Related by context. Frequent words. (Click for all words.) 54 Christa McAuliffe backup 51 shuttle Challenger 51 teacher Christa McAuliffe 45 Christa McAuliffe 44 space shuttle 44 Shuttle astronauts 42 June Scobee Rodgers 41 Caldwell Dyson 40 shuttle fleet 40 McAuliffe 40 astronaut 39 Rick Husband 39 Space Shuttle Challenger 38 Challenger exploded 38 astronauts 38 Sturckow 38 Challenger 37 commander George Zamka 37 Mars orbiter 37 Nicole Stott 37 Discovery liftoff 37 Michael Foale 37 Zamka 37 shuttle 37 astronauts aboard 37 Mission Control 37 Readdy 37 Space Shuttle Columbia 36 Kalpana Chawla 36 shuttle Endeavour 36 spacewalkers 35 space shuttle Discovery 35 shuttle Discovery 35 Soyuz TMA 35 NASA astronaut 35 Astronaut 35 Tracy Caldwell Dyson 35 Spacewalking astronauts 35 NASA 34 Discovery astronauts 34 Hubble servicing 34 DiBello 34 Bill Gerstenmaier NASA 34 Space Shuttle 34 shuttle disintegrated 34 Dan Tani 34 spaceship 34 Total Reads 34 Mikhail Kornienko 34 Greg Chamitoff 34 liftoff 34 Soyuz capsule 34 Nasa 33 Space Shuttle Atlantis 33 shuttle Atlantis 33 space shuttle Endeavour 33 Shuttle 33 spacecraft 33 orbiting observatory 33 Yurchikhin 33 Gerstenmaier 33 Space Shuttle Discovery 33 Automated Transfer Vehicle 32 shuttle thermal shielding 32 Shuttle Discovery 32 aboard Endeavour 32 Bill Gerstenmaier 32 Space Shuttle Endeavour 32 Gregory Chamitoff 32 Kennedy Space 32 Resnik 32 Hubble 32 orbiter 32 International Space Station 32 Oleg Kononenko 32 spacewalk 32 heat shield 32 Space shuttle Atlantis 32 Shuttle Endeavour 32 orbiting laboratory 32 Eyharts 32 Peggy Whitson 32 Wetherbee 31 unmanned spacecraft 31 CAPE CANAVERAL Fla. 31 Suffredini 31 Leinbach 31 Skylab 31 Space Station 31 shuttle astronauts 31 Hubble Space Telescope 31 Sputnik satellite 31 orbiting complex 31 Two spacewalking astronauts 31 Padalka 31 Mike Suffredini 31 Gerety 31 Dittemore 31 McCool 31 Launius 31 Orion spacecraft