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Space Policy 29 (2013) 175e180
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Space Policy
journal homepage: www.elsevier .com/locate/spacepol
Advancing Earth observation from space: A global challenge
Pierre MorelUniversity of Paris VI, France
a r t i c l e i n f o
Article history:Received in revised form10 June 2013Accepted 10 June 2013Available online 17 July 2013
E-mail address: [email protected].
0265-9646/$ e see front matter � 2013 Elsevier Ltd.http://dx.doi.org/10.1016/j.spacepol.2013.06.008
a b s t r a c t
Global Earth observation goes well beyond taking pictures of the Earth from space. Earth observationaims to identify and characterize planetary-scale processes that occur in the Earth interior or the world’soceans, at the Earth’s surface or within the global atmosphere, on the basis of weak signals that may bedetected in space. This is a truly challenging task that requires the dedicated efforts of professionals andfirm public support commitments. The article reveals the scope of global Earth observation, highlightsthe technical and managerial challenges involved in undertaking it and discusses ways of making it moreeffective. Competent international cooperation and cost-sharing arrangements are essential for the ul-timate success of existing and future activities in this field.
� 2013 Elsevier Ltd. All rights reserved.
By the end of the 1950s, missile and sounding rocket technologyin the USA and the Soviet Union had progressed far enough thatastronautics enthusiasts could envision placing a man-made sat-ellite in Earth orbit. Plans were actually made, under the sponsor-ship of the Office of Naval Research, for launching a small scientificsatellite as a US contribution to the International Geophysical Year.These developments led the White House to call upon an ad-hoc“Blue Ribbon Panel” to assess the potential applications of spacetechnology beyondmilitary uses such as global reconnaissance. Thepanel identified three fields of application in the civilian domain:telecommunications, scientific research and “meteorology”, thelatter notionally embracing Earth science and services in general.
The first domain had the full attention of a powerful commu-nication industry, naturally. The second domainwas promoted by avocal community of scientists eager to explore near-Earth spaceand the Universe beyond the atmosphere. The third putativeapplication, unlike the other two, was lacking a well-establishedconstituency and thus somewhat problematic. Nevertheless,Earth observation from space did flourish almost immediately [1].The first polar-orbiting meteorological satellite, the Television andInfra-Red Observation Satellite (TIROS-1), was launched in April1960. It provided daily pictures of the global cloud cover but scantinformation besides. With the help of such images, meteorologistsidentified incipient tropical storms or hurricanes and other phe-nomena that might well be missed by conventional weather ob-servations. In those days, weather data were scarce over vastswaths of the Northern oceans and almost inexistent over theSouthern hemisphere.
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However, the early TIROS satellites lacked anymeans tomeasureatmospheric temperature and pressure, the basic information usedfor weather forecasting (horizontal pressure gradients essentiallydetermine the atmospheric circulation, at least outside the Tropics).This deficiency was corrected in 1969 by the NASA Nimbus-3experimental weather satellite but the accuracy of these early“remote sensing”measurements was relatively poor. In fact, remotetemperature sounding from space would only be perfected thirtyyears later with the development of the Atmospheric Infra-RedSounder, a component of the NASA Earth Observing Systeminitiative. In the meantime, weather forecasters continued to relyon time-honored techniques, i.e. surface observations and upper-air measurements using balloon-borne sensors (known as radio-sondes) launched twice a day, at the agreed time, from some 800stations worldwide (most of them in the Northern hemisphere). Ittook a serious scientific effort and the strong involvement of theEuropean Center for Medium-range Weather Forecast (ECMWF) toexploit the vast amount of satellite data flowing continuously (i.e.not simultaneously at specified times) from “remote sensing”spacecraft in various orbits. This was finally achieved in the 1980’s,in time for demonstrating the feasibility of global weather predic-tion up to one week in advance (Global Weather Experiment) and atruly global system of polar-orbiting and geostationary meteoro-logical satellites. Satellite data are now considered a crucial sourceof information for operational weather prediction.
Similar stories unfolded in other geoscience disciplines. At first,oceanographers, hydrologists, geologists and geophysicists found itsilly to call upon far-fetched space observations in order to studyphenomena that were occurring in front of their eyes and could bemeasured using familiar tools e such as sensors on oceanographicvessels andmoorings. Earth scientists and engineers were (and still
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are) rather individualistic e much more so than members of themore seasoned astronomical science community e and found itdifficult to manage the unavoidable competition for resources inthis new field. The progression of space observation into thesetraditional fields of Earth science was correspondingly slower.
One should also remember that Earth observation is meant tocapture natural phenomena that are not under our control and areoften random, one-of-a-kind events. Systematic long-term obser-vation or monitoring is the only means to build-up the requireddata basis for unraveling the multiplicity of governing factors andcomplex processes involved in geophysical phenomena. Unlike oneof a kind “science missions” designed to address one or a fewspecific research questions, Earth observation missions are pro-tracted and require setting-up cumbersome quasi-operational fa-cilities and staff for operations and data handling. Such projects areexpensive and not naturally popular with “research-oriented”space agencies that strive for incessant innovation. Nor can they beaccommodated within the constrained budget of existing opera-tional service agencies.
For these reasons, the conception, planning and implementationof successful Earth observation projects pose unique and some-times insuperable challenges to investigators and space agenciesalike. The objective of the present article is to present the scope ofthe topic and then discuss the requirements that apply to theconception, implementation and exploitation of meaningful globalEarth observation from space. The article will then proceed todiscuss the type of governance that could be most effective formanaging such activities, and how the right sort of internationalcooperation could be a powerful means to further enhance existingprograms.
1. The scope of global Earth observation
Why should we want to move to outer space to observe phe-nomena that happen at the Earth surface, in the atmosphere or inthe planet’s interior? The first reason is that satellite-based obser-vations provide the only means to acquire a homogeneous view ofthe global Earth. In the field of meteorology, for example, we arestill facing systematic discrepancies at international boundariesthat result from the use of different measuring equipment. Despitean on-going international effort sponsored by the World Meteo-rological Organization (WMO) for the standardization of basic in-struments, we are still struggling with fickle temperature orhumidity sensors as well as entrenched calibration procedures thatperpetuate systematic cross-border differences. Homogeneity ofmeasurement is an essential asset when looking for weak gradientsor the faint signature of hidden features. This advantage is notunique to viewing from space; it is well known that aerial surveyscan bemore effective for spotting archeological remnants than longexploration treks on the ground. The ability to use, in essence, onesingle sensor for characterizing a vast spatial domain or spanning along time interval is a major advance.
The second reason is that space-borne observation allowsfrequent viewing of the whole planetary domain. Most if not allfeatures of the Earth environment are variable over many differenttimescales: short periods of time (hours to days) in the case ofmeteorological phenomena, somewhat longer periods (weeks toyears) for the ocean circulation and surface conditions, muchlonger periods (decades to centuries) for changes in ice-sheets andglaciers, and even longer timescales for the motions of the Earthcrust and planetary interior. Thanks to the sensitivity and stabilityof space-borne instruments, even minute and/or exceedingly slowmotions (such as continental drift) can be detected and measuredprecisely. Characterizing the full range of natural phenomena re-quires frequent global observations that are beyond the resources
(financial and otherwise) of ground-based observers. How wouldone know about on-going variations in solar radiation reaching theplanet without a succession of overlapping radiometric measure-ments from satellites in space? How would one predict future sea-level rise without high-precision global altimetry surveys andgravity field monitoring from Earth-orbiting satellites, especiallysince coastal tide-gauge data are often contaminated by regionaluplift or sinking motions of the Earth crust that may amount to asmuch as 1 m per century?
The first attempt at global observation of the ocean e the NASA“Ocean Dynamics Satellite”, better known as SEASAT e waslaunched in 1978. The mission was very ambitious: the spacecraftwas 20 m long, weighted more than 2 tons and carried five sensors,three of which had never been tested before: a radar altimeter, asurface wind sensor (microwave scatterometer) and a high-resolution synthetic-aperture imaging radar. It is said that, oncein orbit, the latter instrument was sensitive enough to detect thewake of submerged submarines, to the great dismay of militarycommands. Unfortunately, the spacecraft developed a fault andshut down after only hundred days of operation. It tookmany yearsto rebuild a similar capability with the cooperation of Europe andJapan. The first re-flight of a geodetic radar altimeter was theTOPEX/Poseidon mission, a joint project of NASA and the Frenchspace agency CNES (Centre National d’Etudes Spatiales). Thespacecraft was launched by the Ariane rocket from the KourouSpace Center in Guyana in 1992 and worked faultlessly for morethan thirteen years, until 2006. The TOPEX/Poseidon missionbrought a major scientific contribution to the World Ocean Circu-lation Experiment (WOCE), an international endeavor, involvingmany oceanographic science institutions and researchers, toassemble the first quasi-instantaneous mapping of ocean currentsworldwide. Together with the follow-on Jason altimeter missions,TOPEX/Poseidon provided a continuous high-precision record ofsea-level altitude worldwide (within a fraction of a millimeter inglobal annual average) and systematic monitoring of the ever-changing circulation of the oceans. In fact, TOPEX/Poseidonbrought about a profound renewal of physical oceanography, fromthe “climatological” description of a static mean circulation, to thedynamic concept of oceanic currents and vortices with lots of en-ergy and variability.
In cooperation with the Japanese Aerospace Exploration Agency(JAXA), NASA tested several successive versions of the SEASATwindscatterometer, from NSCAT in 1996 to Seawinds in 1999, and thefinal NASA QuickSCAT mission in 2002. Microwave scatter mea-surements provided themeans to pinpoint the “eye” of typhoons orhurricanes and measure ocean surface winds with satisfying ac-curacy, but there is as yet no indication that this capability will beexploited operationally in the future. In addition, the EuropeanSpace Agency (ESA), JAXA and NASA have launched imaging radarsatellites that provide precise topographic maps of the Earth sur-face as well as observations of continental drift or ice-sheetdeformation, a uniquely effective research tool for geology andglaciology.
From the first Earth Resources Technology Satellite (LANDSAT-1)developed and launched by NASA in 1972 to the most recentcommercial Earth observation ventures, the constant improvementof optical detectors provided the means to monitor global vegeta-tion, topography and other characteristics of the land surface aswell as transient disasters, at the appropriate high spatial resolu-tion (now one meter or a few meters). While the special-purposeimagery collected for strategic or tactical surveillance turned outto be not so useful for civilian applications, commercial Earthobservation programs e such as the succession of French SPOTsatellites since the mid 1980’s, American IKONOS satellites since2000, or the dual-purpose French “Pléiades” satellite system since
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2011e have becomemajor suppliers of high tomoderate resolutionimagery to several Defense Departments as well as a wide range ofcivilian customers.
Repeated high-resolution radar mapping of the Earth’s surfacetopography using the electronic technique of antenna synthesis(combining radar echoes at successive positions of the spacecraft togenerate the equivalent of a very long antenna) shows the de-formations of the surface associated with deep water pumpingfrom aquifers or slippage across geological faults. The same tech-nique led to the discovery of relatively fast “ice streams” thatextend well into the Antarctic ice sheet, thus changing the glaci-ologists’ perspective about potential “fast” changes in the volume ofthis enormous water reservoir. A few years later, in 2002, theingenious Gravity Recovery And Climate Experiment (GRACE) twinsatellites missionwas able to consistently measure minute changesin the Earth’s gravity field and thereby remotely determine theaccumulation (or loss) of mass at the Earth’s surface, such as theaccumulation or melting of ice over Greenland or Antarctica, andchanges in surface water storage as well as underground aquifers.
At this time, one can assert that eventually no large event, takingplace within or around the Earth, will escape detection from space.The advent of artificial Earth satellites has created the new scientificfield of global geodynamics that touches upon all branches of Earthsciences and services, from meteorology, atmospheric physics orchemistry to dynamic oceanography or the internal dynamics ofthe “solid” Earth. We can reasonably expect that this new foundknowledge will bring forth novel capabilities for weather forecast,climate change projections, Earth resources management, opera-tional oceanography, sea level rise and storm surge prediction, eventhe assessment of crustal strain and earthquake risks.
2. The technical challenges of global Earth observation
From this brief survey, it should be clear that the scope for Earthobservation from space is not limited by a lack of serious problemsfacing the denizens of the planet, nor the enthusiasm for exploringthese problems and experimenting with new ideas for practicalapplications. Rather, like many other advanced endeavors, Earthobservation from space is, first and foremost, subject to the limi-tations of technical and industrial capabilities on the one hand, andappropriate funding on the other.
It is obvious that any remote sensing method is necessarilybased upon the analysis of natural or artificial signals that can reachspacecraft in Earth orbit. There are only two kinds of signals thatcan be exploited: electromagnetic waves and changes in Earth’sgravity field (natural neutron emission could be used to remotelydetect water through vacuum or a thin planetary atmosphere butnot from Earth orbit). Electromagnetic signals span the range ofvisible or invisible light and microwaves up to metric wavelengths(longer waves cannot escape the Earth ionosphere). Thus potentialremote sensing techniques are restricted by the sensitivity ofphoton detectors or radio receivers and by the performance ofartificial sources in the case active systems (such as radars and li-dars). The analysis of variations in the quasi-static Earth gravityfield is one recent development with broad potential, but it has notbeen fully exploited yet.
The basic technical knowledge and capabilities to produce thedevices needed to measure such signals are clearly in the domain ofindustry. While there were some instances of space programsgenerating their own project-specific technologies, the progress ofEarth observation generally depends upon the existence ofadvanced industrial know-how domestically or the availability ofthe required industrial products abroad. Discussing the societalconditions under which such technical resources are likely toappear exceeds the scope of this article, but it should be clear that a
meaningful space program cannot flourish without a strong tech-nological foundation.
A further scientific and technical challenge is that of ensuringthe consistency of Earth observation data over the long term. Manyoperational Earth observing systems are actually designed to serveshort-term objectives such as weather forecasting, environmentalcatastrophe assessment, or crop yield projections. Beyond a fewweeks, the data are perceived as no longer useful and may well bediscarded. In the early 1980s, for example, the twice-hourly Earthimage data from four geostationary weather satellites wereroutinely deleted after a few weeks. Such “cinematographic” datasets were very large by the standards of the time and overtaxed thecapacity of available data storage equipment. It took a special effortby the World Climate Research Program to organize the partialrescue and storage of these cloud cover data for later reference, andalso to coordinate observations of selected reference targets (e.g.suitably uniform cloud field) by geostationary and polar-orbitingsatellites in order to achieve adequate a posteriori photometriccalibration of image data from different geostationary satellites.More recently, a long-running argument about the significance ofglobal warming trends derived from microwave radiometry mea-surements by operational NOAA satellites was finally resolved bytaking into account a slow drift of the spacecraft orbital parametersand consequent changes in the field of view of the instruments.Arcane issues e in this case involving celestial mechanics e andradiation transfer though the atmosphere e could well influencethe long-term significance of remote sensing data. One must keepin mind that Global Change Research is often aiming to quantifyvery small global trends, in this instance a few hundredths of adegree Kelvin per year.
While the historical operators of global environmental obser-vation systems e NASA and the National Oceanic and AtmosphericAdministration (NOAA) of the USA, ESA and EUMETSAT in Europe,and the Japanese Space Agencies e have gone a long way towardaccommodating scientific needs for accurate calibration of satellitemeasurements and full documentation of data reduction pro-cedures, many more satellite programs are actually run for purelyoperational purposes, for which “old news is no news”. Such pro-grams, especially qualitative imaging from space, may be adequatefor military surveillance purposes, the acquisition of commercialintelligence or assessing natural disasters, etc. but they contributelittle to the scientific understanding of global Earth processes, a factthat may escape politically-minded international players (see thesection on International Cooperation below).
Just keeping abreast of the latest technical developments,let alone mastering the know-how to effectively assemble space-craft components or information systems software, is no simpletask for amateurs, even famous scientists. The active involvementof professional technical support teams is indispensable. This ex-plains the essential role of space technology institutions, such asthe NASA Goddard Space Flight Center near Washington, the JetPropulsion Laboratory in Los Angeles, ESA’s Technical Center in theNetherlands or the French Toulouse Space Center. Even thoughNASA vowed to revitalize its own Earth observation program byentrusting the leadership of individual satellite missions to aca-demics and university professors, the truth is that no such projecthas successfully been implemented without the direct support ofone or the other NASA technical center.
This dependence upon specialized technical centers that mayemploy thousands of highly competent technical and scientificexperts is not without its own problems. Such centers may be in-clined to develop their own strategies, aiming to enhance theirfuture participation in up-coming projects and further developtheir perceived domains of expertise. The fierce competition be-tween NASA centers is a measure of the involvement of technical
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support personnel in framing future policies and does raise theissue of the relative weight of technical expertise and political in-fluence versus management vision. The NASAGoddard Space FlightCenter, for example, has had up to 10,000 professionals in itsemploy and was the largest single employer in the state of Mary-land, a fact that did not pass unnoticed in the state legislature. Thisis not an issue unique to democratic nations. The struggle betweendifferent military establishments in planned-economy nations isoften a matter of public record and media stories. The predilectionof technical centers for homegrown projects is always a challengefor prospective outside investigators as well as agency officials.
3. The managerial challenges of global Earth observationprograms
The high visibility and relatively high cost of space endeavorsnaturally elicit the interest and involvement of “decision-makers”well beyond the pay grade of professionals involved in actualimplementation. From the very beginning, the proponents of as-tronautics and space ventures in general have relied upon publicand political support to push their objectives through. The very firstartificial satellite was launched in Earth orbit for obvious politicalpurposes: Sputnik did not provide any scientific information orservice to humanity. Highly publicized “space events” were andremain a major driving factor of the US space program. Quiteirrespective of any scientific or practical achievement, the veryexistence of NASA as an independent agency is founded upon theexistence of one highly visible central mission: its unique manned-flight program for maintaining or at least promising the presence ofastronauts on the “Last Frontier”. To an extent that still bafflesskeptical Europeans, this image-building activity is still quitepopular with the public and compelling for political authorities.Space spectaculars have played, in the USA, in the Soviet Union andeven worldwide, a role not unlike that of the Circus Maximus inRome.
This is not a critique inasmuch as citizens need some drama andlofty challenges to inspire their daily life. In this sense, astronauticexploitse like landing active and “intelligent” robots on the surfaceof planet Marse continue to play a positive role in our societies. Onthe other hand, the “Hollywood” component of space activities maybecome an impediment when faced with financial arbitration.There is no lack of skeptics when substantial appropriations arebeing discussed. This has been a particular challenge for Earthobservation programs because they are neither overly spectacularnor obvious enough to compel the attention of non-experts. In theearly days, astronautics advocates could rely upon their awesomereputation. When asked why satellites in space had to be gold-plated, Wernher von Braun famously answered that spacecraftmade of solid gold would be too heavy! Earth observation had amuch more difficult run and needed to demonstrate its usefulness.When challenged about the justification of its geostationary satel-lite program, the National Weather Service representative had arough session on the floor of the US Senate during one particularafternoon in the 1980’s. Over the same evening, however, theMidwest was struck by 33 tornadoes, 32 of which were successfullytracked by the satellite and announced to the public. On the nextmorning, the budget request was approved without furtherdiscussion.
Micromanagement or even high-minded interventions by top-level officials can be devastating. The USA used to operate two in-dependent polar-orbiting meteorological satellite systems, one forcivil weather forecast, managed by the National EnvironmentalSatellite, Data and Information Service (NESDIS), and the other formilitary applications (Defense Meteorological Satellite Program).Each program maintained a pair of spacecraft in morning and
afternoon orbits. The two satellite systems did carry different in-strument suites but used essentially the same spacecraft platforms.Nonetheless, during the Clinton Administration, Vice-PresidentGore initiated an effort to “save money” and replace two fairlycost-effective concurrent systems by a single National Polar-Orbiting Environmental Satellite System (NPOESS) initiative, to bemanaged jointly by the Department of Defense, NOAA and NASA,that would aim at nothing less than “observing, assessing andpredicting the Total Earth System”.
An independent Integrated Program Office was created in 1994,to proceed forthwith with the collation of “user requirements”across the USA and definition of a comprehensive instrument suite.In the next step, the whole undertaking was contracted out to in-dustry for implementation in the traditional manner of the USAFprocurement office. Five years later, the development of the nom-inal NPOESS instrument payload was facing such delays and costoverruns that the timely replacement of existing operationalweather satellites became problematic. In the meantime, NASA hadinitiated a NPOESS Preparatory Project (NPP), initially presented asa “pathfinder mission” to provide an early opportunity for testingfive essential NPOESS sensors (in essence, replacements for in-struments already flying in the previous NOAA program). The initialplan was to launch NPP in the mid-2000s.
By 2005, further delays had made the original NPP scheduleunrealistic. A Department of Defense internal review boardconcluded that the NPOESS program woes “were largely self-inflicted, stemming from a tri-agency governance structure thatwas unmanageable” [2]. The program nevertheless continuedlimping forward until it was formally terminated by a decision ofthe US government in 2010. The formerly “integrated program”wasagain split into its original two components: a civil servicecomponent e christened “Joint Polar Satellite System” e consistingof one single satellite on the former early afternoon orbit and asingle pre-dawn “Defense Weather Satellite System” to serveessential military requirements. By mid-2011, the latter programwas already in jeopardy for budgetary reasons. On the other handNPP, now renamed “Suomi National Polar-orbiting Partnership”,was launched successfully in October 2011 (the satellite is namedfor the late Professor Verner E. Suomi whose pioneering role in thedevelopment of weather observation from geostationary orbit waswidely acclaimed). Hopefully, NPP will then serve as the proof-of-concept model for the future NOAA-NASA Joint Polar SatelliteSystem.
In summary, the initiative of an over-confident high governmentofficial to mastermind the replacement of two efficient programs,run by competent working-level organizations, with a grandiose“integrated” program managed by newcomers turned out to be anunmitigated disaster. In this perspective, one wishes that EuropeanUnion officials would reexamine their ambition to lead the futureEuropean space programs.
4. The pioneering role of space agencies
This story hints at the problems faced by national or multi-national space agencies that seek common ground between theambitions of scientific or technical experts and the indecision ofgovernmental decision-makers. In order to gain acceptance frompoorly informed officials, program agencies often resort to thesimple expedient of following NASA’s lead and replicating existingmission objectives and techniques. Few agencies did choose toproceed independently, like the distinctive Meteor weather satel-lite program initiated in 1969 by the former Soviet Union andstill operational today. The French space agency (CNES), for itspart, elected to seek gaps in the broad range of Americanachievements and focus on new projects that could conceivably
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deliver a breakthrough as well as a chance of successful exploita-tion in the long run. Its first attempt, the EOLE project involving afleet of constant-level (floating) weather balloons and data collec-tion and location by an orbiting spacecraft, was not a viable solutionfor a novel global observing system: the balloons were costly andtoo fragile, even though several did fly for more than a year andcircumnavigated the planet many times. On the other hand, long-term perspectives did materialize: the operational ARGOS datacollection and navigation system (managed by a CNES subsidiary)and the international SARSAT search and rescue satellite system areboth offshoots of the EOLE project.
Even ESA prevaricated in formulating a sensible strategy andtypically chose to follow two distinct and contrary design philos-ophies at the same time. Totally impressed by NASA’s ambitiousEarth Observing System (EOS) program, ESA embarked upon thedevelopment of the biggest civilian Earth observation spacecraftever: the 8-ton ENVISAT satellite. In this instance, ESA had failed torecognize that the large platform concept adopted by NASA at thattime was dictated internally by the need to protect its (politically)essential Space Shuttle program and to provide suitably largepayloads for Shuttle launchings. ESA was indeed fortunate that itsmonster spacecraft was successfully orbited in March 2002 anddelivered excellent data for ten years thereafter. On the other hand,under pressure by member states to produce some early results,ESA did adopt the medium-size SPOT spacecraft concept of theFrench space agency in order to quickly develop an ocean-orientedEarth Resource Satellite (ERS) program, emulating to some extentthe capabilities of the defunct SEASAT. Both ERS-1 launched in 1991and ERS-2 launched in 1995 operated faultlessly and producedgood data for periods far exceeding their design lifetime, ten andfifteen years respectively.
Since the 1980s, several Asian nations have developed state-of-the-art imaging satellites and deployed many Earth observingmissions, especially Japan, China and India. Japan initiated its cur-rent Himawari geostationary weather satellite program already in1977 and the Japanese National Space Development Agency(NASDA) undertook the development of its own (relatively con-servative) Earth resources observation satellite JERS-1, whilesimultaneously cooperating with NASA to develop the innovativeTropical Rain Measuring Mission (TRMM). Both spacecraft werelaunched the same year in 1997. Japan then embarked uponconsiderably more ambitious but still relatively conservative pro-jects: the multipurpose Advanced Earth Observing Satellites(ADEOS 1 and 2) launched in 1996 and 2002, and eventually theAdvanced Land Observation Satellite (ALOS) launched in 2011.
China developed polar-orbitingmeteorological missions alreadyin 1988, while India flew its first geostationary meteorologicalsatellite in 1983 (China followed suit in 1997). Since then India haslaunched an abundant crop of lower-orbit observation satellites, atthe rate of about one every second year, while China developed afull gamut of oceanic, Earth resources and natural disaster obser-vation satellites. Yet few truly innovative concepts for global Earthobservation or new Earth science findings emerged from this vastand diverse activity. Like Brazil, Israel, etc., Asian space programslargely emulated the observing missions and techniques pioneeredin the West.
Nevertheless, the primary purpose of national space agencies isto blaze new trails for further innovation and to open new per-spectives for national industries. Just following the leader is notenough. Except for some quite impressive scientific exploration orastronomical survey missions, few among the recent entrants havecontributed real innovations in the field of Earth observation fromspace, where NASA has been the unchallenged leader since theearly days. Combining strong scientific flair with the “can do” spiritof its technical staff, while maintaining strong popular support for a
wide range of space initiatives, has been a truly impressiveachievement of NASA, especially considering that the agency wascreated as a (largely) policy-driven response to an unlikely andunforeseen challenge from abroad. All the same, advances in Earthobservation and Earth system science have been contingent uponthe sheer determination of a few strong personalities within NASAand NOAA, as well as some valiant academic supporters, not theresult of a firm agency commitment. Indeed, since its inception, theprogram has been the target of all sorts of challenges from politicaldecision-makers as well as the academic scene and remains fragileto this day: NASAmaywell be unable tomaintain its leadership roleindefinitely. Mustering efforts to empower space science andtechnology talents, as they may exist, ought to be a high priority ofthe world’s Earth science community, lest the information servicesthey now depend upon eventually fade out.
5. Promoting global Earth observation through internationalcooperation
Redundant developments and the replication of existing Earthobservation programs by a growing number of space-faring nationscan be perceived as awaste of resources or, alternatively, a potentialreserve for new groundbreaking innovations. Joint commitmentscould be a powerful means of stabilizing new space initiatives inthe face of budgetary turbulence, even though this idea appears tobe ignored by many space agency managers. The emergence of aformal, mutually supportive, sharing of responsibilities betweenNOAA in the USA and the weather satellite consortium EUMETSATin Europe is certainly a welcome step in that direction. The on-going global ocean altimetry program of the USA and Europe orthe US/Japan TRMM mission were both significant advances in theart of sharing implementation responsibilities as well as brilliantscientific achievements in their own right, judging by the amountof data acquired and the wide inter-disciplinary science impact.Actually many responsible officials, including successive ScienceAdvisors to US Presidents, recognized the value of internationalcooperation in the field of Earth science and applications. Fifteenyears ago, the NASA Earth System Science Enterprise had alreadyendorsed a cooperative approach to the planning and imple-mentation of such programs, in the form of an “Integrated GlobalObserving Strategy” for Earth observation from space [3]. Thisfarsighted proposal was certainly discussed, but not acted upon, byNASA’s international partners in the Committee on Earth Obser-vation Satellites (CEOS).
Several governmental organizations also took interest in thistopic and proposed various institutional initiatives to enhance in-ternational cooperation in their field of interest. In the early 1990’s,the UNESCO Intergovernmental Oceanographic Commission (IOC)instituted a Global Ocean Observing System (GOOS) program toemulate the long-established World Weather Watch of the WorldMeteorological Organization. Not to be outdone, WMO respondedin 1992 by initiating a Global Climate Observing System (GCOS) tocoordinate the long-standing voluntary observers programs run bymember states. UNESCO, FAO and other multinational agencies alsostepped in the fray with a proposed Global Terrestrial ObservingSystem (GTOS) in 1996.
Needless to say, these bureaucratic inventions did not add muchto actual field activities nor future prospects for a more rationalorganization of Earth observation worldwide. In fairness, oneshould mention that the scientific leaders of the World Ocean Cir-culation Experiment capitalized upon their expertise to create aworking system for systematic ocean observation. The system relieson global sea-level measurements by TOPEX/Poseidon and Jasonaltimeter satellites, and in-situ profiling of ocean temperature andsalinity using ARGO automatic sounding devices that periodically
P. Morel / Space Policy 29 (2013) 175e180180
plunge down to 2000 m depth and come back up again to transmitthe measurements through the ARGOS data collection facility. TheJason satellites are a shared undertaking of NOAA and NASA in theUSA, and EUMETSAT and CNES in Europe. The array of some 3000ARGO neutral buoyancy floats drifting in the world’s oceans is theproduct of worldwide cooperation among national agencies andacademic oceanographic institutions.
This incipient interest in global environmental monitoringinspired the European Commission to establish a Group on EarthObservation (GEO), consisting in some 88 Member States and 64Participating Organizations at the last count, to consider the sameissues. The Group proceeded with a succession of “Earth Observa-tion Summit” conferences and the formulation of a “Global EarthObservation System of Systems” (GEOSS) initiative. Pictures in Ref.[4] should give a realistic idea of the proceedings and foreseeableoutcomes, such as the “GEOSS Implementation Plan” (11 pages)adopted by the third “Summit” in Brussels.
Lacking in these institutional initiatives is any kind of criticalscientific judgment about the value of existing capabilities andprospects for new developments. In 2005, NASA did solicit theguidance of the US Academy of Sciences specifically for thispurpose i.e. to define current Earth System Science issues andidentify priorities for new initiatives in global Earth observation.But this “Decadal Study” turned out to be little more than a listof favorite satellite projects of members of the panel convenedby the academy. For example, the panel joined the vocal com-munity of academic supporters who had been advocating e forthe past 20 years e global wind measurements from space usingDoppler lidar techniques. The simple truth is that wind vari-ability in the atmosphere is such that the individual windmeasurements that could be collected in this manner wouldnever be representative of the mean wind velocity field, eitherhorizontally or vertically, let alone yield a realistic assessment ofatmospheric diffusion and transport. The academic panel obvi-ously did not understand this point, thus coming up with inef-fective recommendations.
6. Conclusion
The observation of the Earth from space is nothing like “spacetourism”, the awesome experience of viewing the planet fromnear-Earth orbit or taking pictures for the kids on a brief ride at the edgeof the atmosphere. Earth observation missions begin with figuringout (i.e. modeling) the processes that take place inside the Earth, atthe surface of the planet or in the air, assessing the nature andstrength of signals produced by these processes, identifying tech-nical means to detect such signals from afar, and then solve theproblem of extracting the required information from the flow ofraw data transmitted by orbiting spacecraft. In short, Earth obser-vation projects are demanding scientific undertakings on a par withastrophysical studies, may be even more so, considering that geo-science findings inferred from orbital observations will eventuallyface validation or falsification by ground truth.
Earth observation missions require mastering the challenges ofspace flight: facing the back-breaking stresses of launch and thehard vacuum of space into which even metals can evaporate andexcess heat cannot be dissipated, except through thermal radiationinto the void. It should be understood that any spacecraft is really aprototype, an essentially unique artifact that must function on itsown, sometimes for many years, without a chance of even minorrepairs. Every possible mishap must be foreseen and taken care ofbefore launch. For this reason, engineering expertise and flightmission experience are uniquely valuable assets that must becarefully husbanded over whole careers.
Space agencies cannot forfeit their responsibility for definingfuture development strategies in their own domain, nor can theyrely upon the generic expertise of the scientific community, nomatter how senior or famous. Instead, space agencies must callupon experts who have been involved personally in the imple-mentation of past programs and are willing to spend the timeneeded for assimilating the current scientific and technical contextin consultation with their peers. Interdisciplinary scientific in-stitutions or bodies could also play a constructive role. NASAactually conducted, for the first time in 1998, a broad consultationacross Earth System Science disciplines based on a “request forideas” and assessments of potential new techniques. Unlike thelater National Academy of Science “Decadal Study”, this process didnot fail to identify the one glaring gap in Earth observation fromspace today: systematic measurement of global precipitation.
Nor should space agencies forfeit their responsibility to overseespace missions through their full implementation cycle. Modernobservation systems are based upon a sophisticated understandingof Earth processes as well as specialized engineering know-how.Neither can be developed overnight. This requirement precludesblithely contracting out the implementation of such projects toindustry, as demonstrated by disastrous precedents. In brief, theutilization of space techniques for earth science and services is nobusiness for amateurs and must be approached professionally.Concerned citizens should hope that such professionals will stillexist to discharge these responsibilities in the future and to developthe global Earth observation tools that may help find a safe paththrough future global environmental crises.
References
[1] US National Academy of Science, Board of Atmospheric Science and Climate.Earth observation from space: the first 50 years of scientific achievements.Washington, DC: National Academy Press. Available from: www.nap.edu/catalog.php?record_id¼11991; 2008.
[2] Quotation from Defense Industry Daily, November 28, 2011. Available from:www.defenseindustrydaily.com/major-shifts-flow-from-npoess-polar-satellite-program-crisis-01557/.
[3] Kennel Charles, Morel Pierre, Williams Gregory. Keeping watch on the earth, anintegrated global observing strategy. Consequences: the nature and implica-tions of global change, vol. 3, No. 2. Washington, DC: US Global ChangeResearch Information Office; 1997.
[4] The European Commission Group on Earth Observation. Earth observationsummits. Available from: ec.europa.eu/research/environment/index_en.cfm?section¼geo&pg¼eo-summits; 2007.
