Related by context. Frequent words. (Click for all words.) 56 manned spacecraft 56 Space Shuttle 55 spacecraft 55 International Space Station 55 space shuttle 54 spacecrafts 54 Mars Pathfinder 53 robotic spacecraft 53 NASA 53 unmanned lunar 53 Sputnik satellite 53 human spaceflight 53 lunar exploration 53 astronaut 52 shuttle Discovery 52 manned spaceflight 52 unmanned spacecraft 52 Skylab 52 lunar missions 51 Shenzhou VII 51 spaceflight 51 Yang Liwei 51 lunar orbiter 51 Soviet cosmonaut Yuri Gagarin 51 Hubble servicing 51 orbit 51 NASA astronaut 50 astronaut Yang Liwei 50 planetary exploration 50 astronauts 50 spaceflights 50 sub orbital 50 Space Station 49 manned missions 49 space shuttles 49 Baikonur Kazakhstan 49 orbiter 49 Shuttle Discovery 49 Space Shuttle Discovery 49 Greg Chamitoff 49 NASA Astronaut 49 Soyuz rocket 49 lunar landing 49 shuttle 49 suborbital flight 49 Russian Soyuz 49 Crew Exploration 48 Alan Shepard 48 Automated Transfer Vehicle 48 shuttle Atlantis 48 Launch Vehicle 48 Dennis Tito 48 Space Shuttle Endeavour 48 Earth orbit 48 shuttle missions 48 Cassini Huygens 48 Mercury Gemini 48 Bigelow Aerospace 48 Space Shuttle Program 48 Shenzhou V 48 Baikonur Cosmodrome 48 Ariane rocket 47 Dragon capsule 47 Soyuz spacecraft 47 Yuri Gagarin 47 suborbital 47 NASA Space Shuttle 47 Shenzhou VI 47 Space Exploration 47 NASA Kepler 47 orbiters 47 space shuttle Discovery 47 Ares rocket 47 Space Agency 46 Astronaut 46 Mike Suffredini 46 Space Shuttle Atlantis 46 aboard Endeavour 46 Soyuz capsule 46 orbiting 46 New Horizons spacecraft 46 Gorie 46 Nicole Stott 46 Orion spacecraft 46 Astronautics 46 Virgin Atlantic GlobalFlyer 46 orbiting laboratory 46 Nasa 46 cosmonaut 46 orbiting outpost 45 orbital outpost 45 Shuttle Endeavour 45 lunar probe 45 spaceports 45 Centennial Challenges 45 shuttle fleet 45 Discovery liftoff 45 Soyuz 45 astronaut Peggy Whitson 45 Shenzhou 45 Shuttle