For a free trial of World Book Online, click here . Astronaut is a person who pilots a spacecraft or works in space, particularly in the space program of the United States. In Russia and the other former republics of the Soviet Union, such men and women are called cosmonauts. The cosmonaut program was a project of the Soviet Union until the country broke up in 1991. Russia then took over the program.
China also has an astronaut-training program.
Astronauts and cosmonauts operate spacecraft and space stations, launch and recapture satellites, and conduct scientific experiments. The word astronaut comes from Greek words that mean sailor among the stars. Cosmonaut means sailor of the universe. They live and train at the Lyndon B. Johnson Space Center in Houston. Astronauts travel into space aboard space shuttles.