Related by context. Frequent words. (Click for all words.) 42 weightlessness 38 motion sickness 36 zero gravity 36 suborbital 35 microgravity 35 suborbital space 34 decompression sickness 34 oxygen deprivation 33 spacecrafts 33 Earth orbit 33 sub orbital 32 cosmic radiation 32 orbital 32 spaceflight 31 Russian Soyuz 31 weightless 31 suborbital flight 31 outer space 31 nausea 31 suborbital flights 31 interstellar 31 orbiting laboratory 31 hypersonic 30 lunar surface 30 curvature 30 spacemen 30 capsule 30 geosynchronous orbit 30 Astronaut 30 lunar orbit 29 interplanetary 29 Eileen Collins 29 astral 29 spacecraft 29 Mars 29 astronauts 28 Soyuz 28 cosmonauts 28 Martian surface 28 NASA Astronaut 28 orbital outpost 28 Krikalev 28 Red Planet 28 orbiting spacecraft 27 astronaut 27 Huygens 27 Nicole Stott 27 orbit 27 Russian Soyuz spacecraft 27 polar orbit 27 Orion spacecraft 27 manned spacecraft 27 Saturn moon 27 Soyuz rocket 27 NASA astronaut 27 spacesuit 26 simulated 26 cosmonaut 26 Astronauts 26 spaceship 26 Apollo astronauts 26 lunar landing 26 orbiter 26 orbiting lab 26 Virgin Galactic 26 Mars Rover 26 muscle atrophy 25 taikonauts 25 International Space Station 25 disorientation 25 robotic 25 Bigelow Aerospace 25 Lee Archambault 25 orbiting 25 Space Shuttle Discovery 24 Space Station 24 space shuttle 24 Robonaut 24 jetpacks 24 scramjet 24 spherical 24 Russian cosmonauts 24 spacewalking 24 Discovery astronauts 24 crewmates 24 spaceships 24 UP Aerospace 24 Spacecraft 24 jet propulsion 24 Daniel Tani 24 commander Peggy Whitson 23 Bill Gerstenmaier NASA 23 SpaceShipTwo 23 Russian Soyuz rocket 23 Skylab 23 shuttle Atlantis 23 Shuttle Discovery 23 Atlantis 23 Orion capsule 23 orbiting outpost 23 splashdown