Related by context. Frequent words. (Click for all words.) 70 satellites 67 geostationary satellites 64 satellites orbiting 63 geostationary satellite 60 interplanetary spacecraft 60 geostationary orbit 60 geostationary 60 geosynchronous orbit 59 satellite 59 remote sensing satellites 59 orbiting satellites 58 Earth orbit 58 polar orbit 57 orbits 56 spacecrafts 56 spacecraft orbiting 55 spacecraft 55 orbit 55 microsatellites 54 geosynchronous transfer 54 Oceansat 2 54 orbiting spacecraft 54 Resourcesat 2 54 lunar soil 54 meteoroids 54 circular orbits 53 Kuiper Belt objects 53 radar altimeter 53 remote sensing satellite 53 solar corona 53 observatories 52 payloads 52 geoid 52 geostationary transfer 52 polar orbiting 52 circular orbit 52 robotic spacecraft 52 planets 52 polar vortex 51 moonlets 51 TerraSAR X 51 lunar surface 51 meteoroid 51 Doppler radars 51 optical wavelengths 51 orbiting 51 lunar missions 51 Beidou 51 optical telescopes 51 orbital 51 troposphere 51 tropospheric 50 HiRISE camera 50 SMOS 50 synthetic aperture radar 50 magnetars 50 robotic explorers 50 ionospheric 50 alien civilizations 50 robotic probes 50 elliptical orbit 50 interferometers 50 CubeSats 50 cirrus clouds 50 GPS satellites 50 lunar poles 50 latitudes 50 spectrographs 50 astronomical objects 50 MetOp 49 Earthlike 49 downlinks 49 Cosmic rays 49 Ariane rocket 49 habitable planets 49 COROT 49 orbiter 49 Voyager spacecraft 49 landers 49 moon Europa 49 orbited 49 super Earths 49 terrestrial 49 cirrus 49 ProtoStar 49 IKONOS 49 asteroids 48 Tropical Rainfall Measuring 48 astronomical observations 48 equatorial regions 48 planetary missions 48 SIRTF 48 band transponders 48 satellite constellation 48 ionosphere 48 reconnaissance satellites 48 regolith 48 WASP #b 48 orbiters 48 nano satellites 48 Satellites