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(Click for frequent words.) 78 Martian surface 72 Mars 71 Martian 67 martian 66 lunar surface 65 Saturn moon 65 lander 64 Martian soil 64 rover Opportunity 63 Martian arctic 63 Opportunity rover 62 rovers 62 spacecraft 61 rover Spirit 61 martian surface 61 Phoenix Mars Lander 61 NASA rovers Spirit 61 Huygens probe 61 Martian atmosphere 60 Martian arctic plains 60 Mars rover Opportunity 60 Phoenix lander 60 Meridiani Planum 60 robotic explorer 60 Mars lander 60 Martian landscape 59 Mars Reconnaissance Orbiter 59 Martian equator 59 Cassini Huygens 59 Martian crater 59 Cassini 59 Saturnian moon Titan 59 Meridiani 58 rovers Spirit 58 Mars rovers Spirit 58 lunar 58 Mars Lander 58 NASA Spirit rover 58 Gusev crater 58 comet 58 NASA twin rovers 57 Mars Odyssey spacecraft 57 Mars rovers 57 twin rover Spirit 57 Huygens 57 rover 57 spacecraft Cassini 57 orbiting spacecraft 57 Comet #P/Churyumov-Gerasimenko 57 NASA rovers 57 moon Titan 57 twin rovers 56 arctic plains 56 Rosetta spacecraft 56 NASA Mars rover 56 NASA Cassini spacecraft 56 moon 56 orbiter 56 asteroid Vesta 56 robotic rovers 56 Earth 56 innermost planet 56 NASA Cassini 56 Mars Reconnaissance Orbiter MRO 56 Ulysses spacecraft 56 Jupiter icy moons 56 Mars Odyssey orbiter 56 Comet Hartley 2 56 Mars Exploration 56 Mars moon Phobos 56 lunar craters 56 Cassini Huygens spacecraft 55 comet Churyumov Gerasimenko 55 Mars Odyssey 55 asteroid Eros 55 Nasa spacecraft 55 orbiting Mars 55 permanently shadowed craters 55 comet nucleus 55 Galileo spacecraft 55 ESA Mars 55 ringed planet 55 Sojourner rover 55 lander Beagle 2 55 Orbiter MRO 55 outer planets 55 ESA Huygens probe 55 Voyager spacecraft 55 Stardust spacecraft 55 Jovian moon 55 Isidis Planitia 55 martian soil 55 Mars Rover 55 extraterrestrial 55 NASA Opportunity rover 55 Martian polar 55 Lunar Reconnaissance Orbiter LRO 55 Itokawa asteroid 54 Rover Opportunity 54 Orbiter LRO 54 asteroid Itokawa 54 probe Huygens 54 Mars Gusev Crater 54 Huygens lander 54 comets 54 moon Europa 54 MARSIS 54 Saturn Cassini 54 robotic spacecraft 54 asteroid 54 planet 54 Orbiter 54 NASA Mars Odyssey 54 Martian rover 54 polar craters 54 Mars rover 54 twin rover Opportunity 54 Mars Pathfinder 54 Stardust capsule 53 Martian plains 53 Earthlike planets 53 Gliese #c 53 robot rovers 53 Cassini flyby 53 Sensing Satellite LCROSS 53 Spirit rover 53 gaseous planet 53 twin rovers Spirit 53 NASA Stardust spacecraft 53 Gusev Crater 53 Solar System 53 New Horizons spacecraft 53 Martian rocks 53 planets 53 Mars rover Spirit 53 Kepler spacecraft 53 ESA Rosetta 53 NASA Mars Reconnaissance 53 Martian dust 53 robotic lander 53 cosmos 53 MESSENGER 53 Mars northern latitudes 53 Mars Global Surveyor 53 EPOXI mission 53 extrasolar planets 52 Cassini spacecraft 52 Corot 7b 52 Hayabusa probe 52 Odyssey orbiter 52 Victoria Crater 52 martian atmosphere 52 icy moons 52 Saturn moon Enceladus 52 twin Voyager spacecraft 52 Jupiter moons 52 Martian orbit 52 Churyumov Gerasimenko 52 stationary lander 52 Phobos 52 six wheeled rover 52 PASADENA Calif. NASA 52 moon Enceladus 52 NASA MESSENGER spacecraft 52 Viking Lander 52 spacecrafts 52 WISE telescope 52 Endurance crater 52 Viking landers 52 Comet Lulin 52 Comet Hartley 52 Enceladus 52 lunar orbit 52 robotic geologist 52 Earthlike planet 52 Nasa 52 icy comets 52 outer space 51 Endurance Crater 51 asteroids 51 moon permanently shadowed 51 Phoenix Mars lander 51 Planck satellite 51 unmanned probes 51 robotic explorers 51 exo planet 51 Martian rovers 51 extrasolar planet 51 Jovian moons 51 cometary 51 Comet Boethin 51 telescopic observations 51 Huygens mission 51 Rover Spirit 51 Global Surveyor 51 ESA Huygens 51 subsurface ocean 51 rover Sojourner 51 rover Spirit landed 51 Curiosity rover 51 sister rover Spirit 51 robotic landers 51 MARSIS radar 51 Martian terrain 51 martian landscape 51 International Space Station 51 Epoxi 51 Solar Dynamics Observatory 51 NASA Kepler 51 NASA THEMIS 51 comets asteroids 51 #P/Churyumov-Gerasimenko 51 habitable worlds 51 Cryosat 51 NASA 51 NASA rover Opportunity 51 Saturn moons 51 Nasa Jet Propulsion 51 Saturnian moon 51 Lunar Prospector 51 Lunokhod 51 orbiting observatories 51 WISE spacecraft 51 orbiting observatory 51 asteroid Steins 51 lunar orbiters 51 Mars Orbiter 51 NASA rover Spirit 51 Comet Tempel 1 51 exoplanetary 51 Mars orbiting spacecraft 51 Tempel 1 51 DISR 50 Voyager probes 50 Meridiani plains 50 planet Gliese #g 50 HiRISE camera 50 Cosmonaut Yuri Gagarin 50 NASA STEREO 50 LCROSS mission 50 Huygens descent 50 Saturn rings 50 Martian lander 50 flyby spacecraft 50 planets orbiting 50 Itokawa 50 sols 50 Yinghuo 1 50 Huygens Probe 50 NASA MESSENGER 50 comet Tempel 1 50 unmanned spacecraft 50 Messenger spacecraft 50 Ranging MESSENGER spacecraft 50 APXS 50 robotic geologists 50 Kepler Mission 50 Titan Saturn 50 comet chaser 50 Earth orbit 50 comet Hartley 2 50 Saturnian system 50 CoRoT satellite 50 interstellar particles 50 Wolszczan 50 Nasa Mars Odyssey 50 NASA LCROSS 50 robotic rover 50 Manned missions 50 Fomalhaut b 50 comets orbiting 50 Hubble 50 Saturn Enceladus 50 STEREO spacecraft 50 Mars Orbiter Camera 50 COROT 50 crewed spacecraft 50 lunar poles 50 Mars orbiter 50 Rover MER 50 Upsilon Andromedae 50 Venusian surface 50 BepiColombo 50 Herschel Space 50 planet Uranus 50 microscopic imager 50 dust devils 50 Gliese #d 49 Shackleton crater 49 Comet Churyumov Gerasimenko 49 Mercury flyby 49 NASA Kepler spacecraft 49 lunar equator 49 simulated lunar 49 Titan flyby 49 Vastitas Borealis 49 Mars Meridiani Planum 49 Hubble Space Telescope 49 COROT 7b 49 Pluto Charon 49 comet Wild 49 LCROSS 49 planets orbiting distant 49 spacecraft orbiting 49 Opportunity rovers 49 lunar crater 49 OSIRIS REx 49 Venusian atmosphere 49 Kepler Space Telescope 49 Stardust NExT 49 shadowed craters 49 DIXI 49 Mars landers 49 orbit 49 noctilucent clouds 49 Spirit Mars rover 49 Opportunity Mars rover 49 rocky planets 49 journal Meteoritics 49 Kepler 9c 49 SPICAM 49 orbiting 49 planetary 49 Asteroid Belt 49 orbiting telescope 49 interplanetary spacecraft 49 Microscopic Imager 49 comet particles 49 reconnaissance orbiter 49 HiRISE camera aboard 49 Ranging spacecraft 49 Noachian era 49 exo planets 49 Venusian 49 NASA Solar Terrestrial 49 celestial bodies 49 rock outcrop 49 Mars Pathfinder lander 49 astrobiological 49 LADEE 49 Comet Machholz 49 GOCE satellite 49 Earth asteroid Itokawa 49 HiRISE image 49 comet #P/Churyumov-Gerasimenko 49 landers 48 Solar TErrestrial RElations Observatory 48 comet Lulin 48 solar corona 48 Lake Vostok 48 highly elliptical orbit 48 Nasa Mars Reconnaissance 48 Hesperian Epoch 48 northern arctic plains 48 Lander robotic arm 48 Cassini flybys 48 shadowy craters 48 orbiting Hubble telescope 48 EPOXI spacecraft 48 comet dust 48 Mars Spirit rover 48 LCROSS spacecraft 48 smallest exoplanet 48 JIMO 48 Kepler Telescope 48 robotic rover Spirit 48 Terra Meridiani 48 Apollo missions 48 Reconnaissance Orbiter 48 Exoplanet 48 Philae lander 48 astrobiologists 48 moons orbiting 48 cosmic collisions 48 Comet Halley 48 Sojourner Rover 48 spaceship 48 NASAs 48 MESSENGER spacecraft 48 navigate autonomously 48 lunar soil 48 polar regions 48 orbiting Saturn 48 martian rocks 48 extrasolar 48 phyllosilicates 48 LRO 48 Herschel Space Telescope 48 HiRISE 48 NASA Deep Impact 48 Jonathan Lunine 48 Jupiter moons Europa 48 Olympus Mons 48 astronomer Percival Lowell 48 Purgatory Dune 48 Sensing Satellite 48 Kuiper Belt Objects 48 bedrock outcropping 48 planetary surfaces 48 Mars CRISM 48 Cassini Equinox 48 permanently shadowed crater 48 Horizons spacecraft 48 perihelion 48 Investigation DIXI 48 RQ# 48 Observatory SDO 48 Orbiter spacecraft 48 Epsilon Aurigae 48 spacecraft Chandrayaan 1 48 slender crescent 48 Hubble Space telescope 48 manned lunar 48 chemically reactive salt 48 Lunar Reconnaissance Orbiter 48 interstellar dust grains 48 Cassini Huygens Mission 48 planet Gliese #c 48 aurorae 47 Earth asteroids 47 swingby 47 lunar regolith 47 planemos 47 moons Phobos 47 Relations Observatory STEREO 47 orbiting Hubble Space Telescope 47 SIRTF 47 Mars Phobos 47 Diviner 47 exosphere 47 cometary debris 47 heavily cratered 47 habitable planet 47 NASA Lunar Prospector 47 Galaxy Evolution 47 Huygens spacecraft 47 Hubble Telescope 47 substorm 47 Mojzsis 47 Earthlike 47 permanently shadowed 47 Viking orbiters 47 Lutetia 47 NASA Mars Orbiter 47 moon Io 47 SOHO spacecraft 47 LORRI 47 Interstellar Boundary Explorer 47 VIRTIS 47 Bruce Jakosky 47 biosignatures 47 Valles Marineris canyon 47 Proba 2 47 northern latitudes 47 Planck spacecraft 47 Ocean Salinity 47 Mars Polar Lander 47 satellites orbiting Earth 47 Antarctic Dry Valleys 47 Spacecraft 47 HD #b [002] 47 GJ #b [001] 47 ADM Aeolus 47 Shackleton Crater 47 ray Space Telescope 47 Galilean satellites 47 Descent Imager Spectral Radiometer 47 Deep Impact Extended 47 Bonneville Crater 47 Mars orbiters 47 Earth magnetosphere 47 earthlike planets 47 planetary Transits 47 inhabitable planets 47 Hesperian epoch 47 Ocean Salinity SMOS 47 twin Mars rovers 47 Cabeus crater 47 Lunar Exploration 47 NASA Spacecraft 47 Convection Rotation 47 Kuiper belt 47 Gliese #g 47 NASA EPOXI mission 47 asteroid Lutetia 47 Express orbiter 47 Emily Lakdawalla 47 Mars Squyres 47 Nili Fossae 47 Heliospheric Observatory SOHO 47 Upsilon Andromedae b 47 Saturn moon Iapetus 47 NASA Lunar Reconnaissance 47 planets orbiting stars 47 NASA Interstellar Boundary 47 exosolar planets 47 Planetary Fourier Spectrometer PFS 47 Deep Impact comet 47 moon Charon 47 THEMIS Images 47 Envisat satellite 46 Deep Impact eXtended Investigation 46 Explorer WISE 46 thin crescent 46 Earth Asteroid Rendezvous 46 celestial observations 46 visit http:/saturn.jpl.nasa.gov 46 Cometary 46 exoplanets orbiting 46 moon Deimos 46 highly elliptical orbits 46 lunar orbits 46 Oort cloud 46 Syrtis Major 46 aerobraking 46 Lunar Orbiter 46 Nasa Deep Impact 46 Toutatis 46 planets moons 46 THEMIS 46 P/# A2 46 Diviner instrument 46 Chandrayaan 46 OMEGA instrument 46 LISA Pathfinder 46 flyby 46 Martian meteorite 46 spacecraft orbited 46 twin Viking landers 46 KBOs 46 Mars Opportunity rover 46 orbiters 46 airglow 46 Hale Bopp 46 KAGUYA 46 interstellar dust samples 46 polar orbit 46 Solar Terrestrial Relations 46 extrasolar planetary systems 46 Hubble Space Telescope HST 46 Apophis 46 NASA Mars rovers 46 CRISM 46 occultations 46 orbiting gamma ray 46 exoplanets planets 46 EPOXI 46 NASA Lunar Crater 46 Jean Pierre Bibring 46 NASA Kepler telescope 46 Hayabusa spacecraft 46 Gerhard Schwehm 46 Planetary Transits 46 coronal loops 46 Titan flybys 46 Zeta Ophiuchi 46 celestial sphere 46 Valles Marineris 46 Cydonia region 46 Gliese #e 46 Phobos Grunt 46 Deep Impact spacecraft 46 David Southwood ESA 46 WASP #b 46 Iapetus 46 Halley comet 46 Atlantis 46 Neutron Detector 46 asteroidal 46 orbiter Cassini 46 NROL 46 http:/saturn.jpl.nasa.gov 46 Global Surveyor spacecraft 46 robotic probes 46 planetoid 46 Opportunity parachuted 46 planets orbiting sun 46 lander Philae 46 comet McNaught 46 Cassini orbiter 46 Lunar Rover 46 alien civilizations 46 Huygens probe landed 46 shuttle Endeavor 46 Deep Impact flyby spacecraft 46 moonbase 46 regolith 46 ESA ASI 45 smoothest flattest spot 45 interstellar space 45 N. Rathnasree 45 faraway planets 45 comet tail 45 GOCE 45 UA Lunar 45 equatorial regions 45 mesosphere 45 Mars Color Imager 45 Prof Pillinger 45 Kuiper Belt object 45 moon Phobos 45 Solar Dynamics 45 Japan Hayabusa spacecraft 45 interplanetary 45 orbits 45 NEAR Shoemaker 45 Perseid Meteor Shower 45 Comet Hale Bopp 45 ExoMars rover 45 Hayabusa capsule 45 CoRoT 7b 45 orbiting Kepler telescope 45 orbited Jupiter 45 HRSC 45 Oort Cloud 45 rover Curiosity 45 orbital rendezvous 45 Comet 9P/Tempel 1 45 retrograde orbit 45 IBEX spacecraft 45 layered outcrops 45 orbiting Cassini spacecraft 45 orbiter lander 45 exoplanets 45 Orbiting Carbon Observatory 45 # Apophis 45 YU# 45 Eta Aquarid meteor shower 45 volcano Olympus Mons 45 Stardust NExT mission 45 vast Gusev Crater 45 meteoroid 45 called gray hematite 45 Shenzhou IV 45 outerspace 45 Shuttle Discovery 45 Snowball Earth 45 CloudSat 45 polar vortex 45 Martian craters 45 permanently shadowed regions 45 Titan smoggy 45 equatorial plains 45 Sedna 45 Enceladus flybys 45 http:/www.nasa.gov/cassini 45 comet nuclei 45 Hubble Space 45 Endeavour Crater 45 lunar crust 45 NASA Cassini orbiter 45 lunar missions 45 WD5 45 OSIRIS Rex 45 Project Ozma 45 Gerard Kuiper 45 cometary nucleus 45 Spaceguard Survey 45 THEMIS Image 45 lander robotic arm 45 Fermi telescope 45 ExoMars mission 45 Martian southern hemisphere 45 planet Nibiru 45 shuttle Discovery 45 sunlike star 45 Hellas Basin 45 Jupiter Ganymede 45 Saturn icy moons 45 interstellar distances 45 Jupiter moon Io 45 Steve Squyres 45 CryoSat mission 45 GEochemistry 45 Antarctica 45 Samuel Oschin Telescope 45 meteorite bombardment 45 planetary exploration 45 Fuk Li Mars 45 Ed Weiler NASA 45 Orionids 45 OSIRIS 45 COROT exo 3b 45 penumbral shadow 45 Bernard Foing 45 waitress Ingrid Sufan 45 planets Uranus 45 Earth orbiting satellites 45 Clementine spacecraft 45 O OREOS 45 Stardust 45 Taurus Littrow Valley 45 SIM PlanetQuest 45 Mars rovers Opportunity 45 GJ#b 45 Kepler observatory 45 Ontario Lacus 45 ecliptic plane 45 Cassini Huygens mission 45 comet flyby 45 Squyres 45 irregularly shaped asteroid 45 photosphere 45 reentry capsule 45 interstellar dust particles 45 Professor Pillinger 45 hydrated minerals 45 polar 45 NASA Voyager spacecraft 45 Mars Odyssey Orbiter 45 Lunar Surface 44 lunar exploration 44 cometary dust 44 Michael Studinger 44 Saturn outermost moon 44 Carina constellation 44 planetary missions 44 Imaging Spectroradiometer MODIS instrument 44 constellation Virgo 44 gamma ray observatory 44 Lunar Orbit 44 ESA SMART 44 NASA Stardust NExT 44 Ringed Planet 44 manned lunar landing 44 C1XS 44 XMM Newton 44 shadowed crater 44 Interior Laboratory GRAIL 44 Lulin 44 Apophis asteroid 44 lunar perigee 44 ESA Planck 44 distant supernovae 44 outer corona 44 Cosmic Microwave Background 44 moons 44 solar flares 44 planets circling 44 distant galaxies 44 Trojan asteroids 44 Charon Pluto 44 Kazakhstan steppe 44 simulated Martian 44 layered bedrock 44 lunar meteorites 44 Asteroid Itokawa 44 unmanned lunar 44 Orbiting Carbon Observatory OCO 44 Saturn moon Mimas 44 SMOS 44 lunar landing 44 Observatory STEREO 44 heat shield 44 magnetotail 44 Earth Asteroid 44 NASA Orbiting Carbon 44 Foton M3 44 lunar explorer 44 rocky extrasolar planet 44 magma ocean 44 closest flyby 44 waxing gibbous 44 Galilean moons 44 Jupiter flyby 44 habitable zones 44 cosmic ray 44 astronauts 44 Uranus Jupiter 44 asteroid belt 44 lunar orbiter 44 Martian volcanoes 44 spacecraft flyby 44 Flyby 44 sized planets orbiting 44 laser altimeter 44 Earthlings 44 impactor spacecraft 44 Hadley Rille 44 Mars Atmosphere 44 micrometeorite 44 Epsilon Eridani 44 meteoroids 44 field Infrared Survey 44 THEMIS mission 44 Chang'eI 44 Astrobiology Magazine 44 MAVEN 44 habitable planets 44 Tunguska meteorite 44 planetesimals 44 planetary alignments 44 transiting exoplanet 44 LightSail 44 protoplanet 44 asteroids comets 44 asteroids Ceres 44 waxing crescent 44 Geminid meteor showers 44 Jupiter Icy Moons 44 orbiter Mars Odyssey 44 coldest driest 44 Comet Elenin 44 NASA Jet Propulsion Laboratory 44 Comet McNaught 44 Robotic Exploration 44 Shuttle Endeavor 44 GA6 44 Uranus 44 JAXA 44 ejecta plume 44 Spaceguard 44 infrared telescopes 44 Magnificent Desolation 44 BP Psc 44 planet orbiting 44 ammonia hydrates 44 Soil Moisture 44 constellation Hercules 44 Kuiper belt object 44 STSS Demo 44 Jean Pierre Lebreton Huygens 44 Mars Surveyor 44 waning crescent 44 terrestrial planets 44 Martian gullies 44 geyser plumes 44 stellar occultations 44 Eta Aquarids 44 Geminid meteor shower 44 robotic arm 44 NuSTAR 44 coldest windiest 44 Martian equatorial plains 44 Solar Orbiter 44 exoplanet 44 onboard Chandrayaan 44 Mini TES 44 Pete Theisinger 44 THEMIS spacecraft 44 NEAs 44 sub glacial lakes 43 Cloud Aerosol Lidar 43 Atlantis undocks 43 Earths 43 lunar lander 43 infrared telescope 43 Martian moons Phobos 43 clumpy soil 43 aphelion 43 smoggy atmosphere 43 Andromeda Galaxy 43 Jakosky 43 SHARAD 43 geosynchronous orbit 43 Cancri e 43 Mission SRTM 43 duration spaceflights 43 Infrared Pathfinder Satellite 43 extravehicular activities 43 orbit GEO 43 Jean Luc Margot 43 ESA Envisat satellite 43 astronaut Eugene Cernan 43 neutrino particles 43 asteroid flyby 43 Arabia Terra 43 Shenzhou VI craft 43 lunar module Eagle 43 Mimas 43 X ray observatory 43 comet chaser Rosetta 43 aboard Skylab 43 Nibiru 43 detect gravitational waves 43 Kiruna Sweden 43 Extrasolar Planets 43 moons orbiting Saturn 43 planet TrES 43 Bug Nebula 43 hypersonic speeds 43 Origins Spectral Interpretation 43 Saturnian 43 primordial soup 43 planetary geologists 43 Hubble observations 43 Mössbauer 43 Deep Impact probe 43 laboratory Skylab 43 Leonid Meteor Shower 43 Cassini radar 43 Shepherding Spacecraft 43 HL Tau 43 southernmost continent 43 lunar orbiter Chang'e 43 constellation Aquarius 43 Doug McCuistion director 43 mission Chandrayaan 43 Exoplanets 43 Geminid meteors 43 Hubble telescope 43 MARSIS instrument 43 Saturn magnetosphere 43 Sasselov 43 circular orbit 43 Shenzhou spacecraft 43 Kepler telescope 43 mu Arae 43 periodic dimming 43 Viking Orbiter 43 gray hematite 43 SMOS mission 43 Oceanus Procellarum 43 ultraviolet wavelengths 43 SKY WATCH 43 magnetic polarity 43 NASA satellites orbiting 43 substorms 43 Rosetta orbiter 43 interstellar dust 43 polar caps 43 Meteorites 43 Cassini spacecraft orbiting 43 Martian microbes exist 43 Kepler #b 43 journal Icarus 43 polar plateau 43 Mars# 43 celestial object 43 Squyres Cornell 43 Laurie Leshin 43 Moderate Resolution Imaging 43 comet Hale Bopp 43 Space Shuttle Discovery 43 equator 43 S/# P2 43 Chandrayan 43 extraterrestrials 43 GRB #B 43 WMAP satellite 43 Ultraviolet Imaging Spectrograph UVIS 43 planetary explorations 43 lobate scarps 43 Lunar Crater 43 Shackleton expedition 43 manned lunar mission 43 planet HD #b 43 countdown dress rehearsal 43 Wilkinson Microwave Anisotropy Probe 43 SMOS Soil Moisture 43 gibbous moon 43 Climate Sounder 43 thin crescent moon 43 airborne particles affect 43 KH #D 43 constellation Eridanus 43 extra terrestrials 43 equatorial latitudes 43 perchlorate salts 43 Centaur rocket 43 icy moon Enceladus 43 CALIPSO 43 Quadrantids 43 spacefaring 43 preset orbit 43 Utopia Planitia 43 Astrobotic 43 space shuttle Discovery 43 Beagle 43 Deep Impact 43 planets orbits 43 carbonaceous chondrite 43 orbiting laboratory 43 #/#-hour parachute 43 NASA ICESat 43 asteroid Apophis 43 MUSES C 43 ESOC 43 Pluto 43 thermal emission spectrometer 43 Mini Thermal Emission 43 binary asteroid 43 Extrasolar 43 Lunar Module Eagle 43 antarctic 43 terraforming Mars 43 Shuttle Endeavour 43 GLAST 43 imaging spectrometer 43 Saturn moons Titan 43 Space Station 43 Evolution Explorer 43 Shenzhou VII spacecraft 43 protoplanets 43 lunar landers 43 star Gliese 43 lander rover 43 Larry Soderblom 43 manned spacecraft