For other uses, see Astronaut (disambiguation).
"Cosmonaut" redirects here. For other uses, see Cosmonaut (disambiguation).
NASA Astronaut Bruce McCandless II using a Manned Maneuvering Unit outside Space Shuttle Challenger on shuttle mission STS-41-B in 1984.
An astronaut (or cosmonaut) is a person trained by a human spaceflight program to command, pilot, or serve as a crew member of a spacecraft. Although generally reserved for professional space travelers, the terms are sometimes applied to anyone who travels into space, including scientists, politicians, journalists, and tourists.[1][2]