Related by context. Frequent words. (Click for all words.) 72 spacecraft 68 spacecrafts 62 robotic spacecraft 62 lunar missions 62 orbiter 61 manned spacecraft 61 orbit 61 orbiters 60 spaceship 59 Earth orbit 58 International Space Station 57 outer space 57 orbiting spacecraft 57 payloads 57 astronauts 57 lunar orbit 57 unmanned spacecraft 57 lunar orbiter 56 orbiting 56 orbital 56 manned missions 56 NASA 55 Nasa 55 spaceships 55 human spaceflight 55 polar orbit 55 lander 54 landers 54 lunar lander 54 Orion spacecraft 54 space shuttle 54 unmanned 54 lunar exploration 53 missions 53 Soyuz rocket 53 satellites 53 Mars rover 53 Space Agency 53 Space Shuttle 53 Soyuz craft 53 rovers 53 planetary exploration 52 geosynchronous orbit 52 outer planets 52 Mars rovers 52 remote sensing satellites 52 manned spaceflight 52 interplanetary 52 shuttle 52 JAXA 52 GOCE 52 astronaut 51 microgravity 51 Mars 51 Shenzhou VII 51 orbiting telescope 51 lunar landing 51 lunar 51 cosmodrome 51 Shenzhou VI 51 Soyuz 51 spaceflight 51 Automated Transfer Vehicle 51 moon 51 Orion capsule 50 Perminov 50 astronaut Yang Liwei 50 hypersonic 50 Space Station 50 lunar surface 50 Hubble servicing 50 payload 50 spaceflights 50 Shuttle astronauts 50 taikonauts 50 Agency JAXA 50 Soyuz spacecraft 50 geostationary satellites 50 Soyuz capsule 50 suborbital flight 50 Red Planet 50 moon Europa 49 shuttle Atlantis 49 spacesuits 49 flybys 49 rover 49 circular orbit 49 ISS 49 space shuttles 49 propulsion 49 spacemen 49 lunar rover 49 Chandrayaan 49 geostationary 49 orbiting laboratory 49 Itokawa 49 Crew Exploration 49 Orbiter 49 microsatellites 49 cometary 49 remote sensing satellite