Related by context. Frequent words. (Click for all words.) 44 Cernan 42 Lee Archambault 41 Aldrin 41 Mars 37 Mike Fincke 37 Mark Polansky 37 orbit 37 crewmates 36 astronaut 36 manned missions 36 suborbital flight 36 outer space 36 Foale 35 Hobaugh 35 Nasa 35 Space Station 35 Rick Husband 35 International Space Station 35 Brent Jett 34 astronauts 34 Space Shuttle Atlantis 34 Alan Poindexter 34 space shuttle Discovery 34 Buzz Aldrin 34 Space Shuttle Endeavour 34 orbiting 33 Yuri Gagarin 33 Padalka 33 NASA 33 Orbiter 33 Apollo astronauts 33 commander Rick Sturckow 33 moon 33 spaceship 33 lunar exploration 33 Hubble 33 ISS 32 Apollo 32 Space.com 32 human spaceflight 32 Eileen Collins 32 Lopez Alegria 32 Daniel Tani 32 shuttle missions 32 space shuttle 32 Astronaut 32 spacecraft 32 Alan Shepard 32 shuttle 32 Wakata 32 Skylab 32 Malenchenko 31 Nicole Stott 31 lunar module 31 lander 31 Space Shuttle Discovery 31 Shuttle Discovery 31 Neil Armstrong 31 cosmonaut 31 Readdy 31 moon landings 31 lunar orbit 31 unmanned spacecraft 31 rover 31 weightlessness 31 spacemen 30 Planetary Society 30 Roskosmos 30 shuttle Discovery 30 NASA astronaut 30 astrobiology 30 astronaut Buzz Aldrin 30 Gagarin 30 Bill Gerstenmaier 30 Gerstenmaier 30 lunar landing 30 Bolden 30 orbiter 30 Armstrong 30 manned spaceflight 30 Krikalev 30 Martian surface 30 SPACE.com 29 Kopra 29 Squyres 29 Mission Specialists 29 aboard Endeavour 29 Mission Control 29 Yurchikhin 29 Nibali 29 lunar lander 29 Fincke 29 Vinogradov 29 Caldwell Dyson 29 lunar surface 29 taikonauts 29 Mars Exploration 29 Spirit rover 29 Melroy 28 Discovery astronauts 28 JPL