An astronaut (from the Greek"astron", meaning "star", and "nautes", meaning sailor) 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]"Astronaut" technically applies to all human space travalers regardless of nationality or alliegence, however astronauts fielded by Russia or the Soviet Union are typically known instead as cosmonauts (from the Russian "kosmos", meaning "universe", also borrowed from Greek) in order to distinguish them from American or otherwise NATO-oriented space travallers.