Related by context. Frequent words. (Click for all words.) 71 Eugene Cernan 62 Edwin Buzz Aldrin 61 Cernan 60 NASA astronaut 59 Soviet cosmonaut Yuri Gagarin 58 Neil Armstrong 58 Buzz Aldrin 58 astronaut 58 NASA Astronaut 55 astronaut Buzz Aldrin 54 Astronaut Buzz Aldrin 54 Apollo astronauts 52 lunar landing 51 Alan Shepard 51 Yuri Gagarin 51 Mars Pathfinder 50 Mercury Gemini 50 Astronaut 50 moon 50 spaceflight 50 lunar rover 50 lunar surface 49 Piers Sellers 49 lunar module 48 administrator Sean O'Keefe 48 NASA 48 Mission Specialists 48 Julie Payette 48 Gorie 48 Leland Melvin 48 John Grunsfeld 48 Astrophysicist 47 Aldrin 47 Skylab 47 spaceship 47 spaceflights 47 Tim Kopra 46 Eileen Collins 46 outer space 46 astronauts 46 NASA Administrator 46 NASA astronaut corps 46 space shuttle 46 astronaut Julie Payette 46 Yang Liwei 45 Wernher von Braun 45 Koichi Wakata 45 astronaut Peggy Whitson 45 Peter Diamandis 45 ESA astronaut 45 Hobaugh 45 Professor Stephen Hawking 45 Mariana Trench 44 Bertrand Piccard 44 Space.com 44 G Madhavan Nair 44 astronaut Yang Liwei 44 polar explorer 44 Right Stuff 44 Mars Rover 44 Space Shuttle 44 Dennis Tito 44 Sally Ride 44 Adler Planetarium 44 Space Shuttle Discovery 44 Anousheh Ansari 44 Commander Peggy Whitson 44 Heidemarie Stefanyshyn Piper 44 Von Braun 43 Arctic explorer 43 sub orbital 43 interplanetary 43 astronautics 43 Christa McAuliffe backup 43 Richard Feynman 43 Fyodor Yurchikhin 43 Nasa 43 Michael Foale 43 Zamka 43 June Scobee Rodgers 43 suborbital flight 43 Gagarin flight 43 Oleg Skripochka 43 Orbiting 43 crewmates 43 cosmonaut 43 Rex Walheim 43 Space Station 42 Shenzhou V 42 Shuttle astronauts 42 Krikalev 42 Expedition 42 Burt Rutan 42 Hubble servicing 42 Japanese astronaut Soichi 42 Commander Eileen 42 orbited 42 International Space Station 42 Cassini Huygens 42 Robert Heinlein 42 spacesuit