Related by context. Frequent words. (Click for all words.) 73 Sputnik 56 Sputnik moment 50 Yuri Gagarin 50 manned spacecraft 50 Soviets 50 spacecraft 50 lunar orbiter 49 Challenger exploded 49 Gagarin 49 space shuttle 48 lunar landing 48 unmanned spacecraft 47 lunar exploration 47 Chandrayaan 46 lunar probe 46 human spaceflight 46 Soviet Union 46 Apollo astronauts 45 spacecrafts 45 Alan Shepard 45 manned spaceflight 45 Taepodong 44 outer space 44 Skylab 44 Cold War 44 moon landings 44 Neil Armstrong 44 spaceship 44 rocket 44 Planetary Society 44 Soyuz rocket 43 lunar module 43 Soyuz capsule 43 Ansari X 43 manned missions 43 Soviet 43 Baikonur Cosmodrome 43 NASA 43 suborbital flight 43 Nasa 43 X Prize 42 orbiting 42 orbit 42 rocketry 42 shuttle fleet 42 LTCM 42 Space Shuttle Columbia 41 astronauts 41 space shuttles 41 asteroid 41 orbiter 41 Columbia disintegrated 41 Burt Rutan 41 orbiters 41 SpaceShipOne 41 CryoSat 41 blastoff 40 astronautics 40 Russian Soyuz rocket 40 Dennis Tito 40 Earth orbit 40 Khrushchev 40 USSR 40 ICBM 40 Atomic Scientists 40 lunar missions 40 orbital debris 40 lander 40 moon 40 lunar surface 40 lunar lander 40 tank foam insulation 40 Korolyov 39 sub orbital 39 Soyuz spacecraft 39 Soviet empire 39 liftoff 39 Saturn V 39 Space Shuttle 39 intercontinental ballistic missile 39 missile interceptor 39 Mars rovers 39 polar orbit 39 Jules Verne 39 Dwight Eisenhower 39 cosmonaut 39 Space Shuttle Discovery 39 astronaut 39 Apophis 39 Soyuz 39 Space Agency 38 Apollo 38 International Space Station 38 shuttle Discovery 38 Sriharikota 38 atomic bomb 38 Russians 38 Perminov 38 thermonuclear 38 satellites 38 Roscosmos