Related by context. Frequent words. (Click for all words.) 60 Buzz Aldrin 49 Neil Armstrong 48 Apollo astronauts 47 astronaut 46 Fincke 44 astronauts 43 Padalka 41 Melroy 41 Satcher 41 Alan Shepard 41 Chiao 40 Nasa 40 lunar landing 39 Eileen Collins 39 Zhai 39 Apollo 39 Yuri Gagarin 39 NASA astronaut 39 Planetary Society 39 Noguchi 39 NASA 39 Astronaut 38 Mark Polansky 38 Discovery 38 Tani 38 spacesuit 38 Wakata 37 Gagarin 37 moon 37 Grunsfeld 37 lunar surface 37 cosmonaut 37 spacewalker 37 NASA Administrator 37 Pontes 37 Gerstenmaier 37 Lopez Alegria 36 Space Shuttle Discovery 36 manned spaceflight 36 International Space Station 36 Endeavour astronauts 36 orbit 36 Russian cosmonauts 36 spaceflight 35 Astronauts 35 moonwalk 35 Mars 35 lunar exploration 35 Mike Fincke 35 Bowersox 35 orbiter 35 spacecraft 35 Sharipov 35 Squyres 35 Mission Control 35 Hayabusa 35 ISS 34 Dittemore 34 cosmonauts 34 spacewalkers 34 Roco 34 Bolden 34 Shenzhou 34 crewmates 34 Discovery astronauts 34 space shuttle 34 outer space 34 manned missions 34 human spaceflight 34 Soyuz 33 Hubble 33 Parazynski 33 SPACE.com 33 Space Shuttle 33 Garriott 33 Heras 33 microgravity 33 HTV 33 Endeavour 33 space 33 Soyuz capsule 33 space shuttles 33 Armstrong 33 Mars Rover 33 Massimino 33 Baikonur 33 manned spacecraft 33 Solar Impulse 32 shuttle missions 32 Atlantis 32 Tondo 32 JPL 32 Reisman 32 Constellation 32 zero gravity 32 lunar orbit 32 Baikonur Cosmodrome 32 Space Station 32 weightlessness 32 Soyuz TMA 32 Merckx