Related by context. Frequent words. (Click for all words.) 50 Frank Borman 49 Challenger exploded 48 shuttle Challenger 48 astronaut Ilan Ramon 46 teacher Christa McAuliffe 46 Soviet cosmonaut Yuri Gagarin 45 Kalpana Chawla 45 Ilan Ramon 45 Eugene Cernan 45 Owen Garriott 44 Judith Resnik 44 Space Shuttle Columbia 44 Nasa Jet Propulsion 44 NASA astronaut 44 Mercury Gemini 43 Ron Garan 43 NASA Astronaut 43 lunar landing 42 Edwin Buzz Aldrin 42 Haise 42 Fyodor Yurchikhin 42 Surayev 42 Apollo missions 42 Apollo 42 Dorthea 42 Apollo astronauts 42 Alan Shepard 42 Skylab 41 space shuttle 41 Christa McAuliffe backup 41 Rick Husband 41 Dryden Flight Research 41 cosmonaut Yuri Gagarin 41 Christa McAuliffe 41 Mission Specialists 41 Space Shuttle Challenger 40 Cernan 40 Space Shuttle Discovery 40 lunar landings 40 NASA astronaut corps 40 Apollo lunar 40 Lunar Module 39 Astronaut 39 crewmates 39 ISS Expedition 39 astronaut 39 Virts 39 orbited Earth 39 Mars Pathfinder 39 Leland Melvin 39 NASAs 39 Julie Payette 39 Israeli astronaut Ilan 38 Bahcall 38 Space Shuttle 38 June Scobee Rodgers 38 Yuri Malenchenko 38 Alexander Kaleri 38 James Doohan 38 crewmembers aboard 38 Russian cosmonaut Yuri Malenchenko 37 NEEMO 37 Tim Kopra 37 Commander Eileen 37 Japanese astronaut Soichi 37 Oleg Skripochka 37 Joan Higginbotham 37 satellite Sputnik 37 astronauts 37 shuttle disintegrated 37 Zamka 37 Yuri Gagarin 37 Hobaugh 37 Discovery STS 37 Gorie 37 Cape Canaveral Fla. 37 commander Fyodor Yurchikhin 36 Mikhail Kornienko 36 lunar module 36 NASA 36 crewmate 36 TJ Creamer 36 Space Shuttle Endeavour 36 Saturn V 36 Space Shuttle Atlantis 36 Gagarin 36 Jet Propulsion Lab 36 Sputnik satellite 36 Eric Boe 36 USS Forrestal 36 Piers Sellers 36 Joseph Acaba 36 Doug Wheelock 35 Shuttle astronauts 35 Mars Polar Lander 35 NASA Administrator 35 moon 35 crewmen aboard 35 JPL manages 35 Megan McArthur 35 Neil Armstrong