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(Click for frequent words.) 66 National d' Etudes 65 agency CNES 64 Spatiales 62 Spatiales CNES 61 Yannick d' Escatha 59 EADS Astrium 59 ESA CNES 59 IFREMER 59 Thales Alenia Space 58 EUMETSAT 57 Astrium 57 ESTEC 57 ESRIN 57 SRON 57 Earth Observation 56 SMOS 55 Alenia Spazio 55 GMES 54 Alcatel Alenia Space 54 Cosmo SkyMed 54 ESA 54 Observatoire de Paris 53 ONERA 53 Space Agency 53 Helios 2B 53 ESOC 53 Metop 53 Cloud Aerosol Lidar 53 D CIXS 53 TerraSAR X 52 MetOp 52 Spatiale des 52 INRIA 52 Studies CNES 52 EarthCARE 52 Telespazio 52 Astrium GmbH 52 ESA Cluster 52 Infoterra 52 planetary Transits 52 Eumetsat 52 SIRAL 52 ESA ESTEC 52 ESA Herschel 52 SAR Lupe 52 Eurobot 51 Thales Alenia 51 Simonetta Di Pippo 51 ESTRACK 51 COROT 51 Planetary Transits 51 Meteorological Satellites 51 OHB Technology 51 Hubert Curien 51 ADM Aeolus 51 ESA Earth Observation 51 Earth Observation Programmes 51 Galileo Joint Undertaking 51 Redu Belgium 51 Astrium Satellites 51 Mars Climate Sounder 51 COSPAR 51 Proba 51 BepiColombo 50 OHB System AG 50 Alcatel Alenia 50 NASA Stratospheric Observatory 50 CIRAD 50 LCROSS Observation Campaign 50 CIEMAT 50 Frascati Italy 50 Rosaviakosmos 50 Starsem 50 ASPERA 50 COROT satellite 50 Smos 50 Infrared Pathfinder Satellite 50 Centre BNSC 50 ASTRON 50 ATV Jules Verne 50 Alphabus 50 Joint Undertaking 50 nanosatellite 50 Pierre Simon Laplace 50 Medspiration 50 ENVISAT 49 ESMD 49 nEUROn 49 FORMOSAT 49 Moon Mineralogy Mapper M3 49 ESA GOCE 49 EADS SPACE 49 Eurockot 49 ADEME 49 Southern Observatory ESO 49 Climate Experiment GRACE 49 VIRTIS 49 e GEOS 49 UKIRT 49 SRON Netherlands Institute 49 Megha Tropiques 49 Tecnalia 49 CBERS 2B 49 Grenoble Observatory 49 GeoForschungsZentrum Potsdam 49 de Calcul 49 ESA Astronaut 49 Galileo Avionica 49 EADS Astrium GmbH 49 NASA Landsat 49 BMBF 49 OHB System 49 SCISAT 49 MPIfR 49 Volker Liebig 49 PPARC 49 ESA Envisat 49 ESA astronaut 49 Pôle 49 Shallow Subsurface Radar 48 Ocean Surface Topography 48 Mars# 48 IK4 48 ESA Planck 48 Continuity Mission LDCM 48 Infrared Astronomy SOFIA 48 Elsag Datamat 48 Mission TRMM 48 TIROS 48 polar orbiting 48 GIOVE B 48 GMES Space 48 Simonetta Di Pippo ESA 48 Anny Cazenave 48 ESA Integral 48 Decadal Survey 48 Arianespace 48 Scuola Superiore Sant'Anna 48 LIGO Scientific Collaboration 48 Infoterra GmbH 48 XMM Newton X ray 48 ANTRIX 48 Leopold Eyharts 48 Astrophysical Institute 48 ExoMars rover 48 UNU MERIT 48 TanDEM X 48 Rosetta orbiter 48 Security GMES 48 ESRIN ESA 48 Near Infrared Camera 48 Christiaan Huygens 48 Earth Observations GEO 48 FP6 47 MTSAT 47 RSC Energia 47 Convection Rotation 47 Paul Sabatier 47 SCIAMACHY 47 COSMO SkyMed 47 Foton M2 47 NPO Lavochkin 47 CALIPSO 47 Agency Jaxa 47 Envisat 47 EPOCh 47 Carlo Gavazzi Space 47 Kayser Threde 47 Galileo satellites 47 CEA LETI 47 visit http:/saturn.jpl.nasa.gov 47 Vega launcher 47 NSPO 47 Phobos Grunt 47 astrometric 47 Novespace 47 NASA Goddard 47 ESA ERS 47 SENER 47 Sumbandila 47 Onera 47 Galileo constellation 47 ExoMars mission 47 Spacecraft Operations 47 ISRO 47 Sofradir 47 E ELT 47 Forschungszentrum Jülich 47 Payload Operations 47 DCNS 47 Audiovisuel 47 GOCE 47 DEISA 47 SMOS Soil Moisture 47 Lunar Exploration 47 situ measurements 47 astronomical telescope 47 Credits ESA 47 7th Framework Programme 47 infrared astronomy 47 STScI 47 Deutsches Zentrum für Luft 47 Total Ozone Mapping 47 Verhaert 47 Arts et Métiers 47 ESA SMART 47 Eurostar E# 46 Kepler Mission 46 Earth Observation Satellite 46 Reflection Radiometer ASTER 46 National Astronomical Observatory 46 TU Delft 46 Fucino 46 Descent Imager Spectral Radiometer 46 Gaele Winters 46 Ecole Nationale Superieure de 46 Astrophysical Research 46 Environmental Satellites POES 46 Armement DGA 46 AFNIC 46 Ocean Salinity SMOS 46 ESO VLT 46 ESA XMM Newton 46 Jules Verne ATV 46 Youthsat 46 LEOP 46 Atacama Large Millimeter submillimeter 46 IYA 46 Space Physics 46 Envisat satellites 46 Forschungszentrum Julich 46 Roddam Narasimha 46 SSETI Express 46 Cassini Huygens 46 Infrared Astronomy 46 Center Deutsches Zentrum 46 Array ALMA 46 Pecresse 46 Ocean Salinity 46 Telespazio embody 46 ESO astronomer 46 RapidEye 46 ESA Rosetta 46 Cartosat 2B 46 Environnement 46 EUROCONTROL 46 NRENs 46 GIFAS 46 Planck satellite 46 Geostationary 46 Pascale Sourisse 46 INRS 46 ITER International Thermonuclear 46 Multi Purpose Logistics 46 GPS Block IIF 46 JAMSTEC 46 Envisat satellite 46 DMCii 46 Dordain 46 AMASE 46 GPS IIR 46 Alphasat 46 Alpha Particle 46 Insat 4B 46 Isro 46 HRSC 46 Max Planck Institut fuer 46 CHIPSat 46 TECNALIA 46 NASRDA 46 Jülich 45 Landsat Data 45 YES2 45 RADARSAT 2 45 O OREOS 45 CNSA 45 Astrosat 45 Planetary Fourier Spectrometer PFS 45 Operations Centre ESOC 45 Délégation Générale pour l' 45 CBERS 45 Laser Interferometer Gravitational Wave 45 Volker Liebig ESA 45 HISDESAT 45 Observatory STEREO 45 MeerKAT 45 Faint Object 45 GSTB V2 45 Aquarius SAC 45 PRACE 45 NOAO 45 International Astronautical Federation 45 GOSAT 45 geodesy 45 THALES 45 INAF IASF 45 VLBI 45 Kosmotras 45 E sciencE EGEE 45 ESFRI 45 THEMIS mission 45 Alessandro Morbidelli 45 Stratospheric Observatory 45 CFHT 45 Instituut voor 45 Oberpfaffenhofen 45 Ariane launcher 45 Eurely 45 Proba 2 45 Meteorological Satellite 45 Agency JAXA 45 Ariane launchers 45 SIMDAT 45 GIOVE 45 ATV Johannes Kepler 45 CANEUS 45 EUTELSAT 45 Wide Angle Search 45 meteorological satellites 45 JAXA 45 Francois Auque 45 Meteosat 45 OHB 45 Seventh Framework Programme 45 Eutelsat Communications 45 Aero Sekur 45 Enabling Grids 45 AZTI Tecnalia 45 Huygens mission 45 OHB Technology AG 45 LAGEOS 45 Foton M3 45 THEMIS satellites 45 ASTRA 1KR 45 EADS SPACE Transportation 45 Ocean Observing 45 Radiation Dose Monitor 45 Vehicles Directorate 45 Environmental Satellite POES 45 NASA Cosmic Background 45 COMSATBw 45 ISAS 45 CubeSat 45 ROCSAT 2 45 Latécoère 45 CCLRC 45 Nanosat 45 Noordwijk Netherlands 44 NASA Solar Terrestrial 44 ScanEx 44 AECID 44 GPS IIR M 44 Esrange Space Center 44 Optical Gravitational Lensing Experiment 44 EUSI 44 pressurized module 44 AATSR 44 WLCG 44 Huygens Probe 44 OMPS 44 Antenna LISA 44 Reshetnev 44 NASA Exobiology 44 Aldebaran Robotics 44 Payloads 44 Gran Telescopio Canarias 44 RUAG 44 Ecole des Mines 44 6th Framework Programme 44 Recovery Experiment SRE 44 de Recherche Clinique 44 GJU 44 Spacelab 44 International Geosphere Biosphere 44 Magnetospheric 44 National Polar Orbiting 44 Kopernikus 44 TV5 Monde 44 ST5 44 ISS Reshetnev 44 NuSTAR 44 geo synchronous transfer 44 NASA WMAP 44 Polar Operational 44 Earthscope 44 Cubesat 44 EPFL 44 Risø 44 Sécurité Civile 44 Arts et Metiers 44 NASAs 44 Cosmic Vision 44 Giove B 44 ESA Proba 44 C NOFS 44 enters lunar orbit 44 Solar TErrestrial RElations Observatory 44 GALEX 44 Earth Observation EO 44 Rockot 44 Koreasat 6 44 Technology Centre ESTEC 44 Agenzia Spaziale Italiana 44 Observing System 44 AKARI 44 SNECMA 44 Esrange 44 culturel 44 SunSpace 44 Direction Générale de l' 44 Robotic Exploration 44 gamma ray observatory 44 Marchis 44 und Raumfahrt 44 Tenesol 44 Interior Laboratory GRAIL 44 Observatory SDO 44 W3A 44 Lunar Reconnaissance Orbiter LRO 44 STSS Demonstration 44 ESA CryoSat 44 Mars CRISM 44 Comité d' 44 SAMTECH 44 iNavSat 44 CSTB 44 Highly Adaptable Satellite 44 NASA STEREO 44 ENAV 44 SICRAL 1B 44 Cosmic Background Explorer 44 Technical Thermodynamics 43 ESA ASI 43 André Kuipers 43 Astra 1M 43 RUAG Aerospace 43 geostationary satellite 43 ARISSat 43 Herschel Planck 43 Pegasus XL 43 Kourou spaceport 43 JWST 43 Artificial Intelligence DFKI 43 GPS IIF 43 NASA THEMIS 43 Atmospheric Physics 43 HIAPER 43 Ingénierie 43 Synthetic Aperture Radar SAR 43 Experimental Reactor 43 Météo France 43 Ångström 43 Solar Terrestrial Relations 43 geosynchronous 43 Steward Observatory 43 Euroconsult 43 THEMIS 43 Relations Observatory STEREO 43 Mars Color Imager 43 GOCE satellite 43 AMIE camera 43 Jean Yves Le Gall 43 HELLAS SAT 43 PSLV C7 43 SSP FRR 43 Surrey Satellite 43 JCMT 43 Centre d' études 43 Japanese Aerospace Exploration 43 Solar Orbiter 43 Institut Gustave Roussy 43 twin STEREO spacecraft 43 Johann Dietrich Worner 43 Hakan Svedhem 43 Delfi C3 43 GFZ 43 NanoRacks 43 IBEX spacecraft 43 XMM Newton 43 Laboratory RAL 43 ESA Hubble 43 AMPERE 43 German SAR Lupe 43 SMOS satellite 43 Deutsche Forschungsgemeinschaft DFG 43 Politecnico di Milano 43 Telstar #R 43 RADARSAT 43 Daniel Sacotte 43 Dominique Cassini 43 orbiter Cassini 43 Moderate Resolution Imaging 43 FP7 43 BEinGRID 43 CNIM 43 Fifth Framework Programme 43 Mössbauer 43 e VLBI 43 polarimetric 43 PSLV C# 43 für Luft und Raumfahrt 43 SORCE 43 Caisse des Dépôts 43 Infoterra Ltd 43 Lars Prahm 43 spaceborne 43 radio occultation 43 XMM Newton observatory 43 EIAST 43 Quasi Zenith Satellite 43 NASTAR Center 43 Envisat ASAR 43 Human Spaceflight Microgravity 43 ESA Envisat satellite 43 Le Gall 43 GKSS Research 43 Catherine Cesarsky 43 SSETI 43 nanosatellites 43 IFM GEOMAR 43 CSSS 43 Guiana Space 43 Fondation pour la Recherche 43 altimetry 43 Yuri Koptev 43 INTEGRAL 43 Astro E2 43 SMOS mission 43 CERAM 43 CETel 43 OCCAR 43 Multi Purpose Logistics Module 43 ASTRA 1M 43 UPV EHU 43 Forschungszentrum Karlsruhe 43 Paulo Nespoli 43 DLR 43 Japan NAOJ 43 Economique 43 Tod Strohmayer 43 Kourou 43 operator Eutelsat 43 Orolia 43 Meteo France 42 LIGO 42 SP Korolev 42 SumbandilaSat 42 COBE satellite 42 infrared observatory 42 Earth orbiting satellites 42 SSTL 42 Eutelsat Communications Euronext Paris 42 EGEE 42 IPEV 42 Skynet 5C 42 Kliper 42 MARSIS 42 KA SAT 42 Satellites GOES 42 Roberto Danovaro 42 ExoMars 42 HiRISE 42 TecSAR 42 Jet Propulsion Laboratory JPL 42 Hubble Space Telescope HST 42 NSBRI 42 Cosmic Origins Spectrograph COS 42 Planck spacecraft 42 orbiting gamma ray 42 orbital rendezvous 42 Léopold Eyharts 42 planetary missions 42 Jean Pierre Bibring 42 Katholieke Universiteit Leuven Belgium 42 MicroSat 42 Rosetta comet chaser 42 CX OLEV 42 XMM Newton satellite 42 Conductivity Analyzer 42 Diehl BGT Defence 42 Space Telescope GLAST 42 Moonwatch 42 Anisotropy Probe WMAP 42 Antrix ISRO 42 IKONOS 42 Bureau d' Enquetes 42 Insat 3A 42 Optiqua 42 spokesman Andreas Schuetz 42 Centro Studi 42 Gravity Recovery 42 DG ECHO 42 KOMPSAT 42 Hellas Sat 42 Optical Spectroscopic 42 Foing 42 APXS 42 Geodis 42 ITER 42 microgravity experiments 42 Y1A 42 deorbiting 42 NASA GSFC 42 Polar Satellite Launch 42 SPICAM 42 Mission SRTM 42 Geosynchronous 42 Atmospheric Oceanic 42 Robotic Lunar Exploration 42 CIXS 42 Fraunhofer institutes 42 spacecraft orbited 42 W2M satellite 42 Spacebus 42 Leverhulme Trust 42 Heterodyne Instrument 42 INSAT 3A 42 JTIs 42 Foton M3 mission 42 scientist Bernard Foing 42 FP5 42 Biogeochemistry 42 Helmholtz Zentrum Berlin 42 JPL Caltech 42 ARCTUS 42 Eurostar E# platform 42 NASA GLAST 42 Loic Damilaville deputy 42 David Southwood ESA 42 Linear Acceleration 42 Keck Interferometer 42 ARTEMIS 42 Eutelsat 42 Eurockot Launch Services 42 IRCM 42 UK DMC2 42 De Winne 42 Sukhrob Kamolov 42 unstowed 42 momagri 42 Soil Moisture 42 SHARAD 42 Gerhard Schwehm 42 Nanosatellite 42 MEPAG 42 Aboard Endeavour 42 microsatellite 42 Jean Jacques Dordain 42 SOHO spacecraft 42 Ecole Supérieure 42 Shuttle Radar Topography 42 Prodware 42 Luft und Raumfahrt 42 Jupiter Icy Moons Orbiter 42 BLG #Lb 42 Institut Laue Langevin 42 LOFAR 42 Mike Cerneck 42 AeroGRID 42 PReVENT 42 Neutral Mass Spectrometer 42 Council PPARC 42 Foundation ESF 42 Planck telescope 42 Alexander Smoleyevsky 42 NPOESS Preparatory Project 42 Max Planck Institut fur 42 Instrument OMI 42 GOES O 42 Rosetta spacecraft 42 Extremely Large Telescope 42 Bajcsy 42 Japan Kibo laboratory 42 INGV 42 IRNSS 42 SELEX Sensors 42 CETL 42 onboard Chandrayaan 42 exoplanet hunter 42 Framework Programmes 42 SeaWiFS 42 Calar Alto 42 Aviation Civile 42 Ruag 42 GEOSS 42 Johannes Kepler 42 Skylogic 42 Ozone Monitoring 42 OrbView 3 42 ESSP 42 heliophysics 42 Fraunhofer FOKUS 42 European XFEL 42 Institut Universitaire de 42 Fraunhofer IESE 42 Aerospatiale Matra 42 MBDA Italia 42 ASTRA 3B 42 Landsat satellites 42 Hansjörg Haber 42 Reusable Launch Vehicle 42 Astrophysics Laboratory 41 interplanetary spacecraft 41 geo synchronous 41 Hyperspectral Imager 41 TerraSAR X satellite 41 NASA JPL 41 ESA ESOC 41 Brera Observatory 41 Alenia Space 41 Martian rover 41 Aeronautic 41 Astronautical Science 41 ROSAT 41 COM DEV 41 EDHEC Risk Institute 41 EGNOS 41 QuikSCAT 41 Sud Aviation 41 Lunar Surface 41 NASA Orbiting Carbon 41 Chinasat 6B 41 Louis Stodieck 41 Euromap 41 Earth Observation satellites 41 Anik F3 41 Odontology 41 Hispasat 41 EVGN 41 Uninhabited Aerial Vehicle 41 Roberto Vittori 41 Cegelec 41 Hinode 41 ASRC MS 41 Rockot launch 41 Wageningen UR 41 AERONET 41 Freie Universität Berlin 41 Oceansat 2 41 Erasmus Mundus 41 CCSDS 41 ESA SMOS 41 Cryosat 41 DEIMOS 41 Berinstain 41 Full Operational Capability 41 GALILEO 41 WebTAS 41 Orbit Validation 41 SR.Teleperformance 41 NASA Wallops 41 DISR 41 Universidad de Granada 41 GFZ Potsdam 41 KIPAC 41 Publicis Conseil 41 Mini SAR 41 Long Baseline Interferometry 41 LDCM 41 ESA Mars 41 WIYN telescope 41 Diego Urbina 41 Japanese Experiment Module 41 Infrared Array Camera 41 CryoSat 41 Avio SpA 41 Jacques Laskar 41 CxP 41 Evert Dudok 41 via AlphaGalileo 41 Express AM# 41 Hispasat 1E 41 Ikerlan 41 Reflection Radiometer 41 Solar Sail 41 NASA Goddard Spaceflight 41 Multi Object Spectrograph 41 Experiment Logistics 41 Skynet 5B 41 Eutelsat Communications SA 41 SES ASTRA 41 Meteosat satellites 41 Forschungszentrum Dresden Rossendorf FZD 41 Oberpfaffenhofen Germany 41 EbS 41 VIMOS 41 Agency astronaut Soichi 41 Aéro Montréal 41 Space Infrared Telescope 41 Orbital Express 41 INTERREG 41 Vikram Sarabhai Space 41 NASA Far Ultraviolet 41 Ariane rocket 41 Landsat Data Continuity 41 CNPV 41 Resourcesat 2 41 JHU APL 41 LADEE 41 Européenne 41 SELEX Communications 41 Block 5D 41 satellite GSAT 41 Theodore von Karman 41 Vehicle ATV 41 Skynet 5A 41 COSPAS 41 geostationary satellites 41 Tropical Rainfall Measuring 41 Marcello Coradini 41 ULIS 41 remote sensing satellites 41 W2A satellite 41 INSAT 4CR 41 Thales 41 NASA 41 Space Propulsion 41 abertis telecom 41 Helmholtz Zentrum München 41 X ray telescope 41 SpeedCast 41 Express orbiter 41 Earth Observations 41 HAMSAT 41 agency Roskosmos 41 aboard ESA Envisat 41 Orbiter MRO 41 A# spacecraft 41 THEOLIA 41 Europa Orbiter 41 Philae lander 41 INMS 41 Newtec 41 Bepi Colombo 41 Cathy Peddie LRO 41 Laser Interferometer Space 41 XTAR EUR 41 Snecma Moteurs 41 Roskosmos 41 RADARSAT Constellation Mission 41 Human Spaceflight 41 experimental payloads 41 Sixth Framework Programme 41 King Baudouin Foundation 41 Stork Fokker 41 Stork Aerospace 41 Commercial Resupply Services 41 WGS Block 41 Oceansat 41 Space Interferometry Mission 41 Sergei Gorbunov spokesman 41 nano satellites 41 Vinasat 41 ExoMars Trace Gas 41 broadband subsidiary Skylogic 41 Research Organisation Isro 41 GEANT2 41 Anik F1R 41 MetOp satellite 41 Snecma 41 STRATIS 41 Direction Générale 41 Space Administration CNSA 41 NASA MSFC 41 Interorbital Systems 41 Sevastyanov 41 JPSS 41 ASKAP 41 EIDHR 41 Interferometer 41 LMCSS 41 MATERNA 41 STEREO spacecraft 41 Astronaut Julie Payette 41 Manchester Jodrell Bank 41 Extra Vehicular Activity 41 Kiruna Sweden 41 I3P 41 journal Meteoritics 41 Vitaly Davydov 41 EUROCORES 41 NLSI 41 UNCCD 41 DIXI 41 SES Euronext Paris 41 ESO telescope 40 XFEL 40 Interreg IIIA 40 ILS Proton 40 Imaging Spectrometer 40 Research BMBF 40 FEMIP 40 NAVSTAR Global Positioning System 40 CIRS 40 orbiting observatories 40 IVAM 40 Lunar Laser Ranging 40 Claudie Haignere 40 CCLRC Rutherford Appleton 40 DubaiSat 1 40 BMC2 40 builder Bigelow Aerospace 40 TV5MONDE 40 Selex Galileo 40 VINCI Construction 40 eTEN 40 Relative Navigation 40 Herschel Space 40 Spaceguard 40 Remote sensing 40 Organisation Internationale de 40 NASA Microgravity 40 CNIL 40 geosynchronous satellites 40 windshield wiper maneuver 40 Astrium Eurostar 40 LSAM 40 remote sensing 40 ERDF 40 VINASAT 40 KICs 40 Liebherr Aerospace 40 SenterNovem 40 RWTH Aachen University 40 IODP 40 EuropeAid 40 STIB 40 Dnepr rocket carrying 40 HZB 40 RENATER 40 commander Leroy Chiao 40 SATLYNX 40 TDRSS 40 CoRoT satellite 40 Chandrayan 40 Astrium Space 40 KA SAT satellite 40 NARAC 40 NigeriaSat 40 long baseline interferometry 40 MIRTHE 40 Europrop 40 Fokker Elmo 40 Aerodata 40 Yinghuo 1 40 COPUOS 40 Webb Telescope 40 airborne observatory 40 Lunar Orbiter 40 CARTOSAT 40 Goce 40 Luan Enjie 40 DG TREN 40 EPOXI mission 40 EMBL EBI 40 GLONASS constellation 40 Fraunhofer Institutes 40 Alain Bouillard 40 Shepherding Spacecraft 40 KUSTAR 40 Sopra Group 40 CoRoT 40 Shallow Radar instrument 40 IZM 40 Vitrociset 40 Sergei Gorbunov 40 ITEA 40 Specialist Greg Chamitoff 40 Infracom 40 NASA GeneSat 1 40 laser altimeter 40 Satellite Successfully Launched 40 http:/www.nasa.gov/cassini 40 Control INRIA 40 GLONASS M 40 Chinasat 9 40 Analyses BEA 40 NOAA GOES 40 Commercial Reusable Suborbital 40 shuttle Canadarm 40 Cospas Sarsat 40 weather satellite TIROS 40 DMSP F# 40 EPSC 40 RPWS 40 Klinkrad 40 Eutelsat W2A satellite 40 Rheinmetall Defence Electronics 40 MEDEA + 40 Deutsche Forschungsgemeinschaft 40 Astrium wholly owned 40 stratospheric balloon 40 Unmanned Combat Air 40 #/#-ton truss 40 Jules Verne Automated Transfer 40 SAT DSA 40 EMRC 40 exactEarth 40 Global Precipitation Measurement