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(Click for frequent words.) 65 Panoramic Survey 64 Pan STARRS telescope 63 Great Observatories 62 gamma ray observatory 62 Telescope LSST 61 Subaru telescope 61 Atacama Large Millimeter Array 60 Keck Telescope 60 IfA 60 IceCube 60 Keck Telescopes 60 Large Synoptic Survey 60 Spaceguard 60 Laser Interferometer Gravitational Wave 60 Keck Observatory 60 Keck telescopes 60 Subaru Telescope 60 infrared telescope 60 EarthScope 59 E ELT 59 optical telescopes 59 Robert Jedicke 59 Solar TErrestrial RElations Observatory 59 UKIRT 59 extrasolar planetary systems 59 Keck telescope 59 inch Samuel Oschin 58 LSST 58 microlensing events 58 telescope 58 microlensing 58 Submillimeter Array 58 Faulkes Telescope 58 ESO VLT 58 submillimetre 58 neutrino telescope 58 Optical Gravitational Lensing Experiment 58 Hubble Space Telescope HST 57 Spacewatch 57 astrometric 57 Earthscope 57 ATST 57 LOFAR 57 optical infrared telescope 57 optical telescope 57 NEOWISE 57 XMM Newton 56 orbiting observatories 56 infrared astronomy 56 WM Keck Observatory 56 THEMIS satellites 56 Earth Asteroid 56 JDEM 56 astronomers 56 Kepler Mission 56 exoplanetary 56 AKARI 56 USArray 56 KamLAND 56 imaging spectrometer 56 Infrared Astronomy 56 Astrophysics MOA 56 gamma ray detector 56 Faint Object 56 Keck Interferometer 56 MicroFUN 56 ASKAP 56 Galaxy Evolution 56 radiotelescope 56 Nasa Kepler 56 NuSTAR 56 GALEX 56 Fermi telescope 55 Stratospheric Observatory 55 Planck satellite 55 meter Keck telescope 55 Steward Observatory 55 STEREO mission 55 LROC 55 SIRTF 55 meter Keck telescopes 55 astrometry 55 infrared telescopes 55 telescopes 55 gravitational lenses 55 SuperWASP 55 LIGO 55 SDSS II 55 NASA STEREO 55 Thirty Meter Telescope 55 EPOCh 55 NASA THEMIS 55 Microlensing Observations 55 astronomical observatory 55 geoid 55 inch refractor telescope 54 NEOSSat 54 Wide Angle Search 54 Adaptive Optics 54 Gemini telescopes 54 Lunar Reconnaissance Orbiter Camera 54 astrophysical phenomena 54 observatory 54 Decadal Survey 54 atop Mauna Kea 54 COROT 54 ESA Planck 54 Solar Orbiter 54 heliophysics 54 aperture telescope 54 Helioseismic 54 Palomar Observatory 54 Advanced LIGO 54 particle detector 54 Great Observatories Origins 54 astronomical telescope 54 Spaceguard Survey 54 exo planet 54 NOAO 54 ESA XMM Newton 54 BLG #Lb 54 NASA Stratospheric Observatory 54 GRB #B 54 ESO telescopes 54 orbiting gamma ray 53 observatories 53 SIM PlanetQuest 53 spectrographs 53 distant supernovae 53 VISTA telescope 53 Nankai Trough Zone 53 Werthimer 53 NASAs 53 cryo electron microscope 53 Kuiper belt objects 53 Infrared Telescope Facility 53 astronomical observatories 53 hyperspectral 53 Long Wavelength Array 53 neutrino detector 53 Fomalhaut b 53 hexagonal mirrors 53 PlanetQuest 53 OSIRIS REx 53 NEAs 53 Borexino 53 D CIXS 53 Astrophysical 53 Solar Observatory 53 Telescope Array 53 VLBI 53 AERONET 53 Sagittarius Window Eclipsing 53 ESA Integral 53 Atacama Large Millimeter submillimeter 53 Array ALMA 53 Herschel Space 53 Arecibo Observatory 53 planetary Transits 53 APEX telescope 53 SDSS III 53 multibeam 53 infrared observatory 53 SELENE 53 Descent Imager Spectral Radiometer 53 dimming starlight 53 WFC3 53 SINFONI 53 fainter objects 53 Telescope 53 Eric Becklin 53 NASA Kepler 53 airborne observatory 53 Terrestrial Planet Finder TPF 53 Extrasolar Planet Search 53 laser altimeter 53 NSLS II 53 Anisotropy Probe WMAP 52 WMAP satellite 52 SAFOD 52 EVLA 52 OGLE 52 X ray observatory 52 detect gravitational waves 52 gamma ray burst 52 WISE infrared 52 telescope atop Mauna 52 gravitational microlensing 52 Submillimeter 52 X ray telescopes 52 NASA Infrared Telescope 52 JWST 52 RPWS 52 Cosmic Evolution 52 supercomputer simulations 52 Explorer WISE 52 neutron spectrometer 52 spectroscopic 52 NIRCam 52 VORTEX2 52 Gemini Observatory 52 Gamma ray burst 52 ROSAT 52 National Astronomical Observatory 52 Cerro Pachón 52 Krimigis 52 gravitational wave 52 HARPS spectrograph attached 52 Rosetta lander 52 Evolution Explorer 52 geoneutrinos 52 JIMO 52 microshutters 52 Terrestrial Planet Finder 52 Observatory SDO 52 NASA Great Observatories 52 moon Charon 52 Landsat satellite 52 EarthCARE 52 Astrophysical Research 52 spaceborne 52 Extragalactic 52 Kepler spacecraft 52 GJ#b 52 Southern Observatory ESO 52 neutrino detectors 52 ENVISAT 52 Earth orbiting satellites 52 SDSS telescope 52 HIAPER 52 Lulin Observatory 52 LCLS 52 CoRoT satellite 52 Super Kamiokande 52 filamentary structure 52 VIRTIS 52 Dalcanton 51 Interior Laboratory GRAIL 51 HiRISE 51 ESO Paranal Observatory 51 orbiting Hubble Space Telescope 51 ESA Envisat 51 ESO La Silla 51 Climate Experiment GRACE 51 Pluto Kuiper Belt 51 Exoplanet 51 astronomy 51 XENON# [002] 51 Astrophysicists 51 InSAR 51 inhabitable planets 51 spectroscopic observations 51 MINOS 51 Cassini Huygens 51 asteroids orbiting 51 Astronomy 51 Thermal Emission Spectrometer 51 twin Keck telescopes 51 NASA Wilkinson Microwave 51 Cygnus Lyra region 51 Astrobiology Institute 51 polarimetry 51 telescopes atop Mauna 51 Herschel telescope 51 RXTE 51 extrasolar 51 Multi Object Spectrograph 51 HARPS instrument 51 observing satellites 51 Earthlike planets 51 Arecibo radio 51 Adaptive optics 51 Uninhabited Aerial Vehicle 51 RS Ophiuchi 51 ESO telescope 51 Orbiter LRO 51 Japan NAOJ 51 colliders 51 Hinode 51 Magnetospheric 51 Ulysses spacecraft 51 Gravity Probe B 51 Mercury flyby 51 Convection Rotation 51 ExoMars rover 51 SSRL 51 HESS telescopes 51 Lunar Reconnaissance Orbiter LRO 51 ray Space Telescope 51 Pan STARRS PS1 telescope 51 Gamma ray Large 51 CReSIS 51 Kuiper Belt Object 51 Kitt Peak 51 RHESSI 51 Kepler Space Telescope 51 Light Detection 51 SeaWiFS 51 SOHO spacecraft 51 THEMIS 51 optical interferometry 51 TrES 4 51 Space Infrared Telescope 51 multiwavelength 51 Hubble Telescope 51 DIXI 51 particle colliders 51 GLAST 51 Hobby Eberly Telescope 51 Triangulum Galaxy 51 AAVSO 51 neutrino beam 51 Area Telescope LAT 51 Pluto Charon 51 asteroids 51 Cerro Armazones 51 ESA Herschel 51 Observatories 51 Landsat satellites 51 GLAST telescope 51 Microlensing 51 Ocean Observatories Initiative 51 MIRTHE 51 CALIPSO 51 NASA Cosmic Background 51 Jupiter Icy Moons Orbiter 51 Suzaku X ray 51 Large Binocular Telescope 51 gamma ray spectrometer 51 Foing 51 Very Large Telescope 51 distant galaxy clusters 51 Infrared Array Camera 51 submillimeter wavelengths 51 smallest exoplanet 51 GigaPan 50 Mars Climate Sounder 50 TSN PZ camera 50 exoplanet hunter 50 Lick Observatory 50 Adam Riess 50 NAOJ 50 Francis Halzen 50 MEarth 50 VLBA 50 gamma ray telescope 50 X ray spectrometer 50 George Djorgovski 50 Samuel Oschin Telescope 50 orbiting telescopes 50 HiRISE image 50 Mini SAR 50 attosecond 50 Synthetic Aperture Radar 50 decadal survey 50 Delta Cephei 50 e MERLIN 50 Omega Centauri 50 TerraSAR X 50 Heliophysics 50 2MASS 50 particle astrophysics 50 astronomical telescopes 50 Fermi Gamma ray 50 geodesy 50 J# +# [002] 50 MeerKAT 50 rover panoramic 50 Imaging Spectrometer 50 radio occultation 50 Orion nebula 50 extrasolar planets 50 planetary missions 50 Submillimeter Array SMA 50 hyper spectral 50 cosmological parameters 50 APXS 50 geodetic 50 NOvA 50 Compact Muon Solenoid 50 infrared imager 50 Boethin 50 Imiloa Astronomy Center 50 located atop Mauna 50 Ocean Observing 50 heavily instrumented 50 Free Electron Laser 50 BepiColombo 50 SEGUE 50 ESO Very Large Telescope 50 DEIMOS 50 NIRSpec 50 SkyCenter 50 Cosmic Microwave Background 50 Cepheid variables 50 astrophysical objects 50 Pierre Auger Observatory 50 EPOXI 50 globulars 50 geochemists 50 submillimeter wavelength 50 Near Infrared Camera 50 Gravitational lensing 50 CFHT 50 IceCube telescope 50 galaxy redshift 50 extragalactic 50 Planetology 50 XFEL 50 Rosetta orbiter 50 Infrared Telescope UKIRT 50 LINEAR 50 galaxy M# [001] 50 Jupiter Icy Moons 50 HiRISE camera 50 IODP 50 eyepiece #/#s f/#.# 50 Spitzer Space Telescope 50 OSIRIS 50 Burst Alert 50 e VLBI 50 observational astronomy 50 telescopic observations 50 Earth asteroids 50 Antenna LISA 50 UCO Lick 50 reionization 50 Spectrograph 50 neutrino physics 50 cosmic cannibal 50 ChemCam 50 Paranal 50 Comet Halley 49 Extreme Ultraviolet Imaging Spectrometer 49 particle physics experiments 49 HD#b 49 MN4 49 linear collider 49 JCMT 49 HiRISE camera aboard 49 particle detectors 49 distant quasar 49 Cloud Aerosol Lidar 49 Mount Stromlo Observatory 49 Solar Terrestrial Relations 49 GROND 49 spectrograph 49 cosmological observations 49 supersymmetric particles 49 orbiting telescope 49 Cancri e 49 Context Camera 49 orbiting Chandra 49 Solar Dynamics Observatory 49 COBE 49 CDMS II 49 NASA Kepler spacecraft 49 Planck spacecraft 49 La Silla Observatory 49 robotic telescopes 49 rocky extrasolar planet 49 Deep Impact eXtended Investigation 49 Remote sensing 49 N. Rathnasree 49 sub millimeter wavelengths 49 Anisotropy Probe 49 Avishay Gal Yam 49 Hubble telescope 49 Mastcam 49 Infrared Pathfinder Satellite 49 Pascale Ehrenfreund 49 LADEE 49 Higgs bosons 49 VLTI 49 ATLAS detector 49 Arecibo telescope 49 Coma Cluster 49 Wilkinson Microwave Anisotropy Probe 49 IBEX spacecraft 49 interplanetary spacecraft 49 neutrino experiment 49 Envisat satellites 49 Mission SRTM 49 hubble 49 EPOXI mission 49 Orbiter MRO 49 DEEP2 49 Wolszczan 49 eruptive activity 49 ESA Envisat satellite 49 Rolf Kudritzki 49 Hyperspectral Imager 49 Space Telescope GLAST 49 Fermi LAT 49 Main Injector Neutrino 49 International HapMap Consortium 49 Fermi Large 49 CERN LHC 49 Quadrantid meteor shower 49 Observatory STEREO 49 Australian Synchrotron 49 Gemini Telescope 49 SPIRE 49 WISE telescope 49 transiting exoplanets 49 Cometary 49 Cerro Paranal 49 extrasolar planet 49 Magnetic Imager HMI 49 planets orbiting sun 49 radial velocity 49 Boston Micromachines 49 Sara Seager 49 cosmic ray observatory 49 Lunar Exploration 49 Epsilon Aurigae 49 Jay Melosh 49 NASA Far Ultraviolet 49 gigapixel camera 49 STScI 49 super perigee moon 49 NASA Chandra 49 transiting planets 49 Comet Lulin 49 solar corona 49 Galileo spacecraft 49 HIRES spectrometer 49 twin STEREO spacecraft 49 PASADENA Calif. Astronomers 49 eclipsing binary 49 Comet Hartley 2 49 ASTRON 49 astronomy observatory 49 interferograms 49 MMT Observatory 49 TanDEM X 49 SnoMotes 49 TGFs 49 Image NASA JPL 49 Arecibo radar 49 CubeSats 49 distant quasars 49 astrophysicists 49 asteroids comets 49 ALMA antennas 49 JAMSTEC 49 Harald Ebeling 49 NOAA GOES 49 SKA telescope 49 adaptive optics 49 lunar topography 49 airborne LIDAR 49 gamma ray detectors 49 ExoMars mission 49 Terahertz 49 asteroid 49 Mars Color Imager 49 GJ #b [002] 49 correlator 49 Alycia Weinberger 49 Interferometer VLTI 49 WIYN 49 X ray wavelengths 49 John Grotzinger 48 neutrino particles 48 photometer 48 NSLS 48 Hanny Voorwerp 48 Imaging Telescope Array 48 Meteorological Satellites 48 Astronomers 48 Moon Mineralogy Mapper M3 48 Comet Hartley 48 microscopy technique 48 cosmic phenomena 48 detecting gravitational waves 48 Martian rovers 48 RQ# 48 X ray observatories 48 distant supernovas 48 lensless imaging 48 NEOs 48 SNfactory 48 extrasolar planetary 48 gamma ray observatories 48 Chajnantor 48 submillimetre wavelengths 48 Dan Werthimer 48 AMPERE 48 Telescope BAT 48 Ground penetrating radar 48 Cassini Equinox 48 Dean Pesnell 48 NASA Landsat 48 Jupiter moon Io 48 earthshine 48 luminous galaxies 48 Tommaso Treu 48 Infrared Astronomy SOFIA 48 amateur astronomers 48 Mauna Kea Hawaii 48 trans Neptunian objects 48 Alaska Fairbanks Geophysical 48 Infrared Telescope 48 astronomical objects 48 Mid Infrared 48 Cosmic Origins Spectrograph 48 ESA Rosetta 48 Manchester Jodrell Bank 48 largest moon Charon 48 refracting telescope 48 Diviner instrument 48 PSR J# 48 Cerro Tololo 48 Planetary Transits 48 hyperspectral imager 48 gravitational lens 48 Observatory LIGO 48 neutrino experiments 48 CHARA 48 synthetic aperture 48 NLSI 48 GOSAT 48 Nikon D# Kowa 48 Space Telescope 48 astronomical observations 48 Hinode satellite 48 astronomer 48 GJ #b [001] 48 Amateur astronomers 48 XMM Newton X ray 48 NICMOS 48 submillimeter 48 exoplanets planets outside 48 ExoMars 48 Richard Binzel 48 brightest supernova 48 Exoplanets 48 gravitational lensing 48 GEO# 48 polarimetric 48 X ray detector 48 Total Ozone Mapping 48 FORCAST 48 Mars landers 48 Paranal Observatory 48 Hubble Near Infrared 48 Interferometer 48 CoML 48 KIPAC 48 Giovanni Cassini 48 radial velocity technique 48 extrasolar planets orbiting 48 Project Ozma 48 Chikyu 48 Astrophysics 48 Butterfly Nebula 48 Kepler #b 48 Cosmic Background Explorer COBE 48 OGLE TR 48 Lyot 48 wavelength infrared 48 Chilean Atacama Desert 48 Stellarium 48 Andromeda galaxy 48 orbiting Saturn 48 Spallation Neutron Source 48 orbiter lander 48 celestial objects 48 Epsilon Eridani 48 Okeanos Explorer 48 Quadrantids 48 MG J# +# 48 particle physicists 48 CubeSat 48 Square Kilometre Array SKA 48 Synchrotron Radiation 48 gradiometer 48 AIRSS 48 Galilean satellites 48 polar orbiting satellites 48 OOI 48 Planck telescope 48 flyby spacecraft 48 Tropical Rainfall Measuring 48 inch Schmidt Cassegrain 48 William Herschel Telescope 48 bedrock outcropping 48 Kuiper Belt Objects 48 KBOs 48 lunar perigee 48 Astronomical Society AAS 48 Rainer Klement 48 UA Lunar 48 waning gibbous 48 Europa Orbiter 48 Cargo Launch Vehicle 48 windshield wiper maneuver 48 Hubble Space Telescope 48 lidar 48 remote sensing satellite Resourcesat 48 Celestron SkyScout 48 Maciej Konacki 48 Lovell Telescope 48 Cat Paw Nebula 48 gaseous planet 48 dexterous robot 48 Fermilab Tevatron 48 Interferometric 48 LHCb 48 situ measurements 48 SciDAC 48 GLAST Burst Monitor 48 Pierre Auger 48 Gamma ray bursts 47 extraterrestrial civilizations 47 Upsilon Andromedae 47 WISE spacecraft 47 unmanned probes 47 geomagnetism 47 Siding Spring 47 protoplanet 47 satellites orbiting Earth 47 pyrosequencing 47 Medspiration 47 Churyumov Gerasimenko 47 interferometry 47 visit http:/saturn.jpl.nasa.gov 47 ultrashort pulses 47 CloudSat 47 habitable planets 47 Higgs boson particle 47 exobiology 47 Observatory telescope 47 Hubble 47 SMOS Soil Moisture 47 Sky Survey SDSS 47 Jedicke 47 moons circling 47 distant galaxies 47 National Optical Astronomy 47 occultations 47 blazar 47 astrophysical 47 metagenomic 47 Galileoscope 47 planet Gliese #g 47 Flyby spacecraft 47 infrared wavelengths 47 Mary Voytek 47 Bernard Foing 47 ALFALFA 47 QuikSCAT 47 NASA Exobiology 47 Robotic Lunar Exploration 47 Collider Detector 47 Polarimetry 47 Extraterrestrial Intelligence Institute 47 RY Sagittarii 47 spectrographic 47 Andromeda Galaxy 47 Hinode spacecraft 47 NASA Cassini 47 LIDAR 47 Digitized Sky Survey 47 Nankai Trough 47 Substorms mission 47 inch refractor 47 NASA astrobiology 47 deconvolution 47 SDSC 47 infrared spectrometers 47 TNOs 47 LORRI 47 exoplanets 47 ENCODE 47 Las Cumbres Observatory 47 Peony nebula star 47 Square Kilometre Array 47 confocal microscope 47 Ring Nebula 47 steerable radio 47 human microbiome 47 scientist Bernard Foing 47 Astro E2 47 SMEX 47 inch refracting telescope 47 celestial object 47 infrared spectra 47 CitySense 47 radar altimeter 47 Andrea Ghez 47 asteroid impacts 47 Regolith 47 Mauna Kea 47 Fundamental Physics 47 Extremely Large Telescope 47 helium ion 47 infrared spectral 47 Sasselov 47 High Angular Resolution 47 NASA Jet Propulsion Lab 47 Comet Holmes 47 Compact Reconnaissance Imaging Spectrometer 47 Carnegie Observatories 47 astro comb 47 Neutron scattering 47 AMASE 47 High Resolution Imaging 47 DISR 47 Spitzer infrared spectrograph 47 Auger Observatory 47 Plate Boundary 47 MARSIS 47 Type Ia supernovae 47 Heliospheric Observatory SOHO 47 Orion Nebula 47 nanosatellites 47 Observatory NOAO 47 HFIR 47 LISA Pathfinder 47 Human Proteome Folding 47 Heliospheric Investigation 47 DEPTHX 47 High Altitude Airship 47 Phobos Grunt 47 Caltech Palomar Observatory 47 planemos 47 Lyman alpha 47 Landsat images 47 Virgo Cluster 47 gravitationally lensed 47 orbiting observatory 47 constellation Eridanus 47 infrared interferometry 47 Giant Magellan Telescope 47 ESRL 47 Roque de los 47 galaxy M# [002] 47 Mauna Loa Observatory 47 Square Kilometer Array 47 XMM Newton satellite 47 Orionids 47 Fermi Telescope 47 infrared ultraviolet 47 Cassini flyby 47 Mario Livio 47 Canary Telescope 47 noctilucent 47 Moon Mineralogy Mapper 47 Robotic Exploration 47 SPIRE instrument 47 stellar occultation 47 Delfi C3 47 Ellery Hale 47 Interferometric Synthetic Aperture Radar 47 X ray absorption spectroscopy 47 Explorer GALEX 47 Very Large Array 47 Planetary Science Institute 47 microbial ecosystems 47 interstellar boundary 47 physicists 47 GOES satellites 47 ultraviolet spectrograph 47 Kepler observatory 47 Olympus Mons 47 geodynamic 47 Deep Impact comet 47 optofluidic microscope 47 AB Aurigae 47 Titan Saturn 47 Michael Studinger 47 neutrino observatory 47 SMOS mission 47 Kuiper Belt object 47 Landsat imagery 47 YU# 47 SpaceWeather.com 47 WIYN Observatory 47 ASPERA 47 microlensing technique 47 UAVSAR 47 Viking Lander 47 Dumbbell Nebula 47 substorm 47 Spectroscopic Explorer 47 Archimedes Palimpsest 47 Desert RATS 47 ARGUS IS 47 Field Infrared Survey 47 Grillmair 47 Space Interferometry Mission 47 Shuttle Radar Topography 47 Energy Stereoscopic 47 transmission electron microscope 47 twin Voyager spacecraft 47 interferometer 47 Meteorological Satellite 47 Panoramic Camera 47 astrophysics 47 fissure eruption 47 protoplanetary 47 Fornax cluster 47 amateur astronomers peering 47 resolution panchromatic 47 Jean Luc Margot 47 Physics Applied Physics 47 Deep Impact mission 47 planetary science 47 Earth objects NEOs 47 EFRC 47 planetary astronomer 47 IYA# 47 Solar Radiation 47 Deep Field HUDF 47 interplanetary missions 47 Hyperspectral 47 Earthshine 47 cosmological distances 47 Nikku Madhusudhan 47 arcminutes 47 Active Galactic Nuclei 47 YORP effect 47 Aboard Endeavour 47 barred spiral galaxy 47 Aurigid 47 JAXA 47 photometry 47 Cosmic Origins Spectrograph COS 46 SCISAT 46 HUDF 46 cosmic ray 46 optical wavelengths 46 SETI @ Home 46 Saturnian moon Titan 46 retroreflector 46 Ritchey Chrétien 46 impactor spacecraft 46 astrobiological 46 NanoSIMS 46 Mark Zoback 46 millisecond pulsar 46 geohazard 46 Baryon Oscillation Spectroscopic Survey 46 FORMOSAT 46 SECCHI 46 NASA Astrobiology 46 cosmologists 46 supergiant star 46 Large Binocular Telescope LBT 46 Very Energetic Radiation 46 deformable mirrors 46 remote sensing 46 bolometers 46 globular cluster 46 Gliese #c 46 comet Lulin 46 Envisat 46 ESA SMART 46 MARSIS radar 46 synthetic aperture radar 46 HARPS spectrograph 46 Comet Tempel 1 46 Corot 7b 46 axions 46 Galactic Plane 46 OSIRIS Rex 46 Nasser Peyghambarian 46 OGLE TR #b 46 pulsating aurora 46 NASA Interstellar Boundary 46 redshift 46 STEREO 46 ESO astronomer 46 GEOSS 46 cosmic microwave background 46 Red Rectangle 46 SRTM 46 Upsilon Andromedae b 46 synchrotron radiation 46 NFIRE 46 Laser Interferometer Space 46 Richard Mushotzky 46 binary asteroid 46 COSMO SkyMed 46 ICESat 46 La Silla Chile 46 Cyberinfrastructure 46 Cosmic Background Explorer 46 Space Fence 46 nicknamed Xena 46 MINOS experiment 46 geo hazard 46 Mars CRISM 46 X ray telescope 46 polar orbiting 46 XMM Newton observations 46 supernova remnant