Related by context. Frequent words. (Click for all words.) 71 Soviet cosmonaut Yuri Gagarin 66 Yuri Gagarin 61 satellite Sputnik 58 spacecraft 58 Baikonur Kazakhstan 57 Gagarin 57 Messenger spacecraft 56 spaceship 56 Soyuz rocket 56 interplanetary spacecraft 56 Yang Liwei 56 manned spacecraft 55 astronaut Yang Liwei 55 Ariane rocket 55 space shuttle 55 Shenzhou V 54 unmanned lunar 54 Gagarin flight 54 Space Shuttle Discovery 54 New Horizons spacecraft 54 lunar landing 53 Shenzhou VII 53 Space Shuttle Endeavour 53 orbit 53 Ares IX rocket 53 outer space 53 Sputnik satellite 53 Stardust spacecraft 53 manned spaceship 53 International Space Station 52 orbital 52 Soyuz capsule carrying 52 Edwin Buzz Aldrin 52 lunar orbiter 52 astronaut 52 robotic spacecraft 52 unmanned spacecraft 52 Shuttle Discovery 52 Discovery STS 52 Space Shuttle Atlantis 52 Cassini Huygens 52 lunar surface 52 spacecrafts 52 Alan Shepard 52 Russian Soyuz TMA 52 NASA astronaut 52 Alexander Kaleri 51 shuttle Atlantis 51 Dragon capsule 51 Soyuz capsule 51 SpaceX Falcon 9 51 Mars orbiter 51 spaceflight 51 Mars Pathfinder 51 lunar 51 Soyuz spacecraft 51 Shuttle Endeavour 51 orbiter 51 astronauts 51 Mike Melvill 51 Astronaut Buzz Aldrin 51 cosmonaut 51 spacecraft orbiting 50 Red Planet 50 Hubble telescope 50 orbiting 50 moon 50 Plesetsk 50 Space Shuttle 50 shuttle Challenger 50 Astronaut 50 ESA astronaut 50 rover Opportunity 50 Soyuz 50 space shuttle Discovery 50 Neil Armstrong 50 Voyager spacecraft 50 sub orbital 49 Cosmonaut 49 astronaut Julie Payette 49 Tim Kopra 49 Skylab 49 Julie Payette 49 spaceplane 49 ringed planet 49 shuttle Discovery 49 lunar orbit 49 Comet Tempel 1 49 Space Station 49 interplanetary 49 suborbital flight 49 Apollo lunar 49 PSLV C# 48 Venusian 48 moon Charon 48 space shuttle Endeavour 48 Space shuttle Discovery 48 Piers Sellers 48 manned spaceflight 48 tourist Charles Simonyi 48 Automated Transfer Vehicle