VENUSVENUS((Vegetation and Environment New µ-Spacecraft) Vegetation and Environment New µ-Spacecraft)

AA demonstration space mission dedicated to land demonstration space mission dedicated to land surface environment surface environment in the framework of GMES

Selma CHERCHALI, Directorate for Strategy and Programmes, Earth ObservationLand Environment Programme Manager

Context and objectives of the mission

■Despite the existing panoply of space sensors, appropriate measurements tools are still lacking

Very high spatial and temporal variability of earth surfaces parameters, e.g. fast vegetation growth in small crop fields

Earth observation missions currently covering either the temporal variability (AVHRR, VEGETATION, MERIS, MODIS, MSG…) or the spatial variability (SPOT, Landsat…)

Increasing scientific and social demand in environment issues related to land surface environment, e.g. sustainable development, management of water resources and natural or cultivated ecosystems...

Recent and significant scientific advances in the modelling of land surface processes at all scales

■Conciliating the capability to characterise the high spatial variability of land surfaces with its rapid evolution in time is the main driving force of the mission concept

■ Monitoring and understanding the vegetation cycles to improve functioning models

Access to the dynamic of surfaces

■ Useful information over land retrieved from remote sensing data

Reflectances, vegetation index, leaf area index, albedo, surface temperature, solar irradiance, precipitation

Land cover maps Net primary productivity (from simplified model forced by remote sensing data) Time evolution of these variables ...

Need to provide simultaneously high spatial resolution and high temporal revisit data to solve land cover heterogeneity and vegetation dynamics

Context and objectives of the mission

VENµS

■ObjectivesTo provide data for research on land surface functioning : land cover & land

use, water and carbon exchanges, snow

To provide data for research on land surface functioning : land cover & land use, water and carbon exchanges, snow

Data assimilation Automatic land cover mapping Validation of medium resolution satellite products Demonstration of the use of RS data for the implementation of Environmental

regulations (e.g. Grenelle laws in France)

■Main specificity of Venµs multi-temporal observations with constant observation angles

Before the operational space infrastructure, VENUS is a demonstration mission aiming at studying the technical feasibility of the concept and at developing scientific methods over a sample of ground research sites

Developing new processing algorithms is one of Venµs missions VENUS is a demonstration mission which aims is to demonstrate the benefit of

superspectral, high resolution, high revisit frequency, and high quality measurements. One objective of VENUS is

– i) to be the precursor of an operational mission (Sentinel 2) with such characteristics and full global coverage and

– ii) to develop pre-processing algorithms, methods, and applications that will use these data.

(From Venµs Mission Requirements)

VENUS : a demonstration mission in the framework of GMES

Image Features

Venµs image characteristics Resolution 5m-10m, Field of View 27 km 12 spectral bands from 412 to 910 nm Systematic acquisition of 50 sites every second day 2 stereoscopic bands with a low angle difference Constant viewing angle ==> Directional effects are minimised

VENS organization

Israeli Space Agency designs, manufactures and tests the VENS Platform (IMPS). Manufactured by IAI-MBT

CNES is responsible for the camera (manufactured by Elop)

Scientific mission (720 km) 2.5 years

Technological mission (410 km) – 1 year

Orbit change

End of the commissioning phase electrical propulsion system Launch

2012

3 months

~250 kg

■ CNES develops and operates the Science Mission Center and Image Ground Segment (SMIGS), and makes the data available to the users

Programmatic aspects : GMES

■GMES services dedicated to earth environment are under development and validation by the European Commission and ESA, with the support of national space agencies. Services are expected to be operational by 2013;

Services dedicated to land environment are amongst the top priority themes of GMES

■The GMES Space component (sentinels + national missions) specifications have to fulfil the user requirements (priorities, sensors, revisit time, continuity of data…) especially for the first fast tracks “oceanography”, “land monitoring”, “emergency” (and the next ones : atmosphere, security).

The SPOT satellites will be beyond their expected lifetime by 2012 The Sentinel 2 will be the future operational infrastructure for feeding the GMES

services (2013)

a way up to operational services by 2013

■ Venµs is a scientific mission : limited number of sites, no continuity. Free access to the data.

■The European Sentinel-2 mission will provide global coverage of high resolution superspectral data, every 10 days with one satellite and every 5 days with two satellites

One clear image every 15 to 30 days

■ESA, coordinator of the GSC, takes into account the national missions and plans in order to make the GSC coherent, complete and affordable for the users/CE.

■Contribution through national / multi-lateral programme : Demonstration mission : Vénμs

Programmatic aspects : GMES

And what’s the next?

Moreover, a major challenge is to be ready to provide on a operational basis the data and the models required to support the strong evolution of agricultural, environmental and security policies and to feed decision support system (GMES)

■After the race for resolution, the next step will be ~daily revisit with decametric resolution, everywhere (systematic coverage).