, V., Hayakawa, M., Yampolski, Y. and Lizunov, G., ‘AGW as a seismo-ionospheric coupling responsible agent’, Phys. Chem. of the Earth, 2009, 34(6–7), 2009, pp. 485–495.

  Lichtenberger, J., Ferencz, C., Bodnar, L., Hamar, D. and Steinbach P., ‘Automatic whistler detector and analyzer system: automatic whistler detector’, J. Geophys. Res., 113, 2008; doi:10.1029/2008JA013467.

  Rothkaehl, H., Izhovkina, N., Prutensky, I., Pulinets, S., Parrot, M., Lizunov, G., Blecki, J. and Stanislawska, I., ‘Ionospheric disturbances generated by different natural processes and by human activity in Earth plasma environment’, Ann. Geophys., Supplement to vol. 47(2/3), 2004, pp. 1215–1226.

CHAPTER 34

Authors: Rami Vainio, Bernd Heber, Karl-Ludwig Klein, Blai Sanahuja, Eino Valtonen, Ilya G. Usoskin, Felix Spanier, Olga E. Malandraki, Alexander Nindos, Henry Aurass, Daniel Heynderickx, Alexander Afanasiev, Neus Agueda, Markus Battarbee, Stephan Braune, Wolfgang Dröge, Urs Ganse, Clarisse Hamadache, Yulia Kartavykh, Jürgen Kiener, Patrick Kilian, Andreas Kopp, Athanasios Kouloumvakos, Sami Maisala, Alexander Mishev, Tero Oittinen, Athanasios Papaioannou, Osku Raukunen, Esa Riihonen, Rosa Rodríguez-Gasén, Oskari Saloniemi, Renate Scherer, Vincent Tatischeff, Konstantinos Tziotziou, Nicole Vilmer

consortium members: Department of Physics, University of Helsinki, Finland; Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Germany; CNRS-LESIA, Observatoire de Paris, Meudon, France; CSNSM Orsay, CNRS-IN2P3 et Université Paris-Sud, France; Dept. d’Astronomia i Meteorologia & Institut de Ciències del Cosmos, Universitat de Barcelona, Spain; Department of Physics and Astronomy, University of Turku, Finland; Sodankylä Geophysical Observatory, Oulu Unit, University of Oulu, Finland; Lehrstuhl für Astronomie, Julius-Maximilians Universität Würzburg, Germany; Institute of Astronomy and Astrophysics, National Observatory of Athens, Greece; Department of Physics, Section of Astrogeophysics, University of Ioannina, Greece; Solar Physics

Group, Leibniz Institut für Astrophysik Potsdam, Germany; DH Consultancy BVBA, Belgium

AbSTRACT

Solar energetic particles (SEPs) are charged particles (protons, heavy ions and electrons) ejected from the Sun that impact the Earth. The under-standing of their origin and of the way they reach the Earth is a key issue for astrophysics and space weather. Energetic particles are also a poten-tial hazard for technical equipment, communications using the iono-sphere, and human beings in space. The main objective of the SEPServer project is to produce a new tool which greatly facilitates the investigation of SEPs and their origin: a server pro-viding SEP data, related electromag-netic (EM) observations and analysis methods, a comprehensive catalogue of the observed SEP events, and edu-cational/outreach material on solar eruptions. The project is coordinated by the University of Helsinki. The pro-ject will combine data and knowledge from 11 European partners and sev-eral collaborating parties from Europe and the USA.

SEPServer: Data services and analysis tools for solar energetic particle events and related electromagnetic emissions

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SEPServer will add value to several space missions and Earth-based obser-vations by facilitating the coordinated exploitation of and open access to SEP data and related EM observations, and promoting correct use of these data for the entire space research community. This will lead to new knowledge on the production and transport of SEPs dur-ing solar eruptions and facilitate the development of models for predicting solar radiation storms and calculation of expected fluxes/fluences of SEPs encountered by spacecraft in the inter-planetary medium.

During the first year of the project, a prototype server was established which is presently undergoing test-ing by users inside the consortium. The server prototype allows access to about 40 data sets on SEPs and related EM emissions for 115 SEP events, pro-duced by the consortium for the 23rd sunspot cycle (years 1996–2010) after a systematic scan of the data and a preliminary scientific analysis of the identified events. The prototype server allows the user to browse the data sets and make plots of the different varia-bles in a coordinated manner, combin-ing quantities from the different data sets in a single plot. It allows the user to store and apply plot templates to a SEP event list, which enables standard plots for a large number of events to be generated. Later, more functional-ity will be added, e.g. the possibility to download event data and simulation-based analysis tools for further more advanced modelling of the SEP events.

AcHieVed resuLts

Solar energetic particle (SEP) events are outbursts of high-energy pro-tons, ions and electrons from the Sun

(Reames, 1999). These events are the cause of the so-called solar radiation storms that constitute one of the main components of space weather and, more specifically, of the radiation envi-ronment of the Earth (Vainio, 2009). SEP events can be divided in two main categories: (1) impulsive events related to short-duration solar X-ray flares and (2) gradual events related to fast coro-nal mass ejections (CMEs). While pure events in each class are relatively easy to understand in terms of their origin at the Sun and evolution in the inter-planetary space, a large fraction of SEP events show properties that can-not uniquely be associated to either flares or CMEs. Thus, in order to under-stand the relative importance of these two key manifestations of solar activ-ity in the genesis of SEP events, more elaborate data analysis efforts are needed, combining different types of key observations from energetic parti-cle fluxes measured in space to solar radio observations by ground-based observatories.

The SEPServer project (http://www.sepserver.eu) is a 3-year collaborative project aimed at facilitating the data analysis of SEP events by providing a single access point to key observa-tions needed to analyse SEP events, i.e. SEP flux and anisotropy measurements from space-borne and ground-based experiments and electromagnetic (EM) observations from a number of space and ground observatories, including a number of wavelength bands from radio to gamma rays. The server will also provide simulation-based data-analysis tools for inferring the solar release profiles of energetic electrons and protons that will greatly assist the comparison of the SEP and EM observations. Furthermore, the pro-ject will provide, for a large number of

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energetic particle events, initial data analysis results which will be cata-logued and released for further use by the science community.

During the first year of the project, the consortium has concentrated on the analysis of SEP events that occurred during the 23rd solar cycle (1996–2009). The work started by a system-atic scan of the SEP observations to identify the SEP events of the time period. Several event lists covering the period in part or in full have been published recently (e.g., Laurenza et al., 2009; Cane et al., 2010), but the consortium decided to establish a new list of proton events that extend up to energies exceeding 50 MeV to pro-vide focus on the most relevant events from the space weather perspective. Thus, a scan was performed on the ~ 68 MeV proton flux (particles trav-elling at about a third of the speed of light) observed by the SOHO/ERNE experiment (Torsti, et al., 1995) and altogether 115 SEP events were iden-tified. A preliminary scientific analysis of the SEP events was performed using SEP observations from SOHO/EPHIN (Müller-Mellin et al., 1995) and ACE/EPAM (Gold et al., 1998); radio obser-vations from European radio obser-vatories (Kerdraon and Delouis, 1997; Lecacheux, 2000; Kontogeorgos et al., 2006; Mann et al., 1992) and Wind/WAVES (Bougeret et al., 1995); and hard X-ray and gamma-ray observa-tions from RHESSI (Lin et al., 2002) and Integral (Vedrenne et al., 2003). A detailed description of the methods applied and the results achieved will be published elsewhere (Vainio et al., 2012). In summary, we identified, for all the 115 events, the solar release time of energetic protons and relativis-tic electrons and the relevant time peri-ods of solar EM observations. We also

prepared detailed summaries of avail-able EM observations that can be used to analyse the temporal link between the solar eruptive phenomena and par-ticle releases. The results of the analy-sis will be released in the first half of the year 2012 in a catalogue format on the project website (http://server.sepserver.eu). While the analysis of the events is far from complete, the results provide a good starting point for event classifications and allow users to apply criteria for selecting events for fur-ther, more detailed analysis using, for example, simulation-based methods to be delivered to the community through the consortium server.

The potential of SEPServer as an anal-ysis tool was demonstrated through the detailed analysis of the 13 July 2005 SEP event, using all the available observations and a large number of the data analysis tools that will be availa-ble through the server (Malandraki et al., 2012). Both data-driven and sim-ulation-based analysis methods were applied to this SEP event and the results of these analyses were com-pared with each other and the solar EM observations made at around the onset time of the SEP event. Although the time period had a lot of activity at the Sun and, therefore, was very diffi-cult to analyse, a consistent picture of the event was achieved using the dif-ferent methods. As a result, it could be concluded that during the SEP event, the interplanetary medium was tur-bulent, resulting in particle scatter-ing delaying the onset of the event at 1 AU. After removing the transport effects due to scattering using simula-tion-based analysis methods, the tim-ing of the particle injection at the Sun could be shown to correspond well with the main radio and hard X-ray emis-sion (Figure 1).

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Figure 1. On the left, the 13 July 2005 CME as observed by SOHO/LASCO/C2 (© SOHO/LASCO CME Catalog) and Nançay radioheliograph (inset in the middle). On the right, we show the solar 50–82 keV electron injection time profile, as obtained from a simulation-based analysis of particle fluxes at 1 AU (first panel); the hard X-ray flux as observed by INTEGRAL (second panel); the dynamic spectrum measured by Wind/WAVES showing a series of so-called type III radio bursts accompanying the event (third panel); the height-time profile of the CME (∙∙∙•∙∙∙) and the soft X-ray flux (—) observed by GOES (fourth panel).

In addition to the preliminary scien-tific analysis of the events, the con-sortium has developed a prototype of the server that will be opened to the community in the end of the pro-ject. The server is based on a MySQL database (using the ESA Open Data Interface under licence) hosting the observational data for the identified SEP events. A graphical user inter-face provides access to the database though the Internet.

The server already provides access to a large number of data sets includ-ing several functionalities. The user can browse and download event lists and produce plots of the event data. An example of such a plot is given in Figure 2, which shows the maximum

~ 68 MeV proton intensities observed during the SEP events against the event start time for the SEP events in the ERNE/SOHO proton event list.

In addition to browsing and plotting event lists, users can browse the meta-data accompanying the observations. Users can also make stacked-panel plots of the different data products ingested in the database, produce plot templates and apply them on all the SEP events in a selected event list. In the future, the users will also be able to upload their own event lists, which may be constructed as subsets of the system generated ones. Each user can store plot templates and event lists for future use and reference purposes in a specific user area.

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Figure 2. The maximum intensities of the SEP events observed by SOHO/ERNE in 1996–2010. Note that the lack of SEP events between 2006 and 2010 is not due to a data gap but due to the abnormally long solar minimum between the 23rd and 24th solar cycles.

CONCLUSIONS

During the first 15 months of the project, SEPServer has achieved its objectives scheduled for this period. It has estab-lished a comprehensive list of space weather-relevant SEP events observed at 1 AU during the 23rd solar cycle and performed an initial analysis of the events. The results will be summarised in a catalogue that will be released dur-ing the year 2012 through the project website. The catalogue will be a use-ful starting point for the more advanced scientific SEP event analyses that can be performed using the data sets stored in the database of SEPServer, which will be released for public use in the end of the project, November 2013.

Prior to the release several new fea-tures still need to be implemented on the server. These include adding data sets, mainly with higher resolution, as well as simulation results and analysis tools based on them. Keeping the sys-tem with such versatile tasks easy-to-use will be a formidable task. To guide this work, a set of user requirements has been established based on the experience of the consortium mem-bers who currently have access to the prototype. With recurrent user surveys and with possible extension of the access to a selected group of exter-nal users, the usability of the data-base will be further improved before release.

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REFERENCES

  Reames, D. V., ‘Particle acceleration at the Sun and in the heliosphere’, Space Sci. Rev., 90, 1999, pp. 413–491.

  Vainio, R., Desorgher, L., Heynderickx, D. et al., ‘The dynamics of the Earth’s particle radiation environment’, Space Sci. Rev., 147, 2009, pp. 187–231.

  Laurenza, M., Cliver, E. W., Hewitt, J. et al., ‘A technique for short-term warning of solar energetic particle events based on flare location, flare size, and evidence of particle escape’, Space Weather, 7, 2009, S04008.

  Cane, H. V., Richardson, I. G. and von Rosenvinge, T. T., ‘A study of solar energetic particle events of 1997–2006: Their composition and associations’, J. Geophys. Res., 115, 2010, A08101.

  Torsti, J., Valtonen, E., Lumme, M. et al., ‘Energetic particle experiment ERNE’, Solar Phys., 162, 1995, pp. 505–531.

  Müller-Mellin, R., Kunow, H., Fleißner, V. et al., ‘COSTEP — Comprehensive Suprathermal and Energetic Particle Analyser’, Solar Phys. 162, 1995, pp. 483–504.

  Gold, R. E., Krimigis, S. M., Hawkins, S. E., III et al., ‘Electron, proton, and alpha monitor on the advanced composition Explorer spacecraft’, Space Sci. Rev., 86, 1998, pp. 541–562.

  Kerdraon, A. and Delouis, J.-M., ‘The Nançay radioheliograph’, G. Trottet (ed.), Coronal physics from radio and

space observations, Springer Lecture Notes in Physics Series, 483, 1997, pp. 192–201.

  Lecacheux, A., ‘The Nançay decameter array: A useful step towards giant, new generation radio telescopes for long wavelength radio astronomy’, R. G. Stone, K. W. Weiler, M. L. Goldstein, J.-L. Bougeret (eds), Radio astronomy at long wavelengths, AGU Monograph Series, 119, 2000, pp. 321–328.

  Kontogeorgos, A., Tsitsipis, P., Caroubalos, C. et al., ’The improved Artemis IV multichannel solar radio spectrograph of the University of Athens’, Experimental Astronomy, 21, 2006, pp. 41–55.

  Mann, G., Aurass, H., Voigt, W. and Paschke, J., ‘Preliminary observations of solar type II bursts with the new radiospectrograph in Tremsdorf (Germany)’, Coronal streamers, coronal loops, and coronal and solar wind composition, ESA SP-348, 1992, pp. 129–132.

  Bougeret, J.-L., Kaiser, M. L., Kellogg, P. J. et al., ‘Waves: the radio and plasma wave investigation on the WIND spacecraft’, Space Sci. Rev., 71, 1995, pp. 231–263.

  Lin, R. P., Dennis, B. R., Hurford, G. J. et al., ‘The Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI)’, Solar Phys., 210, 2002, pp. 3–32.

  Vedrenne, G., Roques, J.-P., Schönfelder, V. et al., ‘SPI: The spectrometer aboard Integral’, Astron. Astrophys., 411, 2003, L63–L70.

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  Vainio, R., Valtonen, E., Heber, B. et al., ‘SEPServer — A new tool for solar energetic particle analysis’, to be submitted to J. Space Weather and Space Climate, 2012.

  Malandraki, O., Agueda, N., Papaioannou, A. et al., ‘Scientific analysis within SEPServer — New perspectives in solar energetic particles research: the case study of 13 July 2005’, submitted to Solar Phys., 2012.

CHAPTER 35

Authors: Sotirios Diamantopoulos, Nikolaos Bezirgiannidis, Ioannis A. Daglis, Athanasios Rontogiannis, Bogdan Ghita, Nathan Clarke, Steven Furnell, Theodoros Amanatidis, Anastasios Malkotsis, Martin Goetzelmann, Christian Laroque, Vassilis Tsaoussidis

consortium members: Space Internetworking Center, Democritus University of Thrace, Greece; National Observatory of Athens, Greece; Plymouth University, United Kingdom; Space Internetworks, Greece; VEGA Space GmbH, Germany

AbSTRACT

Currently, space-data exploitation faces two major obstacles. Firstly, space centres and academic institu-tions have limited access to scientific data since their limited connectivity time via satellites directly confines their scientific capacity. Secondly, space-data collection centres lack suf-ficient resources and capacity for com-municating with interested end users, let alone the lack of mechanisms for data dissemination. Along these lines, the ultimate goal of the ‘Space-data routers’ project is to boost collabo-ration and competitiveness of the European Space Agency, European space industry and European aca-demic institutions towards an effi-cient architecture for exploiting space

data. The proposed approach relies on space internetworking — and in particular on delay-tolerant network-ing (DTN), which marks a new era in space communications, unifies space and Earth communication infrastruc-tures and delivers a set of tools and protocols for space-data exploitation within a single device, the space-data router. Space-data routers implement a dual role: they increase communi-cation flexibility in space and form a mission/application-oriented commu-nication overlay for data dissemina-tion on Earth. Technically, the project achieves these objectives by deploy-ing the delay-tolerant networking stack and by integrating the interfaces of various space and Internet com-munication and networking protocols, including TM/TC, space packets and AOS along with Ethernet, TCP/IP and UDP. In parallel, it employs the agen-cies’ policies for resource and data sharing as well as for data exploita-tion. So far, the research has mainly focused on the requirements and the initial architectural design of the space-data overlay. Indeed, depart-ing from the scenario requirements, where a number of real space com-munication scenarios are described in detail, we continue with the pres-entation of the space-data router architecture, which comprises: (a) the web-based application that facilitates access of end users to space data, and (b) the networking infrastructure that supports this concept.

Space-data routers for exploiting space data

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AcHieVed resuLts

Space-data routers interconnect research centres, academic institutions and ground stations, rendering them capable of exchanging space data in a much more efficient and decentralised

way. For example, as depicted in Figure 1, a satellite over France will be able to transfer data to an institution in Greece, utilising a set of authenticated terrestrial DTN nodes. Therefore, data dissemination towards end users will be augmented considerably.

Figure 1. Data dissemination using space-data routers (© 2012 Google, © 2012 Europa Technologies, © 2012 MapLink/Tele Atlas).

In this context, during the first year of the project, we set the system requirements, establishing the basis of the project and defining to a great extent the work to be performed. Indeed, we departed from the scenario requirements [1]; which correspond to the established scien-tific objectives and schedule the tech-nical part of the project, focusing on the main application characteristics [2], and the network architecture that sup-ports the DTN overlay [3]. We briefly dis-cuss in the next paragraphs the main results achieved so far by the consor-tium that mainly pertain to the appro-priate design of the space-data router architecture [4].

Scenario requirements

Initially, seven space mission scien-tific scenarios were selected in order to establish a reference for comparison of the new space-data routers based architecture with existing schemes for data dissemination. The scenarios span across multiple communication architectures, from single disruptive communications, to collaborative data sources and through to limited line-of-sight. For each scenario, operational and application details were described and the current limitations and restric-tions with respect to data acquisition and dissemination were presented.

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Additionally, emphasis was given to the definition of the scenarios’ require-ments, as well as to the expected impact of the new architecture on each scenario. The seven scientific scenarios are described below.

• The first scenario is related to the study of ecosystem dynam-ics, using the CHRIS (compact high resolution imaging spectrometer) PROBA-1 (project for onboard auton-omy) hyper-spectral data. The pur-pose of this scenario is the use of hyper-spectral images from the CHRIS sensor onboard the PROBA-1 satellite for monitoring vegetation status in space and time.

• The second scenario is concerned with the effective combination of real-time and archived advanced very high resolution radiometer high resolution picture transmis-sion (AVHRR HRPT) data from local HRPT-receiving stations worldwide. Images captured by the AVHRR onboard polar orbiting environmen-tal satellites (POES) satellites of the National Oceanic and Atmospheric Administration (NOAA) are used on a regular basis, both for research and for services provided by NOA/ISARS (National Observatory of Athens/Institute for Space Applications and Remote Sensing). However, due to downlink constraints, NOA/ISARS is able to acquire high-resolution images only when satellites pass over Greece. The possibility of con-tinuous access to POES data would be very beneficial, since it would per-mit NOA/ISARS to acquire images of other parts of the Mediterranean in near-real time as well.

• Scenario 3 deals with a deep space mission and more specifically with

the efficient acquisition and dissemi-nation of hyperspectral images cap-tured by OMEGA onboard ESA’s Mars Express (MEx) satellite. Currently, data are available online through the ESA Planetary Science Archive [5]. OMEGA data are processed by ISARS/NOA for various research pur-poses, e.g. testing the performance of newly developed spectral unmix-ing algorithms.

• Scenario 4 is concerned with the efficient acquisition and dissemi-nation of image data, captured by the optical, spectroscopic and infra-red remote imaging system (Osiris) instrument onboard the Rosetta deep-space mission. Rosetta is an interplanetary spacecraft whose main objective is to rendezvous with Comet 67P/Churyumov-Gerasimenko. Osiris, an instrument onboard Rosetta, com-bines a wide-angle camera with a narrow-angle camera to obtain high-resolution images of the com-et’s nucleus and the asteroids that Rosetta meets on its voyage.

• The fifth scenario is related with new deployments in space and in particu-lar with the case of ESA’s Sentinel sat-ellites. The ESA Sentinels constitute the first series of operational satellites for Global Monitoring for Environment and Security (GMES). ESA will under-take the development of five Sentinel missions in the years to come. In this project we are interested in the first two missions: (a) Sentinel-1, which will focus on synthetic aperture radar applications; and (b) Sentinel-2, which will provide high-resolution optical observation for GMES land and emer-gency services.

• Scenario 6 deals with a cross-mission application that combines data from

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multiple satellite instruments with the aim of studying space weather. Nowadays, information from a sin-gle spacecraft vantage point can be replaced by multi-spacecraft-distrib-uted observatory methods and adap-tive mission architectures that require computationally intensive analysis methods. Future explorers far from Earth will be in need of real-time data assimilation technologies to predict space weather at different solar sys-tem locations.

•A multiple-mission application is also the subject of scenario 7. However, the aim of this application is the study of the time and space varia-tions of land surface temperature (LST) in a city environment using image data from multiple different mission instruments. LST is a key parameter in the land-surface pro-cesses on all scales, combining the results of surface–atmosphere inter-actions and energy fluxes between the atmosphere and the ground.

The aforementioned scenarios have been properly selected to match the four main scientific objectives of space-data routers to demonstrate:

1. the capability of the space-data routers to extend end-user access to space data through communi-cating ground stations and space research centres;

2. the potential of exploiting data from deep space and disseminat-ing it smoothly through unified communication channels;

3. the capability of space-data rout-ers to deliver efficiently to end users vast volumes of data over terrestrial internetworks;

4. the sufficiency of DTN space-data overlays to administer thematic cross-mission space data.

More specifically, scenarios 1 and 2 serve the first objective, scenarios 3 and 4 the second objective, scenario 5 the third objective and, finally, sce-narios 6 and 7 are suited to meet the fourth main objective of the project.

Space-data routers concept

In order to cover the aforementioned sce-nario requirements we design and imple-ment an architecture that comprises two distinct components, namely the space-data overlay and the application. The space-data overlay allows the space-data router to operate on top of existing network protocols and technologies, cre-ating a DTN layer that interconnects net-works with very diverse characteristics, such as space and terrestrial networks. Therefore, DTN provides the basic func-tionality for efficient space-to-earth data dissemination. In addition, the router is developed on top of real space proto-cols allowing for direct interoperation with current space infrastructure. Finally, a sophisticated application is also being designed and implemented in order to support, highlight and assess the sys-tem’s capabilities.

Application architecture

A major technical contribution of the ‘Space-data routers’ project is the implementation of a web-based appli-cation that interconnects all space-data stakeholders. A graphical user inter-face will allow for easy and automated access to the application database. Given the wide user community, spe-cific focus is given on providing a user-friendly environment that will allow for fast browsing between mission profiles.

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Furthermore, the cross-mission catego-risation will facilitate the interdiscipli-nary approach on many data sets.

The application (depicted in Figure 2) is designed as a web front-end cou-pled with a database and interacts with four types of entities: data providers, user institutions, infrastructure provid-ers and administrators. The database

includes metadata information such as data collection instrument characteris-tics, users/institutions and associated credentials, and storage locations and capabilities. For simplicity and process distribution reasons, the application will separate from storage and, there-fore, will only point to storage locations rather than directly include a data stor-age component.

Figure 2. Application design.

With regard to the user institutions, the implementation will use the current examples to aggregate data sources/objects and present them to the user as a design and functionality baseline. In order to gain access to any stored infor-mation, users must be authenticated to the application and their access to vari-ous objects will be logged and availa-ble for inspection by the data provider organisations. The data, depending on whether it is on-demand or real-time, will be either downloaded as a file or as a stream. In the case that the data is streamed in real-time, the applica-tion may launch a client application

to interface with the incoming data stream. The data providers will also require access authorisation/monitor-ing functionality, in order to control and review how users access their data. As a primary function, data providers will be able to enable or disable access to data for a given user organisation that requests it. While its details are yet to be defined, the application is likely to interact with the network, as it will inform the infrastructure of the location of the users who are granted access to each specific type of data and/or down-load that specific type of data on a reg-ular basis. Finally, the administrators

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would be able to oversee and monitor (to a certain degree) the access and permissions to the application by both data providers and data users. Access, and the ability to authorise access, will remain with the data owner only, in order to maintain security.

The application will facilitate three forms of data access: on-demand, real-time and near real-time. From an interaction perspective, the on-demand alternative is built around the traditional request–response model, where data objects that are previously collected and stored are specifically requested by users. When the user requests the object, the application will query the database to locate it and then it will return it to the user. Depending on the frequency of requests and loca-tion of the users, the application will include functionality either to migrate the requested (type of) data in order to move it closer to the most frequent users or to inform the network to dupli-cate this data closer to the users in the case of more widespread demand. The second alternative, real-time access, requires the data to be sent as an automatic upload to the registered users as it arrives from the instru-ments and is recorded in the database. The application, in collaboration with the underlying transport and routing

infrastructure, may decide either to mirror or buffer the data or to com-bine a multicast and unicast approach. Finally, in the near real-time scenario, users would request/receive a data object as soon as it is available, using a notification scheme or a push transfer.

In order to provide the required func-tionality, the application will include several types of process: registration of new users/organisations, registra-tion/upload of new data, user down-loads of data objects, and cross-layer interaction with the network infra-structure. These processes, together with the associated entities involved in the process, have been the basis for a proposed architecture. As part of the normal functionality, information con-tained by the reference database will be queried and used by the network infrastructure to optimise the data paths. In order to support this function-ality, a number of combinations of ded-icated storage locations, Earth stations and cache storage, geographically dis-tributed, will contain the data objects and stream to be retrieved. The data exchange will include several types of exchanges: signalling/AAA/control, data objects/streams download, data objects/streams replication between the SDR and provider database, and data replication within the SDR.

(a) Terrestrial communications (b) Space-to-Earth communications

Figure 3. Protocol stacks of the initial space-data router architecture.

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Space-data overlay architecture

In the framework of this task, we detailed the technical characteristics of the space-data router and highlighted the concepts that need to be evalu-ated in terms of functionality, efficiency, compatibility with ESA infrastructure, and deployability in future ESA mis-sions. More specifically, we described the protocol stack configurations that are required to support both terrestrial and space communications. The proto-col stack that is going to be used in ter-restrial links is depicted in Figure 3(a), while the protocol stack suitable for space communications is depicted in Figure 3(b).

DTN architecture

Delay-tolerant networking (DTN) is the emerging technology to support the new era in space communications, especially for communications in deep space and for interconnecting space agency assets on Earth. Having already been tested in a number of stressed terrestrial envi-ronments, as well as in space conditions, DTN becomes a standard architecture included in both CCSDS (Consultative Committee for Space Data Systems) and IETF standardisation procedures. That said, we tailor the DTN architec-ture, and more specifically the routing and transport mechanisms, to space-data routers’ requirements.

A routing algorithm is being designed, based on a contact graph routing algo-rithm with several additions and modifi-cations. In particular, we have altered the contact plan, which is the input of the routing algorithm, to include extra infor-mation. Existing contact and range input includes information about the uptime between two nodes, the one-way light time distance, and uplink and downlink

data rate. In this routing scheme we have included other input as well, such as link or node usage financial cost, node storage capability and node or owner agency’s trustability. These parameters will be included into the routing deci-sion mechanism with specific weights that will be configured based on spe-cific mission objectives. For example, in a transmission session of vast amounts of data, storage limitations of interme-diate nodes is an important parameter that should be given more weight than others. This extra functionality will come in parallel and will not remove the exist-ing one, which focuses on the earliest plausible data delivery.

An end-to-end protocol on top of the delay-tolerant networking (DTN) archi-tecture is also being designed and implemented. This protocol will com-plement the DTN services offered by the Bundle Protocol (BP) and will operate only at the endpoints of the communication system enabling the following end-to-end services:

• application data aggregation and elision;

• in-order delivery of application data;

• end-to-end retransmission-based reliability;

• duplicate suppression.

Space-data link

Three different configurations will be provided for the space-data link proto-col part of the space-data router.

(a) Use of existing hardware

This configuration will make use of the ESOC Simsat simulation infrastructure

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and will integrate two standard sys-tems, used in satellite ground stations:

• the ESA portable satellite simulator, which consists of a standard PC run-ning the SIMSAT software and the Integrated Modem and Baseband Unit, which implements the TM and TC layer and a space link modem;

• Cortex XL2, a TM/TC processing system.

The aforementioned systems will be interfaced at IF, simulating the space link. Standard CCSDS SLE services will be used to transmit telemetry frames and CLTUs between the TM/TC proces-sor and the ground-based DTN node, and CCSDS packets will be exploited to encapsulate LTP packets.

(b) Simulation of existing hardware

The hardware units of the previous configuration will now be replaced by simulated protocols, enhancing the flexibility of the space-data over-lay, as far as testing and validation is concerned.

(c) Integration of data link protocols in the test bed

The provided space-data link proto-cols will be integrated into the DTN node, without the use of other soft-ware of hardware models. The LTP segments will be transmitted via the simulated space link as encapsulation packets. TM protocol will be supported for the downlink and TC and AOS for the uplink.

CONCLUSIONS

During the first year of the ‘Space-data routers’ project, we considered

a number of distinct space-data dis-semination scenarios that led us to the design of the space-data router architecture. The consortium concen-trated its effort on implementing the network mechanisms needed to build the space-data overlay. After installing a number of nodes at each partner’s premises, we are currently working on DTN overlay and link layer protocols. Furthermore, the initial router architec-tural design was set and the details of the space-data router technical char-acteristics and concepts that need to be evaluated for their functionality, efficiency and compatibility with ESA infrastructure were highlighted. We have also focused on the design and implementation of an application that will be used by interested end users to download space data. This application consists of a web front-end interface coupled with a database; it intercon-nects all interested parties allowing for different forms of automated data access.

As a conclusion, the space-data rout-ers concept will constitute a pioneer-ing technological target for Europe, for two major reasons: (i) it will allow the exploitation of massive data, thus increasing the return of all scientific missions; and (ii) it will bridge both the communication gap between deep space and Internet working protocols and the lack of agency interoperabil-ity. In essence, the ‘Space-data routers’ project satisfies both technological and scientific objectives of European mis-sions towards exploiting and dissemi-nating space data.

REFERENCES

   ‘Scenario requirements report’, Space-data routers, March 2011,

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(http://www.spacedatarouters.eu/wp-content/uploads/2010/12/D21.pdf).

   ‘Application requirements report’, Space-data routers, March 2011, (http://www.spacedatarouters.eu/wp-content/uploads/2011/05/D22.pdf).

   ‘Scenario requirements report’, Space-data routers, March 2011, (http://www.spacedatarouters.eu/

wp-content/uploads/2010/12/D23.pdf).

   ‘Initial router architecture report’, Space-data routers, May 2011, (http://www.spacedatarouters.eu/wp-content/uploads/2010/12/D51.pdf).

   The European Space Agency’s Planetary Science Archive (PSA) (http://www.rssd.esa.int/PSA).

CHAPTER xx Space technology

CHAPTER 36 DEPLOYTECH: Large deployable technologies for space

Authors: Juan Fernandez and Vaios Lappas

consortium members: University of Surrey, University of Cambridge and RolaTube Materials Ltd, the United Kingdom; Astrium S.A.S., France; DLR Braunschweig, Germany; Athena/SPU, Greece; TNO: Netherlands Organisation for Applied Scientific Research, the Netherlands; NASA/Marshall Space Flight Centre, the United States of America; CGG Technologies, the Netherlands

AbSTRACT

Large deployable space structures are needed as the backbone and as an integral part of large reflectors, Earth observation satellite antennas and radars, radiators, Sun shields, solar arrays, for various space sys-tems. Advances in launch vehicle design have been limited to date, and have not resulted in an increase in fairing size in the last three decades. Deployable structures come with the promise and capability of reduc-ing mass substantially on spacecraft and allowing for very compact sys-tems to be stored during the launch phase. Also, there is a current grow-ing need for larger apertures, solar panels, thermal shields and gossa-mer sails. Hence, it is important that large deployable structures are fur-ther developed and de-risked. The Technology Readiness Level (TRL) of

a great part of these technologies is still very low, in the order of 2–3. Thus, the objective of DEPLOYTECH is to develop three specific, useful, robust, and innovative large deploya-ble space structures to a TRL of 6–8 in the next three years. These include: a 5 m × 5 m sail structure that uses inflatable technology for deploy-ment and support; a 5 m × 1 m roll-out solar array that utilises bistable composite booms; and 14 m solar sail CFRP booms with a novel deploy-ment mechanism for extension con-trol. Also, during this project several specific modelling activities will take place, including, an analysis of proper folding for membrane and tube struc-tures, to controllability of extension, modelling the deployment dynamics of several structures, and an improved analytical model for bistable compos-ite tubes.

IMPACT

The DEPLOYTECH project addresses two key areas required for the development of critical technolo-gies of large deployable space struc-tures as described in the FP-7-2011 SPA.2011.2.2-02 call:

1. Large thin-walled deployable boom and membrane structures;

2. Large thin-walled inflatable structures.

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In addition the project contributes in another important aspect to the devel-opment of large deployable structures for space. The DEPLOYTECH consortium is building on the team’s existing com-petencies and facilities on the manu-facturing, assembly, integration and functional tests of deployable technol-ogies fulfilling a key gap in European deployable structures, facilities and capabilities.

Furthermore, three key, large, deploya-ble space technologies will be qualified and ready to be tested for flight at the completion of DEPLOYTECH. The pro-ject team has already shortlisted flight opportunities for the technologies to be developed that can be used for flight qualify deployable technologies in the project:

(i) InflateSail: An ultralight sail struc-ture has been selected as a payload to be flown on the QB50 CubeSat mission in early 2014. InflateSail will be stored in a 3U CubeSat structure and the launch costs will be freely covered as part of the space tech-nology flight demonstrator mission. InflateSail demonstrates the rigidi-sation of an inflatable structure in orbit.

(ii) Roll-Out Solar Array: A highly com-pact 5 m2 solar array/panel can be delivered for flight testing on a small satellite research and development microsatellite in 2013–14 in the TechDemoSat-2 mission currently in discussion.

(iii) Solar sail booms: Four 14 m booms will be provided for flight qualification in 2013 to DLR as part of a joint ESA/DLR solar sail demon-stration mission called ‘Gossamer-2’. The four booms are intended to

support a 20 m × 20 m square solar sail to be launched in 2014–15.

AcHieVed resuLts

Even though DEPLOYTECH officially started at the beginning of 2012, the consortium partners have already started developing the three different concepts as part of other small feasi-bility studies. This section will explain the achieved results to date at compo-nent and subsystem levels.

InflateSail (Figure 1) is a circular sail supported by an inflatable structure that can potentially be used as a drag brake for deorbiting, as a solar sail propulsion system, as a large reflec-tor/antenna, or as a Sun shield. It is to have a total sail area of approxi-mately 25 m2 with a 5.5 m diameter inflatable torus frame that stretches the sail film by a series of equidistant cords. The torus is to be suspended from the satellite bus by three 7 m long inflatable booms. Given the tight volume constraint (3U CubeSat) of the QB50 mission, it is possible that a smaller version will be space-quali-fied and designed for stowage within a 10 cm × 10 cm × 25 cm volume.

The inflation of the three booms and torus frame is to be carried out uti-lising TNO’s patented technology. To inflate an inflatable space structure there are three main methods that can be used: a pressurised gas system, a cool gas generator (CGG) and a hot gas generator with cooling. The last option is technology which is immature in Europe and is therefore not relevant for the present project. When evaluat-ing the first two options for small pack-aging and gas requirements, cool gas generators outperform pressurised gas

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Figure 1. InflateSail concept and key technologies.

systems in terms of total system mass and volume. Therefore, for the inflation of the three booms and torus frame of InflateSail a new miniaturised ver-sion of TNO’s space-qualified CGGs has been chosen. Several cylindrical CGGs will be mounted on a manifold having a mass of below 40 g occupying a vol-ume of just 6 cm × 1 cm × 4 cm. The possibility of using a single dedicated gas generator will also be studied dur-ing the project to lower the dedicated mass and volume.

Astrium’s expertise on rigidisation technology will be applied to the inflatable structure of InflateSail. For the past few years Astrium has been developing a new patented technol-ogy for curing in orbit using ultra-violet radiation on thin composite walls of cylindrical inflatable booms. Significant steps have been taken towards validating the technology which is currently at a TRL of 5–6.

Also, as part of an inflatable deor-biting concept called IDEAS for the Microscope satellite, Astrium has been

developing a rigidisation technology using metallic laminate yielding. This consists of applying sufficient defor-mation to the structure material, which is applied by internal pressure, to sup-press geometrical defects created by yielding of the material during fold-ing. Once the defects are suppressed, the mechanical behaviour of the struc-ture is ensured by its own stiffness. The material used to ensure this function is a Kapton/Aluminium/Kapton lami-nate. For InflateSail different rigidisa-tion technologies will be reviewed and compared to ensure the optimal solu-tion for this kind of structure.

The roll-out solar array developed dur-ing DEPLOYTECH is expected to be one of the most highly compact and light-weight concepts of its class. The solar array is also designed to be scalable to much larger lengths than the 5 m one that will be built and tested. The deployable supporting structures of the thin film photovoltaic (TFPV) solar panel are two bistable carbon fibre booms. RolaTube’s patented product, Bistable Reeled Composites (BRCs), are

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essentially Storable Tubular Extendible Members (STEMs) that have the unique feature of being stable in the rolled-up coiled configuration. This significantly simplifies the storage of these booms allowing for lighter and more compact designs.

Furthermore, the transition between the high strain energy stable state (coiled) to the zero energy extended one occurs only at a single point as the BRC booms unravels. Thus the exten-sion of the masts becomes very pre-dictable following a deterministic path and self-deployment of the structures becomes a very attractive solution. On DEPLOYTECH self-deployment will be studied to deploy the drum where the TFPV solar panel is rolled onto. A 4 m long prototype of the solar array that uses self-extension has already been manufactured and tested to get a first impression of the dynamic behaviour during deployment.

Also, the possibility of using TNO’s CGGs in this concept will be considered. For the size proposed here (5 m) the elas-tic strain energy stored during coiling of the BRC tubes is enough to guaran-tee self-extension and maintain a rea-sonable stiffness during deployment. Nevertheless, for future scaled-up ver-sions, this energy may not suffice and an extra mechanism will be required. For this, instead of considering the con-ventional motor-controlled option, a small bladder running along the inside part of the masts and inflated using TNO’s lightweight technology could prove very innovative. An equivalent pneumatic actuator has been produced to study this option. As can be seen from Figure 2(b), given that the coiled mast is bistable, the tip can be fixed and the extension of the drum can be com-pletely controlled (even stopping and

restarting it at chosen times) without the risk of the rest of the coiled boom blossoming in a chaotic way.

The project involves significant effort in the analysis of the composite structure, as the bistable behaviour is not fully understood. The University of Cambridge along with the Surrey Space Centre are leading this activity. Also, considera-ble effort is being put into achieving a cost-effective and new manufacturing process for the BRC masts, which uses space qualified materials in order to extend this innovative technology to the space sector as well.

DLR has been working for the last dec-ade on ultralight carbon fibre rein-forced plastic (CFRP) lenticular-shaped booms for space applications. However, the previous deployment mechanism involved a motor fixed to the drum which the masts were coiled around. The booms were reeled out and at the end of their extension, the mast root was stilled coiled-in, resulting in a low stiffness configuration in an area that is critical for transmitting the loads to the satellite. To enable a root with the stiffer extended shape throughout deployment, DLR has recently decided to study two new mechanisms that provide a drum extension.

The first one consists of a motor-driven extension of the casing that stores the boom. This mechanism will be ulti-mately ejected to space at the end of the deployment, and thus it is only envi-sioned for non-Earth orbiting applica-tions which enable new international policies against generation of space debris.

The second mechanism entails an inflatable polymer membrane inside the boom that will provide the energy

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required to consistently brake the Velcro line that is placed on the outside of the mast. The Velcro has the func-tionality to prevent the coiled boom from self-deploying in a chaotic way as DLR booms are not bistable. However, this Velcro line has a detrimental effect on the final packaging volume of the structure.

During DEPLOYTECH a longer 14 m ver-sion of the CFRP masts will be developed and the deployment mechanism used for it will be traded off. The possibility

of designing a new mechanism if none of the above options become feasible for Gossamer-2, a 20 m × 20 m solar sail, will also be considered. Also, the work under this project will focus on the flight qualification of these structures and additional design work to develop a reliable low shock release mechanism to improve the existing motor-driven deployment mechanism for a triggered release. A study will also be performed into a scalable concept design for a solar sail and this study will include a verifi-cation strategy to test the deployment.

a) Solar array mock-up (b) BRC mast with inflatable bladderFigure 2. Deployment concepts for the roll-out solar array: (a) self-extension, (b) pneumatic actuation.

Figure 3. DLR’s motor-driven and pneumatically-driven deployment concepts for their booms.

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CONCLUSIONS

DEPLOYTECH is set to advance the TRL of various deployable technologies for space applications. The project not only relies on experimentation and validation of the developed concepts but also has the ultimate aim of producing technolo-gies that are ready to fly by the end of the project. The three key technologies developed are planned for actual space missions and therefore qualification and verification testing on them will be car-ried out.

The extensive modelling work of these technologies carried out during WP100 is envisioned to aid in the design of reliable systems right from the con-ceptual level. Analytical and computa-tional models, such as the one currently being developed for the bistable com-posite tubes, are set to extend the basic knowledge of how these large deploy-able space structures behave. A more detailed prediction of their performance during packaging and extension can then be made for a more deterministic final result.

REFERENCES

  Barket, R., Guest, S., ‘Inflatable Triangulated Cylinders’, IUTAM-IASS Symposium on Deployable Structures: Theory and Applications, September 1998, Cambridge, UK, editors, Pellegrino, S., Guest, S., Kluwer, pp. 35–364.

  Dupuy, C., Le Couls, O., ‘Gossamer Technology to Deorbit LEO Non-Propulsion Fitted Satellites’, Proceedings of the 40th Aerospace Mechanisms Symposium, 12–14 May 2010, NASA/KSC.

  Fernandez, J., Lappas, V., Daton-Lovett, A., ‘Completely Stripped Solar Sail Concept using Bi-stable Reeled Composite Booms’, Acta Astronautica 69, 2011, pp. 78–85.

  Fernandez, J., Kukula, S., Lappas, V., ‘Bistable CFRP deployable booms for solar arrays’, UK Technology Strategy Board Final Report, Feasibility Project Number: 10422-53506/130444, August 2011.

  Guest, S., Pellegrino, S., ‘Analytical models for bistable cylindrical shells’, Proceedings of the Royal Society: Mathematical, Physical & Engineering Sciences, 462, 2010, pp. 839–854.

  Sanders, B., Schuurbiers, C., Van Vliet, L., Tata Nardini, F., ‘Results of Qualification and Flight Tests of Cool Gas Generators’, Space Propulsio Conference, 2–6 May 2010, San Sebastian, Spain.

  Sickinger, C., Assing, H., Koke, H., Straubel, M., ‘Verification methodology for self-deploying support frames’, 1st CEAS European Air and Space Conference, 11–13 September 2007, Berlin, Germany.

  Straubel, M., Block, J., Sinapius, M., Huhne, C., ‘Deployable Composite Booms for Various Gossamer Space Structures’, 52nd AIAA Structures, Structural Dynamics, and Materials Conference, 4–7 April 2011, Denver, Colorado.

  Schenk, M., Guest, S., ‘Origami Folding: a structural engineering approach’, 5th International Conference on Origami in Science, Mathematics and Education and Folding Convention, 13–17 July 2010, Singapore.

CHAPTER 37

Authors: Annamaria Colonna, Giuseppe Piscopiello, Giovanni Tuccio, Walter Errico, Franco Bigongiari, Pietro Tosi, Stefano Rachiele, Elena Cordiviola, Bruno Bacci, Vincenzo Pii, Luca Fanucci, Sergio Saponara, Massimiliano Donati, Alessandro Vincenzi, Frederic Reiter, Francesco Nuzzolo, Rainer Leupers, Maximilian Odendahl, Sergey Yakoushkin

consortium members: Sitael S.p.A., Italy; INTECS Informatica e tecnologia del software S.p.A., Italy; Consorzio Pisa Ricerche S.c.a.r.l., Italy; Space Applications Services N.V., Belgium; RWTH Aachen University, Germany

AbSTRACT

In the last decade, technological evo-lution led to an exponential explosion in the complexity of space-oriented applications that require the capability to handle large amounts of on-board data processing. Available Digital Signal Processor (DSP)-based modules offer a typical computing power of 20 Mega Instructions Per Second (MIPS) and more noticeably 20 to 60 Mega Floating Point Operations per Second (MFLOPS). Although this amount of processing power was considered sufficient a few years ago, current and future applica-tions have significantly more demand-ing requirements. These requirements, together with the strong need to reduce Europe’s dependence on foreign critical

technologies, raise the necessity for the development of the next generation of European general-purpose high perfor-mance DSPs.

DSPACE project aims to develop a high performance DSP for space applications running at up to 1 Gigaflops (GFLOPS). The architecture is conceived to meet the scalability, multi-purpose and usa-bility requirements, and is intended to be used both as a stand-alone signal processor integrated into embedded systems and as a building component of a massively parallel architecture. A complete software environment, includ-ing a low-level code optimiser layer, will be created to enable the development, testing, debugging and deployment of space-related applications.

A key objective of the project is to emu-late the DSP Core into a commercial Field Programmable Gate Array (FPGA) to demonstrate/validate its perfor-mances, and make this advanced proto-type available to the space application developers’ community.

During the first six months of DSPACE Project activities, DSP reference archi-tecture has been selected, preliminary Instruction Set Architecture (ISA) has been depicted and a Coarse Grained Architecture Exploration has been per-formed. This last step allowed the pro-duction of an early version of an initial Very High Speed Integrated Circuits Hardware Description Language (VHDL)

Data Signal Processor (DSP) for Space Applications (DSPACE)

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model obtained by tool simulator. Indeed the structure of DSP SW tool-chain has been defined together with specifications on benchmarks perfor-mances evaluation and DSP validation.

AcHieVed resuLts

DSPACE Architecture (consolidation of requirements and architecture definition)

The high level architecture for DSPACE DSP is depicted below and it is com-posed of:

• a Data Processing Unit (DPU) in charge of fetching, decoding and elaborating low-level instructions;

• two separate Instructions (I-Cache) and Data (D-Cache) caches;

• a Direct Memory Access (DMA) con-troller for transferring data between caches and external memory space;

• a generic interface toward the exter-nal memory space where external devices and peripherals (also on-chip memories) can be mapped.

An ‘ordered and symmetric’ Very Large Instruction Word (VLIW) (or also an Explicitly Parallel Instruction Computing = EPIC) architecture is pro-posed for the DPU, where eight (or four in a reduced version) RISC-like instructions can be executed in paral-lel. Eight execution units are arranged in two equal 4-units subsets. Each subset is composed of a register file with 32 × 32-bit locations and the fol-lowing computational units:

•One Address Generation Unit (AGU) assigned to generate addresses to point the operands for the remaining three calculation units;

• Two equal (two instances of) Arithmetic and Logic Units (FP ALU) capable of all the logic, arithmetic,

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but excluding multiplication, and conversion operation on the Integer and single precision floating point 32-bit operands;

•An integer 32 × 32 and Floating-Point Multiplier (FP MUL) dedicated to multiply operations on the Integer and single precision floating-point 32-bit operands.

Each computational unit has its own port to the register file and there is also the possibility for all of them to use source operands coming from the other register file through a rout-ing logic. All the execution units are planned to work as pipelined opera-tors assuring throughputs of one oper-ation per cycle. The fetch and decode stages retrieve instructions from the I-Cache and dispatch them to the exe-cution units along with the operands. As a baseline, the instructions will be packed at compilation time to exploit the maximum parallelism without need of data/resource hazards control at run time. The assignment among instruc-tions and execution units will be made explicit into op-code encoding so that the hardware support for their dispatch will be minimised.

In order to keep the design simple two separated single level caches have been inserted for instructions (I-Cache) and data (D-Cache). While a direct-mapped implementation is planned for I-Cache, D-Cache looks out a more criti-cal design for the need of providing AGU units with at least two ports working in parallel. This implies the need for tech-nologies with dual port memory macro-cells support, or the design of more complex memory blocks management.

An external DMA engine has been inserted to transfer data between the

caches and the memory interface. The control of this data-path has been moved outside the caches to give the programmer the possibility to directly manage the local data pre-fetch/save according to a cache-less paradigm.

The drawn memory interface block is a fully general interface module to be intended both towards external (EEPROM/SRAM/DRAM/DDRAM) devices or internal peripheral Advanced Microcontroller Bus Architecture (AMBA) buses.

DSPACE Software Development Environment (SDE)

The availability of a complete, mature and reliable programming chain is a critical turning point for the success of the new DSP development as the software developers (i.e. the project final users) strongly require such an environment.

Since the definition and design of a new SDE tailored on the new DSPACE device is an unfeasible process (due to the time it would take), the role of a pre-liminary investigation and the selection of adequate reusable software compo-nents has been particularly relevant. The following key aspects have been taken into account during this activity:

• the reliability of the reference SDE;

• the controllability of code generation;

• the accessibility of the compiler back-end component.

The aim of DSPACE SDE is to reuse to a large extent an already existing tool-chain, making its output compati-ble with DSPACE devices by a low-level software layer: DSPACE Software Layer. This component will be in charge of

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translating ground DSP SDE output into DSPACE assembly by integrating and interacting with SDE compiler back-end. This aspect highlights the importance of having this back-end component acces-sible, both legally (the software license must be compatible with this require-ment) and physically (as a software).

Many different SDEs were analysed in order to determine a suitable refer-ence for DSPACE tool-chain (e.g. G21 package, VisualDSP++ development software, TriMedia SDE). This analy-sis underlined first that all commercial SDEs are ruled by licence that prevents them being used on different hardware than the one produced by the same SDE manufacturer and second that, regarding open source projects, it is not possible to find something as complete and mature as Sourcery CodeBench.

Sourcery CodeBench is a complete development environment which is based on GNU tool-chain (ggc, gdb …) and supports a variety of tar-get platforms and also features a C/C++ plug-in for the Eclipse IDE. Since it is built around GNU tool-chain, CodeBench SDE takes full advantage of the maturity, reliability, complete-ness and quality of this open source software collection and represents a well-known and appreciated solution among the open source community. This product is made up of both pro-prietary (owned by Mentor Graphics) and open source components.

Due to licensing restrictions, propri-etary components cannot be reused for DSPACE activities, so a fallback to the basic version of this software, CodeBench Lite Edition, is required.

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More particularly, the Lite Edition com-ponents and their licences are the following:

•GNU Compiler Collection — GNU General Public Licence 3.0;

•GNU Binary Utilities GNU — General Public Licence 3.0;

•GNU Debugger GNU — General Public Licence 3.0;

• CodeSourcery Common Startup Code Sequence — CodeSourcery Licence (proprietary, not to be used);

•Newlib C Library — BSD Licence;

•GNU Make — GNU General Public Licence 2.0;

•GNU Core Utilities — GNU General Public Licence 2.0.

As an outcome of this survey on exist-ing SDEs, Sourcery CodeBench Lite Edition has been selected as SDE to be integrated into DSPACE tool-chain.

Integration will be performed adding an appendix to CodeBench tool-chain which translates into an intermedi-ate language, plus another component which produces the optimised DSPACE assembly.

With this approach, DSPACE software layer is designed by means of two sub-modules separating two different adap-tation roles: Glue Software and Code Optimiser.

Glue Software transforms Codebench Lite assembly into DSPACE Linear Assembly.

Code Optimiser transforms DSPACE Linear Assembly into optimised DSPACE assembly.

391D A T A S I G N A L P R O C E S S O R ( D S P ) F O R S P A C E A P P L I C A T I O N S ( D S P A C E )

DSPACE Linear Assembly consists of a particular kind of assembly which is independent and unaware of the hardware characteristics (as an example, it will ignore pipeline tim-ings, functional units and machine registers) and acts as abstract-linker-interface between the above-mentioned sub-modules.

This approach has many advantages:

• The design is modular, powerful, flex-ible and easy to maintain and test:

° Changes to SDE software layer will impact only on Glue Software component;

° Changes to the hardware will impact only on Code Optimiser component.

•DSPACE Linear Assembly decouples hardware from software (pipeline, registers, functional units, schedul-ing can be ignored).

•DSPACE Linear Assembly can be writ-ten manually. This allows a developer to write C code portions in Assembly for an increased efficiency and also to quickly write test programs.

• The definition of a Linear Assembly in conjunction with a Code Optimiser module is a standard and tested approach which is also envisaged by important manufacturers such as TI or NXP — TriMedia.

DSPACE Validation Benchmarks

In order to measure the performance of DSPACE DSP, software benchmarks that are representative of typical DSP use in space have to be specified, developed and executed on the proto-typed processor.

The starting point for the definition of DSPACE benchmarks is represented by DSP benchmarks specification established by ESA in the document ‘Next Generation Space Digital Signal Processor Software Benchmark’ (TEC-EDP/2008.18/RT, December 2008). This ESA benchmark specification is made applicable to DSPACE project and minor tailoring of it has been performed for adaptation to the specific characteris-tics of DSPACE development.

The benchmark set-up will consist of a prototype platform and a bench-mark support PC. The prototype plat-form is an FPGA board, with the FPGA

392D A T A S I G N A L P R O C E S S O R ( D S P ) F O R S P A C E A P P L I C A T I O N S ( D S P A C E )

programmed with DSPACE DSP. The benchmark support PC is a Linux work-station equipped with specific hard-ware interface devices (for connection with the prototype board) and related software drivers.

The software to be developed in the frame of the benchmarking activi-ties consists of two items: the bench-mark software itself, to be executed on the prototype DSP, and the bench-mark support software, which will run on the PC and will provide the user with the capability to configure and control benchmark execution and to receive information about benchmark status and results.

DSPACE benchmarks will implement five different application scenarios. The main algorithm kernels involved in the various data processing scenarios are Fast Fourier Transform (FFT) and real Finite Impulse Response (FIR) filters. Also some compression algorithms Consultative Committee for Space Data System standards for Image Data Compression and Lossless Data Compression) are part of the bench-mark processing.

ESA benchmarks have been analysed in this phase not only to facilitate their subsequent software implementation but also to support the parallel activ-ity of DSP architecture definition. In fact, the impact on benchmarks perfor-mance of various architectural features has been evaluated in order to support architectural trade-offs. In this regard, the main aspects that have been taken into consideration for implementation trade-offs are: hardware support to complex or Single Instruction Multiple Data (SIMD) arithmetic, supported data formats (single vs. double pre-cision floating point, 32-bit vs. 16-bit

integers), circular addressing, efficient bit manipulation instructions (e.g. log-ical and arithmetic shifts, binary field extraction and insertion), hardware support for low-overhead loops.

CONCLUSIONS

•A very good definition level of DSP base characteristic essential to cor-rectly proceed in next design tasks has been performed. Outputs pro-duced and the possibility to support VHDL implementation of DSPACE architecture by means of a power-ful tool like LISA depict an encour-aging prospective for next project development.

• The main problem encountered, con-sisting in the impossibility to retar-get a consistent and consolidated commercial SDE on project activity has been overcome with the adop-tion of open sections of Sourcery Codebench Lite Edition and the clear definition of their integration strat-egy in DSPACE SDE.

•Also a good definition level has been reached for benchmarks suitable for a correct validation of the device. This will allow also early benchmark-ing activity during first VHDL design phase that will prevent major issues and risks and will improve Code consistency.

•Dissemination on DSPACE started with production of Project Website (http : / /www.dspace-project .eu) and its improvement is still ongo-ing thanks to the active effort of all partners.

After all, goals related to the first phase of project activity have been

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completely reached and guidelines for correct development of a DSP able to reach EU requests and specifications have been rightly traced.

REFERENCES

  Crain, S. H., Velazco, R., Alvarez, M. T., Bofill, A., Yu, P., Koga, R., ‘Radiation effects in a fixed-point digital signal processor’, Radiation Effects Data Workshop, 1999, pp. 30–34.

  Fanucci, L., Forliti, M., Gronchi, F., ‘Single-chip mixed-radix FFT processor for real-time on-board SAR processing’, Proceedings of ICECS ’99, The 6th IEEE International Conference on Electronics, Circuits and Systems, 1999, Vol. 2, pp. 1135–1138.

  Fuller, R., Morris, W., Gifford, D., Lowther, R., Gwin, J., Salzman, J., Alexander, D., Hunt, K., ‘Hardening of Texas Instruments’ VC33 DSP’, Radiation Effects Data Workshop (REDW), 2010 IEEE, p. 5.

  Hoffmann, A., Kogel, T., Nohl, A., Braun, G., Schliebusch, O., Wahlen, O., Wieferink, A., Meyr, H., ‘A novel methodology for the design of application-specific instruction-set processors (ASIPs) using a machine description language’, IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, Vol. 20, Issue: 11, pp. 1338–1354.

  Leupers, R., Hohenauer, M., Ceng, J., Scharwaechter, H., Meyr, H., Ascheid, G., Braun, G., ‘Retargetable compilers and architecture exploration

for embedded processors’, IEE Proceedings Computers and Digital Techniques, Vol. 152, Issue 2, pp. 209–223.

  Nohl, A., Schirrmeister, F., Taussig, D., ‘Application specific processor design: Architectures, design methods and tools’, 2010 IEEE/ACM International Conference on Computer-Aided Design (ICCAD), pp. 349–352.

  Quinn, H., Graham, P., Pratt, B., ‘An Automated Approach to Estimating Hardness Assurance Issues in Triple-Modular Redundancy Circuits in Xilinx FPGAs’, Nuclear Science, IEEE Transactions, Vol. 55, Issue 6, Part: 1, pp. 3070–3076.

  Rezgui, S., Louris, P., Sharmin, R., ‘SEE Characterisation of the New RTAX-DSP (RTAX-D) Antifuse-Based FPGA’, Nuclear Science, IEEE Transactions, Vol. 57, Issue 6, Part: 1, pp. 3537–3546.

  Ruan, Z., Han, Y., Cai, H., Jin, S., Han, J., ‘A Dynamically Partial-reconfigurable FPGA-based Architecture for Data Processing on Space Solar Telescope’, Industrial Embedded Systems, 2007, SIES ’07, International Symposium, pp. 194–199.

  Saponara, S., Fanucci, L., Marsi, S., Ramponi, G., Kammler, D., Witte, E. M., ‘Application-Specific Instruction-Set Processor for Retinex-Like Image and Video Processing’, IEEE Transactions on Circuits and Systems II: Express Briefs, Vol. 54, Issue 7, pp. 596–600.

CHAPTER 38

Authors: Jussi Ahoranta, Juhani Huovelin, Seppo Korpela, Mikko Kiviranta, Torsten May, Jan van der Kuur, Ernst Kreysa, Jari Penttilä, Jens Kobow, George Fraser

consortium members: Department of Physics, University of Helsinki, Finland; VTT Technical Research Centre of Finland, Finland; IPHT Jena — Institute of Photonic Technology, Germany; SRON — Space Research Organisation Netherlands, the Netherlands; MPG — Max-Planck-Gesellschaft, Germany; Aivon Oy, Finland; Supracon AG, Germany; University of Leicester, the United Kingdom

AbSTRACT

The E-SQUID project drives the pro-gress in the development of versa-tile SQUID (Superconducting QUantum Interference Device) readout of Cryogenic Detectors with the main exploitation focus in space instruments, but with a significant potential also for ground-based applications. The most competitive technology in this area is presently available from non-European sources. A core target of E-SQUID is to upgrade the performance of European solutions and challenge the very best achievements in the world.

SQUIDs can be designed for opti-mised readout of X-ray micro-calorim-eter arrays, as well as similar detectors for longer wavelengths extending to far infrared/sub-mm wavelengths. This technology is already used in modern ground-based astronomical instruments such as SCUBA-2 at James Clerk Maxwell Telescope [1]. The performance and array sizes of presently available solutions are, however, not sufficient for the scientific aims of future instruments like the X-ray micro-calorimeter for Athena (Advanced Telescope for High ENergy Astrophysics) [2]. Hence, the development of improved Cryogenic Detector systems with larger arrays and lower noise are very impor-tant to the future of European space science, and advancing the X-ray micro-calorimeter technology in Europe to match the requirements of Athena is a suitable goal for the E-SQUID project.

The practical task of the E-SQUID pro-ject is to develop prototypes for next generation multiplexed SQUID read-out schemes of cryogenic X-ray and far-infrared Cryogenic Detector arrays, modifications of which may then be applied also for optical wavelengths. The improvements are performed in several steps, ensuring the validity of each improvement by tests, and moving onwards to next phase using improved guidelines provided by the test results.

E-SQUID: SQUID-based multiplexers for large Infrared–to-X-ray imaging detector arrays in astronomical research from space

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The goal is to find an optimal scalable multiplexing method for each wave-length that enables future design and application for large detector arrays with minimised noise characteristics. The signal multiplexing means a reduced amount of signal lines between the Cryogenic Detectors and room tempera-ture main electronics, which enables, in practice, the use of considerably bigger detector arrays, and also reduces elec-trical disturbances and heat conduction.

During the first year of E-SQUID pro-ject, the first readout prototype sys-tems for X-rays and Far Infrared have been designed and are currently being assembled. After the assembling, func-tional and performance tests will be made for the prototypes. The test results will provide support and addi-tional guidelines for the next stages of planned development work.

scientific BAcKGround

One of the main focuses in modern space science is the examination of the early Universe and the evolutionary scenarios after the Big Bang. The sig-nature of this evolution is recorded in the electromagnetic radiation from the deep space, including the ubiquitous cosmic microwave background and the faint glow from stars and galax-ies. A detailed walk through this multi-billion-year tale requires instruments capable of imaging and spectroscopy with an extreme level of sensitivity, since science requires no less than precise measurements of X-rays orig-inated in the vicinity of the super-mas-sive black holes in the nuclei of the first galaxies, and the infrared radiation by the cool gas in the interstellar space up to a distance of more than 10 billion light years.

Figure 1. A sample spectrum of 55Fe Mn-Kα emissionline pair measured with a Transition Edge Sensor (TES) detector fabricated at SRON. The detector is similar to those used in the E-SQUID project. The performance of TES detectors can be improved to fulfil the scientific requirements of e.g. the Athena mission X-ray microcalorimeter instrument [2], which is used as the X-ray band reference instrument in E-SQUID project. [3][4]

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Superconducting Cryogenic Detectors that operate at temperatures very close to the absolute zero play a key role in the quest towards these goals. The measurement principle of these detec-tors is based on sensing extremely small changes of temperature in a supercon-ducting detector material caused by individual photons absorbed in it, which gives rise to their name, micro-calorim-eters and micro-bolometers.

Very small noise in reading out the signal can be achieved by a versa-tile device called SQUID. SQUIDs can be designed for optimised readout of X-ray micro-calorimeter arrays, as

well as similar detectors for longer wavelengths up to the far-infrared and sub-millimeter wavelengths. This technology is already used in ground-based astronomical observatories, and it is suitable for future space missions such as Athena [2]. Hence, to make the most out of the project, we are run-ning the technology development in three wavelength bands: Far infrared/Submm, Optical and X-rays.

For setting up the scientific requirements for the photon detectors of each energy range, we have selected the following reference instruments. They are APEX [5] at far infrared/submm, S-Cam 3 [6] at

Figure 2. Cold, interstellar dust around newborn stars in M16. The technology developed in E-SQUID project will bring more power in observation instruments, yielding a better understanding of cosmic evolution in star forming regions. Photo: ESA/ISOGAL team

398E-SQUID: SQUID-BASED MULTIPLEXERS FOR LARGE INFRARED–TO-X-RAY IMAGING DETECTOR ARRAYS IN ASTRONOMICAL RESEARCH

optical, and Athena at X-ray range. The stated performance of the refer-ence instruments is to provide obser-vations of the cold interstellar dust to enable tracing of the history of star for-mation (infrared), multicolour observa-tion capability of the exoplanet transits across the parent stars (optical), and black hole accretion disk observations, providing information on space-time structure of the black hole event hori-zon (X-rays). In parallel, the require-ments serve also the more general aim, which is to develop larger ultra-sen-sitive Cryogenic Detector arrays with lower noise for sensors that can be used for space astronomy and ground-based applications.

MuLtiPLeXinG scHeMes And TEST SETUP

The X-ray micro-calorimeter test sys-tem is based on Transition Edge Sensors (TES) and is being built at University of Helsinki (UH). The system will be oper-ated in high quality vacuum in a dilu-tion refrigerator (Bluefors BF-SD250), which can be cooled down to ~ 10 mK operation temperature. The refrigera-tor’s other thermal stages above this bottom temperature are flanges at 0.7 K, 4 K, and 50 K.

The wiring from room temperature to the bottom experiment stage consists of two continuous wiring sets; one from room temperature to 4 K, and one from there downwards. The operation tem-perature of the detectors is defined by the TES transition temperature, which is approximately 100 mK. This tempera-ture is maintained by negative electro-thermal feedback in the TES circuitry.

The TES signals are read and mul-tiplexed with a Superconductive

Quantum Interference Device (SQUID), which is capable of measuring changes in ambient magnetic field in units of magnetic field quanta. SQUIDs are also used in amplifying the signal in the cold end hence yielding a sufficiently high signal to noise ratio for the trans-fer into the noisy room temperature electronics.

To limit thermal conductance from room temperature electronics into com-ponents working near absolute zero, the wiring between the two temperature domains must be minimised. As we are developing the readout system for large pixel arrays, the only way to limit the number of wiring sufficiently is to trans-fer intelligently coded detector signals from several detector pixels through common wires, i.e.by multiplexing.

There are several methods that can be used in signal multiplexing, including time domain (TDM), frequency domain (FDM) and code domain multiplexing (CDM) (Figure 3). TDM has the short-coming of having the effective read-out amplifier noise increasing by N 0.5 as a function of number of detectors N, which limits the usability in large detector arrays. FDM has also some undesired complications, e.g. need to deal with continuous (sinusoidal) base functions which require a large dynamic range and demand accurately controlled high-Q filters.

We have thus decided to study a CDM scheme with Hadamard-Walsh coding, which is a novel approach in our appli-cation field. CDM provides the capabil-ity to multiplex an unlimited number of pixels without any penalty in noise. In addition to that, the basis signals have only two levels, which eases the signal generation and handling as compared to FDM.

399E-SQUID: SQUID-BASED MULTIPLEXERS FOR LARGE INFRARED–TO-X-RAY IMAGING DETECTOR ARRAYS IN ASTRONOMICAL RESEARCH

The electronics in the UH measurement system are divided in separate parts; at room temperature, at 4 K flange and at ~ 50 mK. The multiplexers and initial signal amplification are situated in the cold end near the TES array, filters and some other signal handling electron-ics at 4 K, and demultiplexers with all other electronics at room temperature.

In the X-ray microcalorimeter test sys-tem we use TES detectors developed by SRON as a part of the development. The performance of these detectors is well known and will therefore provide a solid foundation for the characterisation work of the readout schemes (see e.g. ref. [7]). Our goal is to demonstrate mul-tiplexing with a chip that can multiplex 32 channels without noise penalty, and ultimately build two such signal chains for 2 × 32 pixels. The state-of-the-art multiplexing of microcalorimeters of today is the 2 × 8 pixel time domain demonstration performed by NASA/GSFC [8]. As mentioned, this method of multiplexing has a noise penalty which limits the number of pixels in array.

tecHnicAL resuLts And ONGOING wORK

We are currently preparing the test system for the UH cryostat for the first E-SQUID project X-ray measurement. Most of the electronic units required in UH’s test system have been manu-factured and we are currently testing the electronics and writing required software.

The first generation readout chip device layouts are ready and the devices are in fabrication. In the E-SQUID project we will produce chips in two different foundries; at IPHT in Jena, Germany and VTT in Espoo, Finland. The two

foundries evolve their standard pro-cesses towards design-level compati-bility, so that the foundries can act as back-ups of each other. All the fabri-cated chips will consist of three super-conductive metallisation layers and allow high-density designs. The chip designs must also be applicable in large coherent SQUID arrays.

The first fabrication round is per-formed in the IPHT clean room. The fabrication layouts contain 16 pieces of 3.2 × 3.2 mm2 area chips, most of which aim to demonstrate supercon-ductive code domain multiplexers. Different layouts are fabricated to sup-port different types of measurements. The most ambitious layout of the first fabrication round is the complete 15-channel Hadamard multiplexer, which implements all the required sub-systems on a single chip. The design layout for the chip is shown in Figure 4.

After the fabrication, the measure-ment phase of round one can start. We will test the chips combined with SRON TES’s at two distinct locations, at IPHT Jena and University of Helsinki. First step in our measurement plan is to test multiplexing of two TES signals as a preparation of larger number of signals summed in later test phases.

The whole E-SQUID project develop-ment plan comprises of four genera-tions of multiplexer chip builds, each set utilising the test results of the pre-vious sets. At the top of the four-gen-eration development ladder we expect to understand how to build the optimal readout design. We will use the final design to demonstrate multiplexing of signals with the best possible perfor-mance level, and the aim is to have a match with the scientific requirements set by our reference instruments.

400E-SQUID: SQUID-BASED MULTIPLEXERS FOR LARGE INFRARED–TO-X-RAY IMAGING DETECTOR ARRAYS IN ASTRONOMICAL RESEARCH

Figure 3. Common multiplexing methods include frequency, time and code domain multiplexing. The multiplexer combines the TES signals in cryostat from where the signals are conducted to demultiplexer at room temperature. The present understanding and the working hypothesis in E-SQUID project is that the most suitable method for reading large TES arrays is code domain multiplexing.

Figure 4. Layout of a 15-channel Hadamard multiplexer. The chip includes all subsystems needed in the signal multiplexing.

401E-SQUID: SQUID-BASED MULTIPLEXERS FOR LARGE INFRARED–TO-X-RAY IMAGING DETECTOR ARRAYS IN ASTRONOMICAL RESEARCH

CONCLUSIONS

In the E-SQUID project we develop new technology required in readout elec-tronics of large cryogenic microcalo-rimeter/bolometer arrays for the use of future space science missions. We demonstrate code domain multiplex-ing which has advantages over other multiplexing methods when applied to large TES arrays. This alternative has had much less attention among the developers than other multiplexing schemes, although it requires simpler electronics than FDM and induces prac-tically no noise penalty in large arrays when compared to TDM.

The technology developed in E-SQUID enables a new type of cryogenic instru-ments for a large span of the electro-magnetic spectrum, from infrared to X-rays. In addition to the space science applications, E-SQUID results will be useful also for other fields of scientific and other applications, where observa-tion instruments with supreme perfor-mance level are required.

As a whole, being a purely European effort, the E-SQUID project contributes

in a very clear way to the European Union’s objective of non-dependence in the field of critical technologies.

REFERENCES

  http://www.roe.ac.uk/ukatc/projects/scubatwo

  http://sci.esa.int/science-e/www/area/index.cfm?fareaid=103

  Gottardi, L. et al., J Low Temp Phys 151, 2008, pp. 733–739.

  Y. Takei, et al., J Low Temp Phys 151, 2008, pp. 161–166.

   http://www.apex-telescope.org

  http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=36685

   de Korte, Piet A. J. et al., Proc. of SPIE, Vol. 5501, 2004, p. 167

   Kilb ourne, C. A. et al., Proc. of SPIE, Vol. 7011, 2008, 701104-01

CHAPTER 39

Authors: Sabine Storm, Arnd-Dietrich Weber, Thomas Straubinger, Gerd Trachta, Stefan Müller, Patrick Waltereit, Marie-Antoinette Poisson, Erik Janzen, Urban Forsberg, Peder Bergmann, Jörg Splettstößer

consortium members: SiCrystal AG, Germany; Fraunhofer Institute for Applied Solid State Physics, Germany; Alcatel Thales III-V Lab, France; Linköping University, Department of Physics, Chemistry and Biology, Sweden; United Monolithic Semiconductors GmbH, Germany

The objective of the project ‘High Quality European GaN-Wafer on SiC Substrates for Space Applications’ (EuSiC) is the development of high-quality semi-insulating 3-inch SiC-substrates, which are superior to those available from non-European sources.

High quality Gallium Nitride (GaN) epi-taxial-wafers are the basis for micro-wave power transistors and microwave monolithic integrated circuits (MMICs). Any weakness in the Silicon Carbide (SiC) substrate and/or the epitaxial lay-ers will directly influence the perfor-mance, quality and homogeneity of the transistors and other circuit elements.

The report describes the results of the investigations of the quality of the semi-insulating SiC substrates EuSiC

substrates — developed within the frame of the EuSiC project. The EuSiC substrates were characterised with respect to their electrical and structural properties and compared to semi-insu-lating 3-inch SiC benchmark substrates. Also, first measurement results of a high-electron-mobility transistor (HEMT) structure will be reported.

SiC crystals were grown using the physical vapour transport process (PVT) [1, 2]. The PVT-method uses a semi-open graphite crucible which is almost dense for silicon and car-bon containing gas species, while the inert gas pressure can still be adjusted by gas exchange through the crucible walls. Semi-insulating behaviour in sili-con carbide crystals was achieved by reduction of residual impurities (e.g. nitrogen) and compensation of rest impurities by incorporation of suitable extrinsic doping elements (e.g. vana-dium) during crystal growth forming deep level states in the band gap. As the evaporation temperature of vana-dium is different from that of silicon carbide, the extrinsic doping elements cannot simply be added to the silicon carbide powder source. A process [3] with an external vanadium reservoir, which is located at a lower tempera-ture outside the crucible and connected to the growth cell, enables growth of high quality silicon carbide with homo-geneous resistors above 1E10 Ω cm.

High Quality European GaN-Wafer on SiC Substrates for Space Applications (EuSiC)

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Semi-insulated SiC (EuSiC) substrates of 3-inch diameter were prepared from the grown boule and were character-ised with respect to their electrical and structural properties.

Electrical substrate characterisation was performed using a COREMA-WT system for contactless resistivity map-ping on 32 × 32 points across the entire wafer area. Low ohmic parts or inclusion can be identified which could drastically decrease the performance of high fre-quency properties of transistor devices.

Both EuSiC (Figure 1) and benchmark (Figure 2) semi-insulating SiC sub-strates show a very high mean bulk resistivity larger than 1E10 Ω cm and

good homogeneity across the entire wafer. The substrates show perfect compensation of residual carriers in the material, so the Vanadium-doping of the boule for EuSiC substrates results in a similar resistivity to the intrinsic compensation, which is used for the benchmark substrate.

Additionally the temperature depend-ence of the resistivity up to ~ 600 K was evaluated, using the COREMA-VT. The Arrhenius plot obtained by varia-ble temperature measurements yields the Fermi level and other details of the compensation process. The system provides additional information about the compensation level in semi-insu-lating SiC substrates.

Figure 1. COREMA-WT resistivity topogram of an EuSiC semi-insulating SiC substrate, which shows a high bulk resistivity of > 1E10 Ω cm.

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Figure 2. COREMA-WT resistivity topogram of a benchmark semi-insulating SiC substrate, which shows a high bulk resistivity of > 1E10 Ω cm.

Figure 3. Arrhenius plot (COREMA-VT system) to evaluate the temperature dependence of the resistivity up to ~ 600 K. The corresponding activation energy of the EuSiC substrate is 818 meV.

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Figure 3 and 4 show the COREMA-VT measurement with an Arrhenius plot of the temperature dependence of the bulk resistivity of an EuSiC sub-strate (Figure 3) and a benchmark sub-strate (Figure 4) and the corresponding activation energy of 818 meV for the EuSiC and of 975 meV for the bench-mark substrate. The measurement was performed in the dark. If the sam-ple is illuminated by ambient light, the benchmark substrate shows a persis-tent photoconductivity (see spike in the measurement due to the generation of carriers by the light, Figure 4), while the EuSiC substrate does not show such behaviour. The activation energy of the EuSiC substrate can be directly corre-lated to the vanadium doping of the substrate, confirming the good compen-sation of the material.

The structural properties were ana-lysed with a crossed polariser system, which allows qualitative analysis of the lateral stress distribution of a whole wafer on a sampling basis per crystal boule. Additionally, X-ray omega scans

were performed to verify the struc-tural homogeneity of the substrates. Overall the structural quality of EuSiC substrates and benchmark substrates are good, however it was found that the line widths of the benchmark sub-strates (Figure 5) tend to be lower and more homogeneous than for EuSiC material, see Figure 6.

Furthermore the micropipe density (MPD) was evaluated. Micropipes are a well-known silicon carbide specific defect, with a high impact on device quality. Micropipes are small hollow tubes extending approximately parallel to the c-axis through the crystal boule (Figure 7).

The MPD was measured using a Normarski microscope. This non-destructive method identifies micro-pipes by their optical appearance in an automated microscopic inspection including image processing. The typical MPD of the EuSiC substrates is in the range of 2 cm-2 (Figure 8).

Figure 4. Arrhenius plot (COREMA-VT system) to evaluate the temperature dependence of the resistivity up to ~ 600 K. The corresponding activation energy of the benchmark substrate is 975 meV. The benchmark substrate shows a persistent photoconductivity (see spike) in the

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measurement due to the generation of carriers by the light.

Figure 5. Cross polarisation image and line widths from X-ray omega scans for a semi-insulating SiC benchmark substrate.

Figure 6. Cross polarisation image and line widths from X-ray omega scans for

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a typical EuSiC substrate.

Figure 7. System of interacting growth spirals originating from a micropipe (atomic force microscopy).

Figure 8. EuSiC substrate with an average micropipe density (MPD) of 2 cm-2. Micropipe free areas are shown by green coloured fields. Areas with higher micropipe densities are shown by white (1 cm-

2), yellow (2 cm-2) and orange (3 cm-2) marked fields, respectively. The lateral distribution shows first clustering of micropipes near the wafer edge, which is clearly indicated by several yellow and orange-

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coloured grid elements surrounded by micropipe free regions.

Subsequently, a high electron mobil-ity transistor (HEMT) structure consist-ing of an isolating (Al, Ga)N buffer, a 22-nm thick AlGaN barrier layer with nominally 18 % Aluminium and a 3-nm thick GaN cap has been grown by MOCVD (metal organic chemical vapour deposition) on the EuSiC and the benchmark substrates.

X-ray rocking curves were performed to verify the quality of the grown HEMT structures (Figure 9). A signifi-cant shift of the AlN nucleation layer grown on EuSiC substrates in com-parison to the benchmark substrate was observed, probably caused by different strain induced in the first steps of the epitaxy due to the higher

roughness observed on EuSiC sub-strates. This modification of the strain should have an impact on the piezoe-lectric field leading to some difference in the carrier density, pinch-off volt-age and sheet resistance of the HEMT structures. No shift of the AlN nuclea-tion layer was observed after chemo-mechanically polishing of the EuSiC substrates.

The EuSiC substrates were charac-terised with respect to their elec-trical and structural properties and compared to semi-insulating 3-inch SiC benchmark substrates. Also, first measurement results of a high elec-tron mobility transistor (HEMT) struc-ture were reported.

Figure 9. X-ray rocking curves of HEMT structures grown on several semi-insulating SiC substrates. A shift of the AlN nucleation layer grown on EuSiC substrates in comparison to benchmark substrate was observed, probably caused by strain induced in the first steps of the epitaxy due to the higher roughness observed on EuSiC substrates.

411H I G H Q U A L I T Y E U R O P E A N G A N - W A F E R O N S I C S U B S T R A T E S F O R S P A C E A P P L I C A T I O N S ( E U S I C )

The overall results for the substrate quality are very promising as the struc-tural and electrical data on benchmark and EuSiC semi-insulating SiC sub-strates are very similar.

The surface preparation was found to have a strong influence on the strain within the AlN nucleation layer. Further research will be focused on the influ-ence of the quality of the semi-insu-lating SiC substrates on the GaN hetero-epitaxial layer growth and the device performance, respectively.

REFERENCES

  Tairov, Y. M. et al., ‘General Principles of Growing Large-Size Single Crystals of Various Silicon Carbide

Polytypes’, Journal of Crystal Growth, 52, 1981, p. 146.

   Ziegler, G. et al., ‘Single Crystal Growth of SiC Substrate Material for Blue Light Emitting Diodes’, IEEE Trans. Electron. Devices ED-30, 1983, p. 277.

   Straubinger, T. L. et al., ‘Aluminium p-type doping of silicon carbide crystals using a modified physical vapour transport growth method’, Journal of Crystal Growth, 240, 2002, p. 117.

CHAPTER 40

Authors: Alexandre Pollini, Hans Krüger

consortium members: Centre Suisse d’Electronique et de Microtechnique SA (CSEM), Switzerland; Deutsches Zentrum für Luft- und Raumfahrt (DLR), Germany

AbSTRACT

This paper describes the project Flash Optical Sensor for TErrain Relative NAVigation (FOSTERNAV), an activity funded by the European Commission within its third call of the space theme of the seventh research framework programme.

The orientations of the project are: to review space exploration missions’ requirements for which the use of Light Detection And Ranging (LiDAR) sen-sors is foreseen, to design and build a three-dimensional (3D) imaging flash LiDAR prototype and to assess it on test-benches for soft-landing and ren-dezvous applications.

FOSTERNAV started in January 2011 and will last three years. So far, the project’s team has gone through the first phase of the project, focusing on identifying and analysing several mis-sions’ term of requirements for soft-landing and rendezvous, and to derive from the investigation, system and subsystems specifications. The second

phase will concentrate on the sensor prototype design and the third on the assessment.

introduction

The origin of the project finds its roots in the stated need by space agen-cies for new Guidance, Navigation and Control (GN&C) technologies to ful-fil future medium-term robotic explo-ration missions, or long-term human space exploration missions’ terms of requirements. Step improvements in GN&C sensors performances and func-tionalities are needed.

The development of new type of key components for LiDAR, like imagers generating three-dimensional (3D) images for example, has triggered the reconsideration of LiDAR architec-tures. CSEM has developed for sev-eral years a particular type of these imagers: Time-Of-Flight (TOF) Active Pixel Sensor (APS). By considering these imagers which are designed in the first place for ground rather than space applications, innovative optical remote sensing sensor architectures can now be imagined to fulfil demand-ing mission requirements like the Mars Sample Return (MSR) mission. MSR is a showcase for the flash imaging LiDAR architecture studied in the project. The general scenario of the mission aims at bringing back samples collected on Mars (1).

FOSTERNAV: Flash Optical Sensor for Terrain Relative Navigation

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Four phases of the mission would ben-efit from the flash architecture: the control of the descent and soft-landing of the lander, the rover navigation, the in-orbit rendezvous between the sam-ple container and the orbiter, and the deployment monitoring of the orbit-er’s equipment. The common need of these applications is a sensor with the ability to capture 3D images of various targets.

The innovative approach explored in FOSTERNAV is to merge a specific illu-mination source generating a variable number of laser beams with control-lable divergence together with a TOF APS into one 3D imaging LiDAR archi-tecture. It addresses directly the intrin-sic disadvantage of flash compared to flying-spot LiDARs: The optical power density on flash imaging LiDARs detec-tor’s sensitive surface is lower due to the larger divergence of the illumina-tion beam used (see Figure 2).

The rational to investigate a flash architecture is to reduce drastically the size of imaging LiDAR sensors. This

overall aim has been translated in four main orientations for the project:

• The development of a flash optical sensor architecture up to a technol-ogy readiness level (TRL) of four;

• The applicability evaluation of the sensor for object relative robotic navigation according to space mis-sions’ scenarios for soft-landing and rendezvous;

• The establishment of assessment protocols allowing a complete trans-parency of the comparison of diverse type of 3D imaging devices with active illumination;

• Increasing the awareness of the strong potential of the flash technol-ogy in Europe for space applications; so far flash technology has been mainly developed in the US (3).

In order to take into account the right expertise for the different challenges of the project, a European consortium has been created and includes the

Figure 1. Mars Sample Return scenario (2).

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Technical Research Centre of Finland (VTT), EADS Astrium SAS Toulouse (France), the ‘Bremen Deutsches Zentrum für Luft- und Raumfahrt’ (DLR Germany), Modulight (Finland) and the Swiss Centre for Electronics and Microtechnology (CSEM Switzerland).

AnALysis of eXPLorAtion MISSIONS’ REqUIREMENTS

The core of the effort in the first phase of the project was to derive the spec-ifications of the flash sensor from missions’ requirements while taking into account limitations of the cur-rent technologies used for imaging LiDAR architectures. Several planned missions have been reviewed: Mars Sample Return (Rendezvous and land-ing scenarios) and Marco Polo for asteroid landing scenario.

For the design of 3D imaging LiDAR for space applications, the main chal-lenge is to create an instrument tak-ing into account in optimal manner the various limitations and features of the building-blocks of LiDAR systems as well as the requirements provided by missions’ planners. The statement-of-work of the ‘Miniaturised Imaging LIDAR system’ is an up-to-date over-view of the expected performances of 3D imaging systems by explora-tion missions’ planners at ESA for three exploration mission phases: entry, descent and soft-landing (land-ing), and docking of canister trans-porting samples with orbiting craft (rendezvous/docking).

The requirements include: maximum range (e.g. 1 600 m at far range or 700 m at close range for Mars land-ing), minimum range (e.g. 700 m at far range or 275 m at close range

for Mars landing), ranging accuracy or vertical accuracy (e.g. < 1 m at far range or 0.05 m at close range), frame rate (> 1Hz), horizontal accuracy (e.g. < 0.7 m or < 0.3 m), area to be imaged (e.g. 200 m × 200 m at far range), overall system figures (e.g. weight 7 kg, power consumption 40 W, tem-perature range – 20 to 50 °C, lifetime > 1 day), some spacecraft attitude information (e.g. horizontal veloc-ity 20 m/s at 500 m, vertical velocity 20 m/s at 500 m, view angle 30 ° at 500 m, attitude 2.5 °/s), some infor-mation about the ground character-istics to be discriminated (e.g. slopes higher than 20 °, size of the landing site 6 m × 6 m), etc.

Missions’ term of requirements listed above push the required performances of technologies entering in a 3D imag-ing sensor to the limit and beyond. 3D flash LiDAR under development for several years do not offer the perfor-mances derived from these require-ments (4). Moreover, they have been defined for systems having the ability to change the Field-of-View (FoV) as the distance to the target change like flying-spot or scanning imaging LiDAR which are equipped with mechanical device steering the laser beam on the target (see Figure 2). The feature of flash architectures which have theo-retically fixed the illumination solid angle is not taken into account.

The necessary compromises between missions’ requirements and today’s technological limitations are the starting point of the design of the FOSTERNAV flash sensor. To illustrate the necessary trade-offs to be bal-anced by system designers, we con-sider for example the desired FoV and the angular resolution for the ren-dezvous application. The horizontal

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resolution specification of the photo-detector array to be considered can be estimated to be 1 000 by 1 000 pixels. This horizontal resolution is available only with some of the most recent photo-detector arrays for space appli-cations but they do not integrate ‘demodulation pixel’ — as for the APS used in FOSTERNAV — that are needed to generate 3D images (5). Another system trade-off is the one balancing the maximal optical power, the sensitivity of the photo-diodes of the APS and the integration time nec-essary to generate sharp images in all illumination conditions and spacecraft attitudes derived from the craft tra-jectory dynamic.

3d fLAsH oPticAL sensor PreLiMinAry desiGn

The design of the flash optical sensor is a complex iterative process consider-ing alternatively missions’ requirements and realistic performances achievable by building-blocks entering in the sen-sor’s architecture. There is a large range of parameters including hardware, soft-ware co-design, and GN&C system opti-misation (hybridisation) to achieve the requested performances and provide the requested functionalities.

During the first phase the iterative design process has been started. A capi-tal step has been to define illumination strategies depending on the distance to target considering at the same time missions’ requirements and technolo-gies’ limitations.

Figure 2. Flying-spot and flash imaging LiDAR principles

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Target illumination: variable number of laser beams with controllable divergence

LiDAR systems for GN&C applications can be roughly split into two fami-lies: flash and flying-spot families. These families can be distinguished by the way three-dimensional images or Digital Elevation Maps (DEM) are generated.

Theoretically, with flash LiDAR archi-tectures, the scene of interest is entirely illuminated by a laser beam with a relatively large divergence; 3D images or DEM are captured in one snapshot. The light reflected by the target is detected by a two-dimen-sional photo-detector array. For fly-ing-spot architecture, the scene of interest is scanned in x and y axis by a laser beam — with a relatively low divergence — steered over the full area of interest by a complex opto-mechanical part. The 3D image is gen-erated by a zero- or one-dimensional photo-detector sequentially collecting the light reflected. The flash approach aims at suppressing the need for this part and hence at lowering the com-plexity of imaging LiDAR.

At first glance, for long distance rang-ing — flash devices have an intrinsic disadvantage over flying-spot sys-tems; the optical power density hitting the surface of interest — and conse-quently the corresponding detected light is lower. The difference is roughly proportional to the relative diver-gence ratio of the beam for the fly-ing-spot and the flash architectures. This is a disadvantage to overcome but the reward is a higher potential of miniaturisation for flash architec-ture and 3D images can be generated more easily: the necessity of precise

indication of the scanner position and pointing direction is suppressed.

Illumination of a target with sev-eral beams is not a new concept. The Lunar Orbiter Laser Altimeter (LOLA) use five laser spots of 5 m diameter from a 50 km orbit (6). For FOSTERNAV, it has been defined that the illumina-tion source will generate either one or five beams with variable divergence depending on the distance to the tar-get. The characteristics of the illu-mination source have been defined following simulations showing that —according to the flash principle of illu-minating in one shot the overall scene of interest — the Signal-To-Noise Ratio (SNR) collected for far range operation considering FoV suggested by missions’ requirements is too low to allow the generation of DEM with reasonably limited error on the range measurement for a limited power sup-ply, volume and mass of the imaging LiDAR (at night 0.2 W of optical power per square meter are needed to have 5 cm precision on the range).

Following this result, three modes of operation have been defined:

•At very far range, the illumination head emits one laser beam with small relative divergence. No imag-ing of the target is possible, only one distance to the target can be determined.

• At far ranges five beams with low divergence illuminate the target. Five distances to the target can be deter-mined. Hence, slopes between the five lighted points can be computed. In addition, 3D images of the five illu-minated patches on the target can be generated as soon as the SNR of the detected light becomes sufficient.

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•At close ranges surface obstacles of a few tens of centimetres are revealed by a large divergence sin-gle beam.

The multi-beam illumination of the target is considered to alleviate the intrinsic disadvantage of the lower optical power density on the detector for flash architectures. The aim is to provide a system capability to allow maintaining a sufficient margin for the SNR on the imager. The limited avail-able optical power is more efficiently used to light the target to provide the performances and functionalities needed by the GN&C system.

Indirect range determination with photons TOF measurement

The key critical elements of a 3D flash imaging LiDAR are the light source and the detector array (with a demod-ulation circuit for each pixel) (7). The features of one influence strongly the characteristics of the other. In FOSTERNAV, the detector provides the range for each pixel by measur-ing the TOF of the photons emitted by the illumination head, reflected by the target’s surface and detected by the APS. Due to the cost of designing and making chips, the one used for FOSTERNAV has not been developed specifically for long range application and acquire 3D images at long range but for microscopy (7).

APS arrays offer a good compromise between speed, noise, dynamic range, Field-Of-View (FoV) and affordabil-ity without multiplicative noise. The expected characteristics of the TOF APS array to be used in the frame of the project are: 5 pA/cm2 dark cur-rent, 23 e-read-out noise, sensitivity 69.8 µV/e-, 200 frame/s, 256 × 256

active area 1.6 × 1.6 mm, 28 % @650nm quantum efficiency, 55 dB dynamic, pixel size 6.3 × 6.3 µm2, no multiplicative or excess noise (8).

TOF is calculated by finding the time delay between the emitted and detected modulated light. The APS of FOSTERNAV demodulates the received light modulated in amplitude by a pseudo-random noise sequence. The picture below shows some details of the imaging LiDAR architecture.

ASSESSMENT OF THE PROTOTyPE

The last step of the project is the assessment of the 3D flash imaging LiDAR prototype for landing and ren-dezvous applications. The goal of the third phase is not only the test of the prototype but also the definition of assessment protocols allowing a com-plete and fair comparison of various type of active illumination 3D vision systems.

In the frame of FOSTERNAV, a four steps approach is planned for the test-ing phase. The steps 2, 3 and 4 will be executed at DLR facilities:

1. Static test in laboratory to check subsystems and system functionalities;

2. Test of the prototype on a test-bench especially developed to assess optical navigation sensors like camera and LiDAR for landing applications;

3. Test of the prototype on a test-bench especially developed to assess optical navigation sensors for rendezvous applications,

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Figure 3. Imaging LiDAR block diagram.

4. Test on an airfield in order to assess the prototype with high relative speed between sensor and target conditions and outdoor parasitic light.

The facility for the step 2 is the Testbed for Robotic optical Navigation (TRON) located at the DLR institute of Space Systems in Bremen. It is a Hardware-in-the-Loop Test facility. Active and passive optical sensors can be evaluated with this tool. The dynamic, the geometry and the opti-cal conditions of a landing phase of an exploration mission on the Moon, on Mars and on Asteroid can be emu-lated with various options for the ter-rain models and light conditions.

The step 3 will be achieved with EPOS 2.0 located at DLR Oberpfaffenhofen after rebuild of the facility in 2009 (*). EPOS is aiming at providing test and verification capabilities for complete rendezvous and docking phases of on-orbit servicing mis-sions. It comprises a hardware-in-the-loop simulator based on two industrial robots (of which one is mounted on a 25 m rail system) for physical real-time simulations. This test-bed allows utmost realistic simulations of real rendezvous and docking processes.

* http://www.weblab.dlr.de/rbrt/OOS/EPOS/EPOS.html

The step 4, the most challenging of the test foreseen for the FOSTERNAV

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Figure 4. TRON at current state of development (left) and EPOS facilities.

prototype will be executed on an airfield with a 1.8 km long runway. Like TRON it is a test facility of the GNC depart-ment of the DLR institute of Space Systems in Bremen. It is aimed to serve as a general purpose facility allowing the assessment of GN&C or proximity sensor at long-range and high relative speed between sensors and targets.

CONCLUSIONS

The main objective of FOSTERNAV is to design, build and assess a 3D imag-ing LiDAR prototype based on TOF APS technology and adaptable multi-beam illumination.

In the first phase, the main character-istics of the LiDAR have been estab-lished by mixing specifications derived from missions’ terms of requirement and realistic features of key compo-nents of flash sensor: illumination head and imager. In parallel, test pro-tocols have been elaborated and will be implemented in the next phases of the project.

The requirements’ review established that the derived imaging sensor spec-ifications cannot be all matched as they are with a standard flash LiDAR

as theoretically such sensors do not have the ability to change the illumina-tion angle as the distance or the atti-tude of the spacecraft relative to the target change.

By choosing modes of operation chang-ing the illumination footprint on the tar-get with the distance, the FOSTERNAV imaging LiDAR architecture has the potential to achieve the specifications derived from the requirements. As a result, functionalities such as: range meter, slope imaging and hazard imag-ing are all integrated in one single instrument. On this base a prototype will be constructed and its applicabil-ity for landing and rendezvous assessed during the second and third phases of the project.

REFERENCES

  Fisackerly, R., Pradier, A., Houdou, B., Philippe, C., Santovincenzo, A., ‘Entry, descent and landing for Mars Sample Return: the European technology development and demonstration approach’, ESA, ESTEC.

   Preliminary Planning for an International Mars Sample Return Mission, Report of the International

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Mars Architecture for the Return of Samples’, iMARS working group, June 2008.

   Epp, C. D., Robertson, E. A., Brady, T., ‘Autonomous landing and hazard avoidance technology (ALHAT)’, IEEE 2008.

   Keim, J. A., Mobasser, S., Kuang, D., Cheng, Y., Ivanov, T., Johnson, A. E., Goldberg, H. R., Khanoyan,, G. and Natzic, D. B., ‘Field Test Implementation to Evaluate a Flash Lidar as a Primary Sensor for Safe Lunar Landing’, Jet Propulsion Laboratory California Institute of Technology Pasadena, CA 91109, Jason.A.Keim@jpl.nasa.gov. IEEEAC paper #1686, Version 5, Updated 5 January 2010.

   Beletic, J. W. (*), Blank, R. (*), Gulbransen, D., Lee, D., Loose, M., Piquette, E. C., Sprafke, T., Tennant,

W. E., Zandian, M., and Zino, J., ‘Teledyne Imaging Sensors: Infrared imaging technologies for Astronomy & Civil Space’, Teledyne Imaging Sensors., Camarillo, California, USA 93012.

   Riris, H., Cavanaugh, J., Sun, X., Liiva, P., Rodriguez, M., Neuman, G., ‘The Lunar Orbiter Laser Altimeter (LOLA) on NASA’S Lunar Reconnaissance Orbiter (LRO) Mission’, International Conference on Space Optics, 4–8 October 2010.

   Büttgen, B., El Mechat, M., Lustenberger, F., Seitz, P., ‘Pseudonoise Optical Modulation for Real-Time 3-D Imaging With Minimum Interference’, 2007 IEEE.

   Coates, C. and Campillo, C., ‘CCDs lose ground to new CMOS sensors’, Laser Focus World, March 2011.

CHAPTER 41

Authors: Jose-Luis Perez-Diaz and Efren Diez-Jimenez

consortium members: Universidad Carlos III de Madrid, Spain; Universitá degli Studi di Cassino, Italy; Consiglio Nazionale delle Ricerche – SPIN, Italy; CAN Superconductors, Czech Republic; BPE, Germany; LIDAX ingeniería, Spain; Fundação da Faculdade de Ciências da Universidade de Lisboa, Portugal

AbSTRACT

The objective of this project is to design, build and test a magnetic-superconductor cryogenic non-con-tact harmonic drive (MAGDRIVE). This harmonic drive is a mechanism pro-vided with an input axle and an output hub with a great reduction ratio and it will be able to function at cryogenic temperatures. This harmonic drive is based on “non-contact magnetic teeth” instead of fitting teeth on a flexural wave as conventional harmonic drives are based on. Non-contact magnetic teeth are activated by a magnetic wave (similar to an electrical engine) and stabilized by the use of super-conductor materials. This can solve the problems of contact wearing and mechanical fatigue. Superconductors are also used for non-contact bearings and for shielding the magnetic fields to

avoid electromagnetic interferences or emission.

This project started in February 2011 and the first preliminary analyses show very promising mechanical per-formances of the reduction gear. They have demonstrated that the trans-mitted torque density capability is independent of the size of the gear. Also, the choice of the material for the soft-magnetic teeth is not a criti-cal decision provided that they have a minimum required magnetic permea-bility. Moreover, some dynamical simu-lations have shown that the reduction ratio is achieved.

introduction

The Harmonic Drive (HD) mechanism is a power transmission capable of devel-oping high ratios, providing a high posi-tional precision to the assembly, with relatively low weight/volume ratio, high torque capability and near zero backlash. It was invented by Musser in 1955 for aerospace applications and it is widely used now in robotics, medi-cal equipment, printing presses, vehi-cles or military industry.

The application of HD mechanisms at very low temperature (T<100 K) is lim-ited by lubrication. Any kind of oil or grease freezes at cryogenic conditions

Magnetic-Superconductor Cryogenic Non-contact Harmonic Drive (MAGDRIVE)

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losing all the lubricant properties. Other dry lubricants present also problems like grating, clutching, rapid wear out, instability of friction coefficient, forma-tion of cold weld centres and losses or decomposition of the lubricant at cry-ogenic conditions. In addition, fatigue due to the intrinsic flexural function-ing of the HD also limits its effective work life.

On the other hand, the number of cry-ogenic devices and instruments used in space industry is rapidly increas-ing. The signal/noise ratio in any sensor usually increases as the temperature decreases. Therefore, the demand for the most sensitive sensors is linked to an increasing need for cryogenic mechanisms for satellites, rovers, space scientific instruments (e.g. infra-red spectrometers), cryopumps (e.g. for cryogenic fuel) or different on earth uses (medical instruments, etc.).

The objective of this project is to design, build and test a magnetic-supercon-ductor cryogenic non-contact harmonic drive (MAGDRIVE). This harmonic drive is a mechanism provided with an input axle and an output hub with a great reduction ratio and it is intended to be able to function at cryogenic tem-peratures. It is based on a non-con-tact interaction between magnets, soft magnetic materials and superconduc-tors. Therefore, the drive shows neither any wearing nor any fatigue and it will not need any lubrication. This greatly increases the life time of the drives. As drives are frequently used in many dif-ferent fields the result of this project is a qualitative jump that will open many opportunities.

This harmonic drive is based on “non-contact magnetic teeth” instead of fitting teeth on a flexural wave as

conventional harmonic drives are based on. Non-contact magnetic teeth are activated by a magnetic wave (similar to an electrical engine) and stabilized by the use of superconductor materials. This can solve the problems of contact wearing and mechanical fatigue.

Superconductors are also used for non-contact bearings and for shield-ing the magnetic fields to avoid elec-tromagnetic interferences or emission. The latest available technologies are being used for selecting and manufac-turing magnetic and superconducting materials as well as for designing the magnetic-superconductor non-contact mechanisms.

Such a kind of MAGDRIVE will be use-ful for space and cryogenic devices in many fields. The main objective of this project is to check experimentally its usability and to establish its real per-formances. This means to classify it in a technology readiness level 5 (TRL5) according to the NASA-ESA standards. (TRL5 means component and/or bread-board validation in a relevant environ-ment – i.e. cryogenic conditions).

In order to achieve a TRL 5 standard, a prototype and a breadboard will be designed, built and tested at a temper-ature of 60 K. Performances and real mechanical properties, such as maxi-mum speed, speed ratio, torques and load capability, as well as clearances, position and orientation of the moving partswill be characterized in order to establish the criteria for the usage of these MAGDRIVEs in space and other applications. The mechanism is intrin-sically “cryogenic-friendly” and it is expected to have a better performance at a lower temperature.

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As this project started in February 2011, we can only present the first pre-liminary analyses in this paper.

STATE OF THE ART

Harmonic Drives

Conventional “Harmonic Drives” (HD) are outstanding mechanisms based on the flexural properties of materi-als in which an inner “wheel” pushes a spline that gears an outer stator. The obtained speed ratios for them are extremely high and where a large number of teeth are involved, their load capabilities are high as well. Limits for these mechanisms are fatigue and wear, especially if lubri-cants are not available, for example at cryogenic conditions.

Every HD is composed of three distinct parts: the Wave Generator (WG), the Flexspline (FS) and the Circular Spline (CS). The application of HD mecha-nisms at very low temperature (T<100 K) is limited by lubrication. Any kind of oil or grease freezes at cryogenic con-ditions, losing all the lubricant proper-ties. Other dry lubricants present also problems like grating, clutching, rapid wear out, instability of friction coef-ficient, formation of cold weld cent-ers and losses or decomposition of the lubricant at cryogenic conditions. In addition, fatigue due to the intrinsic flexural functioning of the HD also lim-its its effective working life.

Magnetic Gears

Different magnetic gearings have been described and patented since 1933. They use a “magnetic wave” concept similar to the “elastic wave” in HD. They are not only reliable and trouble-free in

operation, but also ensure a silent and vibration-free drive train while provid-ing extremely high gear ratios.

Chubb, working for the Westinghouse Electric & Manufacturing Company, invented in 1933 a Vernier motor for use as a magnetic reduction gear [1], which involved three relatively mov-ing parts, any one of which could be held stationary, whereupon the other two parts were able to take up their definite speeds relative to the station-ary part.

In 1967, Reese [2] patented a mag-netic gearing arrangement comprising a high speed shaft and a low speed shaft. The input high speed shaft was intended to be connected to a motor. The output low speed shaft was intended to be connected to a load to be driven. When the load is to be driven at a low speed by a high speed motor, the gear means may act as a speed reducing gear.

In 1984, Shigeo and Moichi [3] patented a non-contact type electromagnetic reduction gear comprising two parts with magnetic excitation (Fig.4). Due to the advances on magnetic materials of the 1980’s this device increased con-siderably the torque capability.

In 1999, Ackermann [4] provided an improved magnetic drive arrangement. This embodiment of the invention has a higher mechanical stability as it is capable of transmitting substantially the same torque.

In 2001, Atallah et al. [5] proposed a novel high-performance magnetic gear. The paper describes the design and performance of a magnetic gear, which employs permanent rare-earth magnets.

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In 2003, Razzell and Cullen [6] pat-ented a compact electrical machine comprising a combined magnetic gear-box and an electrical generator.

Bright proposed a gearbox with varia-ble ratios. By providing pole members with coils between them and associ-ated switches, it is possible to create open circuit, closed circuit and varia-ble impedance configurations to more actively adjust the magnetic flux mod-ulation capacity across the arrange-ment. In such circumstances, a wider range of gear ratios is achieved [7].

In 2007 Atallah and Rens [8] patented a magnetic gear for sealed systems such as pumps and turbines. In these appli-cations the high speed is an important limiting factor for conventional gears.

The same principle of a large number of gearing teeth activated by a flex-ural wave may be expanded to a large number of “non-contact magnetic gearing teeth” activated by a mag-netic wave –as in the inventions cited above. From this point, in this project we are exploring the usage of the best combination of hard magnets and soft magnetic materials. We will use com-mercially or easily sinterable materials. The optimization of this kind of materi-als and the size and shape of the parts is a key point in order to improve the mechanical performances of these

kinds of gears. Shape and size are very important and optimization is not trivial as well. Moreover, the usage of magnet-superconductor non-contact bearings is another research field that this project is involved in. The magnet-superconductor bearings are based on the Meissner repulsive forces between a magnet and a superconductor. They are the natural bearings for cryogenic applications.

PRELIMINARy ANALySES RESULTS

The first model developed for MAGDRIVE consists on a cylindri-cal gear composed of three mag-netic parts: input, output and stator as shown in Fig 1.

This first model has 60 mm of exter-nal diameter and 100 mm length. The materials considered in the simulations are NdFeB permanent magnets and different soft magnetic materials. For this case, the combination of number of teeth chosen gets a reduction ratio of ten. We have carried out static and dynamic analysis.

Scale

From the initial static analysis we have studied the variation of the maximum torques versus the scale factor of the

Figure 1. Scheme of the MAGDRIVE

conceptual design.

427M A G N E T I C - S U P E R C O N D U C T O R C R Y O G E N I C N O N - C O N T A C T H A R M O N I C D R I V E ( M A G D R I V E )

Figure 2. Maximum torques in each part vs. scale factor.

whole model. For example, a scale fac-tor of 6 corresponds to 360 mm exter-nal diameter.

It can be derived from Fig 2 that the maximum torque acting on the out-put axle is ten times the maximum torque applied on the input axle as expected according to the reduction ratio. Moreover, we find that the sum of all the three torques (input axle, out-put axle and stator) is approximately zero. We can estimate that the value of the torques increments quadratically. Considering that the volume incre-ments also quadratically with respect this scale factor, we can say that the maximum torque density of the gear does not dependent on the scale factor.

Material

The properties of the magnetic materi-als involved are essential for the work-ing efficiency of the MAGDRIVE. Hard magnetic parts need to be composed

of the highest quality of permanent magnets; in this case the best option is NdFeB sintered magnets. For the soft magnetic parts different aspects as magnetic permeability, magnetic coercivity, remanent field or mechani-cal and machining properties must be considered.

As an example we present in Fig 3 the maximum transmitted torque vs. the magnetic permeability of different materials. We can notice that the use of a highly permeable material could increase the torques transmitted but this point is not critical to reinforce the capability of the gear. Other aspects like magnetic coercivity or mechanical properties could be more determining in the final choice of the material.

Dynamical analysis

Some dynamical simulations have been performed in order to check the intended behaviour of the MAGDRIVE,

428M A G N E T I C - S U P E R C O N D U C T O R C R Y O G E N I C N O N - C O N T A C T H A R M O N I C D R I V E ( M A G D R I V E )

concretely to check the reduction ratio in the angular speed.

In the simulation shown in Fig 4, an external torque of 1.4 Nm is exerted on the output axle. The dynami-cal simulation demonstrates that the

angular displacement is “clutched” at the beginning but, as soon as the input starts moving (red line), the angular displacement of the output increments in the favorable direction leading to a ten times reduction ratio.

Figure 3. Maximum transmitted torque vs. magnetic permeability of different materials.

Figure 4. Angular displacement for both the input axle (red line) and the output axle (purple line) with a load torque.

429M A G N E T I C - S U P E R C O N D U C T O R C R Y O G E N I C N O N - C O N T A C T H A R M O N I C D R I V E ( M A G D R I V E )

CONCLUSIONS

The first preliminary analyses show very promising mechanical performances of the reduction gear. Nevertheless, sev-eral aspects must be still optimized in order to completely achieve the project objectives.

It has been demonstrated that the transmitted torque density capabil-ity is independent of the size of the gear. This is very interesting because it allows smaller prototypes to be built, tested and ensures the extensibility of those prototypes for higher or smaller torque requirements.

Moreover, the choice of the mate-rial for the soft-magnetic teeth is not a critical decision provided that they have a minimum required magnetic permeability. This allows the designers to choose the materials to accomplish other needed energetic or structural requirements.

Moreover, some dynamical simulations have shown that the reduction ratio is achieved. Although the reduction ratio chosen for these initial analyses is small, the principles of functioning of MAGDRIVE have been proven.

REFERENCES

  Chubb, L. W., (Westinghouse Electric & Manufacturing Company) 1933. Vernier motor. US patent application 1894979. 1933-01-24.

  Reese, G. A., (The Magnavox Company) 1967. Magnetic gearing arrangement. US patent application 3301091. 1967-01-31.

  Ackermann, B. and Honds, L., (U.S. Philips Corporation) 1997. Magnetic drive arrangement comprising a plurality of magnetically cooperating parts which are movable relative to one another. US patent application 5633555. 1997-05-27.

  Ackermann, B., (U.S. Philips Corporation) 1999. Magnetic drive arrangement. US patent application 5994809. 1999-11-30.

  Atallah, K. and Howe, D. “A Novel High-Performance Magnetic Gear”. IEEE Transaction on magnetics, vol. 37, no. 4, pp. 2844-2846, 2001.

  Razzel, A. G. and Cullen, J. J. A., (Rolls-Royce PLC) 2003. A compact electrical machine. EP patent application 1353436 A2. 2003-10-15.

  Bright, C., (Rolls-Royce PLC) 2007. A magnetic gearbox arrangement. WO patent application 2007/107691 A1. 2007-09-27.

  Atallah, K. and Rens, J. J., (Magnomatics Limited) 2009. Magnetically gearing for sealed systems. GB patent application 2457226 A. 2009-08-12.

CHAPTER 42

Author: Ali Gülhan

consortioum members: Deutsches Zentrum für Luft- und Raumfahrt (DLR), Germany; Centro Italiano Ricerche Aerospaziali (CIRA), Italy; Thales Alenia Space Italia S.p.A (TAS-I), Italy; EADS Astrium GmbH (ASTRIUM), Germany; Central Research Institute of Machine Building (TsNIImash), Russia; Central Aerohydrodynamic Institute (TsAGI), Russia; Institute for Problems in Mechanics (IPM), Russia; Institute of Theoretical and Applied Mechanics (ITAM), Russia

AbSTRACT

Today the USA is the only nation, which succeeded landing a rover on the Mars surface. The first European attempt for landing on the Mars with Beagle2 lander in 2003 was unfortu-nately not successful. The reason of the loss of Beagle2 after its separa-tion from the Mars Express orbiter is still unknown. The success of future exploration missions like Mars Entry and Landing strongly depends on the technological readiness level in mis-sion analysis, definition of loads, vehicle design and qualification of components in ground facilities. Mission analysis and load definition require reliable data on the Martian

atmosphere at nominal conditions and at higher temperatures representative for the aero-capture and entry phases of the mission [1]. When entering a planetary atmosphere the high speed deceleration of blunt bodies leads to a strong bow shock formation in front of a capsule and heating of the gas and subsequent heating of the vehicle. The internal structure of the vehicle is thermally protected using a Thermal Protection System (TPS). Most of the capsules use a TPS based on abla-tion materials. figure 1 shows major possible physical processes around a capsule in Martian atmosphere. The modelling of complex chemical pro-cesses in the boundary layer flow around the ablation and inside the ablation materials is very challeng-ing and needs reliable experimental data gained by means of sophisti-cated measurement techniques. In order to extract the influence of dif-ferent parameters on the aerothermal heating during Martian entry a study on selected and well defined materi-als is an important step.

Therefore the main objective of SACOMAR is the experimental and numerical study of gas-surface interaction phenomena in the high enthalpy flow field behind the bow shock in front of a model at Martian entry flow conditions. The improve-ment of physical modelling using

Technologies for Safe and Controlled Martian Entry (SACOMAR)

431T E C H N O L O G I E S F O R S A F E A N D C O N T R O L L E D M A R T I A N E N T R Y ( S A C O M A R )

Figure 1. High temperature non-equilibrium flow phenomena around a capsule.

experimental data and its implemen-tation into numerical simulation codes is essential to understand and inter-pret the physical processes. At the end the project will allow to estimate the aerothermal loads on the vehicle more accurately. Main activities of the pro-ject are:

– Definition of requirements on exper-iments, modelling and CFD codes using realistic Mars mission profiles

– Experiments on the measurement of flow parameters in the free stream and behind the shock and stagnation point heat flux rate

– Improvement of existing physical models with respect to non-equilib-rium effects, transport properties and gas-surface interaction chemistry

– Implementation of improved physi-cal models into the CFD codes and simulation of experiments

– Synthesis of the data and extrapola-tion to flight

AcHieVed resuLts

According to the workplan of SACOMAR in the early phase of the project, the following main activities have been performed:

– Overview on the current physico-chemical modelling techniques for CO2 high enthalpy flows, includ-ing transport properties, gas phase kinetics and surface chemistry, their status and chances for improvement.

– Identification of type of CFD simu-lations needed to gather informa-tion about the implementation of the developed models, and of a standard method for data exchange,

– Definition of the requirements on the experimental activity to be

432T E C H N O L O G I E S F O R S A F E A N D C O N T R O L L E D M A R T I A N E N T R Y ( S A C O M A R )

performed to exploit the Martian atmosphere’s relevant properties in a typical entry trajectory,

– Definition of criteria for the valida-tion of numerical simulations results over experimental data, and of their use for the extrapolation to flight task.

Complete details of this work are provided in the SACOMAR delivera-ble in the report on Requirements on Modelling and Simulation [2].

Following these requirements and after a detailed analysis of the perfor-mance of testing facilities and their comparison with the important trajec-tory data points of the Exomars entry phase, a test plan has been defined. With reference to the EXOMARS tra-jectory four test conditions were identified which enable direct facil-ity-to-facility comparison. Gas-phase chemistry in Martian atmosphere and its influence on heat fluxes is a topic that itself is dominated by com-plex physico-chemical phenomena. Therefore, the geometry of the model that is used for heat flux evaluation should not introduce major addi-tional complexity. It should be kept as simple as possible to enable best possible link between heat flux meas-urements on one side and the meas-ured free stream properties as well as modelling parameters and correlated numerical results on the other side.

Vehicles that are supposed to enter Martian atmosphere are designed as blunt bodies which in an hyper-sonic flow field cause the formation of a strong bow shock on the front side generating sub stantial heating of the gas and subsequently of the vehicle. Of course, the test configuration should

reflect this scenario. A well-suited sim-plification of a cap sule-like geometry is a flat-faced cylinder. Its principal geom-etry is sketched in figure 2. Compared to other blunt geometries, a flat-faced cylinder provides the largest possi-ble shock stand-off distance for the hypersonic test facilities (HEG, IT-2 and L2K). By that, it maximizes the experimental possibilities of prob-ing the gas properties in the shock layer. The flat-faced cylinder geom-etry will be used for all facility tests. To avoid grid related problems related to sharp edges during numerical simu-lation the edge of the cylinder should be rounded. Due to individual con-straints, which either arise from facility size or from measurement techniques, a fully identical test geometry cannot be used in all facilities. For the plas-matron facilities the cylin der’s diame-ter will be D = 50 mm and the edge radius re = 11.5 mm. At almost all long duration high enthalpy facilities corre-sponding models and model holders are available which keeps the manu-facturing necessities for the SACOMAR test programme small and provides good chances for an easy comparison to already existing data from different atmospheres.

Finally, a test matrix was defined spec-ifying test conditions in terms of total enthalpy and Pitot pressure for each test facility. Based on experiences and capabilities of the facilities, measure-ment techniques were specified to be applied for heat flux measurements and flow characterization [3]. As shown in figure 3 the most critical trajec-tory points with respect to aerothermal loads are selected for the simulation. The test matrix and test models includ-ing the instrumentation have been described in the SACOMAR report ‘Test plan for Experiments’ [3].

433T E C H N O L O G I E S F O R S A F E A N D C O N T R O L L E D M A R T I A N E N T R Y ( S A C O M A R )

Figure 2. The model geometry and a SiC model in the hypersonic high enthalpy flow.

Figure 3. Selected SACOMAR trajectory points.

Parallel to the experiments a review of physico-chemical CO2 modeling and recommendation for improvements have been carried out [4]. During entry the dissociated atoms in the shock layer reach the surface of the body and tend to recombine at the surface releasing the dissociation energy which contrib-utes to the overall heat flux into the Thermal Protection System. The mech-anisms governing catalytic recombina-tion are still poorly understood, in part due to difficulties in performing sur-face diagnostics at realistic pressure

and temperature conditions. One com-monly used model assumes the limit-ing case of a non-catalytic surface. This assumption leads to the lowest possi-ble heating rates, and therefore is not often employed for design purposes due to its non-conservative nature. Another limiting case is the fully-cat-alytic modelling of the gas mixture at the wall to local thermochemical equi-librium. Sometimes partially-catalytic modelling with the possibility to con-sider different recombination efficien-cies for the chemical surface reactions

434T E C H N O L O G I E S F O R S A F E A N D C O N T R O L L E D M A R T I A N E N T R Y ( S A C O M A R )

is employed. This requires the proper selection of values for different recom-bination probabilities. As demonstrated by Marshall [5] under test conditions at room temperature, for recombination on quartz, platinum, constantan, stain-less steel and chrome surfaces, atomic oxygen recombination O+O to molecu-lar oxygen is the dominant mechanism, while other models consider only CO+O recombination or both recombination processes occurring at the same time but with different efficiencies.

In framework of the project, the tests were performed in IPG-4 facility in dissociated CO2 flows for the pres-sure and enthalpy conditions close to the ones prescribed by the SACOMAR test matrix for IPM: P=80 and 40 hPa, he=13.8 and 9.0 MJ/kg [6]. The tests were made with use of a lengthened

discharge channel that consists of the usual quartz tube equipped with the special segmented water-cooled noz-zle with exit diameter 40 mm and length 80 mm in order to decrease flow enthalpy and to improve quality of subsonic flow at low generator power. Calculation of the heat flux envelopes was made on the basis of numerical solution of the nonequilibrium bound-ary layer equations with account for finite layer thickness in framework of the standard IPM model of sur-face catalysis. The results of heat flux measurements and calculated data for different tested materials are shown in figure 4 by the symbols: triangle, rhomb, square are used for water-cooled calorimeters with the surface made of silver, copper, stainless steel, and the circle shows the heat flux to the quartz probe [7].

Figure 4. Heat flux envelope and data for testing materials at the CO2 test regime: P=80 hPa, Nap=40.4 kW, Z=40 mm, he=14.0 MJ/kg.

435T E C H N O L O G I E S F O R S A F E A N D C O N T R O L L E D M A R T I A N E N T R Y ( S A C O M A R )

The heat flux values are calculated on the basis of the simple model of sur-face catalysis in dissociated CO2 mix-ture by using the effective probability gw introduced to describe in total the effect of catalytic reactions. gw = gwO

= gwCO = gwC. Values of gw are scaled in Figure 4 on the right hand side axis. Values of gw calculated for the tested materials by the measured heat fluxes qw(Cu), qw(steel), qw(SiO2) are presented in the Table 1 for the four test regimes.

p [hPa] N_ap [kw]

Z [mm]

h_e [Mj/kg]

γ_w (cu) γ_w (steel)

T_w [sio2)

γ_w (sio2)

80 40.4 40 14.0 2,21 E-2 8,43 E-3 755 7,84 E-3

80 34.0 40 8.8 1,93 E-2 1,07 E-2 599 4,97 E-3

40 35.0 72 14.4 1,87 E-2 1,13 E-2 606 5,71 E-3

40 35.0 122 9.5 2,39 E-2 8,77 E-3 500 3,42 E-3

Table 1. Effective probability gw determined for the tested materials (copper, stainless steel, quartz) for the four test regimes.

CONCLUSIONS

All experimental activities of the SACOMAR project have been com-pleted. Comparative tests were car-ried out in European and Russian high enthalpy facilities. It seems that in contrast to the Earth’s atmosphere the Martian atmosphere silver sur-face is more catalytic than the cop-per. The SiO2 coating has even lower catalycity than silver, copper and steel. Modelling activities are in pro-gress and their output will be used for the final CFD simulation of the experiments. SACOMAR provides par-tially very unique results concerning the role of the surface catalycity on the heat flux rate in Martian atmos-phere. The work concerning the crea-tion of an electronic library containing recombination coefficients and energy accommodation coefficients, which are relevant for the surface reactions and to hypersonic re-entry flow fields in a CO2/N2 atmosphere, is in progress. This data will be used for the synthe-sis of the experimental and numerical data and extrapolation to flight.

REFERENCES

EXOMARS 09 DM, Mars Exobilogy Descent Module, CFD Study Report, ESA-ESTEC, CFD-14©, DEc. 2002, (see ftp://estec.esa.nl/pub/aurora/Rover/CDF-14(C), ExoMars09DM_Study_Report_Dec2002.pdf for an electronic copy).

Mareschi, V.; Requirements on Modelling and Simulation, SACOMAR, Del. No. 4.1, April 2001.

Esser, B.; Gülhan, A.; Test plan for Experiments, SACOMAR. Del. No. D5.1, June 2011.

Nöding, P.; Review of Physico-Chemical CO2 Modelling and Recommendation for Improvement, SACOMAR. Del. No. D6.1, November 2011.

Marschall, J.: Experimental Determination of Oxygen and Nitrogen Recombination Coefficients at Elevated Temperatures Using Laser-Induces Fluorescence. 1997

436T E C H N O L O G I E S F O R S A F E A N D C O N T R O L L E D M A R T I A N E N T R Y ( S A C O M A R )

National Heat Transfer Conference, Baltimore, MD, 1997 (AIAA Paper 97-3879).

Kolesnikov, A.F., Gordeev, A.N., Vasilevskii, S.A.: Results of Experimental Study in the IPG-4 Facility. SACOMAR. Del. No. D5.4. November 2011.

Kolesnikov, A.; Vasil’evskii, S.; Levitin, A.; Gordeev, A.; Report and library on surface chemistry, SACOMAR. Del. No. D6.4. January 2012.

CHAPTER 43

Author: Cristiano Calligaro

consortium members: RedCat Devices, Italy; University of Milano, Italy; University of Padova, Italy; Tower Semiconductors, Israel; University of Jyvaskyla, Finland; University of Cyprus, Cyprus; University of Uppsala, Sweden; University of Santiago de Compostela, Spain

AbSTRACT

The project aims to realise a strong methodology for the development and design of non volatile memories using standard CMOS silicon process actu-ally used for consumer electronics. Since standard silicon memories, such as other silicon devices for consumer market, fail under irradiation, two dif-ferent approaches are envisaged: the first one is to develop specific techno-logical processes able to sustain heavy ions and other charged particles, while the second one is more devoted to use specific design and architectures. The first approach, also known as Radiation Hardening by Process (RHBP), is very expensive and tied to technological issues, which can can only be man-aged by large companies and, due to

the very low amount of final devices to be realised, very difficult to follow (great deal of effort for a small niche market). The second approach, also known as Radiation Hardening by Design (RHBD), takes the best from standard CMOS con-sumer processes and, using very accu-rate design methodologies, mitigates radiation effects on silicon processes.

Semiconductor memories, among rad hard integrated circuit scenario, are one of the most critical topic and non vola-tile memories in particular.

Actually both volatile and non volatile memories are integrated using stand-ard processes and standard architec-tures acting on one side on rad hard packages and on the other side on the level of qualification of the single die. This means that the final device is typ-ically Rad-Tolerant and not Rad-Hard and failure during mission is avoided using Error Correcting Code techniques, including redundancy (more devices of the same type are used in voting man-ner) at board level.

The basic goal of the project is to give a methodology for the development of a generic rad hard non volatile mem-ory with features actually used in con-sumer market and realise a prototype

SkyFlash Development of Rad Hard non volatile Flash memories for space applications

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(1Mbit Flash Memory) in order to vali-date the approach.

introduction

SkyFlash is focused on the develop-ment of a strong rad-hard by design (RHBD) methodology for non volatile semiconductor memories to be used in space applications taking the best from standard CMOS (Complementary Metal-Oxide Semiconductor field effect transistors) submicron (180nm) silicon processes. The main ideas at the base of the project are the following:

1. Development of rad-hard inte-grated silicon devices acting on the design more than on fabrica-tion process

2. Application of non volatile memory technology (floating gate/floating trap cells) in space applications

A key feature of integrated circuits des-tined to be used for space applications is that of radiation tolerance. Beyond the atmosphere (meaning in electronic equipment for satellites, probes or more in general spacecrafts) many particles (electrons, protons, high energy ions) collide with silicon devices releasing energy and possibly disrupt operations.

There are two main effects of radia-tions on silicon devices:

1. Long term effects (TID, Total Ionizing Dose)

2. Short term and randomic effects (SEE, Single Event Effects)

The first one, TID, gives a progres-sive degradation of devices thus tak-ing the chip to a general malfunction

after months or years while the second one, SEE, is strongly dependent on the amount (and nature) of energized parti-cles and in the worst case scenarios can be destructive.

Non volatile semiconductor memo-ries in space market have been faced with old antifuse technologies till now; this means that media can be writ-ten (or burned) before the mission and only read later on. This kind of device is called OTP (One Time Programmable) memory and is typically used for star maps or boot software storage and is the only one actually chosen by the space market.

The real breakthrough for the introduc-tion of programmable and erasable non volatile memories is the introduc-tion of floating gate (or floating trap) memory cells.

Many problems arise on this well known technology since the 1960s but never used for rad-environments. The first one is the retention of the bit: a float-ing gate cell stores electrons in a sand-wich of polysilicon (or silicon nitride for floating trap, also known as charge trap) surrounded by silicon dioxide, thus lead-ing to a variable threshold proportional to the amount of electrons trapped. The exposure of the cell to an amount of radiation can move, during time, the threshold itself so changing the bit. Moreover, in terms of single events, a high energy particle can collide with a floating gate and if the energy is suf-ficiently high, it is possible that trapped electrons can gain enough energy to migrate outside their traps.

It is worth mentioning that even if these aspects had been studied, the technology and the methodology adopted would be commercial.

442S K Y F L A S H D E V E L O P M E N T O F R A D H A R D N O N V O L A T I L E F L A S H M E M O R I E S F O R S P A C E A P P L I C A T I O N S

seMiconductor rAdiAtion HArdeninG tecHniQues

Silicon devices radiation hardening can be seen from two points of view: a) process and b) design. The first one, Radiation Hardening by Process (RHBP), takes into account the base technology to be used for the devel-opment of silicon base integrated cir-cuits, while the second one, Radiation Hardening by Design (RHBD), applies dedicated design methodologies for the same purpose.

RHBP falls under large silicon found-ries efforts, but more recently RHBD has taken place thanks to a grow-ing knowledge coming from research institutes (e.g. CERN), not directly related to such foundries. Moreover RHBD is considerably less expensive than RHBP processes that, in every phase, must be managed strictly in order to comply with the require-ments of space radiation resistance. So, starting from a standard and con-solidated silicon process, a reason-able resistance to radiation can be achieved focusing on RHBD.

RHBD can be divided into different approaches depending on the level of

complexity with which silicon device is considered. In a top-down approach the top level is represented by Radiation Hardening by Architecture (RHBD-AL, Radiation Hardening by Design at Architecture Level) where, before sin-gle blocks development, the whole chip is floorplanned and considered in its entirety. Starting from power sup-ply distribution macro-blocks are built (and eventually made redundant in order to reduce the impact of radia-tion and energy released in silicon dice.

In RHBD-AL the entire architecture must be considered taking in mind that heavy ions can strike, in a random way, every part of the device. If the impact involves a single memory cell we may have an error but if the same impact involves, for example, a row decoder we may have more errors along a word line (at least 8 if we consider the byte) thus leading to a proliferation of errors. RHBD-AL methodologies suggest repli-cating row decoders to reduce on one side the probability of errors and on the other the entity. So, architecturally speaking, the array can be divided in more sub-arrays, each one independ-ent to the others (autonomous row and column decoding).

Figure1. Radiation Hardening Top Down Approach

443S K Y F L A S H D E V E L O P M E N T O F R A D H A R D N O N V O L A T I L E F L A S H M E M O R I E S F O R S P A C E A P P L I C A T I O N S

Figure 2. Typical array organization following RHBD-AL techniques

Radiation Hardening by Circuit (RHBD-CL, Radiation Hardening by Design at Circuit Level) is the typical domain of analog semiconductor designers. In this domain the single block or circuit such as oper-ational amplifiers, input/output buffers, differential stages, multiplexers, NANDs, NORs or even the single inverter are taken into account. At this level many precautions must be taken. First of all avoiding feedback loops (in particu-lar positive ones) or, if needed, con-trolled by alternative topologies. A good example could be the latch as the core of a Flip-Flop or as the core of a SRAM cell. As known in literature two invert-ers are connected the output of the first to the input of the second thus forming a positive feedback loop and so lead-ing to a metastable device with two different states which can be obtained through other circuits stimulating in the right way the ensemble. Nevertheless a high energy particle can collide with the latch and, if enough energy is released, it may change one stable state with the other, acting just like a stimulat-ing circuit. To avoid this problem many

solutions can be used such as the con-nection of a capacitor in parallel to the feedback loop (Miller Capacitor) in order to enhance stability of each state, or a resistor in the same feedback loop thus reducing the gain and giving enough time to the inverter pair to release the extra-energy provided by the particle.

Radiation Hardening by Layout (RHBD-LL, Radiation Hardening by Design at Layout Level) is the domain of layout designers. According to the architecture floor planned and using libraries of elementary blocks the final chip is obtained drawing every level of metal, polysilicon and defining active areas of transistors.

This domain is very tied to semiconduc-tor physics and radiation effects must be considered either in short time terms (SEE, Single Event Effect) and long time terms (TID, Total Ionizing Dose).

One of the well known degradation effects is the decrease of threshold voltage in n-channel MOS transistors

444S K Y F L A S H D E V E L O P M E N T O F R A D H A R D N O N V O L A T I L E F L A S H M E M O R I E S F O R S P A C E A P P L I C A T I O N S

due to silicon dioxide impurity; some traps can in fact retain charges (holes) and if these trap areas are sufficiently close to transistor channels they can vary the threshold of the transistor, thus leading to a very elementary block having a behavior changing in time.

The solution could be the physical design of a transistor not presenting edges in the direction of thick oxide: this is called EdgeLess Transistor (ELT) or Annular Transistor or Ring Transistor (due to its typical shape). ELTs are very robust to total dose effects but, unlike traditional stacked transistors, they occupy large areas, in particular when minimum lithogra-phy is required. ELTs represent a typi-cal RHBD-LL solution.

SKyFLASH FIRST TEST VEHICLES

In order to obtain the final proto-type containing the expected 1Mbit flash memory several test vehicles are foreseen. Since a rad-hard repro-grammable NVM must contain circuits devoted to gain access to the memory

array (row and columns decoders) in RC27FSKY1 has been integrated a small matrix array of NV cell with row decoding final stages with a small multiplexer. Rad-hard PADs contain-ing ELT transistors for ESD has been designed to mitigate the effects in terms of total dose.

The test chip is a 1mm x 1mm with PAD rings and all final structures fore-seen in final silicon dice and has been integrated using a commercial 180nm CMOS flow from Tower Semiconductors.

Samples will be completed by the fab-rication line on April 2012 and tested under X-Ray and Heavy Ions on May and June 2012.

CONCLUSIONS

SkyFlash project on this fourth month of life cycle has delivered a first test vehicle for testing purposes. All radi-ation hardening by design techniques foreseen have been integrated in spare parts in order to evaluate the behav-ior of CMOS 180nm standard process under X-Ray and Heavy Ions.

Figure 3. Rad-hard cell ensemble following RHBD-LL techniques

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Figure 4. RC27FSKY1 Test Vehicle

REFERENCES

  R01. G. Anelli et Al. “Radiation tolerant VLSI circuits in standard deep submicron CMOS technologies for the LHC experiments: practical design aspects”, IEEE Trans. Nucl. Sci., vol. 46, no. 6, pp. 1690-1696, Dec. 1999.

  R02. A. Johnston, “The influence of VLSI technology evolution on radiation-induced latchup in space systems”, IEEE Trans. Nucl. Sci., vol 43, no. 2, pp. 505-521, Apr. 1996.

  R03. C. Calligaro, V. Liberali, A. Stabile “A Radiation Hardened 512 Kbit SRAM in 180nm CMOS Technology”, 16th IEEE International Conference on Electronics, Circuits, and Systems (ICECS), Hammamet (Tunisia), Dec. 2009, pp.655-658.

  R04. T. Hoang et Al. ”A Radiation Hardened 16-Mb SRAM for Space Applications”, IEEEAC, paper no. 1572, December 21, 2006.

  R05. C. Calligaro, V. Liberali, A. Stabile “Design of a Rad-Hard Library of Digital Cells for Space Applications”, 15th IEEE International Conference on Electronics, Circuits, and Systems (ICECS), Malta, Sep. 2008, pp.149-152

  R06. C. Calligaro, V. Liberali, A. Stabile, M. Benigni “Design of Rad-Hard SRAM Cells: A Comparative Study”, 27th International Conference on Microelectronics (MIEL2010), Nis (Serbia), May 2010.

  R07. S. Gerardin, M. Bagatin, A. Paccagnella, G. Cellere, A. Visconti, E. Greco “Heavy-Ion Induced Threshold Voltage Shift in Sub 70 nm Charge-Trap Memory Cells” RADECS2010 Conference, 20-24 Sept. 2010, Langenfeld, Austria, Proceedings S3-2.

CHAPTER 44

Authors: Jorge Barcena, Claudio Badini, Sandro Gianella, Volker Liedtke, Konstantina Mergia, Alberto Ortona and Christian Wilhelmi

consortium members: Tecnalia Research and Innovation, Spain; Politecnico di Torino, Italy; Erbicol SA, Switzerland; Aerospace & Advanced Composites GmbH, Austria; National Centre for Scientific Research ‘Demokritos’, Greece; SUPSI, Switzerland; EADS Innovation Works, Germany

AbSTRACT

The aim of this project is the develop-ment of ceramic composites structures, such as hot parts of space vehicles for orbital re-entry, which are needed for applications in extreme space environ-ments where oxidative and high tem-perature resistant components are required. The proposed thermal pro-tection systems (TPS) solution is based on a novel reusable and Proof-of TPS architecture which can withstand the extreme environment conditions during earth atmospheric re-entry. Smartees aspires to create a strong collabora-tion among the seven partners (coming from six different European countries) that comprise the consortium. A spe-cific strategy for the exploitation of the intellectual property will be carried out,

to create a European supply chain of the TPS component. and special consid-eration will be given to the relationship among the industrial partners: EADS, Erbicol and AAC (as end-users and SMEs respectively). Moreover bilateral collab-oration will be established with other non-space sectors (nuclear, automotive) that have a strong potential of technol-ogy transfer of the results of the pro-ject. Smartees targets the development of advanced ceramic composites struc-tures for reusable thermal protection systems. A non-dependent access to the critical space technology is required at European level. Therefore, the aim of Smartees is the achievement of a European autonomous technology for thermal protection systems (TPS). The main objective is to achieve a proof-of TPS design. This will be the result of the completion of the validation of the TPS performance and the achievement of a Technology Readiness Level of TRL 4.

AcHieVed resuLts

The technical approach is focused on the development of a multilayer con-cept based on high temperature ceram-ics (HTCs) and ultrahigh temperature ceramics (UHTCs) with tailored prop-erties. Their joining processes to con-ventional structural ceramic matrix composites (CMCs) or novel porous sand-wich structures, and the final attachment

Smartees: Multifunctional Components for Aggressive Environments in Space Applications

447S M A R T E E S : M U LT I F U N C T I O N A L C O M P O N E N T S F O R A G G R E S S I V E E N V I R O N M E N T S I N S P A C E A P P L I C A T I O N S

Figure 1. Modelling of ErbiSiC ceramic foams (Erbicol S. Gianella). Credit: SUPSI (A. Ortona)

to metallic structure. A proof-of TPS design is being provided within the project, having a real ongoing re-entry mission as reference for the project.

The project consists of six differ-ent technical work packages for the selection of a mission profile, defi-nition of specifications and require-ments of that mission, procurement and manufacture of the different parts of the TPS, characterisation of materials, thermo-mechanical model-ling and simulation, final TPS design and re-entry testing. An iterative pro-cess among the outputs of each work package is being followed to obtain a proof-of final design.

The TPS novel design incorporates advanced ceramic composites with tailored properties and porous struc-tures in order to obtain a unique TPS architecture. The TPS solution is being aided by material modelling. A com-puted tomography technique will be used to obtain a real model of each part of the system. This will help to obtain an accurate and realistic sim-ulation of the insulation capability

and performance of the system. The thermo-mechanical characterisa-tion of this part will be carried out over different temperature ranges (RT-1 600 ºC) and comprises the measurement of flexural strength and modulus, coefficient of thermal expansion, thermal conductivity and diffusivity, and so on. The output of this work will help to calculate critical design parameters in order to obtain a proof-of TPS technological sample.

In a final stage the technology sam-ple will be tested in a relevant ground facility simulating the re-entry condi-tions. The testing will determine the fundamental performance and the degradation mechanisms. This final step will give insight into the overall performance of the TPS, identify pos-sible modes of failure, and assess the efficiency of the thermal insula-tion and the heat fluxes into the sub-structure of a spacecraft. The ground testing outputs will be reviewed in comparison with the outputs of TPS requirements and environment speci-fications where the final milestone of the project will be established.

448S M A R T E E S : M U LT I F U N C T I O N A L C O M P O N E N T S F O R A G G R E S S I V E E N V I R O N M E N T S I N S P A C E A P P L I C A T I O N S

Figure 2. AAC’s Re-Entry Chamber. Credit: V. Liedtke

CONCLUSIONS

A novel TPS concept will be developed in the framework of the Smartees pro-ject, with the aim of developing a space critical technology with a high TRL able to compete with the technologies available outside Europe. Europe will benefit from the results of Smartees by improving its access to space crit-ical technologies. The next generation launcher (NGL) will take advantage of this concept. Another important asset is the contribution to the crea-tion of an independent industrial sup-ply chain. Space exploration in general may take advantage of the novel reus-able TPS technologies. There is a high potential for its use in cargo and crew space return vehicles, i.e. for a cost effective, safe and reliable return from the international space station (ISS). It is expected that the space indus-trial and scientific community will take

advantage of the results of the project in a way to create an autonomous sup-ply chain of the component.

REFERENCES

  Barcena, J., Coleto, J., Zhang, S. C., Hilmas, G. E. and Fahrenholtz, W. G., ‘Processing of Carbon Nanofiber Reinforced ZrB2 Matrix Composites for Aerospace Applications’, Advanced Engineering Materials, 12, 2010, pp. 623–626.

  Biamino, S., Liedtke, V., Badini, C., Euchberger, G., Huertas Olivares, I., Pavese, M., Fino, P., ‘Multilayer SiC for thermal protection system of space vehicles: Manufacturing and testing under simulated re-entry conditions’, J. Eur. Ceram. Soc., 28, 2008, pp. 2791–2800.

449S M A R T E E S : M U LT I F U N C T I O N A L C O M P O N E N T S F O R A G G R E S S I V E E N V I R O N M E N T S I N S P A C E A P P L I C A T I O N S

  European Non-Dependence on Critical Space Technologies: EC-ESA-EDA List Of Urgent Actions For 2009, EC-ESA-EDA Joint Task Force. www.cordis.europa.eu

  Liedtke, V., ‘Ground Testing of Re-Entry Materials — Methods, Challenges, and Significance for Application, ExtreMat Workshop ‘Space Materials for

High Temperature Applications’, Politechnico di Torino (I), 26/27 June 2007.

  Ortona, A., Pusterla, S., Fino, P., Mach, F. R. A., Delgado, A., Biamino, S., ‘Aging of reticulated Si-SiC foams in porous burners’, Advances in Applied Ceramics, 2010, Vol. 109, No 4, pp. 246–251.

CHAPTER 45

Authors: Stephan Schiller, Axel Görlitz, Alexander Yu. Nevsky, Soroosh Alighanbari, Sergey Vasilyev, Charmel Abou-Jaoudeh, Gregor Mura, Tobias Franzen, Uwe Sterr, Stephan Falke, Christian Lisdat, Ernst-Maria Rasel, André Kulosa, Sebastien Bize, Jérome Lodewyck, Guglielmo M. Tino, Nicola Poli, Marco Schioppo, Kai Bongs, Yesphal Singh, Patrick Gill, Geoffrey Barwood, Yuri Ovchinnikov, Jürgen Stuhler, Wilhelm Kaenders, Claus Braxmaier, Ronald Holzwarth, Alessandro Donati, Steve Lecomte, Davide Calonico, Filippo Levi

consortium members: Heinrich-Heine-Universität Düsseldorf, Germany; Physikalisch-Technische Bundesanstalt, Germany; Leibniz Universität Hannover, Germany; Observatoire de Paris, France; Università di Firenze and LENS, Italy; University of Birmingham, the United Kingdom; National Physical Laboratory Teddington, the United Kingdom; TOPTICA Photonics AG, Germany; EADS Astrium Friedrichshafen, Germany; Menlo Systems GmbH, Germany; Kayser Italia S.r.l., Italy; Centre Suisse d’Electronique et de Microtechnique SA, Switzerland; Istituto Nazionale di Ricerca Metrologica, Italy

AbSTRACT

The use of ultra-precise optical clocks in space (‘master clocks’) will allow for a range of new applications cover-ing the fields of fundamental physics (tests of Einstein’s theory of General Relativity, time and frequency metrol-ogy by means of the comparison of distant terrestrial clocks), geophysics (mapping of the gravitational poten-tial of Earth), and astronomy (provid-ing local oscillators for radio ranging and interferometry in space).

Within the ELIPS-3 programme of ESA, the ‘Space Optical Clocks’ (SOC) project aims to install and to operate an opti-cal lattice clock on the International Space Station (ISS) towards the end of this decade, as a natural follow-on to the Atomic Clock Ensemble in Space (ACES) mission (which is based on a cesium microwave clock), improving its performance by at least one order of magnitude.

The payload is planned to include an optical lattice clock, as well as a fre-quency comb, a microwave link, and an optical link for comparisons of the ISS clock with ground clocks located in several countries and continents.

Towards Neutral-atom Space Optical Clocks (SOC2): Development of high-performance transportable and breadboard optical clocks and advanced subsystems

453TOWARDS NEUTRAL-ATOM SPACE OPT ICAL CLOCKS (SOC2) : DEVELOPMENT OF H IGH-PERFORMANCE TRANSPORTABLE

Undertaking a necessary step towards optical clocks in space, the EU-FP7-SPACE-2010-1 project no 263500 (SOC2) (2011–15) will develop two ‘engineering confidence’, accurate transportable lattice optical clock demonstrators having relative fre-quency instability below 1×10-15at 1 s integration time and relative inaccu-racy below 5 × 10-17. This goal perfor-mance is about 2 and 1 orders better in instability and inaccuracy, respec-tively, than today’s best transportable clocks. The devices will be based on trapped neutral ytterbium and stron-tium atoms. One device will be a breadboard. The two systems will be validated in laboratory environments and their performance will be estab-lished by comparison with laboratory optical clocks and primary frequency standards.

In order to achieve the goals, SOC2 will develop the necessary laser sys-tems — adapted in terms of power, linewidth, frequency stability, long-term reliability, and accuracy. Novel solutions with reduced space, power and mass requirements will be imple-mented. Some of the laser systems will be developed towards particularly high compactness and robustness lev-els. Also, the project will validate cru-cial laser components in relevant environments. This paper will give an overview of the project and of the results achieved during the first year.

introduction

The principle of an optical lattice clock is shown in Figure 1. A laser inter-rogates an ensemble of ultra-cold atoms, by exciting them to a long-lived atomic state via the clock tran-sition. The atoms are trapped inside

a standing-wave laser field (‘optical lattice’) and possess a temperature of a few micro-Kelvin. The interroga-tion results in a signal proportional to the absorption of the laser light, which depends on the laser frequency ν. The signal is maximum when the laser fre-quency coincides with the centre of the atomic resonance n0. With a feedback control, the laser frequency ν is con-tinuously kept tuned on n0. The result-ing ultra-stable laser optical frequency n0 can be converted to an equally sta-ble radio-frequency by means of a fre-quency comb.

The implementation of a lattice clock is shown in Figure 1, top right. An atomic beam produced by an oven travels towards the right through a spatially varying magnetic field. In it, the atoms are slowed down by a laser beam (blue arrow, from laser subsystem BB 1, see Figure 1 bot-tom) that finally nearly stops and traps the atoms inside the experimen-tal chamber (square), in the 1st stage of a magneto-optical trap (MOT). Subsequently, they are cooled further to a lower temperature of a few tens of micro-Kelvin in a 2nd MOT stage by another laser subsystem (BB 2). In a third step, they are then transferred to an ‘optical lattice’ made of counter-propagating laser waves generated by a third laser subsystem (BB 4). Since the lattice potential ‘wells’ are deeper than the thermal energy of the atoms, they are trapped in the potential min-ima. There, the atoms are localised spatially in one dimension to well below one wavelength of the clock laser (BB 5) and this condition leads to an excitation spectrum free of 1st order Doppler spectral broadening or shift. Perturbing effects of the lattice light field on the atomic energy levels of the clock transition are minimised

454TOWARDS NEUTRAL-ATOM SPACE OPT ICAL CLOCKS (SOC2) : DEVELOPMENT OF H IGH-PERFORMANCE TRANSPORTABLE

Figure 1. Top left, principle of an optical atomic clock based on atoms trapped by laser light. Top right, schematic of a lattice clock apparatus. Red: laser beams for 2nd stage cooling and trapping in the MOT. Orange–red: lattice laser standing wave; yellow: clock laser wave. Inset: variation of the potential felt by the atoms due to the lattice laser. Bottom, subsystems of a lattice optical clock.

by choosing a so-called ‘magic’ wave-length [Katori 2003, Porsev 2004]. The clock transition excitation is per-formed by the clock laser (BB 5). The laser subsystem BB 3 furnishes auxil-iary laser light.

The subsystems of a lattice clock are shown in Figure 1 bottom. The laser light produced by the laser breadboards is transported via optical fibers to diag-nostic and frequency stabilisation units, to the frequency comb, and to the vac-uum chamber containing the atoms.

The work of this project involves devel-oping all subsystems, in part in form of compact breadboards, and to inte-grate them into two transportable

clocks, one operating with strontium (Sr), the other with ytterbium (Yb). 87Sr and 171Yb are currently considered as the most promising isotopes.

AcHieVed resuLts

Laser system for Strontium clock

The design of the laser system for the Sr lattice clock is modular, and all modules are connected by optical fib-ers to the vacuum apparatus. This choice ensures high stability and reli-ability needed for long-term opera-tion of a clock. Moreover, the modular approach allows for independent test-ing of the subcomponents and, during

455TOWARDS NEUTRAL-ATOM SPACE OPT ICAL CLOCKS (SOC2) : DEVELOPMENT OF H IGH-PERFORMANCE TRANSPORTABLE

the course of the project, simple replace-ment of components by more advanced components. The developments in the field of commercial lasers have produced impressive improvements in size, mass, stability and reliability of lasers and other optoelectronic components. The result is that the complete laser system for the Sr lattice optical clocks is based on off-the-shelf commercial components of moder-ate size and high reliability, such as diode lasers. The specifications are given in Table 1.

Based on ruggedised commercial sys-tems, the lasers (TOPTICA) have been

integrated into compact subsystems where several output beams, controlled in amplitude and frequency via acousto-optical modulators, are produced: a main output to the atomics package, an out-put for the laser frequency stabilisation subsystem, and other additional ser-vice outputs. All outputs are provided in single-mode, polarisation-maintaining fibers.

The following laser sources have been developed and have been integrated with the atomic package (see Sec. 3): a fre-quency doubled diode laser (461nm) for 1st cooling (BB 1), a high-power 813 nm

Laser breadboard wavelength frequency stability size in cm3, mass

Power at fiber outputs

BB 1: Cooling #1 461 nm ECDL+SHG

1 MHz 60×45×10 20 kg

140 mW to distribution breadboard

BB 1: Cooling #1 distribution

461 nm 1 MHz 30×45×10 12 kg

50 mW MOT,30 mW slower, 1 mW setection,1 mW (IR) FSS

BB 2: cooling #2 689 nm ECDL

< 1 kHz in 1 h, linewidth < 1 kHz with additional FM

60×45×12 20 kg

10 mW MOT , 1 mW FSS 1 mW to stirring breadboard

BB 2: Stirring and spin polarisation

689 nm ECDL

Offset-phase-locked to 689 nm cooling

30×45×10 10 mW MOT, 2×1 mW spin polarization

BB 3: Repumper 707 nm, 679 nm ECDL

FM +/- 3 GHz with a few kHz modulation frequency; center: 100 MHz

30×45×10, 12 kg

2 mW each wavelength to MOT, 1 mW to FSS

BB 4: Lattice 813 nm ECDL

< 10 MHz in 10 h 30×45×10 12 kg

>200 mW to atomics, 1 mW to FSS

BB 5: Clock laser 698 nm ECDL

<1 Hz 60×45×12 20 kg

2 mW to atomics, 2 mW to comb, 0.5 mW to cavity, 1 mW to FSS

BB 5: Clock cavity 698 nm thermal noise 5×10-16

55×55×55, 30 kg

FSS: Frequency stabilization system

all, excluding 698 nm

to levels indicated above

30×20×10, 10 kg

fiber input for the above fiber outputs

Table 1. Detailed specifications of the laser and stabilisation subsystems for the Sr clock.

456TOWARDS NEUTRAL-ATOM SPACE OPT ICAL CLOCKS (SOC2) : DEVELOPMENT OF H IGH-PERFORMANCE TRANSPORTABLE

Figure 2: Overview of the laser subsystems for the strontium lattice clock, comprising seven lasers and the respective frequency stabilisation units (698 nm cavity of BB 5 and FSS). Figure 2 shows the Sr laser subsystems assembled during the first year of the project. Together, they occupy a volume of ca. 300 litre with an approximate power consumption of 100 W and 150 kg mass.

laser for the dipole lattice trap (BB 4), two repumper lasers at 679 nm and 707 nm (BB 3). In addition, the highly frequency-stable 689 nm laser for 2nd stage cooling on the intercombi-nation transition (BB 2) and the clock laser at 698 nm for the spectroscopy of the clock transition will soon also be integrated.

Laser system for the Ytterbium clock

For the operation of an Yb optical lat-tice clock, lasers with five different wavelengths are required. In the proj-ect, we develop compact and trans-portable laser sources based on state-of-the-art diode and fiber laser technology, see Figure 3.

For the first-stage cooling radiation at 399 nm and for the lattice laser at 759 nm external-cavity-diode-lasers

(ECDL) based on narrow-band interfer-ence filters [Baillard 2006, Tackmann 2010] are being developed, which promise improved stability compared to the commonly used grating-stabi-lised ECDLs. A prototype interference-filter ECDL at 399 nm using standard laser diodes and delivering up to 40 mW has already been tested suc-cessfully as a master laser. It is used to inject another, free-running laser diode and provides light for initial atom slowing. The higher power of a few 100 mW that is required at the optical lattice wavelength of 759 nm will be achieved using a self-injected tapered amplifier.

A compact repumping laser at 1 389 nm, required to reduce fluctua-tions of the clock interrogation signal, has been developed. The unit is based on a DFB laser diode with fiber output,

457TOWARDS NEUTRAL-ATOM SPACE OPT ICAL CLOCKS (SOC2) : DEVELOPMENT OF H IGH-PERFORMANCE TRANSPORTABLE

and exhibits a low free-running fre-quency instability (about 15 MHz/day linear drift) that will allow using the laser without further frequency stabilisation.

The post-cooling laser at 556 nm is a laser system based on fiber laser technology. It is designed to have a total volume of 3 litre. The all-fiber optical setup consists of three stages. The seed signal at 1111.60 nm is generated by a NKT Photonics BASIK module. The infrared signal is ampli-fied in an amplifier pumped by two pump laser diodes at 974/980 nm. Second harmonic generation (SHG) at 555.80 nm is performed by an all-fiber coupled waveguide periodically poled lithium niobate (PPLN) device. An output power of 20 mW has been achieved, exceeding the design goal by a factor of two.

The most sophisticated laser system is the clock laser system at 578 nm for which a stability and linewidth in the 1 Hz range are required. Our approach for providing the 578 nm clock radiation

is based on second harmonic gener-ation of an external cavity quantum dot laser (QD-ECDL) at 1 156 nm, in a PPLN waveguide. The required laser stability has been achieved by stabilis-ing the laser to a highly stable ULE ref-erence cavity.

Atom preparation in the Strontium clock

The design of the first-generation compact vacuum apparatus, which is fully operational, is shown in Figure 4. Strontium atoms are first evaporated in a low-power-consumption oven work-ing at 450–500 °C. The atomic beam is generated by a set of capillaries at the output of the oven and the atoms are then decelerated in a 30 cm long Zeeman slower and finally loaded into a 1st stage MOT, which uses the dipole-allowed 1S0-

1P1 transition at 461 nm.

The typical number of loaded atoms is about 108. By observing the expan-sion of the atoms from the MOT, an atomic temperature of about 2 mK was determined.

Figure 3. Overview of the laser system for the ytterbium lattice clock, comprising five lasers. Frequency stabilisation units for the first, second and fourth laser are not shown.

458TOWARDS NEUTRAL-ATOM SPACE OPT ICAL CLOCKS (SOC2) : DEVELOPMENT OF H IGH-PERFORMANCE TRANSPORTABLE

The second-stage MOT is applied on the 1S0 -

3P1 transition at 689 nm. Pending availability of the newly developed 689 nm laser, a prototype master-slave laser delivering up to 50 mW has been employed. The slave laser is optically injected with a beam coming from the pre-stabilised master laser, with a fre-quency offset of 160 MHz from atomic resonance. In order to tune the laser fre-quency on resonance and to provide the necessary power level and frequency modulation for the 2nd stage MOT, a double-pass acousto-optical modulator (AOM) is used. Triggering of the asso-ciated synthesizer is performed by a computer-controlled FPGA. As shown in Figure 5, the 2nd stage MOT trap-ping and cooling consists of two main phases, A 120 ms long ‘broadband’ phase during which the frequency of the cooling laser is broadened to 5 MHz to cover the Doppler width of the atoms at the end of the 1st stage MOT, followed by 30 ms of ‘single-frequency’ phase. The broadband phase allowed cooling and trapping about 1 × 107 88Sr atoms at 22 mK, while the ‘single-frequency phase’ further cooled to the 2 mK level, with a final population of 1 × 106 atoms. The atoms are then loaded with about 50 % efficiency into a vertically oriented 1D lattice, realised by means of the new 813 nm laser source from this project.

Atom preparation in the Ytterbium clock

Within the first year of the project we have succeeded in preparing ultra-cold ensembles of the two isotopes 174Yb and 171Yb in a one-dimensional opti-cal lattice which operates at 759 nm, the magic wavelength for Yb [Barber 2006]. Our approach for the reali-sation of such a magic-wavelength optical lattice includes enhancement resonators which are placed in the

vacuum chamber in which the cold Yb ensembles are prepared. Inside two perpendicular resonators a large-volume optical lattice (either one- or two-dimensional) can be formed with only a few 100 mW power from a diode laser (Figure 6 left). The resona-tor mirrors, two of which are mounted on ring piezo actuators, are glued to a monolithic structure, made out of the steel alloy invar, in order to increase the passive stability of the optical lat-tice. The end mirrors are transparent for the clock transition wavelength of 578 nm, which makes it simple to superimpose the radiation at the clock wavelength with the optical lattice.

Loading of a 1D optical lattice was so far achieved by using one of the two enhancement resonators with a beam waist of ~ 150 µm. We estimate that currently the maximum achievable trap depth is on the order of 50 µK. Yb atoms are loaded into the lattice by carefully aligning the position of the 2nd stage MOT to the lattice posi-tion and ramping down the 556 nm cooling light field (see Figure 6). Successful loading of the optical lat-tice is observed by turning the cooling light field back on after a variable hold time and detecting the fluorescence of the atom that remained trapped in the lattice in the meantime. Without the lattice light field, no atoms are recap-tured after roughly 20 ms while with the light field recapturing is possible even after 300 ms. The longest lifetime in the optical lattice observed so far is 130 ms, sufficient for the operation of an optical lattice clock.

In the currently used prototype setup we can transfer more than 20 % of the atoms from the 2nd stage MOT into the optical lattice, amounting to roughly 105 atoms, as aimed for. Since the

459TOWARDS NEUTRAL-ATOM SPACE OPT ICAL CLOCKS (SOC2) : DEVELOPMENT OF H IGH-PERFORMANCE TRANSPORTABLE

Figure 4. Section view of the 1st generation Strontium atomics package. Red, Zeeman slower. The extension of the vacuum system is about 110 cm × 35 cm × 40 cm, corresponding to a total volume of about 150 litres.

Figure 5. Top and centre: absorption images of the Sr atoms and time-of-flight (TOF) measurements of the temperature (graphs) at the end of the ‘broadband’ and ‘single-frequency phase’. Bottom: absorption image taken 12 ms after turning off the 689 nm beams. A significant fraction of the atoms remain trapped in the 1D lattice (813 nm), while the untrapped fraction falls in the gravitational field.

460TOWARDS NEUTRAL-ATOM SPACE OPT ICAL CLOCKS (SOC2) : DEVELOPMENT OF H IGH-PERFORMANCE TRANSPORTABLE

temperature of the atoms in the MOT is typically 30–50 µK we may infer that the transfer efficiency is limited by the depth of the optical lattice. This limit should be overcome in an advanced resonator setup, which is designed to allow for lattice depths of several 100 µK and higher transfer efficiency.

Next-generation subunits

The 461 nm cooling light for Sr is obtained by second-harmonic genera-tion. As a potentially simpler and more robust alternative to the conventional generation in an external enhance-ment cavity (used in the laser devel-oped for this project), we have tested the single-pass generation in periodi-cally poled KTP waveguides (ADVR). We could couple fibres with waveguides such that the input coupling efficiency to the waveguide was up to 70 % (at 922 nm) and could obtain up to 40 mW of power at 461 nm. The output power could not be increased to more than 100 mW, as required. Therefore, an evaluation of different waveguide types is planned to follow.

For a transportable clock, robustness, compactness and moderate mass are desirable. In this respect, we have

compared two different techniques for realising the UHV environment in the atomic package: lead sealing and gluing. Although both techniques have yielded vacuum in the range of 10-11-10-12 mbar, the gluing tech-nique has resulted in a more com-pact and lightweight vacuum chamber which can be baked well above 200 °C. In the process, we have analysed different combinations of materials for the chamber, windows and glues. We have found that although several combinations are possible, MACOR/titanium for the chamber material together with BK7/YAG for windows is a good combination from the thermal expansion point of view. We have also found that the two adhesives H77 and 353ND work quite well.

Two novel approaches for loading atoms into a lattice optical clock are being investigated.

For the first approach, a two-dimen-sional (2D) MOT loaded from a dispenser is being tested. We have obtained some preliminary results where a 3D MOT is loaded from the 2D MOT system. We have observed clear enhancement in the atom number in the 3D MOT when loaded from the 2D MOT (Figure 7

Figure 6. Left, photograph of the monolithic resonator setup for 1D and 2D optical lattices. Right, transfer efficiency into the optical lattice as a function of 2nd stage MOT position. The MOT position is controlled via the current through one of the MOT magnetic field coils.

461TOWARDS NEUTRAL-ATOM SPACE OPT ICAL CLOCKS (SOC2) : DEVELOPMENT OF H IGH-PERFORMANCE TRANSPORTABLE

inset). Having gained from the above experience, we have realised a prelimi-nary design for a 2nd generation com-pact and lightweight vacuum chamber as required for the project (Figure 7 main).

The design is flexible in the sense that either a 2D MOT or a Zeeman slower can be used for slowing. The ultra-high vacuum will be maintained by

ion pumps. In addition to the optical access for lasers for 2nd stage cool-ing, detection, lattice trapping, etc, a thermal enclosure will be designed for the atomics package, which allows control of temperature to better than 0.1 K at the position of the atoms, necessary for controlling the black-body systematic frequency shift. Closed-loop magnetic field control will also be installed.

Figure 7. Main figure, preliminary design of the second-generation atomics package, where a 3D MOT (centre) will be loaded from a 2D MOT (left side). The design is also adaptable to a Zeeman slower replacing the 2D MOT. Blue: cooling and detection beams; red: 2nd stage cooling and lattice trapping beams; yellow: ion pumps. Inset, two images of a 88Sr 3D MOT loaded without (left) and with (right) a 2D MOT on, in a separate setup. The enhancement of the atom number is clearly visible.

Figure 8. Left, top view of Zeeman slower using permanent magnets. Centre, schematic of MOT/lattice chamber with blackbody tubes. Right, photo of blackbody tube showing heater section external to UHV chamber.

462TOWARDS NEUTRAL-ATOM SPACE OPT ICAL CLOCKS (SOC2) : DEVELOPMENT OF H IGH-PERFORMANCE TRANSPORTABLE

The second, conventional, approach for capturing atoms and loading them into a lattice trap consists in slowing the hot atoms emitted from the oven using a Zeeman slower, as is done in the 1st generation breadboard (Figure 4). Typically, in a Zeeman slower a tapered solenoid is used. We have developed a novel transverse mag-netic field Zeeman slower [Ovchinnikov 2008], which uses permanent mag-nets situated at adjustable distances from the beam axis (Figure 8 left), and which works equally well for both 87Sr and 88Sr isotopes. This has potential for achieving a clock apparatus with smaller footprint, reduced mass and no dissipation.

Finally, one of the major frequency shifts encountered in neutral atom lat-tice clocks is the black-body radiation shift due to the surrounding apparatus. Its value needs to be known in order to reach the goal accuracy of the space clock. We have developed a blackbody chamber to test calculations of the Sr black-body shift coefficient. The cham-ber includes two narrow copper tubes that approximate to well-defined black-body sources (Figure 8). Cold Sr atoms at micro-Kelvin temperatures will be transported into either tube by a moving-lattice beam, then trans-ferred into the ‘magic-wavelength’ lattice for interrogation by the clock laser. By sequentially probing the lat-tice-trapped atoms in the two tubes at different temperatures, the differ-ential blackbody shift is measured, allowing validation of the black-body coefficient.

CONCLUSIONS

The new Sr laser subsystems have in part been integrated with the Sr

atomics subsystem and have already allowed trapping Sr atoms in the optical lattice. Once fully integrated, we expect to be able to provide and to interrogate cold atomic samples with desired fea-tures. The subunits of the Yb clock are also working well individually, with the atoms routinely trappable in the optical lattice. The upcoming work for the 2nd year of the project will include (i) com-pletion of the integration, spectroscopy of the clock transition, initial character-isations of the clocks’ performances, and optimisation; and (ii) progress on the development of the second-gen-eration subunits (lasers, atomics pack-age components), so that they can be integrated into the clocks in year 3.

Preparatory activities are also in pro-gress for the later robustness testing of lasers and for the full characterisa-tion of the transportable optical clocks after moving them from the integration labs to national metrology labs, and for next-generation compact optical fre-quency combs.

At the end of the project we expect to have an operational lattice clock that will represent the baseline design for the production of the flight model for the ISS space clock.

This report is based on work presented at the European Time and Frequency Forum, Gothenburg (Sweden), 2012, and published by the IEEE.

REFERENCES

  Baillard, X., Gauguet, A., Bize, S., Lemonde, P., Laurent, P., Clairon, A., and Rosenbusch, P., ‘Interference-filter-stabilised external-cavity diode lasers’, Opt. Comm., 266, 2006, p. 609.

463TOWARDS NEUTRAL-ATOM SPACE OPT ICAL CLOCKS (SOC2) : DEVELOPMENT OF H IGH-PERFORMANCE TRANSPORTABLE

  Barber, Z. W., Hoyt, C. W., Oates, C. W., Hollberg, L., Taichenachev, A. V. and Yudin, V. I., ‘Direct excitation of the forbidden clock transition in neutral 174Yb atoms confined to an optical lattice’, Phys. Rev. Lett., 96, 2006, 083002.

  Katori, H., Takamoto, M., Pal’chikov, V. G. and Ovsiannikov, V. D., ‘Ultrastable optical clock with neutral atoms in an engineered light shift trap’, Phys. Rev. Lett., 91, 2003, 173005.

  Ovchinnikov, Y. B., ‘A permanent Zeeman slower for Sr atoms’, Eur. J. Phys. Special topics 163, 2008, p. 95.

  Porsev, S. G., Derevianko, A., and Fortson, E. N., ‘Possibility of an optical clock using the 6 1S0 → 6 3P0 transition in 171;173Yb atoms held in an optical lattice’, Phys. Rev. A, 69, 2004, 021403.

  Tackmann, G., Gilowski, M., Schubert, C., Berg, P., Wendrich, T., Ertmer, W., Rasel, E. M., ‘Phase-locking of two self-seeded tapered amplifier lasers’, Optics Express, 18, 2010, 9258.

CHAPTER 46

Author: Steve Parkes

consortium members: University of Dundee, the United Kingdom; St. Petersburg State University of Aerospace Instrumentation, Russian Federation; Submicron, Russian Federation; ELVEES, Russian Federation; Astrium GmbH, Germany

AbSTRACT

The SpaceWire-RT research programme aims to conceive and create commu-nications network technology, suitable for a wide range of demanding space applications where responsiveness, determinism, robustness and durabil-ity are fundamental requirements. This is a critical component technology for future spacecraft avionics and payload data-handling. The creation of this tech-nology will substantially strengthen col-laborative bonds between the Russian and European organisations involved in the research, and lead to technol-ogy of vital importance for future space missions.

SpaceWire-RT will:

• use virtual channel concepts to pro-vide a variety of Quality of Service (QoS);

• provide broadcast and multicast capability;

• increase performance;

• provide low latency message delivery;

• include extremely low latency time and out-of band signalling mechanisms;

• incorporate novel fault detection, isolation and recovery methods;

•make the network fully responsible for information transfer, decoupling application and data transfer;

• implement appropriate communica-tion mechanisms in relatively simple hardware.

The main achievements of the SpaceWire-RT project (at the end of March 2012) were:

•a consolidated and justified set of requirements and use cases for SpaceWire-RT covering both space-craft payload and avionics, which take into account requirements from spacecraft primes and equip-ment manufacturers, from the European Union, Russian Federation, and internationally;

•a baseline concept for SpaceWire-RT, which builds on the SpaceFibre standard being developed by the European Space Agency (ESA) for very high-speed networking, and provides a coherent set of proto-cols covering a wide range of space-craft data-handling and avionics applications;

SpaceWire-RT (SpWRT)

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• inputs on Quality of Service approaches to the SpaceFibre stand-ard being developed by University of Dundee for ESA, particularly con-cerned with the integration of dif-ferent QoS approaches into a single concept.

AcHieVed resuLts

Introduction

The trend towards ‘Operationally Responsive Space’, where spacecraft can be rapidly assembled, configured and deployed, to meet specific mission needs, e.g. disaster support, requires flexible on board communication net-works with plug-and-play capability. The growing autonomy of scientific missions to remote planets requires networks that are robust and durable, able to recover from transitory errors and faults automatically. The impor-tance of spacecraft mass reduction motivates the sharing of networks for payload data-handling and avionics. Avionics and robotics impose require-ments on network responsiveness and determinism. Increasing international collaboration on scientific and Earth observation spacecraft requires stand-ard network technology where a com-ponent developed by one nation will interoperate effectively with equipment developed by another. SpaceWire-RT aims to fulfil these demanding require-ments with a flexible, robust, respon-sive, deterministic and durable standard network technology that is able to support both avionics and pay-load data-handling applications.

SpaceWire [1],[2],[3] is a very success-ful first step in this direction, provid-ing networking technology for payload data-handling on over 30 major space

missions. It falls short, however, of the requirements for avionics systems.

SpaceFibre [4],[5],[6] is a very high-speed serial data-link currently being developed by ESA which is intended for use in data-handling networks for high data-rate payloads. SpaceFibre is able to operate over fibre optic and copper cable and support data rates of 2 Gbit/s in the near future and up to 6 Gbit/s long-term. It aims to comple-ment the capabilities of the widely used SpaceWire onboard networking stand-ard: improving the data rate by a factor of 10, reducing the cable mass by a fac-tor of four and providing galvanic iso-lation. SpaceFibre aims to support QoS along with fault detection, isolation and recovery (FDIR). An important feature of SpaceFibre is that it transfers SpaceWire packets, so that several SpaceWire links can be easily multiplexed over a single SpaceWire link, and so application soft-ware designed for SpaceWire can oper-ate over SpaceFibre.

A QoS layer is needed for SpaceWire and SpaceFibre to support mixed avi-onics and data-handling applications. SpaceWire-RT will: use virtual channels to provide a variety of QoS; provide broadcast and multicast capability; support extremely low latency time and out-of band signalling; and incor-porate novel fault detection, isolation and recovery methods. The network will be fully responsible for information transfer, decoupling application and data transfer.

The creation of this technology will substantially strengthen collabora-tive bonds between the Russian and European organisations involved in the research, and lead to technology of vital importance for future space missions.

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The principal aims of SpaceWire-RT are:

• support all or most spacecraft onboard communication requirements:

— instrument interfacing

— device and sub-system networking

— inter-processor communications

— gathering housekeeping information

— deterministic command and control

— time distribution

— sub-system synchronisation

— event signalling

• provide a coherent set of protocols covering:

— full range of operational speeds

• 1 Mbit/s to 20 Gbit/s

— full range of operational distances

• 0.1 m to 100 m

— using a range of physical media and signals

Requirements Gathering

Astrium GmbH and Submicron gath-ered requirements from spacecraft manufacturers and spacecraft equip-ment suppliers across Europe and Russia respectively. These require-ments covered many aspects of pay-load data-handling and avionics networks. A qualitative summary of the major communication requirements is provided in Table 1.

An important aspect of this work on requirements was the need for a range of QoS depending on the particular application. These include the capability to reserve network bandwidth to pre-vent different data flows interfering with one another, deterministic data delivery for control applications, and high pri-ority, very low-latency communication for time-synchronisation and side-band signalling.

distance Rate Latency Packet size qoS

Data-handling network

Short to long Low to very high

Not important Short to long Reserved bandwidth

Control bus Short to long Low Low Short to long Deterministic delivery

Telemetry bus Short to long Low Low Short Reserved bandwidth

Computer bus Short Very high Low Short to long Reserved bandwidth

Time-sync bus Short to long Low Very low Short High priority

Side-band Short Low to high Very low Short High priority

Table 1. Qualitative Communication Requirements

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The requirements were analysed by University of Dundee and com-pared against the characteristics of the planned SpaceFibre standard. It was clear that SpaceFibre would meet the majority of the requirements for SpaceWire-RT and so was adopted as the baseline network technology for very high data-rate applications. The outcome of this analysis was used to inform the work on QoS within SpaceFibre and resulted in a coherent precedence concept being proposed for QoS in SpaceFibre.

QoS for SpaceFibre

SpaceFibre uses virtual channels to multiplex different data flows over a sin-gle SpaceFibre link. Data to be sent over a virtual channel is placed in an output virtual channel buffer (VCB) and read out of an input VCB at the other end of the SpaceFibre link. The data to be sent is chopped up into small segments called frames. Frames from differ-ent data flows can then be interleaved to support concurrent transfer of data from several different data streams over the one SpaceFibre link. A medium access controller determines which out-put VCB is allowed to send the next data frame over the SpaceFibre link at any particular time. When a virtual channel has data to send in its output VCB and has room for data in the input VCB at the other end of the SpaceFibre link, it competes with other virtual channels in a similar state. The virtual channel per-mitted to send a frame of data will be the competing virtual channel with the most urgent need to send data accord-ing to the QoS policies of those virtual channels.

It is possible to have several virtual channels in a SpaceFibre interface, each operating with a different quality of

service. Each virtual channel computes a precedence value based on its quality of service. The medium access control-ler uses this to determine which virtual channel is permitted to send a frame of data next. SpaceFibre provides four QoS classes: priority, bandwidth reserved, scheduled and best effort [6].

Precedence for the priority quality of service is related to the various pri-ority levels. Extremely urgent priority setting results in a very high prece-dence value, which will mean that an extremely urgent priority virtual chan-nel will be able to send data just about as soon as it is ready to go. Other prior-ity settings will have lower precedence values and so will compete with other qualities of service when requesting to send data. Each priority level has a fixed precedence.

Precedence for the bandwidth reserved quality of service is determined by the reserved bandwidth for the vir-tual channel and its recent use of link bandwidth. As a link sends data and uses up its reserved portion of the link bandwidth, so its precedence will drop, making it harder for it to compete with other virtual channels. When it is not able to send data because other virtual channels are sending data, its prec-edence will increase, making it easier for the link to compete against other virtual channels.

Precedence for the scheduled quality of service depends on a schedule table which specifies when a virtual chan-nel is permitted to send data. To sup-port the scheduled quality of service the link bandwidth is split into time-slots, either using a local time register set by a time broadcast message or using a synchronising broadcast message. The schedule table specifies when a virtual

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channel set to scheduled quality of ser-vice is allowed to send data. Such a vir-tual channel is not allowed to send data at any other time, only in its allocated time-slots. When a time-slot starts dur-ing which a scheduled virtual channel is allowed to send data, its precedence setting will be set to the highest possi-ble precedence value to ensure that it is able to send data at that time.

Precedence for the best effort quality of service is set to a very low value so that a best effort virtual channel will only be able to send data when there is no virtual channel with a different quality of service able to send data.

Coherent Set of Network Protocols

SpaceFibre is a very high-speed com-munication protocol. The QoS and FDIR protocols developed for SpaceFibre can potentially be applied to a range of slower speed network technologies. If a consistent set of QoS and FDIR pro-tocols can be applied across network technologies like SpaceWire then the concepts will be common and appli-cation software can be readily reused regardless of the performance required from the network. SpaceWire-RT aims to use the QoS and FDIR protocols being developed for SpaceFibre across a range of different lower level pro-tocol layers to cover a range of data rates and applications.

At present four different link layer pro-tocols are being considered:

• SpaceFibre CML

• SpaceFibre LVDS

• SpaceFibre Oversampled

• SpaceFibre over SpaceWire

The key characteristics differentiating these protocols will now be described briefly.

spacefibre cML: The SpaceFibre pro-tocol is designed to run at multiple Gbits/s using current mode logic (CML) over copper cables for distances up to 5 m or fibre optic cables for distances of 100 m or more. Multiple lanes can be operated in parallel to increase the data rate. SpaceFibre uses 8B/10B encoding and a phase locked loop (PLL), or similar technology, to recover a clock from the received data stream and to perform bit synchronisation.

spacefibre LVds: The SpaceFibre protocol could also be run at slower speed using Low Voltage Differential Signalling (LVDS), which is capa-ble of 600 Mbits/s or possibly up to 1 Gbits/s data rates. LVDS is used in SpaceWire and therefore has space heritage. SpaceFibre LVDS would use 8B/10B encoding and a PLL for bit synchronisation.

spacefibre oversampled: Bit syn-chronisation in SpaceFibre requires a PLL which requires special cir-cuitry to be included on chip. Current space qualified FPGAs do not pro-vide suitable PLL clock recovery cir-cuitry, so an alternative clock recovery scheme is required if SpaceWire-RT is to be implemented in space quali-fied FPGAs. The received signal can be over sampled (sampled with a clock of significantly higher frequency than the received bit rate) and bit synchro-nisation achieved [7]. This approach would use 8B/10B encoding but does not need a PLL. The physical layer would be LVDS. Data rates of up to 100 Mbits/s should be achievable, which is adequate for many space-craft applications.

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spacefibre over spaceWire: SpaceFibre sends and receives SpaceWire pack-ets (high-level SpaceWire packet), chopping them up into data frames and multiplexing frames from differ-ent SpaceWire packets over the sin-gle SpaceFibre link. Each data frame could be placed into its own SpaceWire packet (low-level SpaceWire packet) and then sent across a SpaceWire link. At the far end of the link the data frame would be extracted from the low-level SpaceWire packet, the data frames from one data stream concatenated to reform the high-level SpaceWire packet and that SpaceWire packet passed on to the user application. This would provide a simple means for QoS and FDIR to be provided over a SpaceWire link. SpaceWire data-strobe encod-ing is used, requiring twice as many signal wires as the other techniques [1]. In many cases existing SpaceWire interface devices could be used. Data rates of up to 200 Mbits/s and higher are readily achievable. The overhead imposed by running SpaceFibre QoS and FDIR over SpaceWire is approxi-mately 3 %.

This set of protocols would be suitable for spacecraft applications operating at a few Mbits/s to those requiring many Gbits/s. The packet level (SpaceWire packet level), and QoS and FDIR mech-anisms, are consistent across the set of protocols, allowing many different application requirements to be met with a coherent protocol set.

CONCLUSIONS

At the stage of the SpaceWire-RT pro-ject when this paper was drafted sig-nificant progress had been made, including the gathering of require-ments and the design of a baseline

concept. Requirements for spacecraft onboard network technology have been gathered from European and Russian prime spacecraft manufacturers and equipment developers. Based on these requirements a conceptual design has been produced for a range of space-craft network protocols that integrate important QoS and FDIR capabilities and that cover a wide range of space-craft applications.

The research planned between March and December 2012 covers:

• an outline specification for SpaceWire-RT based on the require-ments and use cases and the concep-tual design and analysis work;

• a validated SpaceWire-RT specifica-tion with important, novel features of SpaceWire-RT networks tested using SDL models;

• a validated chip design for SpaceWire-RT aimed at field pro-grammable gate array (FPGA) implementation;

• an assessment of the feasibility of implementing SpaceWire-RT as an Application Specific Integrated Circuit (ASIC) intellectual property (IP) core considering available ASIC technolo-gies suitable for space;

• a draft standard document for the SpaceWire-RT protocols.

REFERENCES

  European Cooperation for Space Standardisation, Standard ECSS-E-50-12A, ‘SpaceWire, Links, Nodes, Routers and Networks’, Issue 1,

470S P A C E W I R E - R T ( S P W R T )

European Cooperation for Space Data Standardisation, January 2003.

  European Space Agency, ‘SpaceWire Web Page’, European Space Agency, http://spacewire.esa.int/.

   Parkes, S., ‘SpaceWire User’s Guide’, available from http://www.star-dundee.com.

   Parkes, S., McClements, C., Dunstan, M. and Suess, M., ‘SpaceFibre: Gbits/s Link For Use On Board Spacecraft’, International Astronautical Congress, Daejeon, South Korea, October 2009.

   Parkes, S. and Suess, M., ‘Virtual Channels, Broadcast Channels and

SpaceFibre’, International SpaceWire Conference, November 2011, San Antonio, USA, available from http://2011.spacewire-conference.org/proceedings/.

   Parkes, S., ‘SpaceFibre Standard’, Draft D, University of Dundee, February 2012, available from http://spacewire.esa.int/WG/SpaceWire/SpW-WG-Mtg18-Proceedings/

   Sawyer, N., ‘Data Recovery’, Xilinx application note XAPP224 (v2.5), July 2005, available from http://www.xilinx.com.

CHAPTER xx Space weather

CHAPTER 47

Authors: Volker Bothmer, Ronald Van der Linden, Francis Verbeeck, Aleksei Parnowski, Raimund Brunner, Chris Hall, Norbert Jakowski, Claudia Borries, Wilfried Pfeffer, Rodney Viereck, Thomas≈Kraupe

consortium members: Institute for Astrophysics, Georg-August-University Göttingen, Germany; Solar Influences Data Analysis Center, Royal Observatory of Belgium, Brussels, Belgium; Space Research Institute of National Academy of Sciences and National Space Agency of Ukraine, Kyiv, Ukraine; Fraunhofer Institute for Physical Measurement Techniques IPM, Freiburg, Germany; Tromsø Geophysical Observatory, University of Tromsø, Norway; Institute of Communications and Navigation, German Aerospace Center Neustrelitz, Germany; Astrium GmbH Friedrichshafen, Germany; NOAA Space Weather Prediction Center, Boulder, USA; Planetarium Hamburg, Hamburg, Germany

AbSTRACT

AFFECTS is a space research project under the seventh framework pro-gramme of the European Union. The natural hazards of space weather have the potential to catastrophically dis-rupt the operations of technological

systems. In the AFFECTS project European and US scientists are devel-oping an advanced prototype space weather warning system to safeguard the operation of telecommunica-tion and navigation systems on Earth against the threat of solar storms in the timeline of March 2011 until February 2014. The project website is hosted at http://www.affects-fp7.eu

•Solar activity affects the entire Earth environment from the mag-netosphere down to the ionosphere, and even to the lower atmosphere climate system. The natural haz-ards of space weather do not only modify the atmosphere. They also have the potential to catastrophi-cally disrupt the operations of many technological systems, such as communication systems and power grids on Earth. Figure 1 summa-rises the different effects of space weather on the Earth’s environment. Hence the impact of space weather for people’s lives and jobs is very real, and as we approach solar max-imum around the end of 2012, such risks increase. In the AFFECTS pro-ject, European and US scientists are developing an advanced prototype space weather warning system to help mitigate space weather effects on the operation of telecommunica-tion and navigation systems.

AFFECTS: Advanced Forecast For Ensuring Communications Through Space

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Figure 1. Summary of space weather on the terrestrial environment. Courtesy: NASA.

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The key objectives of the AFFECTS pro-ject are:

• state-of-the-art analysis and model-ling of the Sun–Earth Chain of Effects on the Earth’s ionosphere and their subsequent impacts on communi-cation systems based on multipoint space observations and complemen-tary ground-based data;

• development of a prototype space weather early warning system and reliable space weather forecasts, with specific emphasis on iono-spheric applications;

• dissemination of new space weather products and services to end users, the scientific community and the general public.

Solar storms are a consequence of sud-den eruptions of magnetised gas in the Sun’s outer atmosphere. Often such storms start with a sudden release of electromagnetic energy lasting for some minutes, accompanied by an eruption of a giant cloud of magnetised plasma — a coronal mass ejection (CME). The fastest of these ‘space hurricanes’ are

accelerated to speeds of 10 million kilometres per hour and, if heading in the direction of Earth, reach our home planet at a distance of 150 million km in less than a day. Figure 2 provides a generic sketch of the phenomenon.

The impact of the coronal mass ejec-tion on the Earth’s magnetosphere causes a geomagnetic storm if the magnetic field of the coronal mass ejection is oriented antiparallel to the direction of the Earth magnetic field. Through the reconnection of the mag-netic fields large-scale current systems are driven in the Earth magnetosphere causing severe space weather: Polar lights become visible even at equa-torial latitudes, astronauts and air-line crews and passengers become exposed to enhanced radiation doses in the form of energetic particles up to GeV energies, satellites in low Earth orbit experience enhanced orbital drag and can lose hundred of metres in height, navigation and telecommu-nication systems are affected or may even become completely disrupted locally. Power grid transformers can be severely damaged causing power out-ages, such as in Quebec in 1989 or in

Figure 2. Sketch of a coronal mass ejection propagating towards Earth. Courtesy: NASA.

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Malmö in 2003. For an overview on the subject the reader is referred to the book Space Weather — Physics and Effects by Bothmer and Daglis (eds., Springer/Praxis, 2007).

ProJect structure And ACHIEVEMENTS IN yEAR ONE

The AFFECTS project has successfully completed its first year. The project is organised in the following six dedi-cated working packages (WPs):

•WP 1 Administrative, financial and legal management of the project.

•WP 2 Management of the flow of raw and calibrated data required for WPs 3 and 4 as input for early warn-ing and for establishing beyond the

state of the art tools and modelling. Maintenance of instruments and data sets and support of detector development. Definition of common data formats to be used for iono-spheric, thermospheric and space weather modelling activities.

•WP 3 Development of an early space weather warning system.

•WP 4 Provision of tools to forecast geomagnetic indices for TEC (total electron content) maps. Mid-term forecast, modelling improvement and services for overall forecasting system/dissemination.

•WP 5 Development of an ionospheric forecast system for end users pro-viding early warnings and forecasts

Figure 3. Map of Europe showing the ionospheric TEC conditions on 11 February 2010 and the corresponding ionospheric range error. Courtesy: DLR, SWACI (Space Weather Application Center Ionosphere, http://swaciweb.dlr.de).

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of expected ionospheric perturba-tions deduced from analysis of solar, geomagnetic and ionospheric GNSS (Global Navigation Satellite System) data (see Figure 3).

•WP 6 Provision of overall space weather data and in particular early warnings and forecasts to end users, scientific community, and gen-eral public. Organisation of a user workshop.

Figure 4 summarises the working package activities, institutional responsibilities and

interfaces between individual working packages, and also the general workflow of the project.

During the first year, the management of the project has successfully been set up according to the plans of WP1.

WP2 has the overall function to estab-lish and maintain the pipeline of state-of-the-art data from instrumentation in the field, including both satellite and ground-based data to WP3 (early warning) and WP4 (Forecasting Tools and Modelling). For these purposes,

Figure 4. AFFECTS working package structure, institutional responsibilities and project workflow.

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Web-Interface for EUV data, the L1 solar wind and geomagnetic indi-ces database, AE activity monitor-ing and local indices and GNSS based ionospheric data, including verti-cal sounding data from auroral zone and polar cap ionosondes, have been established. The stream of data from instruments on board STEREO, SOHO, SDO, Proba2, ACE, GOES and ISS, and the ground-based magnetometer and ionosonde stations is smoothly main-tained by the AFFECTS partners. Full magnetometer records are accessi-ble since February 2012 to the project members to help study auroral space weather effects.

WP3 has as its main objective to help establish and maintain an early space weather warning system, with spe-cific emphasis on ionospheric applica-tions. The layout for the Early Warning System for GNSS Users has been designed. NOAA-SWPC provides 24/7 flare warnings, but during certain time intervals, the GOES instrument suf-fers from data gaps. Through a spe-cific analysis of data from the Proba2 instrument, LYRA data can now be used to bridge these gaps with a measure-ment accuracy of about 10 %. Coronal mass ejection characteristics were derived from stereoscopic modelling and tracking of CMEs detected with STEREO/SECCHI. The results serve as input for the ENLIL CME simulation code in collaboration with NOAA-SWPC and D. Odstrcil at NASA/GSFC to help estimate proper arrival times for solar storms propagating to Earth since most CMEs are considerably deceler-ated en route to Earth, with the fast-est ones having initial speeds above 2 000 km/s but substantially below 2 000 km/s at 1 AU. The alert time in extreme events can decrease to less than a day. Multiple events from

individual active regions play a major role for extreme space weather as exemplified through solar activity on 1 August 2010 (Temmer at al. 2012). During the October 2003 storm the dTEC variation of about 30 TECU within several minutes (Tsurutani et al. 2006), corresponding to range errors of sev-eral tens of m. Convection of enhanced TEC fronts from the polar zones over Europe took place in less than an hour. Further quantitative event studies are under way.

The role of WP4 is to develop the core components of forecasting modules for integration in the Forecast System Ionosphere developed in WP5. The prototype software tools for forecast-ing geomagnetic indices Dst and Kp as indicators of CMEs impact on Earth (i.e. their geoeffectiveness) with three hours lead time have been developed (Parnowski 2011). Currently the maxi-mum lead time which can be achieved is four hours in advance of solar storms. Alerts from the L1 ACE solar wind data allow 15–30 minute warnings.

WP5 has its objectives in reducing the impact of space weather phenom-ena on telecommunication and navi-gation systems through quantitative forecasts of ionospheric perturbations based on solar, geomagnetic and iono-spheric data up to 24 hours in advance (Forecast System Ionosphere (FSI)). For this system, the architecture has been designed and processor modules are implemented and currently in their test phase. Online dissemination of TEC maps is under implementation at the SWACI AFFECTS website at http://swaciweb.dlr.de/affects/ and com-parisons with the NOAA SWPC CTIPe (Coupled Thermosphere Ionosphere Plasmasphere Electrodynamics model) are undertaken.

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WP6 objectives are to disseminate overall space weather data and gener-ated products, including early warnings, reports and forecasts to end users, the scientific community, and general pub-lic and the organisation of a user work-shop. A dedicated website for data dissemination has been established in the environment of the DLR SWACI web service (see link provided under WP5). The website incorporates a solar, geo-magnetic and ionospheric database. Additionally, it provides equivalent slab thickness products retrieved from vertical sounding data (UoT) and TEC data (DLR). AFFECTS analyses of sev-eral major space weather events have received overwhelming media cover-age (newspapers, radio, journals, TV) since the start of the project in March

2011. The AFFECTS forecasts provided to the media have helped avoid dele-terious warnings in these cases, based on determination of the CME speeds and directions of propagation. The lay-out of the early warning system has been completed and collaboration for dissemination of space weather reports to the general public has been established with the RTL media group through infoNetwork GmbH, Cologne, Germany. The SWACI TEC maps can be consulted in the NASA Space Weather App. for mobile phones. The AFFECTS project is featured through ‘The Sun in 3D’ DVD/blue-ray booklet and red and blue stereo glasses. The AFFECTS logo and trailer have been established and are available through the AFFECTS website at http://www.affects-fp7.eu.

Figure 5. Simulation of the solar wind stream structure between Sun and Earth for a CME event approaching Earth in an ‘onto the ecliptic view’. The different colours represent different solar wind densities, with red colours denoting high and blue colours denoting low plasma densities. The CME can be identified from its reddish shell-like pattern in front of the Earth, labelled as filled green circle.

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Figure 6. CME tracked from Sun to Earth on 1 August 2010 by the STEREO/SECCHI telescopes on board spacecraft A. Courtesy: STEREO SECCHI Consortium, RAL, NASA. The Sun is hidden by the external COR-2 telescope occulter. The CME is seen in the HI-1 image in the middle. The Earth is the small bright point in the center of the HI-2 image to the right. Bright spots in the HI-1 and HI-2 images are Mercury and Venus.

REFERENCES

  Bothmer, V., The Sun as the prime source of space weather, in ‘Space Weather — Physics and Effects’, Eds. Bothmer, V. and Daglis, I. A., Springer/Praxis, 2007.

  Bothmer, V., Daglis, I. A., Eds. ‘Space Weather — Physics and Effects’, Springer/Praxis, 2007.

  Parnowski, A., ‘Regression modelling of geomagnetic activity’, J. Phys. Studies, 15, 2011.

  Temmer, M., Vrsnak, B., Rollett, T., Bein, B., de Koning, C. A., Liu, Y., Bosman, E., Davies, J. A., Möstl, C.,

Zic, T., Veronig, A. M., Bothmer, V., Harrison, R., Nitta, N., Bisi, M., Flor, O., Eastwood, J., Odstrcil, D., and Forsyth, R., ‘Characteristics of kinematics of a coronal mass ejection during the 2010 August 1 CME–CME Interaction event’, Astrophys. J., 749:57, 2012.

  Tsurutani, B. T., Mannucci, A. J., Iijima, B., Guarnieri, F. L., Gonzalez, W. D., Judge, D. L., Gangopadhyay, P., Pap, J., ‘The extreme Halloween 2003 solar flares (and Bastille Day, 2000 Flare), ICMEs, and resultant extreme ionospheric effects: A review’, Adv. Space Res., 37, 2006.

CHAPTER 48

Authors: Ari Viljanen, Risto Pirjola, Ilja Honkonen, Alan Thomson, Ellen Clarke, Magnus Wik, Peter Wintoft, Viktor Wesztergom, Ernö Pracser, Yaroslav Sakharov, Yury Katkalov, Antti Pulkkinen

consortium members: Finnish Meteorological Institute, Finland; British Geological Survey, the United Kingdom; NeuroSpace, Sweden; Swedish Institute of Space Physics, Sweden; Research Centre for Astronomy and Earth Sciences of the Hungarian Academy of Sciences, Hungary; Polar Geophysical Institute, Russia; Catholic University of America, the United States of America

AbSTRACT

The EURISGIC project (March 2011–February 2014) will produce the first European-wide real-time prototype forecast service of geomagnetically induced currents (GIC) in power sys-tems, based on in situ solar wind obser-vations and comprehensive simulations of the Earth’s magnetosphere. By uti-lising geomagnetic recordings, we will also derive the first map of the occur-rence probability of large GIC through-out Europe. Because the most intense geomagnetic storms constitute the most remarkable threat, with a risk of power grid blackouts and damage of transformers, we will also investi-gate worst-case GIC scenarios based

on historical data. EURISGIC will exploit the knowledge and advanced modelling methods developed in Europe and North America. Close communication through-out the project with an Advisory Group will help in directing the research and outreach appropriately. The results of this study will help in the future design of more robust and secure protec-tion against GIC in power transmission grids in Europe, which are anticipated to become increasingly interconnected and geographically wider.

This paper provides an overview of the results of the first project year. We have extended the previous technical capa-bility to model GIC with archived geo-magnetic data to the continental-scale level. Improvements of space plasma simulations have been started to facil-itate the development of the forecast service during the second year.

AcHieVed resuLts

The main objectives of EURISGIC are to derive:

1. a map of the occurrence probabil-ity of large GIC throughout Europe;

2. a European-wide real-time proto-type forecast service of GIC;

3. worst-case GIC scenarios based on historical data.

EURISGIC : European Risk from Geomagnetically Induced Currents

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The first objective has been the major activity during the first project year. The basis for the forecast service has also been developed, and initial con-tributions to the worst-case scenarios have been made.

Initial results with a continental-scale power grid model

The basis for modelling GIC in a power grid is to determine the geoelectric field associated with rapid temporal variations of the geomagnetic field. A widely applied technique is to relate the local magnetic field to the elec-tric field by the surface impedance that is determined by the local ground conductivity structure (for example, Viljanen et al., 2004). When the elec-tric field is known, the next step is to calculate currents which it drives in a given conductor network (for example, Lehtinen and Pirjola, 1985).

Previous GIC studies in Europe have focused on national power grids espe-cially in the Nordic countries and the UK, but EURISGIC investigates the interconnected grids across the con-tinent. This requires a straightfor-ward extension of existing methods to be able to deal with a large geo-graphic area. Additionally, geomag-netic data and ground conductivity models are needed from the whole European region. During the first pro-ject year, the consortium has reached the technical capability to perform continent-wide studies. An example of preliminary results is the estimated maximum GIC at Central and South European transformer stations (Figure 1). Geomagnetic data of the highly active month of October 2003 from European observatories were used as input with a block model of the ground conductivity. The power grid prototype model imitates the true areal structure

Figure 1. Initial results of the largest modelled GIC at transformer stations using geomagnetic data of 2003 and a simplified description of the central and south European high-voltage power grids. The size of the red dot is proportional to the amplitude of GIC.

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of the grid containing a realistic num-ber of transformer stations and trans-mission lines. Although the simplified model must not be expected to provide exact results at single sites, it reveals the general fact that large GIC occur preferably at higher latitudes and at the edges of the grid.

The updated methods will be used to derive GIC statistics across Europe using geomagnetic data of a full sun-spot cycle in 1996–2008 as input. One fixed prototype grid model will serve as a basic starting point, but a few dif-ferent scenarios of extended grids will also be considered.

Steps towards a forecast service

The most challenging part of the project is to develop a test fore-cast service of GIC in Europe. Magnetosphere-ionosphere simu-lations using real-time solar wind observations as input will produce the input geomagnetic field. Two dif-ferent codes will be applied: European GUMICS-4 (based on Janhunen, 1996) and the US Solar Shield (Pulkkinen et al., 2010, http://ccmc.gsfc.nasa.gov/Solar_Shield/Solar_Shield.html). A requirement is that the codes must be fast enough to allow calculation of GIC with about 30 minutes lead time. Solar Shield is already able to do this, and the GUMICS-4 code has been par-allelised to achieve the same goal. As an alternative approach, an empir-ical method by Wintoft et al. (2005) has been extended to relate solar wind parameters directly to ground magnetic field variations. We expect that the initial forecast service will be available in 2012 and will run at least until the end of the project at the Regional Warning Centre Sweden (http://www.lund.irf.se/rwc/).

Worst-case scenarios

To derive the basic GIC statistics, we will use data of one sunspot cycle (1996–2008). This will give a comprehensive understanding of the average geo-graphic, diurnal and annual character-istics in Europe. However, much longer time-scales must be considered to be able to estimate the extreme limits (for example, Thomson et al., 2011). This is a demanding task, since GIC events with major effects on power grids have been rare with the March 1989 and October 2003 geomagnetic storms as the best-known cases. Additionally, large power grids have existed only for some tens of years, which is a short time in solar scales. So we cannot just use GIC recordings, but we must rely on geomagnetic data from which it is pos-sible to estimate GIC in present power grids.

New and old data related to GIC

Besides using readily available sources of data, the EURISGIC project has two specific data tasks. One is to perform GIC recordings in North Europe, and another is to digitise old analogue recordings. New GIC measuring instru-ments have been installed at five sites in north-west Russia (http://eurisgic.org), which is an area where large GIC are probable. Additionally, continuation of the long-term recording of GIC in the Finnish natural gas pipeline will sup-plement this study (http://eurisgic.org).

A uniquely long measurement series of the geoelectric field has been main-tained at the Nagycenk observatory in Hungary since 1957 covering about five sunspot cycles (Kis et al., 2007). A major effort is put on digitising the old analogue recordings until 1996 when digital recordings started.

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CONCLUSIONS

The first year of EURISGIC has provided a solid basis to model GIC in a high-volt-age power grid covering whole Europe, and we expect to be able to derive GIC statistics during 2012. Clearly, the big-gest challenge will be the GIC forecast service, which will inevitably require a lot of further improvement and fine-tuning of the simulation codes and of the empirical modelling. We will also need appropriate metrics to measure the success of forecasts. Another major action, especially in 2013, will be the derivation of worst-case scenarios, for which we have already prepared initial results. Data mining will play a special role to ensure that all available relevant recordings could be available, including the fairly tedious process of digitising the oldest analogue charts of extreme historic storms.

Interest in GIC, and in space weather in general, has again increased with the solar activity. With the first concrete results by EURISGIC we will also have more public outreach actions directed to different types of audiences. In this connection, the role of our external Advisory Group will increase during the next years to ensure that our results will be useful for the end-users. We also welcome feedback from any parties interested in the topic.

REFERENCES

  Janhunen, P., ‘GUMICS-3: A global ionosphere-magnetosphere coupling simulation with high ionospheric resolution’, In: Proceedings of Environmental Modelling for Space-Based Applications, 18–20 Sep 1996, Eur. Space Agency Spec. Publ., 1996, ESA SP-392.

  Kis, A., Koppan, A., Lemperger, I., Prodan, T., Szendröi, J., Verö, J. and Wesztergom, V., ‘Long-Term Variation of the Geoelectric Activity Index’, T. Publs. Inst., Geophys. Pol. Acad. Sc., C-99(398), 2007.

  Lehtinen, M. and Pirjola, R., ‘Currents produced in earthed conductor networks by geomagnetically-induced electric fields’, Ann. Geophys., 3, 1985, 479–484.

  Pulkkinen, A., Hesse, M., Habib, S., Van der Zel, L., Damsky, B., Policelli, F., Fugate, D., Jacobs, W. and Creamer, E., ‘Solar shield: forecasting and mitigating space weather effects on high-voltage power transmission systems’, Nat. Hazards, 53, 2010, pp. 333–345, doi 10.1007/s11069-009-9432-x.

  Thomson, A., Dawson, E. and Reay, S., ‘Quantifying Extreme Behaviour in Geomagnetic Activity’, Space Weather, 9, 2011, p. 10001, doi:10.1029/2011SW000696.

  Viljanen, A., Pulkkinen, A., Amm, O., Pirjola, R., Korja, T. and BEAR Working Group, ‘Fast computation of the geoelectric field using the method of elementary current systems and planar Earth models’, Ann. Geophys., 22, 2004, pp. 101–113.

  Wintoft, P., Wik, M., Lundstedt, H. and Eliasson L., ‘Predictions of local ground geomagnetic field fluctuations during the 7–10 November 2004 events studied with solar wind driven models’, Ann. Geophys., 23, 2005, pp. 3095–3101, SRef-ID: 1432-0576/ag/2005-23-3095.

  Public website of EURISGIC : http://www.eurisgic.org

CHAPTER 49

Authors: János Lichtenberger, Mark Clilverd, Balázs Heilig, Massimo Vellante, Thomas Ulich, Craig Rodger, Andrew Collier, Andres Jorgensen, Jan Reda, Robert Holzworh and Reiner Friedel

consortium members: Eötvös University, Hungary; British Antarctic Survey, the United Kingdom; Eötvös Loránd Geophysical Institute, Hungary; University of L’Aquila, Italy; University of Oulu, Finland; University Of Otago, New Zealand; Hermanus Magnetic Observatory, South Africa; New Mexico Tech, the United States of America; Institute of Geophysics, Poland; University of Washington, the United States of America; Los Alamos National Laboratory, the United States of America

AbSTRACT

The security of space assets is affected by the high-energy charged particle environment in the radiation belts. The controlling principal source and loss mechanisms in the radiation belts are not yet completely understood. During a geomagnetic storm the length of time during which space assets are in danger is determined by the loss

mechanisms, particularly by relativis-tic electron precipitation. The primary mechanism for this precipitation is the interaction of several wave modes with resonant electrons which leads to scat-tering into the atmospheric loss cone. The nature of the wave activity and the interactions between the waves and radiation belt particles are strongly governed by the properties of the plas-masphere. At this point there are few existing and regular measurements of plasmaspheric properties, with exist-ing plasmaspheric models lacking the structures known to exist in the real plasmasphere. There is evidence that enhanced wave activity and enhanced radiation belt losses occur due to such structures. In addition, there are large uncertainties concerning the funda-mental nature of relativistic electron precipitation (REP). To address these uncertainties, PLASMON will provide regular longitudinally-resolved meas-urements of plasmaspheric electron and mass densities and hence moni-tor the changing composition of the plasmasphere, one of the properties which determines wave growth. This will allow us to develop a data assimi-lative model of the plasmasphere. At the same time, we will monitor the occurrence and properties of REP, tying

PLASMON: A new, ground based data-assimilative model of the Earth’s Plasmasphere — a critical contribution to Radiation Belt modelling for Space Weather purposes

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the time-resolved loss of relativis-tic electrons to the dynamic plasmas-phere observations. Our approach will primarily use ground-based networks of observing stations, operating in the ULF and VLF ranges, deployed on a worldwide level.

wORK PROGRAMME, MetHodoLoGy, MiLestones And oBJectiVes

WP1. Automatic retrieval of equatorial electron densities and density profiles by Automatic Whistler detector and Analyser Network (AWDANet):

Recently Eötvös University has devel-oped a new, experimental Automatic Whistler Detector and Analyser (AWDA) system [Lichtenberger et al. 2008] that is capable of detecting whistlers and we plan to use this sys-tem to process lightning whistlers with no human interaction. AWDANet is evolving and now covers low, mid and high magnetic latitudes. Recent devel-opments in whistler inversion meth-ods for multiple-path whistler groups propagating on mid and high latitude [Lichtenberger, 2009] will allow us to retrieve electron density profiles auto-matically for wide range of L-values. The AWDANet will be extended to have better spatial and temporal cov-erage and thus will be able to provide density profiles for different Magnetic Local Times (MLTs), which can be used as a data source for space weather models. We will:

— extend the AWDANet to have bet-ter MLT and latitudinal coverage, develop an automatic whistler analyser (AWA) method based on our new whistler inversion method;

— implement the AWA in AWDANet nodes and develop AWDANet to work in quasi-real-time mode of operation.

WP2. Retrieval of equatorial plasma mass densities by SEGMA and MM100 magnetometer arrays and cross-cali-bration of whistler and FLR method:

The goal of the SEGMA (South European GeoMagnetic Array) [Vellante et al, 2004], and the MM100 array (quasi-Meridional Magnetometer array) [Heilig et al., 2007] is to monitor the plasmaspheric mass density based on the detection of geomagnetic field line resonances (FLRs). None of these ‘monitoring’ sys-tems, however, became operational in the sense that they never produced quasi real-time products. The lati-tude coverage is also not sufficient to monitor the whole plasmasphere. In contrast to the whistler method the FLR method can be used to infer the plasma mass density even in the plasmatrough and to also identify the location of the plasmapause. We plan to unify the isolated European efforts to develop the joint European network, EMMA (European quasi-Meridional Magnetometer Array,) with stations ranging from Italy to northern Finland (L-shells 1.6–6.7) We intend to use and upgrade existing magnetometer networks (IMAGE), which were origi-nally established for other purposes and other requirements (resolution, sampling rate, timing), but the data of which can be exploited for plasmas-phere observations, as well. In accord-ance with these goals we will:

(a) unify and extend the SEGMA, MM100 and IMAGE networks into EMMA;

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(b) develop an automatic FLR identifi-cation and FLR inversion;

(c) develop all EMMA stations to work in quasi-real-time mode of opera-tion, evaluate relative abundances of heavy ions in the plasma com-position from simultaneous deter-minations of mass density (FLR method) and electron density (whistler method).

WP3. Data assimilative modelling of the Earth’s plasmasphere: Even dense measurements only sample the plasma-sphere at limited resolution in both space and time. Yet determining the effect of wave-particle interactions on the radia-tion belts require a continuous map of the plasma density in both time and space. In order to provide such a com-plete map it becomes necessary to inter-polate between measurements, again in both time and space with data assimila-tion schemes to combine plasmaspheric measurements with a numerical phys-ics-based plasmasphere model. The two data assimilation schemes which we are pursuing are Ensemble Kalman filtering and particle filtering.

WP4. Modelling REP losses from the radiation belts using the AARDDVARK network: During a geomagnetic storm the length of time during which space assets are in danger is determined by the efficiency of the loss mechanisms, particularly through relativistic elec-tron precipitation into the atmosphere. We will use the assimilative model of the plasmasphere to identify regions where plasmaspheric structures such as the regions occurring on, inside, and outside of the plasmaspause and/or composition changes are likely to result in enhanced electron losses. We will monitor the occurrence and prop-erties of REP using the ground-based

AARDDVARK network [Clilverd et al., 2009], which will be extended during the project to have better spatial and temporal coverage.

The structure of PLASMON can be seen in Figure 1.

AcHieVed resuLts

WP1: The AWDANet extension has been started, three new AWD stations are operational (Humain, Belgium; Nainital, India and Eskdalemuir, UK), two are under preparation (Kamchatka, Russia and Seattle, USA). Another 20 stations are planned to be installed in the next couple of years (Figure 2)

The AWA algorithm [Lichtenberger et al., 2010] has been implemented and tested on a PC cluster consisting 52 cores/104 threads. The selection of Parallel Processing architecture also has been done, we will use GPU archi-tecture for AWA, because it proved to be the optimal for performance, power consumption, size and price.

WP2: The extension of EMMA mag-netometer network is done; four new sta-tions are operational (Birzai, Lithuania; Szczechowo, Poland; Zagorzyce, Poland and Vyhne, Slovakia) (Figure 3). The decisions on EMMA instrumentation as well as on data flow between stations and central server has also been taken. Work has started on the development of an automatic algorithm for FLR method (the FLRID algorithm).

WP3: To date we have tested the Ensemble Kalman Filter (ENKF) data assimilation loop using in situ den-sity measurements from LANL (Los Alamos National Laboratory) geo-stationary satellites for the period

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Figure 1. PLASMON structure

Figure 2. Global (upper) and European (lower) AWDANet stations. Names in red are operational, names in blue are planned stations. Names of stations in green are/will be installed in PLASMON.

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Figure 3. EMMA magnetometer array. EMMA is a unification of SEGMA, MM100 and IMAGE networks.

around the storm on 14 December 2006. We use the single-parame-ter Sojka et al. [1986] electric field model, and model that parameter as a red noise distribution as described by Evensen [2003]. The upper panel of Figure 4 shows the result of the assim-ilation. The top panel shows the KP index with the storm beginning on the 14th. The lower 5 panels show densi-ties at the five LANL geostationary sat-ellites that were recording data at the time. In each panel are three traces, the black trace being the observations, the blue trace an open-loop run (using KP to set the electric field), and the red trace shows the data assimilated simulated observations. The lower panel of Figure 4 shows a magnified view of two days, and clearly the assimilated traces are a closer match to observations. Although the match is not perfect, it is better than the open-loop run, and demonstrates that data assimilation is feasible with these data.

WP4: The extension of AARDDVARK network has been started, a new sta-tion at Forks, USA is operational; the installation of another two stations is under preparation (Figure 5).

CONCLUSIONS

A new data assimilative model of the plasmasphere will be developed and the ENKF data assimilation loop has been tested. The data input for the model will be provided by two ground-based measuring networks, AWDANet using VLF whistlers and EMMA using ULF FLRs. The model will be used to identify regions where REP losses can occur and the occurrence and proper-ties of REP will be monitored using the ground based AARDDVARK network. The extension of the three networks has been started and better MLT and latitudinal coverage will be achieved in the project.

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Figure 4. Upper panel: Data assimilation of LANL geostationary observations for the period around the 14 December 2006 storm. Top row shows KP, and the lower five rows show (in black) the measured density, (in blue) the simulated density using a open-loop (non-assimilative) run, and (red) the simulated density using a data assimilation run. Lower panel: same as upper one, except that it is for a two-day period. The relative agreement of observations, open-loop, and data assimilation are more apparent.

Figure 5. The AARDDVARK network. The stations installed in PLASMON are denoted by red squares.

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REFERENCES

  Clilverd, M. A., Rodger, C. J., Thomson N. R., Brundell, J. B., Ulich, T., Lichtenberger, J., Cobbett, N., Collier, A. B., Menk, F. W., Seppälä, A., Verronen, P. T. and Turunen, E., ‘Remote sensing space weather events: the AARDDVARK network’, Space Weather, 7, 2009, S04001, doi:10.1029/2008SW000412

  Evensen, G., ‘The ensemble kalman filter: Theoretical formulation and practical implementation’, Ocean Dynamics, 52, 2003, pp. 343–367.

  Heilig, B., Lühr, H., Rother, M., ‘Comprehensive study of ULF upstream waves observed in the topside ionosphere by CHAMP and on the ground’, Annales Geophysicae, 25, 2007a, pp. 737–754.

  Lichtenberger, J., Ferencz, C., Bodnár, L., Hamar, D., Steinbach, P., ‘Automatic Whistler Detector and Analyser system: Automatic Whistler Detector’, J. Geophys. Res., 113, 2008, A12201, doi:10.1029/2008JA013467

  Lichtenberger, J., ‘A new whistler inversion method’, J. Geophys. Res., 114, 2009, A07222, doi: 10.1029/2008JA013799

  Lichtenberger, J., Ferencz, C., Hamar, D., Steinbach, P., Rodger, C J., Clilverd, M. A., and Collier, A. B., ‘The Automatic Whistler Detector and Analyser (AWDA) system: Implementation of the Analyser Algorithm’, J. Geophys. Res., 115, 2010, A12214, doi:10.1029/2010JA015931

  Sojka, J. J, Rasmussen, C. E., and Schunk, R. W., ‘An interplanetary magnetic field dependent model of the ionospheric convection electric field’, J. Geophys. Res., 91, 1986, p. 11281.

  Vellante, M., Förster, M., Villante, U., Zhang, T. L., and Magnes, W. (2007), ‘Solar activity dependence of geomagnetic field line resonance frequencies at low latitudes’, J. Geophys. Res., 112, 2007, A02205, doi:10.1029/2006JA011909.

  Vellante, M., Lühr, H., Zhang, T. L., Wesztergom, V., Villante, U., De Lauretis, M., Piancatelli, A., Rother, M., Schwingenschuh, K., Koren, W., and Magnes, W., ‘Ground/satellite signatures of field line resonance: A test of theoretical predictions’, J. Geophys. Res., 109, 2004, A06210, doi:10.1029/2004JA010392

CHAPTER 50

Author: Giovanni Lapenta

consortium members: Katholieke Universiteit Leuven, Belgium; Belgian Institute for Space Aeronomy, Belgium; Università di Pisa, Italy; Københavns Universitet Astronomical Observatory, Denmark; Turin - Istituto Nazionale di Astrofisica, Italy; Astronomical Institute, Academy of Sciences of the Czech Republic, Czech Republic; University of St Andrews, the United Kingdom

AbSTRACT

The SWIFF project is organised around two major phases:

First, in the development of mathemat-ical models and computational meth-ods and software especially designed to handle the multiple physics and the multiple scales characteristic of space weather phenomena. The project intends to produce an integrated fore-casting framework able to model space weather events from their solar origin to the impact on Earth and its space environment, focusing on the effect on humans and technology in space and on the ground infrastructure.

Second, we intend to demonstrate for practical space weather events and processes the validity and use-fulness of the SWIFF integrated

space weather forecasting frame-work. SWIFF includes all phases of space weather events and will push forward the state of the art in mode-ling specific space weather events and processes.

wORK PROGRAMME

The drivers of the space weather are on the Sun: solar flares, Coronal Mass Ejections (CMEs), and solar energetic particle (SEP) events. The interaction of the solar wind and its disturbances (e.g. shocks, flux ropes) with the Earth’s magnetosphere affects the plasma around the Earth and its magnetic field. The storms in space have vary-ing degrees of geo-effectiveness, with different impacts to activities on the Earth and in space. The discipline that studies these effects is called space weather.

Some of the effects of space weather are enjoyable to most people, such as auroral displays, some are annoying without being dangerous or directly damaging, e.g. the increasing air drag on spacecraft as a result of exces-sive heating of the upper atmosphere and delays imposed on aeromagnetic survey flights as a consequence of a highly disturbed geomagnetic field. Other space weather effects, however, can be dangerous and may cause direct damage like excessive electri-cal charging of spacecraft and intense

Space Weather Integrated Forecasting Framework (SWIFF)

499S P A C E W E A T H E R I N T E G R A T E D F O R E C A S T I N G F R A M E W O R K ( S W I F F )

geomagnetically induced currents in electric power networks and pipeline systems. Long-range radio wave prop-agation and satellite-to-ground radio transmission are areas where space weather effects can be very annoying and may even play a disastrous role when safety and security depend on the quality of wireless communication and navigation. Mathematical mod-els are required to understand and predict the space weather. Figure 1 summarises the challenges of model-ling space weather.

The activities of SWIFF cover all aspects of the complex processes of space weather in the Sun-Earth con-nection. The work is organised into 6 work packages (WP):

•wP1: Management,

•WP2: Multiscale-Multiphysics Modelling,

•WP3: coupling at the sun,

•WP4: coupling in space,

•WP5: coupling at the earth,

•WP6: dissemination.

SWIFF will develop new software that will be made available to the com-munity of space weather forecast-ing. SWIFF will also organize outreach activities for the general public and training for scientists, in collaboration with other European efforts, funded by COST and other international institu-tions. A school on space weather mod-elling will be organised covering not just the activities of SWIFF but more generally the modelling and physics-based forecasting of space weather events.

eXAMPLe of tHe reseArcH EFFORTS

The fundamental challenge in the mod-elling of space weather is the need to account for multiple physics processes developing simultaneously in the same region of space or progressing in a cas-cade in different regions, and charac-terised by widely different spatial and temporal scales. For each process and for each scale the correct and most efficient method is different.

Figure 1 shows typical features par-adigmatic of the challenges in space weather modelling. The figure refers to the series of events in the evolution of space weather events travelling from the Sun to the Earth. Each phase of the process requires its most suited model that needs to be developed in an inte-grated framework able to follow the event. As the event evolves from the Sun to the Earth different conditions are encountered, requiring different models based on different physical equations.

Each phase of the process is further characterised by the concurrent pres-ence of different physics processes developing at different scales. We report in Figure 2 the characteristic scales for the different physical constituents of the Earth magnetotail (the region of plasma situated near the Earth on the night side away from the Sun). As can be seen, the agents are different: elec-trons, ions and electromagnetic fields (here gravity is not important but on the Sun it is adding one more worry for the method developer). Each agent evolves on very different spatial and temporal scales, spanning times from the tens of microseconds to the hours and from hundreds of meters to millions of kilom-eters. The fast small processes are best treated by the study of single particle

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trajectories or by kinetic models, where one studies the statistical probability of finding electrons or ions with a certain velocity in a certain position. But such models are not best suited for larger scales, as the cost of the simulation would be prohibitive. In that case one need to resort to fluid models where the information on the statistical distri-bution is lost and the model treats only average quantities (e.g. density, average flux or temperature).

Moreover different populations of par-ticles are present. For example in space weather events, besides the “usual” solar wind, populations of high energy particles are present travelling at much

faster speeds, close to the speed of light. Such high energy particles are one of the main threats for humans and technology in space. Of course the physical model for such particles is often different from that of other type of particles. Another challenge is that the conditions in different regions can be so different, that models that work in one region, will not work in another; for example the lower strata of the Sun’s surface and atmosphere (photosphere, chromosphere, corona) are much more prone to collision than higher strata, and similarly the upper Earth atmos-phere and ionosphere are more prone than the magnetosphere, where physi-cal processes are largely different.

Figure 1. Challenges of Space Weather modelling. Many processes develop in vast areas of space connected to each other.

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Figure 2. Goals of SWIFF. Bridge the gap between microscopic and macroscopic models to form the basis for a software infrastructure for space weather modelling.

The summary of this short description left out on purpose some aspects in the interest of brevity, but not because such processes will not be considered. Yet from this summary one can imme-diately understand that we must struc-ture SWIFF to achieve two goals that are still elusive for the space weather community:

From this partial summary one can immediately understand that we must structure SWIFF to achieve two goals that are still elusive for the space weather community:

1. The ability to treat concurrently in a single integrated framework microphysics (treated kinetically) and macrophysics (treated with fluid methods). The need to couple fluid and kinetic models is without doubt the most burning and cru-cial challenge, not just for space weather modelling, but also for many other aspects of computa-tional science. The proposing team

has some of the most advanced methods used in the world and the WP2 description below explains in details how such methods can be brought to bear in this case with a strategy that is at the same time a frontier research effort but also an effort with certainty of success.

2. The ability to couple different phys-ics in the same region at the same time or in cascade in the same or different regions. The ability to couple different physical processes operating in different regions in contact with each other or operat-ing in overlapping regions.

This effort is explicitly mentioned as a key goal of the present call from the European Commission. The docu-ment European Commission C (2009) 5893 of 29 July 2009 explicitly asks for “space weather models to improve specification and prediction capabili-ties, with emphasis on the linkage of the different physical processes that

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occur simultaneously or sequentially in many domains.” This is exactly what the WP 3 to 5, in close connec-tion with the modeling efforts of WP2, intends to achieve. We focus solely on developing a software framework to simulate in the modern supercomput-ers the linkage (or coupling) of differ-ent physical processes, not in general way, but with the eye fixed on the spe-cific key areas of linkage, as summa-rised by each WP.

CONCLUSIONS

Two figures summarise these concepts visually. Figure 3 reports results of a simulation of the interaction of the solar wind with the Earth space envi-ronment (magnetosphere). Instabilities arise and the two regions inter-mix. Figure 4 shows the evolution of a

coronal mass ejection outflowing from the Sun in the direction of the Earth. The figure displays magnetic field lines permeating the plasma.

Hydrodynamics mixing of the solar wind and of the Earth’s Magnetosphere. The Sun in on the left and the Earth on the right, both outside the blow-up shown in the figure.

These two examples illustrate the key point that there are small scale pro-cesses embedded in the large-scale evolution. The different levels cooper-ate and play a key role in determining the evolution and need to be treated with completely different models. The large scale processes are treated by fluid models where space is considered as a fluid with a certain density, veloc-ity and temperature. The small scale

Figure 3. Hydrodynamics mixing of the solar wind and of the Earth's Magnetosphere. The Sun in on the left and the Earth on the right, both outside the blow-up shown in the figure.

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Figure 4. Simulation of a coronal mass ejection, displaying the magnetic field on the Sun (in red-blue color scale) and its expansion into space (coloured field lines)

processes instead require a particle description that acknowledges the fact that space is filled not by a fluid but by a population of electrons and ions. In analogy, the fluid model is like know-ing the average income in each city, the kinetic model is like knowing how much each citizen earns. To study space weather the two approaches need to be used each in different scales.

The goal of SWIFF indicated in the Figure 2 is to bridge the gap between

the two approaches and to arrive at a single software able to handle the coupling (the goal of WP2). SWIFF then applies such a software infra-structure to the Sun (in WP3) to the interplanetary space (WP4) and at the Earth (WP4). A robust program of val-idation and verification will test the correct application to specific obser-vational events.

CHAPTER xx Space debris

CHAPTER 51 BETs: Propellant less deorbiting of space debris by bare electrodynamic tethers

Authors: Juan R. Sanmartin, Mario Charro, Enrico C. Lorenzini, Giacomo Colombatti, Jean-Francois Roussel, Pierre Sarrailh, John D. Williams, Kan Xie, Francisco García de Quirós, José A. Carrasco, Roland Rosta, Tim van Zoest, Joseba Lasa, Jesús Marcos

consortium Members: Universidad Politécnica de Madrid, Spain; Universitá degli Studi di Padova, Italy; ONERA-Toulouse, France; Colorado State University, the United States of America; Embedded Instruments and Systems, Spain; DLR Bremen, Germany; Fundación Tecnalia, Spain

AbSTRACT

As a fundamental contribution to limit-ing the increase of debris in the Space environment, a three-year project started on 1 November 2010 financed by the European Commission under the FP-7 Space Programme. It aims at developing a universal system to be carried on board future satellites launched into low Earth orbit (LEO), to allow de-orbiting at end of life. The operational system involves a conduc-tive tape-tether left bare of insulation to establish anodic contact with the ambi-ent plasma as a giant Langmuir probe. The project will size the three dispa-rate dimensions of a tape for a selected de-orbit mission and determine scaling

laws to allow system design for a gen-eral mission. It will implement control laws to restrain tether dynamics in/off the orbital plane; and will carry out plasma chamber measurements and numerical simulations of tether-plasma interaction. The project also involves the design and manufacturing of sub-systems: electron-ejecting plasma con-tactors, an electric control and power module, interface elements, tether and deployment mechanisms, tether tape/end-mass as well as current collection plus free-fall, and hypervelocity impact tests.

AcHieVed resuLts

The BETs project focuses on an activ-ity explicitly recommended in the topic ‘preventing generation of new debris … after mission completion’, based on the FP7- Space 2009 Call. The project thus ignores mitigation meas-ures and surveillance programmes such as ESA’s Space Situational Awareness, as well as debris already accumu-lated in space. Work to be carried out would be Research and Technology development of a de-orbit system, which, in the near future, should be carried on board every spacecraft launched into LEO. A dedicated system is needed because satellites naturally orbit at ionospheric altitudes where air drag is very weak.

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The system considered will deploy a conductive thin-tape bare-tether to collect electrons as a giant Langmuir probe, requiring no propellant and no power supply, and thus generating power on board. The system involves magnetic drag on current flowing along the tether. Like air drag, magnetic drag is a dissipative mechanism aris-ing from the orbiting-tether motion relative to the co-rotating magnet-ised plasma, which induces a so-called motional electric field Em at the ambi-ent plasma, in the frame of the tether. That field drives current into the tether, and the geomagnetic field then exerts a Lorentz force on the current-carry-ing tether. Tether drag is passive like air drag and propulsive like rockets and electrical thrusters.

The scientific/technological objectives of the project are to prove that a tether system capable of de-orbiting could beat alternative systems (air-drag enhancing sails, rockets, electrical thrusters) in simplicity and the com-bined basic metrics: Frontal area x de-orbit time and system-to-satellite mass ratio. The project was to consider de-orbit altitudes from 800 to 1 000 km, for a range of orbital inclination and satellite mass. A prototype tether would be designed, built and tested on the ground, for de-orbiting a representative mass/orbit satellite. Approximate scal-ing laws would then be determined to adapt results to a broad range in those satellite parameters.

NASA tethers TSS1, TSS1R were fully insulated round wires that carried anodic and cathodic contactors at cor-responding ends. The cathodic device was a hollow cathode, a type of highly efficient, electron ejecting plasma con-tactor. The anodic contactor was a large spherical conductor of a radius of

0.8 m that is very large compared to both Debye length and electron ther-mal gyroradius, which are about 5 mm and 30 mm respectively. This makes the sphere highly inefficient in collect-ing ambient electrons.

In the early 1990s the bare tether concept introduced collection with two characteristic lengths (Ref.1). The tether itself, left un-insulated, was to collect electrons in a 2D-OML regime over some segment coming out posi-tively biased. A characteristically small radius R ~ 1 mm allows efficient col-lection in cylindrical geometry. In turn, a quite large tether length L provides a big collecting area. The 2D-OML cur-rent-collection rate is proportional to L, to cross-section perimeter p = 2πR, and to the square root of bias. With bias varying along the tether, collection rate varies too.

For R larger than some value Ram com-parable to the Debye length, current collection drops below the OML value. Also, the current inside the tether can actually be limited by ohmic effects. For dominant such effects, the length-averaged tether current approaches the short-circuit value scEmAt, where sc is the electric conductivity, At = πR2 is the cross-section area, and Em the motional-field component along the tether. Ohmic effects are dominant under condition L >> l1/3 (2At /p)2/3 = l1/3 R2/3, where l ∝ sc

2 Em /Ne2 is a cer-

tain ambient-dependent characteristic length.

A fundamental result from Langmuir probe theory shows that 2D-OML cur-rent collection is equal for all non-con-cave cross sections of equal perimeter (Ref.2). This allowed introducing collec-tion with three characteristic lengths. Consider in particular a thin-tape tether

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of width w and thickness h << w, thus having At = why and p ≈ 2w (and an ‘equivalent’ radius Red = w/4 with regard to OML collection validity). A ‘corresponding’ round tether of equal length and mass would have a radius ofR = wh / π . Collection will thus be greater for the tape in the large factorw / hπ . Also, the ratio 2At /p º h for

the tape is much smaller than its value R for the corresponding round wire; typi-cally, the wire does not reach the ohmic-dominated limit.

Results

The work package (WP) breakdown consists of four large primary WPs:

PWP10 system Analysis and trade-off (work packages 11 through 15);

PWP20 system design (WP21 (sub-divided in WP211 through WP213), 22, and 23);

PWP30 system Manufacturing (WP31 (subdivided in WP311 and WP312), 32 and 33);

PWP40 System Tests (WP41 through WP44).

Furthermore there are also three sim-ple primary work packages:

PWP50 Analysis of results (WP51 and WP52);

PWP60 Management (WP61); and

PWP70 other Activities (WP71 through WP73).

So far just work on PWP10 and PWP20 was carried out over the first year of the project.

System Analysis and Trade-Off (PWP10)

WP11, 12:

Two significant results from analy-sis showed ED tethers in a very posi-tive light for de-orbit operations. First, detailed de-orbit calculations using a full geomagnetic field model showed that tether performance at high incli-nation orbits is much better than usu-ally estimated from using simple field models. This proves critical to tether use as considered here because of the large number of satellite missions at inclination higher than 80 °.

Second, the probability of survival from impacts by space debris can also be much higher than usually estimated. Impact by a piece of debris may cut a tether, if its size is large enough. The fatal impact rate for a thin-tape tether, which involves two widely different cross-section lengths, was proved much lower than the rate for a round tether of equal length and mass. Both ESA (MASTER) and NASA (ORDEM) debris-flux models were used in the analysis. Since de-orbit duration will also be shorter for the tape because of current collection being generically greater due to its larger perimeter, the fatal impact count may be smaller by over two orders of magnitude.

This will allow to stick to a single-line tether-system design. Furthermore, possible material degradation due to multiple impacts by (abundant) very small debris pieces, which are too small to cut the tether, was proved negligible. All of the above allowed establishing convenient design ranges on de-orbit duration and tether sys-tem-to-satellite mass ratio. If the duration is too long, corresponding to

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very low mass ratio, survival to debris might be in danger. If the mass ratio is too high, corresponding to very short de-orbit operation, a rocket system might be lighter.

Two basic effects in cathodic and anodic contact are being considered. New materials having work function as low as 0.6 electronvolts allow for tether systems that are fully pas-sive, with no need for a hollow-cath-ode plasma contactor. The wire itself, if conveniently coated, would act as both anode (collecting electrons in the bare-tether concept along the seg-ment coming out positively biased) and cathode, ejecting electrons by thermionic emission along the seg-ment negatively biased. In turn, simple estimates of adiabatic electron trap-ping in electron collection, when the ion ram motion relative to the orbiting tether is considered, are being studied as complement to the numerical simu-lations and laboratory experiments.

WP13, 14:

A CPU-efficient tether dynamics model (LIBRA) has been developed to ana-lyse stability limits of a tether during de-orbit and to subsequently develop control strategies to stabilise the sys-tem, which, without control, exhibits a librational instability that manifests itself after a few days of de-orbiting at representative values of system parameters. Stability limits have been identified vs. key system parameters, such as orbital inclination and ratio between gravity-gradient and tether-drag forces.

Three different options of control strategies have been analysed: (a) tether current control; (b) using a sta-bilising inert tether; and (c) adding a

libration damper at the tether attach-ment point. Each option, if suitably implemented, could provide stability for a complete de-orbit of the system for different orbital inclinations. These encouraging results are to be verified with a more refined computer code that includes tether flexibility (FLEX). This code was validated through test cases and frequency analysis of vibra-tional modes. Both computer codes incorporate up-to-date environmental models: gravity field, magnetic field, ionospheric density model, and atmos-pheric density model.

Orbital scenarios that represent large classes of spacecraft that will need to be deorbited were identified and this served as the basis for parametric analysis (Ref.3). The CPU-efficient code has been used to study parametrically the de-orbit rate for representative scenarios. The two computer models have been used, whenever appropri-ate, to carry out these analyses. The three control options derived were also coded into the FLEX code to simulate the control options under more realis-tic dynamical conditions.

WP15:

Both numerical simulations using the SPIS code developed at ONERA (Ref.4) and experimental measurements using its JONAS plasma chamber were carried out to determine current col-lection by a positively biased cylindri-cal tether moving relative to plasma under LEO environmental conditions. A first measurement campaign yielded current-voltage tether characteristics for different LEO conditions, varying plasma density, and ion ram energy. To compare the results with the OML theory, a second experimental cam-paign monitored the spatial evolution

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of plasma properties around the tether using Langmuir probes and a triple probe (developed in the frame of this project and successful in determining low plasma density). Probe measure-ments showed tether current oscilla-tions at the electron plasma frequency and oscillations of both tether current and ambient plasma density at the ion frequency.

Results from SPIS simulations for the current-voltage response of three different Langmuir probes yielded plasma parameters and allowed to compare the OML theory to current-voltage characteristics from the first experimental campaign. First results currently do not show a significant deviation from the OML theory. SPIS simulations were also carried out to understand the origin of the oscilla-tions above.

Unsuccessful simulations led to code improvement with enhanced bound-ary conditions, and a time scenario to rapidly enhance ion convergence while keeping possible electron oscillations. This permitted simulating current col-lection by a tether in LEO at high posi-tive bias. First results show oscillations at the electron plasma frequency but it is presently not yet clear whether their origin is numerical or physical. At the moment, no significant deviation from the OML theory has been found. Additionally this work does not impact other work packages.

System Design (PWP20)

WP 22:

The task of designing the control sys-tem in charge of electrically driving the tether involves both power electronics and control issues, as such a system

must deal with a changing load imped-ance and extremely high external potentials in the plasma-tether inter-face during the de-orbit operation. During this first year, the most suita-ble architectures for the power stage and their appropriated control topolo-gies were identified after a deep trade-off survey (Ref.5). A complete system level layout has been designed down to component-level, mostly involving the power stage, where extensive sim-ulations were performed to validate the design concepts. Final implemen-tation details remain to be defined in rounding up the design process, such as those concerning the control loop.

A first approach for mass and volume estimations has been performed, con-sidering identified power semicon-ductors and estimated requirements of the magnetic components. This approach will be refined to a definitive set of requirements during the second period. An important effort was made to adapt electrical parameters coming out from tether physical processes to the requirements of the electrical sys-tem, mostly in terms of output imped-ance and bias voltage at the tether connector. This task is relevant to the goal of identifying and properly defin-ing the operational requirements of power supply in terms of maximum voltage/current.

WP23:

Experience in the reliability and life-time of hollow-cathodes was reviewed, although most experience relates to use in electric propulsion, where they are at the core of generated thrust or drag. For tethers, they just act as ‘neu-tralisers’, and could actually disappear as subsystems in case low work func-tion coating is available. Furthermore,

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in EP the HC requires both neutral-iser and power supply, which is not the case for tethers. The anticipated maximum lifetime of the BETs plasma contactor is ~ 300 days or 7 200 hrs. Hollow cathodes have operated for over 1 200 days. The BETs HC will uti-lise porous tungsten inserts impreg-nated with barium-calcium aluminate.

The key aspects of a Hardware In the Loop (HIL) evaluation scheme were defined that would combine any num-ber of Hollow-cathode Assembly (HCA) sub-systems as well as a simulated tether in a variety of potential oper-ating circumstances. Once all sub-systems have been independently developed and tested, they will be combined in a realistic testing environ-ment, evaluating and verifying their interdependent operation. During HIL testing, electrical signal interference, on/off transients, power supply per-formance and interaction, proper HCA start-up and operation, verification of measured plasma parameters, control analysis and scaling and tether opera-tion impact on the HCA system, will be considered.

HCA design and analysis include struc-tural design of a hollow cathode and a discharge chamber that utilises a ring-cusp magnetic field to enhance plasma production and reduces the impedance between plasma contac-tor and low density ionospheric plas-mas (Ref. 6). The plasma contactor also requires an expellant storage and delivery (ES&D) subsystem that can deliver xenon gas to the cathode and discharge chamber for the duration of the mission. Components include the HCA with a ring-cusp discharge chamber, the ES&D subsystem, and the power controller system (PCS). A flight PCS would operate the plasma

contactor and the flow control valves. It would also include data collection capability, a controller as well as com-munication links to the spacecraft bus.

WP213:

A state of the art survey was carried out to provide an overview of already existing deployment mechanisms, in particular completely passive mecha-nisms that could be adapted to every satellite system. Deployment would start at the end of satellite life with just one signal and no control from the satellite, such as data handling and power supply, which would be required during the unreeling process. Next, effects from environmental parame-ters on the functionality of the deploy-ment mechanism were theoretically analysed. This showed that passive deployment is both very hard to real-ise and highly dependent on environ-mental parameters.

In a second step several deployment concepts were developed based on the existing experience at DLR (Ref.7). They differed in how the tether is stored, in unreeling basics, and in end-mass separation. All those concepts have been realised in bread-board units for deployment tests under dif-ferent conditions. These tests were carried out to study tether unreeling behaviour, to compare different stor-age possibilities, and to record and analyse the required pull force at tether release and during its deploy-ment. Based on test results, an evalu-ation of the concepts was done. This evaluation showed that deployment from a reel presents the best charac-teristics for a passive deployer as well as the lowest risk in tether behaviour during deployment, such as tether entanglement or twisting.

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The best rated deployment mechanism was chosen for final design in CAD. The mechanism consists of end mass, which will be ejected smoothly with separation springs that pull the tether from the reel; the separation springs; the reel on which the tether is reeled; a centrifugal break to ensure that the unreeling speed does not exceed a pre-determined value; a launch lock and a shell for the entire mechanism.

WP211:

Work has been carried out in defining the tether design concept, both with regard to cross-section and length-wise structures. Tape tether materi-als have been preselected and tensile tests performed. The cross-section structure of the tape core is made of ALPET 102510 (Ref.8). Samples of this material have been mechanically tested and analysed by means of SEM images. It comprises three different layers: the core, which is 25–28 µm thick and manufactured in PET (a thermoplastic polymer resin), is sand-wiched by external aluminium layers

of 10–12 µm thickness and tape width of 25 mm. Material procurement has started.

The connectors of the tape tether with both end-mass and satellite have been designed and tested. Tape tether insu-lation in the segment next to the sat-ellite and in the triple-point junctions has been carefully studied. The length-wise structure is as shown in the figure (from the first BETs Periodic Report):

CONCLUSIONS

Important basic results for tether de-orbiting already established are (i) performance at high-inclination orbits proves much better than usually esti-mated, and (ii) survivability to debris impacts greatly increases in moving from round tethers to thin-tape teth-ers of equal length and mass; this applies both to a single-impact tether cut by large enough debris and to material degradation due to nearby multiple impacts by abundant, very small debris.

Figure 1.

1. Conducting joint between Al connector — ALPET, shielded/reinforced by Kapton.2. ALPET(w25 mm) insulated by Kapton/Mylar/Coating(w35–40 mm). Length 220 m (ProSEDS). Coating to avoid ATOX problems CCOR.3. Triple point: Aerodag G. Length 150–300 mm.4. Bare ALPET, Length 5 km.5. Insulation: Al removing + CCOR Length 30–40 mm. Triple point: Aerodag G. Length 150–300 mm.6. ALPET, non-conducting. Length 300 mm.7. Same as at 1.

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High tether survivability will allow use of single-tether systems. It will also allow establishing broad ranges for tether system-to-satellite mass ratio and de-orbit duration. If the mass ratio were too low, it would lead to long duration and high debris risk, if it were too high it could make the tether-system heavier than a de-orbit rocket system. This has a deep effect on designing a tether sys-tem, which is made of the tether itself and auxiliary subsystems (deployer, power module, hollow cathode). A rule of thumb would require total system mass not to be larger than three times the tether mass. This places constraints on the mass of subsystems.

A de-orbit mission representative in satellite mass, altitude and inclina-tion orbit, had been first searched for in order to carry out detailed design, man-ufacture, and tests of an optimum de-orbit tether system. Finally, however, focus has moved to a de-orbit mission at 1 300 km altitude, 65 degree inclina-tion, and mass of order of 500 kg (simi-lar to GMES jason cs, planned by ESA for the near future, with a commitment to de-orbiting within some limited span of time from end of life). This will con-veniently force critical assessment in evaluating subsystems, and will require some degree of systems integration. A light demo flight will be considered in parallel.

Both dynamic modelling and simula-tions/chamber tests of current collection are well advanced. Design is continuing in the first half of the second year.

REFERENCES

  Bombardelli, C., Zanutto, D., and Lorenzini, E. C., ‘De-orbiting Performance of Bare Electrodynamic

Tethers in Inclined Orbits’, J. Guidance, Control and Dynamics, submitted.

  Capel, A., O’Sullivan, D. and Marpinard, J.-C., ‘High-power conditioning for space applications’, IEEE Proceedings, 76, 1988, pp. 391–408.

  Fujii, H. et al., ‘Space Demonstration of Bare Electrodynamic Tape-Tether Technology on the Sounding Rocket S520-25’, AIAA 2011-6503, 8–11 August 2011, Portland, Oregon.

  ‘GEMS — A mole to explore the interior of Mars’, http://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10333/623_read-818/, 12 September 2011.

  Laframboise, J. G. and Parker, L. W., ‘Probe design for orbit-limited current collection’, Phys. Fluids, 16, 1973, pp. 629–636.

  Roussel, J.-F., Rogier, F., Dufour, G., Matéo-Vélez, J.-C., Forest, J., Hilgers, A., Rodgers, D., Girard, L. and Payan, D., ‘SPIS Open Source Code: methods, capabilities, achievements and prospects’, IEEE Trans. Plasma Sci., 36, 2008, pp. 2360–2368.

  Sanmartin, J. R., Martinez-Sanchez, M. and Ahedo, E., ‘Bare wire anodes for electrodynamic tethers’, J. Prop. Power, 9, 1993, pp. 353–360.

  Williams, J. D. and Beattie, J. R., ‘Spacecraft Potential Control using Plasma Contactors,’ 3rd International Workshop on the Interrelationship Between Plasma Experiments in the Laboratory and in Space, IPELS’94, Pitlochry, Scotland, 24–28 July 1994.

CHAPTER 52

Authors: Olive Stohlman, Lourens Visagie, Theodoros Theodorou, Juan Fernandez, Vaios Lappas

consortium members: University of Surrey, the United Kingdom; Astrium S.A.S., France; ATHENA/SPU, Greece; California Institute of Technology, USA; DLR Braunschweig, Germany; Innovative Solutions in Space BV, the Netherlands; Middle East Technical University, Turkey; Stellenbosch University, South Africa; Surrey Satellite Technology Ltd., the United Kingdom; University of Patras, Greece

AbSTRACT

DEORBITSAIL is a cubesat mission to demonstrate in-space deploy-ment of a large thin membrane sail and drag deorbiting using this sail. The sail will be deployed from a 10 cm × 10 cm × 30 cm cubesat plat-form which will be 3-axis controlled.

The DEORBITSAIL design is intended for space debris prevention, although both drag sailing and solar sailing have additional applications in aerob-raking and solar sail propulsion.

The uncontrolled growth of the space debris population has to be avoided in order to enable safe operations in space for the future. Space system operators need to take measures to conserve a space debris environment with tolerable risk levels, particu-larly in low earth orbit (LEO) altitude regions.

This project’s approach is to modify solar sail deployment technology for use as a satellite and/or rocket upper stage deorbiting system. The effec-tiveness of such deorbiting device is predicted to be high at altitudes lower than 1 000 km for minisatel-lites (20 kg to 500 kg) if deorbiting time constraints of 25 years are being considered. The same design will also be capable of using solar radiation

Figure 1. Undeployed DEORBITSAIL satellite (left); solar panel deployment (centre) and sail deployment (right) (source: Surrey Space Centre).

DEORBITSAIL: De-Orbiting of Satellites using Solar Sails

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pressure as a deorbiting force above the 1 000 km mark. In contrast with JAXA’s spin-deployed deep space solar sail, Ikaros (1), DEORBITSAIL will deploy and maintain its shape with rel-atively stiff structural booms. This pro-ject is a pathfinder mission that hopes to create options for deorbiting of sat-ellites and forward the cause of solar sail propulsion.

The stowed satellite will be similar in size to a 3U CubeSat and it will make use of commercially available CubeSat modules for the satellite bus compo-nents. CubeSats have the advantage of a simplified infrastructure, enabling low cost and short development times. The standard also provides a unified inter-face with the launcher, via the P-POD (Poly-Pico-satellite Deployer) or similar deployers. The DEORBITSAIL satellite will make use of the 3U standard as far as possible, devoting approximately 1U of volume to each of the sail deploy-ment system, sail membrane storage, and electronics bus.

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Design results

The 3U CubeSat goal is a critical design driver for DEORBITSAIL. A 3U CubeSat has dimensions of approximately 10 cm × 10 cm × 34 cm, with some loss for the thickness of solar panels and other considerations. This space has been divided into four sections: approximately 10 cm of length for the satellite bus, 4 cm for a 2-axis trans-lation stage, 10 cm for the stowage of the sail membrane, and 10 cm for the sail deployment system. The 2-axis translation stage is an actuator which is part of the attitude control system. The sail deployment system consists

of four deployable booms, which are stowed, like carpenters’ tapes, via elas-tic deformation.

In designing for the 3U CubeSat vol-ume, a number of subsystems have been assembled from commercially available CubeSat parts or miniatur-ised from existing technology. In par-ticular, the attitude determination and control system (ADCS) will implement aggressively volume-saving designs and the booms and their deployment system will be a very densely pack-aged version of a heritage design.

The ADCS processing will be carried out by a software task running on the on-board computer. The estimation and control loop will execute at a rate of 1 Hz. It will make use of sensor data from the following sensors:

•3-axis resistive magnetometer

•Optical sun- and nadir sensors

•3-axis MEMS gyroscope

• Coarse sun sensing using six photodiodes

The ADCS will use a combination of magnetic torquer rods and transla-tion stage for actuation. The latter is located (as shown in Figure 2) between the satellite bus and the sail attach-ment. Translating the sail centre-of-pressure with respect to the satellite bus changes the torque generated by the sail (whether aerodynamic or from solar radiation pressure) and thus can be used to control the attitude of the sail. A Y-body-axis-aligned momentum wheel will give additional stability in the momentum/Y-pitch control mode. The ADCS components are described in detail in (2).

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Figure 2. Attitude control hardware (source: Surrey Space Centre/Stellenbosch University)

The miniaturised components avail-able commercially for CubeSats, combined with the translation stage technology, will make the demon-stration of the drag sail more com-plete than otherwise possible in such a small volume. With an optimal atti-tude for drag deorbiting, the best pos-sible performance for a sail system will be accomplished. Telemetry data will also confirm the demonstration of the translation stage’s effectiveness as an attitude control device.

Similar to the small CubeSat-ready components selected for the ADCS, the sail deployment system is a much smaller version of previous concepts. While some standard off-the-shelf com-ponents are available for the ADCS, the deployment system will be entirely cus-tomised for the goals of DEORBITSAIL.

A boom design already used by the German Space Agency (DLR) Braunschweig has been adapted to the demands of the DEORBITSAIL project.

This type of boom (3) has been devel-oped as a standard design at DLR since the 1990s and is being used in a num-ber of projects, including the Gossamer series (4) (5).

The deployment module will be required to restrain the booms until deployment and to support the roots of the booms under drag and deploy-ment loads.

Figure 3 shows the preliminary design for this system. Deployable doors will double as support arms for the booms. The design is focused on achieving the 3.5 m required boom length in a foot-print no more than slightly larger than the 3U CubeSat standard.

Analysis results

The early analyses have focused on orbit prediction and structural con-cerns. The orbit and attitude model is essential for evaluating the expected performance of the sail for comparison

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Figure 3. Booms and deployment module from above (left) in the stowed configuration and in perspective (right) in the deployed configuration (source: DLR Braunschweig).

with the eventual telemetry data in flight. Structural analysis has been dic-tated by the design process.

Orbit and attitude model

The combination of attitude control strategies allows for robust control of the spacecraft’s attitude despite its very small size. This is an improvement over the Nanosail-D system (6), a simi-larly-sized demonstration mission that deployed a drag sail in orbit in 2010 and deorbited to demise over approx-imately eight months (7). The active attitude control system is expected to produce a substantial improvement over passive attitude control. Simple analysis of drag area concludes that a sail with perfect attitude control should achieve a drag force π/2 higher than the average drag on a tumbling sail.

The orbital analysis predicts a dramatic difference in performance between solar minimum and maximum con-ditions. For an initially circular orbit at 650 km and sail loading factor of 0.16 kg/m2, the decay time is 15 days at maximum solar activity and 130 days for minimum solar activity. The average atmospheric density at 650 km during solar minimum is 9.2 × 10-15 kg/m3, and

at solar maximum it is 1.7 × 10-13 kg/m3 — almost a factor of 20 (using the NRLMSISE-00 model with actual Ap and F10.7 indices). The drag force will thus also be 20 times larger at maximum solar conditions, resulting in a much shorter lifetime. Assuming a launch date for DEORBITSAIL of 1 January 2014 and projected solar conditions, the orbit life-time of a 4 kg satellite with 25 m2 sur-face area is between 33 and 40 days, depending upon drag coefficients. A 3U CubeSat of this mass at this altitude would take over 25 years to deorbit.

Structuralanalysis

Structural and thermal analyses have been approached with the goal of iden-tifying the loads on the booms. The booms are particularly slender and also crucial to the success of the mis-sion. It is therefore essential to evalu-ate the risk of global or local buckling of these gossamer structures.

The sail will be folded and compressed for stowage, and this will leave creases in the membrane material, which in turn will produce a very small spring force in the sail membrane. Creasing will also have a marginal effect on the sail’s efficiency.

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Figure 4. Modelled (top) and experimental (bottom) displacements of sail membranes under gravity. Experimental displacements, at right, are for the section of membrane pictures at left, and were measured by digital image correlation (source: Space Structures Laboratory/Caltech).

Computational modelling and verifica-tion experiments on a sail supported at its corners have thus far concluded that a lightly stretched sail can pro-duce forces in the order of 0.1 N. These tiny forces are relevant to the mission because of the very slender nature of the booms and the modest loads antic-ipated from drag.

Computational thermal analysis has been conducted for a boom as an individual component and to evalu-ate the impact of the sail on the bus. From the point of view of the bus, the sail replaces close to half of the sky. Reflected and blocked sunlight, while not insignificant, is less important to the bus temperature than the temper-ature of the sail itself. The sail’s ther-mal profile, throughout the orbit, is determined by its angle with the sun and its thermal emissivities.

Thermal analysis of the booms is con-cerned with the deformations they will

experience due to uneven heating. The worst-case scenario was taken to be direct sunlight on one side and a low-temperature space environment of 2.725 K. Because thermal conductiv-ity is expected to be relatively low in the booms (values of 2.0–2.8 W/m-K in-plane and 0.53–0.65 W/m-K in the transverse direction were used in the simulation, based upon (8)), radiation between the boom halves is significant and was included in the simulation.

The thermal simulation of the booms in Abaqus/Standard concluded that, at the assumed material properties and in a worst-case environment, a tem-perature differential of 120 K could be maintained between the top and bot-tom surfaces of a boom. This would produce a deflection of 34 mm at the tip of a 3.53 m boom held as a can-tilever. This deflection is important for the continued study of the boom and its tolerance of loads, and can be mod-ified by choice of boom material.

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CONCLUSIONS

DEORBITSAIL has taken on an ambi-tious set of goals, and packaging a complete demonstration mission into the 3U CubeSat volume has driven interesting design results. A number of advances have already been made in design for the small volume available. Every component of the satellite will be held to a high standard for volume utilisation: the electronics bus and its ADCS, the booms and their deployment system, and the 25 m2 sail membrane.

As DEORBITSAIL is a flight mission, ongoing work will produce first an engi-neering model for extensive testing and then a flight model. Moving from the theoretical design to the engineering model is expected to reveal a number of challenges, and work will proceed on several fronts.

The internal bus components will be arranged with an eye to the project’s volume goals and to allow for accept-able thermal bounds. A customised structure will be designed to support the unique demands of the densely packed bus and the large deploya-ble sail system. A carbon-fibre-rein-forced polymer satellite structure is the baseline design for this project, and nonstandard internal connectors will be used to decrease the clearance between electronics boards in the bus.

As with the bus and the boom deploy-ment system, the sail will have to be packaged very tightly to achieve the target volume. Even with theo-retically perfect packaging and a full 10-by-10-by-10 cm volume avail-able, the membrane material thick-ness for a 25 m2 sail could not exceed 40 µm. As volume will be lost to struc-tural requirements and substantial

inefficiencies in the packaging are unavoidable, the required membrane will approach the limits of commonly manufactured materials. The fold-ing pattern, packaging method, and material specification are all being addressed as serious concerns for DEORBITSAIL. Repeatability and ease of testing are points of focus in the selection of a packaging method.

Testing will focus on the deployment system, assuring that the booms and sail will unfurl reliably and without damage to themselves or the support-ing structures.

Development and testing will be ongo-ing throughout 2012, and the project will proceed to preparation of the flight model in 2013.

REFERENCES

   Tsuda, Y. et al., ‘Flight status of Ikaros deep space solar sail demonstrator’, Acta Astronautica, Vol. 69, 2011, pp. 833–840.

   Steyn, W. H., ‘Attitude control actuators, sensors and algorithms for a solar sail CubeSat’, Cape Town: 62nd International Astronautical Congress, 2011.

   Block, J., Straubel, M. and Wiedemann, M., ‘Ultralight deployable booms for solar sails and other large gossamer structures in space’, Acta Astronautica, Vol. 68, 2011, pp. 984–992.

   Geppert, U. et al., ‘The 3-step DLR-ESA Gossamer road to solar sailing’, Advances in Space Research, Vol. 48, 2011, pp. 1695–1701.

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   Straubel, M. et al., ‘Deployable composite booms for various gossamer space structures’, Denver, CO: s.n., 52nd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2011.

   Johnson, L. et al., ‘NanoSail-D: A solar sail demonstration mission’, 5–6, Acta Astronautica, Vol. 68, 2011, pp. 571–575.

   NASA, NanoSail-D Home Page. [Online] 13 January 2012. [Cited: Feb 15, 2012.] http://www.nasa.gov/

mission_pages/smallsats/nanosaild.html.

   Sweeting, R. D. and Liu, X. L., ‘Measurement of thermal conductivity for fibre-reinforced composites’, s.l.: Elsevier, Composites: Part A, Vol. 35, 2004.

   Lappas, V., et al., ‘CubeSail: A low cost CubeSat based solar sail demonstration mission’ s.l.:, Advances in Space Research, Vol. 48, pp. 1890–1901.

CHAPTER 53

Authors: Thérèse Donath, Romain Kervarc, Nathan Welty, Frank Schaefer, Roberto Destefanis

consortium members: OHB-System, Germany; Thales Alenia Space, Italia; Fraunhofer Ernst-Mach-Institut, Germany; TÜBİTAK UZAY, Turkey; Technische Universität Braunschweig, Germany; TELINT RTD Consultancy Services, the United Kingdom

AbSTRACT

The strategic importance of space sys-tems is growing in Europe, for civil and defence applications, such as satel-lite communications, Earth observa-tion, satellite navigation, etc. Recent examples have shown that on-orbit collisions brought on by space debris are actual threats. On one hand, some space debris is routinely tracked, mak-ing collisions predictable, but the increase in collision alerts affects the cost of space missions’ management. On the other hand, most debris items are untracked because they are too small, making prediction impossible. The way to reduce vulnerability is then to reduce the severity of collision and the probability of occurrence.

The P²-ROTECT project aims to assess the risks associated with space debris

collisions and recommend possible solutions (better prediction, better pro-tection or action on debris environment) to reduce vulnerability of future space missions with respect to on-orbit col-lisions. In order to make these recom-mendations, the project first elaborates a vulnerability index and tool which quantifies the efficiency of solutions with respect to trackable and untrack-able debris effects and which provides access to sensitive terms of collision probability or severity. Furthermore, trade-offs are made between effi-ciency and cost to propose new design options for future space infrastructures. In order to work with concrete exam-ples depending on orbit types, three missions of interest for the EU are ana-lysed: Sentinel-1 in low earth orbit, Galileo constellation in medium earth orbit and MTG (Meteosat 3rd genera-tion), the weather observation constel-lation, in geostationary orbit.

The Consortium is led by ONERA and includes well-known companies, includ-ing SMEs capable of analysing space missions at all levels (spacecraft (S/C) component, S/C, mission) and research institutes able to provide innovative solutions for risk reduction.

Less than one year after project kick-off, the achieved results concern the development of the vulnerability index and of the related evaluation tool.

P2-ROTECT: Prediction, Protection & Reduction of OrbiTal Exposure to Collision Threats

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Within this tool, the part dedicated to the impact and effects of untrackable debris on spacecraft components has also progressed and a preliminary ver-sion was available for integration at the end of 2011. An exercise has been performed on Sentinel-1A S/C to sup-port the development of the space mission-level vulnerability evaluation.

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Space mission vulnerability index

Space mission vulnerability is defined here as the risk of functional damage at mission level due to physical dam-age at component or S/C levels (i.e. untrackable debris effects) or due to collision avoidance manoeuvres (i.e. trackable objects effects) which con-sume fuel and act directly on mission life duration.

The proposed vulnerability index [1] reflects a risk assessed taking into account the likelihood of a debris sce-nario (called scenario of interest) with respect to a reference one (e.g. the con-sidered scenario for mission design) and calculating the severity of perfor-mance degradation over time between both scenarios.

This index presents two characteristics:

— It is unified between both domains of untrackable and trackable objects;

— It reflects the situation not only at S/C level, but at space mission level and this is particularly important since innovation related to mis-sion (e.g. fractionation or mitiga-tion guidelines) may be analysed at the same time with innovations

related to S/C or components, e.g. shielding, redundancy …).

Space mission-level vulnerability evaluation tool

The vulnerability assessment of a space mission consists in calculating the pre-ceding index for which an evaluation tool is currently developed. The overall process flow is illustrated in Figure 1.

The first step is related to the assess-ment of untrackable debris effects on S/C and this evaluation requires the development of a dedicated tool PIRAT (Particle Impact Risk and Vulnerability Assessment Tool). The evaluation method and the associated tool are presented in the next paragraph.

The second step is related to the assessment of trackable debris effects on S/C. In the case of an alert for a risky in-orbit collision, the S/C has to manoeuvre and a tool is developed to assess the probability of performing this avoiding manoeuvre [1], [2] which also reduces the payload availability.

The third step of the figure is the evalu-ation of the probabilities of availability of the elementary functions described in the functional architecture of the space mission and the evaluation of elementary resources availability.

The ATLAS (Analysis by Temporal Logic of Architectures of Systems) tool is then used to fuse probabilities of ele-mentary functions [3] and resources consumption/production.

Those four steps are calculated for each of the debris scenarios which are considered as reference or as inter-est and finally, the vulnerability index is evaluated.

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Figure 1. Space Mission Vulnerability Evaluation Process Flow

Spacecraft-level vulnerability evaluation tool

The vulnerability assessment of a space mission with respect to untrackable space debris requires at its core an understanding of the associated risks present at the spacecraft-level. Using a debris flux model and a suitable bal-listic limit equation (BLE), the risk of penetration of the spacecraft wall from debris impacts can be calculated, as is currently done to satisfy safety require-ments for manned space missions such as the International Space Station (ISS) [4]. However, for unmanned missions, penetration of the spacecraft wall is not necessarily critical and penetrating debris particles may not always result

in critical component failures. Thus it would be overly conservative to equate structural penetration with the loss of a satellite mission. To enable a better understanding of the actual risks posed by untrackable space debris to opera-tional satellites, the effects of debris particle impacts on the functionality of components and on the overall system need to be considered.

The Particle Impact Risk and Vulnerability Assessment Tool (PIRAT) is being developed by Fraunhofer EMI within the P2-ROTECT project to serve as the computational core for the quantitative vulnerability assess-ment at the spacecraft-level with regard to untrackable space debris.

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The PIRAT core takes advantage of a newly developed method to predict internal satellite effects resulting from impacts of untrackable space debris particles, specifically the likelihoods of debris-induced component failures [5]. It combines a debris flux model with the Schäfer-Ryan-Lambert BLE, which accounts for the inherent shield-ing of components positioned behind the spacecraft structure wall. Debris impact trajectories and the shadow-ing effects of both external and inter-nal components are considered. As a result, the PIRAT core provides failure probabilities of individual components as a function of mission time. These results can then be used by satellite designers to improve design robust-ness or as inputs for the mission-level vulnerability assessment within the overarching ATLAS tool.

In contrast to a fully stochastic Monte Carlo-based approach, the computa-tional method used by the PIRAT core is semi-deterministic. The overall process flow is illustrated in Figure 3. The latest ESA debris flux model MASTER-2009 is first used to stochastically predict the fluxes of untrackable debris particles

expected to be encountered by the spacecraft within a defined orbit and mission time horizon. Its discretised flux predictions allow the total incident untrackable debris environment to be represented by a finite set of incoming debris particle fluxes. With the assump-tion that particle impact and damage events are probabilistically independ-ent, the incremental risk to space-craft components resulting from each incident debris particle flux can be assessed individually.

The shadowing effects of external com-ponents such as solar arrays or anten-nas can reduce the effective debris flux reaching the S/C outer structure depending on the directionality, size and velocity of the incoming particles. To account for these effects, debris par-ticle fluxes are reduced in proportion to the vulnerable area of the space-craft exposed to the incoming parti-cle and on its capability to penetrate shadowing objects. The likelihood PH that an internal component is hit by a given particle flux is determined using Poisson statistics and by accounting for the internal fragmentation effects of the penetrating debris particle.

Figure 2. Visualisation from PIRAT Computational Core Figure 3. PIRAT Methodology Process Flow

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The Schäfer–Ryan–Lambert (SRL) BLE is a triple-wall BLE used within the PIRAT core to model the vulnerabil-ity of satellite equipment positioned behind the structure wall [6]. For a given impact angle and impact veloc-ity, the SRL BLE calculates the critical projectile diameter necessary to result in penetration or detached spallation of the equipment cover plate. It is conservatively assumed that this pen-etration or detached spallation will result in the functional failure of the component. The likelihood PK|H that an internal component is destroyed fol-lowing an impact is then determined by comparing the characteristic diam-eter of the debris particle with the critical diameter provided by the SRL BLE. In the final step, the aggregate vulnerability of each component is determined by combining the incre-mental failure probabilities over the entire set of incoming debris parti-cles fluxes. The aggregate vulnerabil-ity PK of a component represents the total likelihood of debris-induced fail-ure over the time period of evaluation.

Spacecraft-level vulnerability methodology

To support the development of the space mission-level vulnerability evaluation methodology, an exercise has been performed to assess the vulnerability of the Sentinel-1A S/C to impacts from untrackable orbital debris.

In this exercise, a traditional approach to evaluate damages caused by debris and meteoroids on S/C components has been combined with a FTA (Fault Tree Analysis) methodology. The pur-pose of this exercise was to evalu-ate S/C functional impairment starting

from components failure probability. This approach allows accounting for functional dependencies and redun-dancies avoiding the overestimation of damages caused by Micrometeoroids and Orbital Debris (MMOD) impacts.

As a first step, a simplified physical model of Sentinel-1A has been cre-ated using the ESABASE2/Debris tool, developed under ESA contract. The Sentinel-1A ESABASE2/Debris model includes the external components and the projections of internal com-ponents on the external surfaces (see Figure 4).

In particular, to compute the failure probability of internal components, the Schäfer-Ryan-Lambert BLE has been implemented into ESABASE2/Debris. As explained previously the SRL equa-tion calculates the ballistic limit of an equipment cover plate located behind a sandwich panel structure. It has been assumed that penetration of the equipment cover plate will cause fail-ure of the component.

The ESA Master 2009 environment model was used to evaluate the mete-oroids and debris fluxes on the S/C.

At the same time, the functional archi-tecture of the Sentinel-1A S/C has been studied, modelling functional interdependencies and redundan-cies according to the FTA methodol-ogy. The FTA of the Attitude and Orbit Control System of Sentinel-1A is illus-trated in Figure 5.

Eventually the failure probabilities of the S/C components (external and internal), obtained from the ESABASE2 simulation, have been composed according to the FTA methodology.

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Figure 4. ESABASE2 Sentinel-1A model Figure 5. Sentinel-1A Attitude and Orbit Control FTA

CONCLUSIONS

The P²-ROTECT project began in March 2011 and the Consortium agreed on the formalism given to the space mis-sion vulnerability index and its evalua-tion tool. Preliminary parts of this tool are available:

— The evaluation of vulnerability at S/C level due to the untracka-ble space debris collisions (PIRAT software);

— The evaluation of vulnerability at S/C level due to manoeuvres per-formed to avoid the trackable space debris collisions;

— The evaluation of space mission performance at functional level with respect to a debris scenario.

Current work is carried out on the development of the global evaluation chain and the evaluation of space mis-sion at resource level.

In parallel to the development of the space mission vulnerability evalua-tion tool and of its core part PIRAT,

major work will be done in the follow-ing domains:

— Debris-scenario propositions based on MASTER-2009. The idea is to propose three reference scenarios (Business-As-Usual, Intermediate Mitigation and Full Mitigation). For scenarios of inter-est, they will be built on reference ones including possible frag-mentation events of S/C or R/B. Detailed information will be avail-able soon.

— Space mission functional archi-tectures for all three missions of interest: Sentinel-1, Galileo and Meteosat 3rd generation.

— Improvement of debris collisions prediction. Some results are avail-able concerning the proposal of new indicators for collision risks. They are being analysed in detail before publication.

— Improvement of S/C protection against untrackable debris colli-sions (analysing innovative shield-ing, enhanced redundancy and

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design). A focus on the Sentinel-1 case will be done.

An amendment to the Consortium Agreement has been signed between the partners to enable the Consortium to access information on Galileo and MTG. This is now performed and the work related to these two missions is expected to progress quickly.

Finally, a public workshop (http://www.p2rotect-fp7.eu) was held on 20 and 21 March 2012, in Ankara (Turkey). The one-and-a-half-day workshop focused on the possible three ways of reduc-ing vulnerability: better prediction of collisions of space assets with track-able space debris, better protection of missions from damage caused by unpredictable collisions and action on the debris environment by removing directly the source of the threat.

REFERENCES

  Bertrand, S., Prudhomme, S., Merit, S., Jolly, C., Kervarc, R. and Donath, T., ‘Space systems’ vulnerability assessment to space debris: a methodology and a program’, to be presented at the IEEE Aerospace Conference, 2012.

  Bertrand, S., Bérend, N. and Muller, F., ‘A trade-off study between size threshold of catalogued objects and

track accuracy for the design of a space situational awareness system’, Proceedings of the 61st International Astronautical Congress, Prague, CZ, IAC-10-A6.5.8, 2010.

  Kervarc, R., Louyot, C., Merit, S., Dubot, T., Bertrand, S. and Bourrely, J., ‘Performance evaluation based on temporal logic’, in Proc. of the 9th IMACS/ISGG Meeting on Applied Scientific Computing and Tools, IMACS Series in Computational and Applied Mathematics, 2009.

  O’Connor, B., Handbook for Limiting Orbital Debris, NASA Handbook 8719.14, National Aeronautics and Space Administration, Washington, DC, 2008.

  Welty, N., Rudolph, M., Schäfer, F., Apeldoorn, J. and Janovsky, R., ‘Computational methodology to predict satellite system-level effects from untrackable space debris’, Proceedings of the 62nd International Astronautical Congress, Cape Town, South Africa, IAC-11-A6.3.10, 2011.

  Schäfer, F., Ryan, S., Lambert, M. and Putzar, R., ‘Ballistic limit equation for equipment placed behind satellite structure walls’, International Journal of Impact Engineering, vol. 35, no 12, 2008, pp. 1784–1791.

Authors: Claude Cougnet, Bernard Gerber

consortium members: Astrium SAS, France; Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., Germany; Technische Universität Braunschweig, Germany; University of Southampton, the United Kingdom; University of Leicester, the United Kingdom; Astrium GmbH, Germany; PHS Space Ltd, the United Kingdom; TenCate Advanced Composites BV, the Netherlands; Hiscox Assurance Services, France; Astri Polska Sp. Z.o.o., Poland

AbSTRACT

The quantity of debris in space is con-tinuously increasing even if rules are applied by the space community to limit the generation of new debris. Thus, the presence of debris becomes an increasing risk for the survivability of space assets.

The ReVuS project was started in March with the objective to define design solutions in order to reduce the vulner-ability of future LEO satellites to small debris (typically 1 mm to 5 cm).

A first activity, an assessment of the vulnerability of current LEO satellites to small debris, is being completed. With that aim, two reference satellites have been modelled, and the distribution of

the flux of particles on their surfaces has been generated. Based on that, an evaluation of the satellite items that could be impacted by the particles has been performed, including the assess-ment of the failure risk.

Based on this analysis, solutions to the system and satellite architecture have been identified to minimise the vulner-ability of the satellites, and their anal-ysis was started. The use of shielding protection is one of the main satellite architecture solutions. Thus, shielding materials will be developed and tested during the project.

AcHieVed resuLts

ReVuS project

The ReVuS project started in March 2011 for a 28-month duration. It aims to define design solutions in order to reduce the vulnerability of future LEO satellites to small-sized debris.

The project follows a three-step approach, as illustrated in Figure 1:

• the vulnerability analysis, to evalu-ate the effects of a collision of a sat-ellite in LEO with small-sized debris, the potential damage and the critical parts of the satellite;

• the identification and analysis of potential solutions at system level,

ReVus: Reducing the Vulnerability of Space Systems

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and at satellite architecture level, with a focus on the shielding solu-tions and shielding materials;

• the resiliency analysis, aiming at evaluating the resiliency of the selected solutions with respect to debris impact and at proposing design rules and standards.

Vulnerability analysis

The vulnerability analysis, which is cur-rently ongoing, is based on the evaluation of the orbital debris-related vulnerabil-ity of two representative spacecraft, an Earth observation optical satellite and an Earth observation SAR satellite.

In terms of evolution of the debris pop-ulation, the present debris environment situation, and future scenarios in three possible variants, as implemented in the MASTER-2009 (Meteoroid and Space Debris Terrestrial Environment Reference) model [1] have been considered.

The Business-as-usual (BAU) scenario, which assumes that current practices are to continue into the future, has been taken into account for this vul-nerability analysis as being the worst case scenario.

The object diameter range considered by the analyses is between 1 mm and 5 cm, with the upper limit represent-ing an expected future lower diame-ter threshold for a space surveillance system.

The period used for the analysis cor-responds to the 10 years following 1 January 2020.

This vulnerability analysis uses the impact assessment tool SHIELD 3

that evaluates the probabilities linked to risk of debris penetration and risk of failure.

This tool requires information about the design of the two reference sat-ellites (geometric data, equipment sizes and location, material proper-ties, system data, information about redundancy concept) in order to draw correct conclusions on spacecraft vul-nerability while having a significantly reduced complexity of the model.

To ensure a high reliability of the results of the analysis, a number of iterations had to be performed as the level of detail at which the satellite data was provided had to be increased in some cases. Figure 2 shows a sketch of these reference satellite models.

In parallel, the directional distribu-tion of the debris flux on the satel-lites has been computed using the MASTER 2009 environment model, and forwarded to the SHIELD tool. The SHIELD tool will use this information to determine the flux of debris impact-ing and possibly penetrating the sat-ellites, and to evaluate the probability of non failure of the equipment. By combining this with information on the redundancy concepts and the crit-icality of specific equipment a debris impact-related failure probability for the mission can be derived.

A first issue of this vulnerability anal-ysis has evaluated the flux of debris particles impacting the various faces of the two satellites, and the flux of particles penetrating these surfaces as function of the size of the debris. Figure 3 illustrates these fluxes of debris on two faces of the reference satellites: the front face (along veloc-ity vector) and the Earth face (optical

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satellite) or lateral face (SAR satel-lite). It shows that:

• debris with a size below 1 mm has a high number of impacts, but only few penetrate the wall structure;

• there is a ratio of about 100 between the density of debris in the range

[0.1 cm–1 cm], and in the range [1 cm–5 cm], whether they impact or penetrate the satellite;

• The risk of being impacted or pen-etrated by debris is much higher at 800 km than at 500 km.

Figure 1. Main steps of ReVuS project

Figure 2. Reference satellites

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Figure 3. Impacts and penetration fluxes on the reference satellites

Based on these debris fluxes, the probability of non penetration (PNP) has been evaluated for the different equipment of each satellite. It appears that:

• The equipment located close to the front face and the externally mounted ones present the highest risk of penetration by debris.

• For most of the equipment, the risk of penetration is due to debris with a size higher than 1 mm. They are not vulnerable to debris below 1 mm, except the MLI, solar cells and some equipment only protected by MLI.

• The probability of penetration is in general higher for debris in the range [0.1 cm–1 cm] than in the range [1 cm–5 cm] as their flux density is much higher.

The consequences of the debris pene-tration, and the associated risk of fail-ure, depend on the equipment itself and on the satellite architecture. The main types of consequences are:

• Loss of the mission. It could be the result of penetration of debris in the tank, or in equipment that is not externally redundant (like on-board computer, mass memory, power dis-tribution and control unit, X band electronics, etc). In case of internally redundant equipment, the level of failure (loss of part or all the equip-ment) and consequence for the mission depend on the internal archi-tecture and size of the debris. Only the redundancy level could be degraded.

•Degradation of the performance of the satellite (and mission): that would result from the loss of resources like

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a battery, degradation of solar cells, loss of payload equipment, etc.

• Reduction of satellite reliability, due to the loss of an equipment that is externally redundant, or to the loss of the internal redundancy of an equipment (if not failed)

Taking into account these results, three types of potential solutions to reduce the vulnerability of the satellite to debris impact have been identified, and summarised in Figure 4:

• The utilisation of shielding: differ-ent types of shielding could be con-sidered, based on single layer, multi-layers, type of materials. The shielding will depend on where it will

be implemented (behind a wall, close to a piece of equipment, around a tank, etc). The shielding will be used for protection against debris up to a size TBD (typically 3 mm to 5 mm). This maximum size is currently being evaluated.

• Evolution or modification of the satel-lite architecture. The use of shielding is one of the architecture solutions.

• Solutions at system level, such as fractionated satellite, or distributed concept.

The evaluation of these possible solu-tions, including the design and test of shielding material, constitute the com-ing activities for 2012.

Figure 4. Applicability of the types of solutions as function of debris size

CONCLUSIONS

The ReVuS project aims to define and assess different solutions related to the satellite configuration that could be implemented to reduce the vulnerability

of satellites to small debris, and thus to avoid or minimise any degradation of the mission. It is currently ongo-ing. An analysis of the vulnerability of two reference satellites has been per-formed. It relies on the SHIELD impact

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assessment tool, which has been fed with detailed data on two reference satellites located at different altitudes, and with the directional distribution of the flux of debris on each satellite.

The vulnerability analysis has shown that the satellites are in general not vulnerable to debris having a size below 1 mm, although these particles penetrate the MLI, or could impact solar cells. The satellite has to be protected at first against debris in the range [1 mm–10 mm] as the flux of particles impacting the satellite surfaces, and the resulting flux of particles penetrat-ing these surfaces (most of the impact-ing particles) are about 100 times higher than in the range [1 cm–5 cm]. Likewise, the probability of penetration in the equipment is higher for particles in the range [1 mm–10 mm], although the consequences of a [1 cm–5 cm] particle penetrating the equipment are more dramatic.

Equipment with higher probability of penetration is usually located close to

the front side of the satellite, or exter-nally mounted. The consequences could be the loss of the mission, the degradation of satellite performances and resources, or the reduction of reli-ability level. Possible types of solutions to reduce the vulnerability of the satel-lites to debris impacts depend on the debris size. Shielding concepts will be sized for debris below 1 cm. The review of existing experience has shown that different concepts of shielding could be implemented depending on what has to be protected, its location, etc. Most suitable concepts are two or multi layer ones, but they raise implementa-tion problems.

Solutions at architecture level, such as external redundancy or adequate loca-tion on the spacecraft, and solutions at system level are applicable to larger debris, up to 5 cm.

The evaluation of these solutions is the objective of the activities to be carried out later in 2012.

CHAPTER 55

Authors: Juan Luis Valero, Sergio Albani, Beatriz Gallardo, Jacobo Matute, Anthony O’Dwyer

The European Union Satellite Centre (EUSC), based in Spain, is the only participant in the SPA project.

AbSTRACT

Space activities are increasingly important in areas such as environ-ment, science, navigation and security.

Space Situational Awareness (SSA) refers to the knowledge of location and function of space objects and the space environment. The development of an SSA capability will allow the EU and its Member States to better use space, strengthening their security and economy.

The ‘Support to Precursor space situ-ational Awareness services’ (SPA) pro-ject is an FP7 Support Action (Grant Agreement No 262930) managed by the European Union Satellite Centre (EUSC) under the full control of EU Member States and implemented with the collaboration of SSA key Stakeholders.

SPA is studying possible SSA gov-ernance and data policy models in the EUSC secure environment by

experimenting with a number of SSA preliminary services relevant to civilian security and to the com-mon foreign and security policy such as Satellite Over-flight, Satellite Conjunction Warning and Space Re-entry Prediction.

The final output of the SPA project will be a report providing recommenda-tions for further development of SSA in Europe, particularly on the techni-cal aspects of its governance and data policy.1

introduction

Space assets are essential for the activities of modern societies. Communications, navigation, position-ing and timing, meteorological and scientific services, geospatial infor-mation, understanding of Earth envi-ronment, civilian and common foreign and security policy (CFSP) operations, to name just a few services, rely on space assets. [1] Any disturbance of

1 The content within this publication is solely of the authors. This publication does not constitute any endorsement on behalf of the European Union Satellite Centre. At the time of writing, the engineering architec-ture, governance and data policy of a future European SSA system have not been defined by the appropriate decision-making bodies. This publication in no way prejudges any decisions or specifies any design aspects of a future SSA system in Europe.

SPA: Support to Precursor Space Situational Awareness Services

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them would damage or completely disrupt services needed to ensure the safety, the well-being of European Union (EU) citizens and reduce their associated economical benefits (con-sidering in particular the elevated ROI of a factor 3 for space activities).

The European Commission (EC) has launched a number of research pro-jects on space weather and the secu-rity of space assets from on-orbit collisions in the framework of the EU FP7 R&D programme.

In September 2008, the 5th Space Council [2] underlined the need for Europe to develop a capability for Space Situational Awareness (SSA), drawing on existing capabilities and infrastructures both at national and European level. SSA refers to the knowledge of location and function of space objects and the space environ-ment, including operational satellites, space debris, near-Earth objects and space weather.

The development of a European SSA capability will underpin the exploita-tion of European space assets contrib-uting to the access to (and utilisation of) space for Europe (as requested by the European Space Policy [13]). This way the EU and its Member States will be able to better use space, strength-ening their security and economy in accordance with the Europe 2020 strategy [3].

The SSA Preparatory Programme (PP) [4] launched in 2008 is managed directly by the European Space Agency (ESA) on behalf of the ESA Member States who fund the programme. ESA is actively cooperating with European national authorities, minis-tries of defence, European scientific

and technical organisations, national research establishments and national space agencies as well as institutions and agencies of the EU including the European Defence Agency (EDA) and the European Union Satellite Centre (EUSC). It is expected that the ESA Council at ministerial level will adopt the implementation of the SSA pro-gramme in November 2012 with the objective to be operational by 2020.

While ESA has coordinated the iden-tification of civil user requirements for SSA, the EDA Project Team SSA has elaborated a Common Staff Target (CST) document on harmo-nising defence requirements for SSA; based on both requirements, European SSA High Level Civil-Military User Requirements (prepared in the framework of the Structured Dialogue on Space and Security) have been endorsed by the Political and Security Committee (PSC) in November 2011.

The 7th [10] and the 8th Space Council [12] invited the EC and the EU Council, in close cooperation with ESA and Member States, to propose a govern-ance scheme and a data policy for a future European SSA capability.

The future European SSA System has the potential to be, in its operational phase, a dual use system of systems composed of various elements (civil and military, national and EU) distrib-uting data to a variety of communi-ties of governmental and possibly commercial users. It will probably be based on specific data fusion and dis-tribution facilities, it would have a multilevel data flow with several lev-els of confidentiality and it would be developed in an incremental manner with contributions from international partners.

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THE EUSC’S CONTRIbUTION TO SSA

The EUSC is an EU common foreign and security (CFSP) agency, located in Torrejón de Ardoz, in the vicinity of Madrid, Spain.

The EUSC mission is, in accordance with the European Security Strategy, to sup-port the decision-making of the European Union in the field of the CFSP, in particular of the common security and defence policy (CSDP), including European Union crisis management operations, by providing, as appropriate, products resulting from the analysis of satellite imagery and collateral data, including aerial imagery, and related services [5].

The EUSC has a long and unique exper-tise in handling, analysing and dis-seminating data of both civilian and military origin with multiple levels of confidentiality.

Data sources of the EUSC are com-mercial (acquired at market conditions) and governmental (obtained through Memorandum of Understanding, i.e. agreements with Member States own-ers of governmental systems) as well as open sources; EUSC premises guar-antees the maximum security of the data received from Member States or third parties. The operational data flow currently in place at the EUSC is pre-sented in Figure 1.

The EUSC is contributing to the current European SSA activities through the Support to Precursor Space Situational Awareness services (SPA) project. The SPA project is a Support Action under the seventh framework programme of the EC (Grant Agreement No 262930, theme SPA.2010.2.3-2; Security of space assets from on-orbit collisions)

managed by the EUSC (under the full control of Member States) and started on 1 March 2011 for a duration of 18 months.

SPA is studying and evaluating pos-sible models of SSA governance and data policy in the EUSC secure envi-ronment. Within this context and to provide advice from a technical point of view, SPA is experimenting with a number of preliminary services rel-evant to civilian security and CFSP, e.g. Satellite Conjunction Warning, Satellite Over-flight and Space Re-entry Prediction.

The SPA project is fully complemen-tary to the ESA programme and will contribute to the implementation of the European Space Policy, being totally aligned with the conclusions of the 5th and the 8th Space Council on the development of a European capa-bility for the monitoring and surveil-lance of its space infrastructure and of space debris.

SPA is supporting the CFSP (includ-ing civilian security and CSDP) as the preliminary SSA services to be eval-uated have aims to protect Europe’s citizens, satellite-based services and infrastructures in orbit which in turn will protect future EU missions and operations.

EU Member States contributing to the SPA project are benefiting from the handling of sensitive information at secure premises by personnel with a wide experience on the subject. ESA is benefiting from the early involvement of a secure entity as well as by the proximity of the EUSC to the European Space Astronomy Centre, which cur-rently plays a major role on the tech-nical developments of the ESA PP SSA.

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Figure 1. EUSC data flow © EUSC 2011

SPA PROjECT wORKFLOw And eXPected outcoMes

The SPA activities are performed in the context of the definition of a European SSA System three main segments:

• Space Surveillance and Tracking (SST) of man-made objects;

• Space Weather (SWE) monitoring and forecast;

•Near-Earth Objects (NEO) monitoring (of natural space objects).

The SPA project is focused on the SST segment and services which are sensi-tive and dual use (civil and military) in

nature. At the beginning of the project a number of SSA-SST preliminary ser-vices related to the protection of space infrastructure with relevance to civilian security and CFSP have been described and characterised in cooperation with the European External Access Service (EEAS).

At the same time, needs and relevant requirements related to data policy and governance for generic prelimi-nary services have been identified (and potential improvements out-lined) in cooperation with the European Commission and EU Member States.

Moreover the EUSC is hosting within its already existing secure premises some

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demonstrator software for a number of SSA-SST services; for that purpose, the EUSC is cooperating with ESA and using its experience on the area of the analysis and integration of heteroge-neous data sources with multiple secu-rity levels.

After the validation of the identified requirements for the preliminary ser-vices, the final output of SPA will be a report summarising the knowledge gained, including lessons learned, and describing the achievements of the SPA project with recommendations in view of further developments of SSA in Europe, particularly on the technical aspects of its governance and data policy.

oVerVieW of indicAtiVe EUROPEAN ssA-sst serVices

Within the European SSA capability, the Space Surveillance and Tracking (SST) of man-made objects represents the greatest challenges from a govern-ance and data policy development per-spective. By facilitating autonomous European access to space and security of space assets and of the civilian pop-ulation, the SSA-SST is supporting the implementation of the CFSP.

Here below are described three indic-ative services of the European SSA-SST: Satellite Over-Flight, Satellite Conjunction Warning and Space Re-Entry Prediction.

The Satellite Over-flight service offers an estimation of when a particular satellite (or space object) will be vis-ible from a particular location (and vice versa). The Satellite Over-flight service and calculation chain permits real-time and predictive estimation (by computer simulation) of the evolution of the

orbital parameter values with time of a satellite and its orbit. This allows the prediction of when a satellite has line of site visibility to a particular location on the Earth’s surface; this could be for observation or communication pur-poses. Conversely the ground will have line of sight contact with the satellite.

The Satellite Conjunction Warning ser-vice is intended to greatly reduce the probability of collision between oper-ational European space assets and all other man-made objects. Any European commercial, governmental or military satellite operator could ben-efit from predicted collision warnings and avoid manoeuvre advisories. The collision prediction and avoidance is of ever growing importance; for example, at two size limits, it is estimated that there are more than 600 000 objects larger than 1 cm in orbit and more than 4 000 objects greater than 100 cm in size [6] [7]. Some orbital levels appear to be demonstrating the Kessler Syndrome (uncontrolled debris growth due to collisional cascading [8]).

The Space Re-entry Prediction service is concerned with maintaining a list of objects of high probability of re-entry to the atmosphere and reaching the Earth’s surface (also, to make a pre-diction of the trajectory and debris cloud impact zone location on Earth). With a modest extension of the over-flight service, placing an alarm on the simulations if a space object’s altitude ever goes below a limit altitude (e.g. 130 km) a provisional list of objects at risk of re-entry can be elaborated and maintained. When a space object orbit starts to degrade rapidly at the limits of the Earth’s atmosphere, the precise location of the debris cloud impact zone location on Earth becomes of critical importance to protect human life and

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the environment; governmental author-ities are alerted to coordinate public information and protection services.

tecHnicAL considerAtions

The future European SSA system will potentially have data flows of dual use nature. The EUSC, as a hub han-dling commercial and governmental information, is suitably placed to facil-itate and contribute to the evaluation of preliminary SSA-SST service pro-cessing chains. With particular inter-est on the data policy aspects, a copy of a number of preliminary SST service chains hosted at the EUSC will be eval-uated in the SPA project.

The EUSC demonstrators are heavily based on the output of ESA SSA activi-ties for the implementation of the ser-vices. The EUSC is considering not only existing ESA software and new devel-opments as part of the ESA SSA prepar-atory programme, but also alternative third party software packages.

The setup of the demonstrators and the associated governance and data policy technical exercise will allow the EUSC to provide recommendations, mainly regarding data policy security aspects (e.g. integrity, confidentiality, non-repudiation, availability, etc.) cov-ering areas from system and software architecture to hw/sw baselines.

KEy ISSUES ON GOVERNANCE ModeLs And dAtA PoLicies GOVERNANCE

A key issue for governance is to define an appropriate institutional, techni-cal and financial framework to support decision-making across the multiple

SSA Stakeholders, the rules for deci-sion-making and the mechanisms to ensure conformance with the data pol-icy rules and procedures (including lia-bility issues).

Currently there are a number of exist-ing SSA governance requirements coming from the CST (EDA), the Mission Requirements Document (ESA), the European SSA High Level Civil-Military User Requirements (Structured Dialogue on Space and Security), national and international legislations. It has to be noted that potential tech-nical architectures for SSA in Europe could correspond to different govern-ance models.

dAtA PoLicy

Key Issues and Challenges for SSA data policy

The overall challenge for the European SSA System data policy is to per-mit the optimisation of SSA resources usage including the contribution of Member States capabilities while pro-tecting EU, Member States and allies’ interests through the applicable secu-rity requirements and regulations [9][10]. Respecting these aims, and con-sidering the compilation of existing requirements and needs, an initial list of important issues and challenges is presented here below.

Information and Facility Protection

Securing the various key elements of a European SSA capability from vari-ous forms of interception or misuse through the introduction and imple-mentation of security norms and pro-cedures. It is important to consider that a complete SSA system shall have a

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data policy applied, including the sen-sor sites, data centres, the catalogues, the user interface points, communica-tion and storage methods. The data policy should cater for a distributed and multilayer system.

The user access to the system may be at different privilege levels based on user status. The data dissemina-tion of products may be from classi-fied to public levels among users of different access levels and environ-ments (civil or governmental). Tracing of the origin and evolution of data (and processed data) for security validation authentication and non-repudiation is an important feature of the data pol-icy. The storage of historical data for post analysis is required.

Regarding the detailed rules to set and change an item (catalogue item/object/satellite/process) status from classified to unclassified and vice versa, although these contain fine detail, the consequences are at a national security level. Likewise, it is critical to the data policy to pro-tect against the risks of disclosure of information related to position, orbit, system or functionality characteris-tics of space assets. Due to the fact that there is the possibility to have a concentration of high quality sensitive data stored in a catalogue(s) this is a focal point for security concerns.

Administrative Aspects

A challenge for the data policy is the production, awareness, classification of forms of information exchange agree-ments between European SSA System user states and third entities.

Complex liability aspects are being addressed in the data policy,

considerations such as the potential responsibility of a potential European SSA System operator regarding the correctness of a collision warning mes-sage and the subsequent manoeuvre of an operator and the responsibility of launching states regarding incidents. The potential assignment of liabilities will be underpinned by the traceabil-ity, correctness and validation of the data used to take critical actions or in the investigation past of events. This might impose important constraints on the services offered; a European SSA System operator may only issue advisories for collision avoidance and not issue commands where responsi-bility could lie with the operator (and/or the corresponding launching state) for the correctness of the manoeuvre.

Interoperability and Standardisation

It is expected that the future European SSA capability will be drawn from assets, competencies and skills exist-ing or being developed in Member States, at European level and as appro-priate internationally [11]. The ability to efficiently interoperate assets and communicate is stressed in a num-ber of requirements. Standardisation facilitates the interoperability and data communications and also in future evolutions and changes to the SSA architecture. In addition to physi-cal facilities, efficient communication for timely decision-making is required between all involved actors.

The EU Council security rules for pro-tecting EU classified information (EUCI) shall be used for the management (and de-classification) of SSA classified information as applicable. Regarding security the application of international and national standards for secure infor-mation interchanges between national/

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EU/international systems and users are to be employed.

CONCLUSIONS

The SPA project is a study (under the full control of EU Member States, ben-efiting from their support and coopera-tion) by which the EUSC is contributing to the technical definition of European SSA governance and data policy.

The EUSC is testing possible models of governance and data policy in its secure environment by experimenting with a number of preliminary services (e.g. Satellite Conjunction Warning, Satellite Over-flight and Space Re-entry Prediction) related to the current and future EEAS missions and operations and then supporting civilian security as well as the common foreign and secu-rity policy.

SPA is complementing current SSA activities (e.g. the SPA project is fully complementary to the ESA work pro-gramme) and will contribute to the implementation of the European Space Policy.

The SPA project technical activities are performed in close cooperation with EU Member States, EEAS, EDA, EC and ESA. Furthermore, the EUSC is participat-ing directly or through its governance mechanisms, e.g. EEAS, to the main European forums where SSA is dis-cussed, like the Space Advisory Council, the Structured Dialogue in Space, the ESA SSA Programme Board and the EDA Project Team in SSA.

In addition, representatives of EU Member States up to ambassador level compose the EUSC governance bodies and the EUSC has an extensive network

of users at EU and national level with a wide expertise on the operational use of space technologies and capabilities (e.g. the European Commission, CFSP entities, Institutions and national stake-holders). The privileged position of the EUSC is allowing the discussion of the SPA results with relevant stakeholders in a future European SSA System.

REFERENCES

   European Parliament, ‘The cost of non-Europe in the field of satellite based systems’, December 2007.

   5th Space Council, ‘Taking forward the European Space Policy’, 26 September 2008.

   European Commission, ‘A European strategy for smart, sustainable and inclusive growth’, 3 March 2010.

   European Space Agency, ‘Declaration on the Space Situational Awareness (SSA) Preparatory Programme’, ESA/C/SSA-PP/VII/ DEC (Final), 8 December 2008.

   Council of the European Union, Council Joint Action 2001/555/CFSP, 20 July 2001.

   ESA Master 2005 Object Catalogue: http://www.master-2005.net

   ESA Space Debris website: http://www.esa.int/SPECIALS/Space_Debris/index.html

   CNES Space Debris website: http://www.cnes.fr/web/CNES-en/5001-a-chain-reaction.php

   Council of the European Union, Council decision on the security

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rules for protecting EU classified information, 31 March 2011.

   7th Space Council, ‘Global challenges: taking full benefit of European space systems’, 25 November 2010.

   Council of the European Union, Council Conclusions on ‘Towards a space strategy for the European Union that benefits its citizens’, 31 May 2011.

   8th Space Council, ‘Orientations concerning added value and benefits of space for the security of European citizens’, 2 December 2011.

   Commission Working Document, ‘European Space Policy Progress Report’, COM(2008) 561, September 2008.

AAbaibou, H. . . . . . . . . . . . . . . . . . . .278Abou-Jaoudeh, C. . . . . . . . . . . . . . . .452Aerothermal heating . . . . . . . . . . . . .430Afanasiev, A. . . . . . . . . . . . . . . . . . .360AFFECTS . . . . . . . . 7, 24, 27, 474, 476-480Afonin, V. . . . . . . . . . . . . . . . . . . . .263Agueda, N. . . . . . . . . . . . . . . . .360, 366AGW . . . . . . . . . . . . . . . . . . . 355-357Ahedo, E. . . . . . . . . . . . 309, 316-317, 513Ahmed, F. . . . . . . . . . . . . . . . . . . .232Ahoranta, J. . . . . . . . . . . . . . . . . . .395Albani, S. . . . . . . . . . . . . . . . . . . . .540Alert system . . . . . . . . . . . . . . . . . .193Alighanbari, S. . . . . . . . . . . . . . . . . .452Allain, L. . . . . . . . . . . . . . . . . . . . .309Alparslan, E. . . . . . . . . . . . . . . . . . .254Amanatidis, T. . . . . . . . . . . . . . . . . .367Andrimont, R. d' . . . . . . . . . . . . . . . . 70AquaMar . . . . . . . 6, 16, 174-176, 179-182Araújo, A. . . . . . . . . . . . . . . . . . . . . 94Arlot, J.-E. . . . . . . . . . . . . . . . . . . .287Arnoud, A. . . . . . . . . . . . . . . . . . . . 32ASIMUTH . .6, 15, 182, 186, 188-189, 191-192Astrometry . . . . . . . . . . . . . . . . . . .291Astronomy . . . . 347, 360, 365, 422, 482, 542Attitude control . . . . . . . 310, 336, 517-519Aurass, H. . . . . . . . . . . . . . . . .360, 365Avionics . . . . . . . . . . . . . . . . . . . .465

bBacci, B. . . . . . . . . . . . . . . . . . . . .386Badini, C. . . . . . . . . . . . . . . . . .446, 448Balasco, M. . . . . . . . . . . . . . 254, 258, 260Balikhin, M. . . . . . . . . . . . . . . . . . . .263Bankov, L. . . . . . . . . . . . . . . . .352, 357Barbarossa, S. . . . . . . . . 206, 213-214, 216Barbieri, M. . . . . . . . . . . . . . . . . . . .206Barcena, J. . . . . . . . . . . . . . . . .446, 448Bartalev, S. . . . . . . . . . . . . . . 70, 78, 164Barwood, G. . . . . . . . . . . . . . . . . . .452Barz, E. . . . . . . . . . . . . . . . . . . . . .206Bastiaanssen, F. . . . . . . . .99, 101, 148, 151

Bastiaanssen, W. . 99, 101-102, 148, 151, 153Battarbee, M. . . . . . . . . . . . . . . . . .360Bauwens, I. . . . . . . . . . . . . . . . . . . .232Bayesian statistics . . . . . . . . . . . . . .236Benchmark . . . . . . . 35, 58-59, 61, 391-392,

404-408, 410-411Bergmann, P. . . . . . . . . . . . . . . . . . .404Berthier, A. . . . . . . . . . . . . . . . . . . .278BETs . . . . . . . . 7, 20, 25, 27, 506, 511-512Bezirgiannidis, N. . . . . . . . . . . . . . . .367Bigongiari, F. . . . . . . . . . . . . . . . . . .386Biocontamination . . . . . . . . . . . . . 6, 278Biodiversity . . . . . . . . . . . . . 5, 32-33, 84Biomass . . . . . . . . . 14, 58, 70-71, 75-77,

102, 106-109, 112-114, 118-125, 132, 151, 153, 164, 166-170, 187, 189

Biophysical parameters . . . 63-64, 78, 98, 102BIOS . . . . . . . . . . . 18, 278-279, 281-284BIOSMHARS . . . . . . . . 6, 18, 278, 280-283BIO_SOS . . . . 5, 14, 32-33, 35-36, 40-41, 89Bippus, G. . . . . . . . . . . . . . . . . . . . 46Bischoff, H. . . . . . . . . . . . . . . . . . . 2, 13Bize, S. . . . . . . . . . . . . . . . . . .452, 462Blonda, P. . . . . . . . . . . . . . . . . 32, 41-42Bolomogolov, L. . . . . . . . . . . . . . . . .263Bongs, K. . . . . . . . . . . . . . . . . . . . .452booms . . . . . . . . . . . . 378-383, 517-522Borowiecka, S. . . . . . . . . . . . . . . . . 2, 13Borries, C. . . . . . . . . . . . . . . . .254, 474Bothmer, V. . . . . . . . . . . . . . 474, 477, 481Braune, S. . . . . . . . . . . . . . . . . . . .360Braxmaier, C. . . . . . . . . . . . . . . . . . .452Brazil . . . . . . . 27, 33, 35, 94, 138-139, 142Brefort, T. . . . . . . . . . . . . . . . . . . 2, 13Breger, P. . . . . . . . . . . . . . . . . . . . 2, 13Briess, K. . . . . . . . . . . . . . . . . . . . .352Bruijn, E. De . . . . . . . . . . . . . . . . . .148Brunner, R. . . . . . . . . . . . . . . . . . . .474Buck, O. . . . . . . . . . . . . . . . . . . 82, 90Butane cold gas thruster . . . . . . . .303, 306

CCalligaro, C. . . . . . . . . . . . . . . .440, 445Calonico, D. . . . . . . . . . . . . . . . . . .452Candela, L. . . . . . . . . . . . . . . . . . . . 32

Index

554I N D E X

Capacity Building 118-119, 124, 129, 131, 134Capes, R. . . . . . . . . . . . . . . . . . . . .244Carbon accounting . . . . . . . . 164, 166, 169Carrasco, J. A. . . . . . . . . . . . . . . . . .506Catchment models . . . . . . . . . . . . . . 94Ceramic matrix composites . . . . . . . . . .446Ceriola, G. . . . . . . . . . . . . . . . . . . .174Change detection 42, 108, 111, 113, 141, 143Charro, M. . . . . . . . . . . . . . . . . . . .506Cherniak, Y. . . . . . . . . . . . . . . . . . .254Cherny, I. . . . . . . . . . . . . . . . . . . . .254Clarke, E. . . . . . . . . . . . . . . . . . . . .482Clarke, N. . . . . . . . . . . . . . . . . . . . .367Clilverd, M. . . . . . . . . . . . . . 488, 490, 494Climatology . . . . . . . . . . . . . . . . . .118Coastal monitoring . . . . . . . . . . . . . .198Cold atoms . . . . . . . . . . . . . . . . . .453Collier, A. . . . . . . . . . . . . . . . . .488, 494Colloid thruster . . . . . . . . . . . . .319, 325Colombatti, G. . . . . . . . . . . . . . . . . .506Colonna, A. . . . . . . . . . . . . . . . . . . .386Computed tomography . . . . . . . . . . . .447Confined environments . . . . . . . . . . . .283Contet, A. . . . . . . . . . . . . . . . . . . . .156Cordiviola, E. . . . . . . . . . . . . . . . . . .386Corona . . . . . . . . . . . . . . . . . . . . .500Coronal Mass Ejections . . . . . . . . .361, 498Cougnet, C. . . . . . . . . . . . . . . . . . . .534Coviello, I. . . . . . . . . . . . . . . . . . . .254Crespon, F. . . . . . . . . . . . . . . . . . . .352Crop model . . . . . . . . . . . . . . . . . . 71Crop monitoring . . . . . . . . . . 63, 67, 69, 75Cryogenic Detectors . . . . . . . . . . . 395-397CryoLand . . . . . . . . 5, 14, 46-47, 49, 52-54Crystal growth . . . . . . . . . . . . . . . . .404CubeSat . . . . . . . . . . .303, 320-324, 379,

517-519, 521-522Cusack, C. . . . . . . . . . . . . . . . . . . .186Cuyper, J.-P. de . . . . . . . . . . . . . . . .287

dDaglis, I. A. . . . . . . . . . . . . . 367, 477, 481Damage assessment . . . . . . . . . . . . . 63Data assimilation . . 78, 95-96, 370, 490-493Data fusion . . . . . . . . . 198, 200-204, 541Data mining . . . . . . . . . . . . 352, 355-356Data processing . . . . 6, 17, 21, 35, 47, 70, 73,

141, 343, 352-355, 386, 392Davidson, K. . . . . . . 125, 170, 186-187, 193Daylighting . . . . . . . . . . . . . . . . . . 58Debris . . . . . . . . . . . . 529-532, 535, 547Decision support systems . . . . . . . . . .206Deforestation . . . . . . 5, 13-14, 17, 27, 106,

110, 118-121, 124-125, 128, 131, 133, 138-144

Defourny, P. . . . . . . . . . . . . . . . . 70, 78Degradation . . . . . . . .13, 27, 121-122, 537Dehant, V. . . . . . . . . . . . . . . . .287, 292

Delloye, C. . . . . . . . . . . . . . . . . . . .128Demonstrator . . . . . 327, 330, 379, 521, 544De-orbiting . . . . . . . . . . . . . . . . . . .513Deorbiting 7, 27, 308, 379-380, 506, 516-518DEORBITSAIL . . . 7, 20, 26-27, 516-519, 521Deployable space structures . . . . . .378, 383Deployable structures . . . . . . . . . . 378-379DEPLOYTECH . . . . . . . . . . . 7, 23, 378-383Destefanis, R. . . . . . . . . . . . . . . . . .526Detector arrays . . . . . .7, 395-396, 398, 417Devices . . . . . . .21, 283, 310, 322, 387-388,

392, 399, 405, 415, 418, 424, 440-442, 453, 469

Diamandi, A. . . . . . . . . . . . . . . . . . . 46Diamantopoulos, S. . . . . . . . . . . . . . .367Diez-Jimenez, E. . . . . . . . . . . . . . . . .423Dimopoulos, P. . . . . . . . . . . . . . . . . . 32Direct habitat mapping . . . . . . . . . . . . 82Dirkx, D. . . . . . . . . . . . . . . . . . . . .287Dlamini, S. . . . . . . . . . . . . . . . . . . .232DMC/Deimos-1 . . . . . . 41, 63-68, 148, 151Donath, T. . . . . . . . . . . . . . . . .526, 532Donati, A. . . . . . . . . . . . . . . . . . . . .452Donati, M. . . . . . . . . . . . . . . . . . . .386Dost, R. . . . . . . . . . . . . . . . . . . . . .148Drag sail . . . . . . . . . . . . . . . . . 518-519Dröge, W. . . . . . . . . . . . . . . . . . . . .360DSP . . . . . . . . . .7, 187, 386-389, 391-393DSPACE . . . . . . . . . . . 7, 21-22, 386-392Durgun, Y. Ö. . . . . . . . . . . . . . . . . . . 63Durieux, L. . . . . . . . . . . . . . . . . . 32, 41

EEarth Observation (EO) . . . . 5, 13-14, 16-18,

25, 29, 32, 34-35, 37, 40-41, 47, 58, 62, 78, 82-84,

88-89, 94-96, 101, 109, 118-122, 124, 128-129, 131, 133, 148, 164-165, 169-170, 180, 200,

203, 232-236, 238, 240, 258, 260Earthquake . . . . . . . . . . . . 6, 16-17, 20,

254-256, 259-272, 354Education . . . . . . . . . . . . . . . . 94, 383Eerens, H. . . . . . . . . . . . . . . . . . . . 63Electric Propulsion .303, 309, 317, 322, 325, 510Electric solar wind sail . . . . . . 302, 307-308Electromagnetic wave propagation . . . . .312Emelyanov, K. . . . . . . . . . . . . . . . . .164Endorse . . . . . . . . . . . . . . 5, 14, 58,-62Environment . . . . . 32, 36, 46, 54, 77-78, 84,

102, 114, 119, 124-125, 139, 156, 170-171, 174-175, 193,

220, 244, 369, 388, 535EO data . . . . . . . 35, 37, 40-41, 58, 62, 84,

88-89, 94, 96, 109, 118-119, 124, 131, 169, 233, 238

Ephemerides . . . . . . . . . . 6, 287-288, 292Ergintav, S. . . . . . . . . . . . . . . . .254, 261

555I N D E X

Errico, W. . . . . . . . . . . . . . . . . . . . .386E-SAIL . . . . . . . . . . . . . . . . . . . . . 20ESPaCE . . . . . . . . . . . . . . 6, 19, 287-292E-SQUID . . . . . . . 7, 21, 395-397, 399-401EURISGIC . . . . . . . . . . . . . 7, 24, 482-485EuSiC . . . . . . . . . 7, 22, 404-407, 409-411EU-UNAWE . . . . . . . . . . . . . . 6, 296-299Evapotranspiration . . . 5, 94-95, 97, 99-100,

102, 150, 151-152EVOSS . . . . . . . . 6, 17, 220-224, 226-227

FFalke, S. . . . . . . . . . . . . . . . . . . . .452Fanucci, L. . . . . . . . . . . . . . . . .386, 393Far infrared . . . . . . . . . . . . . . .395, 397Ferencz, C. . . . . . . . . . . . . . 352, 357, 494Fernandez, J. . . . . . . . . . 325, 378, 383, 516Ferreira, F. . . . . . . . . . . . . . . . . . . .148Ferri, F. . . . . . . . . . . . . . . . . . .309, 317Ferrucci, F. . . . . . . . . . . . . . . . .220, 228Field observations . . . . . . . . . . . .108, 124Filizzola, C. . . . . . . . . . . . . . . . .254, 262FLR . . . . . . . . . . . . . . . . . . . . 489-490Forecast . . . . . . . . . . . . . . . 7, 474, 479Forest . . . . . . . . . 5, 13-14, 27, 49, 82, 85,

87, 89, 106-114, 118-125, 128-134, 138-144, 164-171, 237, 513

Forest disturbance . . . . . . . . . . . 167-169Forest resources 5, 14, 128, 144, 164, 168-169Forsberg, U. . . . . . . . . . . . . . . . . . .404Förster, M. . . . . . . . . . . . . . . 82, 90, 494FOSTERNAV . . . . . . . . . . . 7, 22, 414-421FPGA . . . . . . . . . . 386, 391, 393, 458, 469Franke, J. . . . . . . . . . . . . . . . . .138, 232Franzen, T. . . . . . . . . . . . . . . . . . . .452Fraser, G. . . . . . . . . . . . . . . . . . . . .395Friedel, R. . . . . . . . . . . . . . . . . . . .488Furnell, S. . . . . . . . . . . . . . . . . . . .367

GGabon . . . . . . . . . . . . 128-129, 131, 133Gaia, E. . . . . . . . . . . . . . . . . . . . . .333Gallardo, B. . . . . . . . . . . . . . . . . . .540Ganse, U. . . . . . . . . . . . . . . . . . . . .360Gautier, Ph. . . . . . . . . . . . . . . . . . . .326Gebreslasie, M. . . . . . . . . . . . . . . . .232Genzano, N. . . . . . . . . . . . . . . . . . .254Geohazards . . . . . . . . . . . . . . . . . .245Geology . . . . . . . . . . . . . . . . . . . .263Geomagnetically induced currents . . . . . . . . . . . . . . 342, 482, 499Geomagnetic storms . . . . . . . 23, 482, 484Gerber, B. . . . . . . . . . . . . . . . . . . . .534Ghita, B. . . . . . . . . . . . . . . . . . . . .367Gianella, S. . . . . . . . . . . . . . . . . 446-447Gill, P. . . . . . . . . . . . . . . . . . . . . . .452

Gilmore, R. . . . . . . . . . . . . . . . . . . 2, 13Ginzburg, E. . . . . . . . . . . . . . . . . . .254GIS . . . . . . . . .52-54, 82, 84, 86, 101, 110,

131, 134, 138, 161, 203, 220, 232, 235, 240

Glaciers . . . . . . . . . . . . . . . . . . . . 54GMES . . . . . . . . .5-6, 13-17, 21, 25, 32, 40,

46-47, 49, 53-54, 58-60, 70, 82, 88-89, 94, 113, 119,

139, 156-161, 174-175, 182, 186, 189, 191, 206, 211, 215, 217, 221, 236, 244-246, 369, 513

GMES4Regions . . . . . . . . . 5, 15, 156-161GMES Services . . . . . . . . . . . . . . . . . 61Goetzelmann, M. . . . . . . . . . . . . . . . .367Gomez, S. . . . . . . . . . . . . . 118, 124, 325Görlitz, A. . . . . . . . . . . . . . . . . . . . .452Gossamer structures . . . . . . . . . .519, 521Graziani, F. . . . . . . . . . . . . . . . . . . .309Grue, K. . . . . . . . . . . . . . . . . . . . . .309Gülhan, A. . . . . . . . . . . . . . . . .430, 435Gurvits, L. . . . . . . . . . . . . . . . .287, 292Gustafsson, D. . . . . . . . . . . . . . . . . . 46

HHaarpaintner, J. . . . . . . . . . . . . .110, 113HabDir . . . . . . . . . . . . . . . . . 82, 86-87Habitat . . . . . . . . . . . . . . . 32, 41, 82, 88Haest, B. . . . . . . . . . . . . . . . . . . 82, 90Haeusler, T. . . . . . . . . . . . . . . .118, 124Hall, C. . . . . . . . . . . . . . . . . . . 69, 474Hamadache, C. . . . . . . . . . . . . . . . . .360Häme, T. . . . . . . . . . . . 107-108, 113-114Haren, I. van . . . . . . . . . . . . . . . . . .148Harmful algal blooms (HAB) . 175-178, 186-193Harmonic drive . . . . . . . . . . .22, 423-424Heber, B. . . . . . . . . . . . . . . . . .360, 366Heilig, B. . . . . . . . . . . . . . . 488-489, 494Heinzel, J. . . . . . . . . . . . . . . . . . . .113Heliosphere . . . . . . . . . . . . . . . . . .365Hembise Fanton d’Andon, O. . . . . . . . . .174Hendrix, R. . . . . . . . . . . . . . . . . . . . 82Henry, S. . . . . . . . . . . . . . . . . . . . .326HESPE . . . . . . . . . . 6, 20-21, 24, 342-347Heynderickx, D. . . . . . . . . . . . . .360, 365Heyns, W. . . . . . . . . . . . . . . . . . . . . 63High-voltage power grids . . . . . . . . . . .483Hoekman, D. . . . . . . . . . . . . . . . . . .138Holzwarth, R. . . . . . . . . . . . . . . . . . .452Honkonen, I. . . . . . . . . . . . . . . . . . .482Houdt, R. van . . . . . . . . . . . . . .278, 284HPH.com . . . . .6, 19, 309, 311-313, 315-317HTPB . . . . . . . . . . 328-329, 334-335, 339Huovelin, J. . . . . . . . . . . . . . . . . . . .395Hussmann, H. . . . . . . . . . . . . . .287, 292Hüttich, C. . . . . . . . . . . . . . . . . . . .164Hybrid Propulsion . . . . . . . . . 326, 330-333Hydrology . . . . . . . . . . . . . . . .102, 153

556I N D E X

IIasillo, D. . . . . . . . . . . . . . . . . . . . . 32Ilyin, V. . . . . . . . . . . . . . . . . . .278, 284Imaging flash LiDAR . . . . . . . 37, 40, 98, 103,

107-109, 113, 414-421Improvement of physical modelling . . . . .430Inan, S. . . . . . . . . . . . . . . . . . . . . .254Incomati . . . . . . . . . . 5, 14, 148-151, 153Indonesia . . . . . . . . . . . . . 138-139, 142Inflatable structures . . . . . . . . . . . . . .378InfraRed . . . . . . . . . . . . . . . . . . . .223Inglada, J. . . . . . . . . . . . . . . . . . . . 32InSAR . . . . . . . . . . . . . .54, 121, 244-246In situ data . . . . . 32, 41, 94, 118-119, 123,

153, 170, 175-176, 180-181Integrated maritime policy . . . . . . . 16, 199Interferometry . . . . . 52, 200, 203, 216-217,

228, 287, 289, 452International Space Station . . . . . 22, 27, 281,

284, 452, 528Interoperability . 52, 58, 88-89, 208, 374, 546Ionic liquid FEEP thruster . . . . . . . . . . .306Ionosphere . . . . 16, 20-21, 24, 254, 256-257,

259, 261, 263, 265-267, 272, 353-355, 357, 360, 474, 476,

484-485, 494, 500Ionosphere Waves Service . . . . 353, 355-356Ionospheric perturbations . . . . . . . . 478-479ISAC . . . . . . . . . . . . . . . . . 5, 14, 63-64

jJakowski, N. . . . . . . . . . 254, 257, 261, 474Janhunen, P. . . . . . . 302, 307-308, 484-485Janzen, E. . . . . . . . . . . . . . . . . . . .404Jarmain, C. . . . . . . . . . . . . . . . . . . .148Jhonrado, J. . . . . . . . . . . . . . . . . . . 32Jong, B. de . . . . . . . . . . . . . . . . . . .109Jongman, R. . . . . . . . . . . . . . . 32, 41-42Jorgensen, A. . . . . . . . . . . . . . . . . .488

KKaenders, W. . . . . . . . . . . . . . . . . . .452Karna, J.-P. . . . . . . . . . . . . . . . . . . . 46Kartavykh, Y. . . . . . . . . . . . . . . . . . .360Katkalov, Y. . . . . . . . . . . . . . . . . . . .482Katsonis, K. . . . . . . . . . . . . . . .309, 317Kervarc, R. . . . . . . . . . . . . . . . .526, 532Kiener, J. . . . . . . . . . . . . . . . . . . . .360Kilian, P. . . . . . . . . . . . . . . . . . . . .360Kiviranta, M. . . . . . . . . . . . . . . . . . .395Klein, K.-L. . . . . . . . . . . . . . . . . . . .360Kleshchenko, A. . . . . . . . . . . . . . . . . 70Kobow, J. . . . . . . . . . . . . . . . . . . . .395Kokkonen, E. . . . . . . . . . . . . . . . . . .278

Kopp, A. . . . . . . . . . . . . . . . . . . . .360Korepanov, V. . . . . . . . . . . . . . .352, 357Korets, M. . . . . . . . . . . . . . . . . . . .164Korpela, S. . . . . . . . . . . . . . . . . . . .395Kouloumvakos, A. . . . . . . . . . . . . . . .360Kreysa, E. . . . . . . . . . . . . . . . . . . .395Krüger, H. . . . . . . . . . . . . . . . . . . .414Kudryashova, M. . . . . . . . . . . . . . . . .287Kulmala, I. . . . . . . . . . . . . . . . . . . .278Kulosa, A. . . . . . . . . . . . . . . . . . . .452Kurekin, A. . . . . . . . . . . . . . . . .174, 177Kuur, J. van der . . . . . . . . . . . . . . . .395

LLAI . . . . . . . .5, 63-64, 68, 94-98, 100, 102Lainey, V. . . . . . . . . . . . . . . . . .287, 292Land Cover . . . . . . . . . . . . . 96, 102, 134Landsat-TM/ETM+ . . . . . . . . . . . . . . . 63Lang, S. . . . . . . . . . . . . . . 82-83, 88, 90Lapenta, G. . . . . . . . . . . . . . . . . . . .498Lappas, V. . . . . . . . . . . 378, 383, 516, 522Laroque, C. . . . . . . . . . . . . . . . . . . .367Larsen, H. E. . . . . . . . . . . . . . . . 46, 113Lasa, J. . . . . . . . . . . . . . . . . . . . . .506Laser . . . . . . . 103, 107, 287-288, 290-291,

304-305, 415-416, 418, 422, 435, 453-458, 460, 462

Lava . . . . . . . . . . . . . . . . . . . . . .223Lecomte, S. . . . . . . . . . . . . . . . . . .452Lehtimäki, M. . . . . . . . . . . . . . . . . .278Le Maistre, S. . . . . . . . . . . . . . . . . .287Le Toan, T. . . . . . . . . . . . . . 118, 123-125Letterio, F. . . . . . . . . . . . . . . . . . . .206Leupers, R. . . . . . . . . . . . . . . . .386, 393Levi, F. . . . . . . . . . . . . . . . . . . . . .452Levin, B. . . . . . . . . . . . . . . . . . . . .263Leys, N. . . . . . . . . . . . . . . . . . .278, 284Lichtenberger, J. . . . . . . . 357, 488-490, 494Liedtke, V. . . . . . . . . . . . . . 446, 448-449LISA . . . . . . . . . . . . . . . . . . .320, 392Lisdat, C. . . . . . . . . . . . . . . . . . . . .452Lisi, M. . . . . . . . . . . . . . . . . . . . . .254Lizunov, G. . . . . . . . . . . . . . . . .352, 357Ljungqvist, M. . . . . . . . . . . . . . . . . 2, 13Lodewyck, J. . . . . . . . . . . . . . . . . . .452Loizou, J. . . . . . . . . . . . . . . . . . . . .206Lorenzini, E. C. . . . . . . . . . . . . . .506, 513Loyan, A. . . . . . . . . . . . . . . . . .309, 317Lucas, R. . . . . . . . . . . . . . . . . . . 32, 42LULC . . . . . . . . . . . . . . . . 5, 94-97, 102Lyons, K. . . . . . . . . . . . . . . . . . . . .186

MMagdrive . . . . .7, 22, 423-424, 426-427, 429Maguire, J. . . . . . . . . . . . . . . . . . . .186Mairota, P. . . . . . . . . . . . . . . . 32, 35, 42

557I N D E X

Maisala, S. . . . . . . . . . . . . . . . . . . .360Malandraki, O. E. . . . . . . . . . . 360, 362, 366MALAREO . . . . . . . . . . . . 6, 17, 232-240Malaria . . . . . . . . . . . . 6, 17-18, 232-241Malkotsis, A. . . . . . . . . . . . . . . . . . .367Malnes, E. . . . . . . . . . . . . . . . . . . . 46Marcos, J. . . . . . . . . . . . . . 186, 216, 506Margarit, G. . . . 198, 200-202, 204, 214-217Maritime Surveillance . . . . . . 6, 16, 198-199,

203, 206-207, 211, 215Markelov, G. . . . . . . . . . . . . . . .309, 317Martian entry . . . . . . . . . . . . . . . . .430Marty, J.-C. . . . . . . . . . . . . . . . .287, 292Mateus, M. . . . . . . . . . . . . . . . . . . .186Matute, J. . . . . . . . . . . . . . . . . . . .540May, T. . . . . . 49, 65-69, 107, 216, 223, 228,

234, 263, 267, 296, 317, 332, 339, 375, 383, 395, 444-445, 548

Mazzeo, G. . . . . . . . . . . . . . . . . . . .254MEMS . . 6, 283, 310, 319-321, 323-324, 517Mergia, K. . . . . . . . . . . . . . . . . . . .446Mermoz, S. . . . . . . . . . . . . . . . .118, 125Mertens, B. . . . . . . . . . . . . . . . . . . .128Metrology . . . . . . . . . . . . . . . .452, 462Metsämäki, S. . . . . . . . . . . . . . 46, 49, 54Microbiology . . . . . . . . . . . . . . . . . .284Micro-propulsion . . . . . . . . . . . .310, 320MicroThrust . . . . . . . . . . . . . 6, 319-324Miley, G. . . . . . . . . . . . . . . . . . . . .296Mishev, A. . . . . . . . . . . . . . . . . . . .360Mission analysis . . . . . . . . . .308, 319-320,

323, 327-328, 331, 430MOCCCASIN . . . . . . . . 5, 14, 70, 72-75, 77MODIS . . . . 48-49, 63-69, 71-73, 75, 77-78,

96, 98-100, 148, 151, 167, 178-180, 182, 227-228, 232, 236, 238, 258

Mozambique . . . . . . . . . 94, 138-139, 142, 148-149, 232-236, 241

MS.Monina . . . . . . . . . .5, 14, 82-84, 86-89Müller, S. . . . . . . . . . . . .54, 362, 365, 404Mura, G. . . . . . . . . . . . . . . . . . . . .452MyWater . . . . . 5, 14, 94-96, 98-99, 101-102

NNagendra, H. . . . . . . . . . . . . . . 32, 34, 42Nagler, T. . . . . . . . . . . . . . . . . 46, 49, 54Natural hazards . . . . . . . . . . . . . . . .474NEREIDS . . . . . . . . . . 6, 16, 198-204, 210Nevsky, A. Yu. . . . . . . . . . . . . . . . . .452Nindos, A. . . . . . . . . . . . . . . . . . . .360Nini, P. . . . . . . . . . . . . . . . . . . . . .206Non-Dependence . . . . . . . . . . . . . . .449Novikova, N. . . . . . . . . . . . . . . .278, 284Numerical simulation . . . . . . . 329, 431-432Nunes, A. . . . . . . . . . . . . . . . . . . . . 94Nuzzolo, F. . . . . . . . . . . . . . . . . . . .386

OOberst, J. . . . . . . . . . . . . . . . . .287, 292Odendahl, M. . . . . . . . . . . . . . . . . . .386O’Dwyer, A. . . . . . . . . . . . . . . . . . . .540Oittinen, T. . . . . . . . . . . . . . . . . . . .360Optical clocks . . . . . . .7, 452-453, 455, 462Orlandi, O. . . . . . . . . . . . . . . . .326, 332ORPHEE . . . . . 6, 19, 23, 326-327, 330-332Ortona, A. . . . . . . . . . . . . . 446-447, 449Ovchinnikov, M. . . . . . . . . . . . . .309, 317Ovchinnikov, Y. . . . . . . . . . . . 452, 462-463

PP2-ROTECT . . . . . . . . . . . . . . 7, 526, 528Pablo, H. de . . . . . . . . . . . . . . . . . .186Paciello, R. . . . . . . . . . . . . . . . . . . .254Packan, D. . . . . . . . . . . . . . . . .309, 317Padoa Schioppa, E. . . . . . . . . . . . . 32, 41Pakzad, K. . . . . . . . . . . . . . . . . . . . 82PanGeo . . . . . . . . . . . 6, 17, 244-248, 250Papaioannou, A. . . . . . . . . . . . . .360, 366Parkes, S. . . . . . . . . . . . . . . . . .464, 470Parnowski, A. . . . . . . . . . . . . 474, 479, 481Parrot, M. . . . . . . . . . . . . . . 263, 272, 357Pasanen, P. . . . . . . . . . . . . . . . . . . .278Pathe, C. . . . . . . . . . . . . . . . . . . . .164Pavarin, D. . . . . . . . . . . . . . . . .309, 317Pearson, T. . . . . . . . . . . . . . . . . . . .138Pedrazzani, D. . . . . . . . . . . . . . . . . .113Penttilä, J. . . . . . . . . . . . . . . . . . . .395Perez-Diaz, J.-L. . . . . . . . . . . . . . . . .423Pergola, N. . . . . . . . . . . . . . . . .254, 262Pernkopf, L. . . . . . . . . . . . . . . . . 82, 90Pessana, M. . . . . . . . . . . . . 309, 317, 333Petrou, M. . . . . . . . . . . . . . . . 32, 40, 42Pfeffer, W. . . . . . . . . . . . . . . . . . . .474Piana, M. . . . . . . . . . . . . . . 342, 347-348Piankova, O. . . . . . . . . . . . . . . . . . .352Piccard, I. . . . . . . . . . . . . . . . . . . . . 63Piergentili, F. . . . . . . . . . . . . . . .309, 317Pierotti, S. . . . . . . . . . . . . . . . . . . .174Pii, V. . . . . . . . . . . . . . . . . . . . . . .386Pirjola, R. . . . . . . . . . . . . . . 482-483, 485Piscopiello, G. . . . . . . . . . . . . . . . . .386Plasmasphere . . . . . . . . . . . . 7, 479, 488Plasma waves . . . . . . . . . . . . . . . . .267PLASMON . . . . . . 7, 24, 488, 490-491, 493Poisson, M.-A. . . . . . . . . . . . . . .404, 529Pokhotelov, O. . . . . . . . . . . . . . . . . .263Polarimetry . . . . . . . . . . . . . . . 203-204Poli, N. . . . . . . . . . . . . . . . . . . . . .452Pollini, A. . . . . . . . . . . . . . . . . . . . .414POPDAT . . . . . . 6, 20-21, 24, 352-355, 357Pracser, E. . . . . . . . . . . . . . . . . . . .482Predictive model . . . . . . . . . . . . . . . .283Pre-Earthquakes . . . . . . 6, 17, 254, 256-260

558I N D E X

Pre-operational 32, 40, 53, 101, 215-217, 256Pre-operational services . . . . . . . . . 47, 89Provence . . . . . . . . . . . . . . . . . . 60, 62Pulinets, S. . . . . 254-255, 257, 261-262, 357Pulkkinen, A. . . . . . . . . . . . . 482, 484-485Pulliainen, J. . . . . . . . . . . . . . . . . 46, 54Put, P. van . . . . . . . . . . . . . . . . . . .309

qQuality . . . . . 6, 14-17, 22, 34, 53, 84, 94-96,

101, 113, 134, 174-176, 180, 192, 206-209, 256, 279-280, 304, 353, 389, 398, 404, 407, 410-411,

427, 434, 467-468, 499, 546Quirós, F. G. de . . . . . . . . . . . . . . . . .506

RRachiele, S. . . . . . . . . . . . . . . . . . . .386Radar . . . . . . . . . . 164, 214, 216-217, 224Radiation Hardening . . . . . . . 440, 442-443Radioscience . . . . . . . . . . . . . . . . . .288Radon . . . . . . . . . . . . . . . . . . 255-258Rasel, E.-M. . . . . . . . . . . . . . . .452, 463Raukunen, O. . . . . . . . . . . . . . . . . . .360Real-Time . . . . . . . . . . . . . . . . . . .422ReCover . . . . . 5, 14, 27, 106-107, 112-113Reda, J. . . . . . . . . . . . . . . . . . . . . .488REDD . . . . . 5, 13-14, 27, 106, 114, 118-120,

124, 128-134, 138-144REDDAF . . . . . 5, 14, 27, 118, 119, 120, 124REDDiness . . . . 5, 14, 27, 128-131, 133-134Reed, S. . . . . . . . . . . . . . . . . . . . .296Regions . . . . . . . . . . . . . . 156, 158, 160Reiter, F. . . . . . . . . . . . . . . . . . . . .386Remote sensing . . . . . 16, 32-33, 36, 41, 46,

54, 69, 74, 77-78, 90, 97, 101-102, 113-114, 124-125, 134, 138-139, 149, 153, 164,

170-171, 174-175, 182, 189, 190, 204, 216-217, 232-233, 235-237,

240, 244, 260, 262, 369, 414Rendezvous . . . . . . . . . . . . . . . . . .416Renewable energy . . . . . . . . . . . 13-14, 62REP . . . . . . . . . . . . . . . . . 488, 490, 492Republic of Congo . . . . . . . . . . . .113, 129ReVus . . . . . . . . . . . . . . . . . . . 7, 534REVUS . . . . . . . . . . . . . . . . . . . . . 26Ribeiro, D. . . . . . . . . . . . . . . . . . . .148Riihonen, E. . . . . . . . . . . . . . . . . . .360Robert, V. . . . . . . . . . . . . . . . . .287, 488Rodger, C. . . . . . . . . . . . . . . . .488, 494Rodríguez-Gasén, R. . . . . . . . . . . . . . .360Roerink, G. . . . . . . . . . . . . . . . . . . . 70Romanov, A. . . . . . . . . . . . . 254, 257, 262Romanov, Al. . . . . . . . . . . . . . . .254, 262Rontogiannis, A. . . . . . . . . . . . . . . . .367

Roosmalen, V. van . . . . . . . . . . . . . . .138Rosenblatt, P. . . . . . . . . . . . 287, 289, 292Rosta, R. . . . . . . . . . . . . . . . . .308, 506Rothkaehl, H. . . . . . . . . . . . . . . .352, 357Rott, H. . . . . . . . . . . . . . . . 46, 49, 52, 54Roussel, J.-F. . . . . . . . . . . . . . . .506, 513Rozhnoi, A. . . . . . . . . . . 263-265, 270, 272Ruescas, A. . . . . . . . . . . . . . . . . . . .174Ruiz Villarreal, M. . . . . . . . . . . . . . . .186Russia . . . . . . . . . 5, 14, 17, 23-24, 26-27,

70-71, 164-165, 169-170, 254, 263, 268, 271, 278, 281, 290, 309,

316, 430, 466, 482, 484, 490Russo, P. . . . . . . . . . . . . . . . . .296, 332

SSACOMAR . . . . . . . . . . . . . . 7, 430-436Sakharov, Y. . . . . . . . . . . . . . . . . . .482Saloniemi, O. . . . . . . . . . . . . . . . . . .360Sampling . . . . . . . . 35, 71, 85, 97, 107-108,

113, 133, 182, 189, 238, 407, 489Sanahuja, B. . . . . . . . . . . . . . . . . . .360Sanmartin, J. R. . . . . . . . . . . . . .506, 513Sannier, C. . . . . . . . . . . . . . . . . . . .118Saponara, S. . . . . . . . . . . . . . . .386, 393SAR . . . . 49-52, 54, 101, 107-108, 110, 112,

119, 121, 123-124, 139, 141, 143-144, 167-171, 198, 200-204, 208, 210,

213, 215-217, 393, 535-536SAR processing . . . . . . . . . . 208, 215, 393Sarrailh, P. . . . . . . . . . . . . . . . . . . .506Satellite . . . . . . 2, 6, 46, 74, 166, 174, 211,

226, 241, 262, 287-288, 357, 478, 516, 540-542, 544, 547

Satellite missions . . . . . . . . . . . .352, 508Savin, I. . . . . . . . . . . . . . . . . . . . . . 70Schaap, O. . . . . . . . . . . . . . . . . . . .148Schaefer, F. . . . . . . . . . . . . . . . . . . .526Schardt, M. . . . . . . . . . . . . . . . .118, 124Schepaschenko, D. . . . . . . . . . . . . . . .164Scherer, R. . . . . . . . . . . . . . . . . . . .360Schiller, C. . . . . . . . . . . . . . . . . . . . 46Schiller, S. . . . . . . . . . . . . . . . . . . .452Schioppo, M. . . . . . . . . . . . . . . . . . .452Schmitt, U. . . . . . . . . . . . . . . . . . . .118Schmullius, C. . . . . . . . . . . . . . .164, 170Schulte-Braucks, R. . . . . . . . . . . . . . 2, 13Schumacher, V. . . . . . . . . . . . . . . . .156SEBAL . . . . . . . . . . 99, 101-102, 151, 153Security . . . 69, 156, 220, 369, 541-542, 545Selmo, A. . . . . . . . . . . . . . . . . .309, 317SEMEP . . . . . . . . . . . . . . 6, 16, 263, 272Semiconductor . . . . . . . . . . . 22, 441, 443SEPServer . . . . 6, 20, 24, 360-362, 364, 366Shagimuratov, I. . . . . . . . . . . 254, 260-261Shea, H. . . . . . . . . . . . . . . 319, 322, 325Shielding . . . . . . . . . . . . . . . . . . . .539Shklyar, D. . . . . . . . . . . . . . . . . . . .263

559I N D E X

Shvidenko, A. . . . . . . . . . . . . . .164, 170Siberia . . . . . . . . . . . . .14, 164, 167-169SiC substrate . . . . . . . . . . . . . . 405-406SIMTISYS . . . . .6, 16, 206-211, 213, 215-216Singh, Y. . . . . . . . . . . . . . . . . . 78, 452Single Event Effect . . . . . . . . . . . . . .443Sirro, L. . . . . . . . . . . . . . . . . . . . . .114Sitoe, A. . . . . . . . . . . . . . . . . . . . .138Siwe, R. . . . . . . . . . . . . . . . . . .118, 124SkyFlash . . . . . . . . . . 7, 22, 440-441, 444Smartees . . . . . . . . . . . . 7, 22, 446, 448Snow . . . . . . . . . . . . . . . 46, 49, 54, 241SOC2 . . . . . . . . . . . . . . . 7, 22, 452-453Soil moisture . . . . . . . . . . . . . . . . .101Solar arrays . . . . . . . . . . . . 378, 383, 529Solar flares . . . . . . . . . . . 2, 347, 481, 498Solar high energy data . . . . . . . . . . . .342Solar storms . . . . . . . . . . 20, 27, 474, 479Solar wind . . . . . . . 6, 20, 24, 302-303, 305,

307-308, 365, 479-480, 482, 484-485, 498, 500, 502

Solberg, R. . . . . . . . . . . . . . . . . . . . 46Solovieva, M. . . . . . . . . . . . . . . .263, 272SPA . . . . 7, 26, 292, 378, 540, 542-545, 547Space application . . . . . . . . . 312, 332, 386Space communications . . . . . . . . .367, 373Space-data dissemination . . . . . . . . . .374Space-data overlay . . . . . . . . 367, 370, 374Space-data routers . . . . . . . 6, 21, 367-368,

370, 374-375Space debris . . . . . 7, 10, 13, 20, 24-26, 381,

505-506, 508, 516, 526, 528-529, 531-532, 541-542

SpaceFibre . . . . . . . . . . 464-465, 467-470Space mission vulnerability . . . . . . . . . .531Space Weather . . . 7, 10, 13, 23-24, 27, 261,

343, 346, 360-362, 364-366, 370, 474-481, 485, 488-489, 494, 498-501, 503, 541, 543

SpaceWire . . . . . . . . . . . . 7, 23, 464-470SpaceWire-RT (SpWRT) . . . . . . . . . . 7, 464Spanier, F. . . . . . . . . . . . . . . . . . . .360SPARTAN . . . . . . . 6, 19, 333, 336-337, 339Splettstößer, J. . . . . . . . . . . . . . . . . .404SSA . . . . . . . . . . . . . . . . . . . . 540-547Stephenne, N. . . . . . . . . . . . . . . . . .128Sterenharz, A. . . . . . . . . . . . . . . . . .352Sterr, U. . . . . . . . . . . . . . . . . . . . .452Stohlman, O. . . . . . . . . . . . . . . . . . .516Storm, S. . . . . . . . . . . . . . . . . . . . .404Straubinger, T. . . . . . . . . . . . . . .404, 411Stuhler, J. . . . . . . . . . . . . . . . . . . .452Sulphur dioxide . . . . . . . . . . . . . . . .224Sun . . . . . . . . . . . .20, 290, 306, 517, 520Sunderland-Groves, J. . . . . . . . . . . . . .138Swaziland . 148-149, 232-234, 236, 238, 241SWIFF . . . . . . . . 7, 24, 498-499, 501, 503

TTait, S. . . . . . . . . . . . . . . . . . .220, 228Tatischeff, V. . . . . . . . . . . . . . . . . . .360TEC . . . . . 255, 257, 261, 391, 477, 479-480Tether . . . . . . . . . . . . . . . . . .507, 513Theodorou, T. . . . . . . . . . . . . . . . . .516Thermal protection . . . . . . . . . . .446, 448Thermal simulation . . . . . . . . . . . . . .520Thiel, C. . . . . . . . . . . . . . . . 164, 166, 170Thomson, A. . . . . . . 240, 482, 484-485, 494Thuillot, W. . . . . . . . . . . . . . . . .287, 292TID . . . . . . . . . . . . . . . . . 354, 441, 443Tikhomirov, A. . . . . . . . . . . . . . . . . .278Time and frequency . . . . . . . . . . . . . .452Time-series . . . . . . . . . . . . . . . . . . 37Tino, G. M. . . . . . . . . . . . . . . . . . . .452TIR anomalies . . . . . . . . . . . . . . . . .258Tosi, P. . . . . . . . . . . . . . . . . . . . . .386Total Ionizing Dose . . . . . . . . . . .441, 443Trachta, G. . . . . . . . . . . . . . . . . . . .404Tramutoli, V. . . . . . . . . . 254-255, 258, 262Triebning, G. . . . . . . . . . . . . . . . . . . 46Tsaoussidis, V. . . . . . . . . . . . . . . . . .367Tsybulia, K. . . . . . . . . . . . . . . . . . . .254Tuccillo, A. A. . . . . . . . . . . . . . . .309, 317Tuccio, G. . . . . . . . . . . . . . . . . . . . .386Tziotziou, K. . . . . . . . . . . . . . . . . . .360

UUlich, T. . . . . . . . . . . . . . . . . . .488, 494Ultrasonic wire-to-wire bonding . . . . . . .304User survey . . . . . . . . . . . . . . .133, 235Usoskin, I. G. . . . . . . . . . . . . . . . . . .360

VVainio, R. . . . . . . . . . . . 360-362, 365-366Valero, J. L. . . . . . . . . . . . . . . . . . . .540Valkengoed, E. van . . . . . . . . . . . . . .138Valtonen, E. . . . . . . . . . . . . 360, 365-366Vanden Borre, J. . . . . . . . . . . 82, 84, 87, 90Van der Linden, R. . . . . . . . . . . . . . . .474Vasilyev, S. . . . . . . . . . . . . . . . . . . .452Vector control . . . . . . . . . . 6, 17, 232-235Vellante, M. . . . . . . . . . . . . 488-489, 494Verbeeck, F. . . . . . . . . . . . . . . . . . .474Verhoeven, R. . . . . . . . . . . . . . . . . .138Vermeersen, B. . . . . . . . . . . . . .287, 292Verzegnassi, F. . . . . . . . . . . . . . . . . .206VHDL . . . . . . . . . . . . . . . . . . .386, 392VHR . . . . . . . . .32, 35, 37, 40, 88, 108, 110,

112-114, 141, 167, 199, 236-239Viereck, R. . . . . . . . . . . . . . . . . . . .474Viljanen, A. . . . . . . . . . . . . . 482-483, 485Vilmer, N. . . . . . . . . . . . . . . . . .348, 360

560I N D E X

Vincenzi, A. . . . . . . . . . . . . . . . . . . .386Virchenko, O. . . . . . . . . . . . . . . . . . . 70Visagie, L. . . . . . . . . . . . . . . . . . . .516VLBI . . . . . . . . . . . . . . . . . . . 287-291VLF . . . . . . . . 263-268, 272, 357, 489, 492VLIW . . . . . . . . . . . . . . . . . . . . . .387Volcano . . . . . . . . . . . . . . . . . . 6, 220Vounatsou, P. . . . . . . . . . . . . . . . . .232Vrieling, A. . . . . . . . . . . . . . . . . . . .128Vulnerability . . . . . . . .7, 527-528, 534-535

WWald, L. . . . . . . . . . . . . . . . . . . . 58, 62Walker, S. . . . . . . . . . . . . . . . . . . .263Waltereit, P. . . . . . . . . . . . . . . . . . .404Water Framework Directive . . . . . . . . . . 16Water management . . 13-14, 94-96, 102, 148Water quality . . . . . . . 6, 16, 174-175, 192WATPLAN . . . . . . . . . 5, 14, 148, 150-153Wayers, T. . . . . . . . . . . . . . . . . . . .148Weber, A.-D. . . . . . . . . . . . . . . . . . .404Welty, N. . . . . . . . . . . . . . . . . .526, 532Wesztergom, V. . . . . . . . . . . 482, 485, 494Whistler . . . . . . . . . . . 357, 489-490, 494Wiesmann, A. . . . . . . . . . . . . . . . . . 46Wik, M. . . . . . . . . . . . . . . . . . .482, 485Wilhelmi, C. . . . . . . . . . . . . . . . . . .446

Wilken, V. . . . . . . . . . . . . . . . . . . . .254Williams, J. D. . . . . . . . . . . . . . .506, 513Wind . . . . . . . . . . . . 6, 14-15, 20, 24, 52,

58-59, 225, 302-303, 305, 307-308, 365, 479-480,

482, 484-485, 498, 500, 502Winter-kill . . . . . . . . . . . . . . . 70, 76,-77Wintoft, P. . . . . . . . . . . . . . 482, 484-485Wit, A. de . . . . . . . . . . . . . . . . . . 70, 78

XXie, K. . . . . . . . . . . . . . . . . . . . . . .506X-rays . . . . . . . . . . . . . . . 396-398, 401

YYakoushkin, S. . . . . . . . . . . . . . . . . .386

ZZakharenkova, I. . . . . . . . . . . . . . . . .254ZAPAS . . . . . . . . . . . . . . . . . . . . .170Zegers, T. . . . . . . . . . . . . . . . . . . . 2, 13Zimmer, D. . . . . . . . . . . . . . . . . . . 2, 13Zoest, T. van . . . . . . . . . . . . . . . . . .506Zunker, H. . . . . . . . . . . . . . . . . . . 2, 13

European Commission

Let's Embrace Space Volume II

Luxembourg: Publications Office of the European Union

2012 — 560 pp. — 176 × 250 cm

ISBN 978-92-79-2207-8

doi:10.2769/31208