Russian cosmonaut Valeri Polyakov on Soyuz TM-18 leaves for Mir. He would stay on the space station until March 22, 1995, for a record 437 days in space.
Soyuz TM-18 was launched from Baikonur Cosmodrome and landed 112 km north of Arkalyk. TM-18 was a two-day solo flight that docked with the Mir space station on January 10, 1994. The three cosmonauts became the 15th resident crew on board Mir. The crew did research work in space flight medicine, primarily by cosmonaut Valeri Polyakov during his long-term flight, and accomplished 25 different experiments.
An astronaut (from the Ancient Greek ἄστρον (astron), meaning 'star', and ναύτης (nautes), meaning 'sailor') is a person trained, equipped, and deployed by a human spaceflight program to serve as a commander or crew member aboard a spacecraft. Although generally reserved for professional space travelers, the term is sometimes applied to anyone who travels into space, including scientists, politicians, journalists, and tourists."Astronaut" technically applies to all human space travelers regardless of nationality or allegiance; however, astronauts fielded by Russia or the Soviet Union are typically known instead as cosmonauts (from the Russian "kosmos" (космос), meaning "space", also borrowed from Greek) in order to distinguish them from American or otherwise NATO-oriented space travellers. Comparatively recent developments in crewed spaceflight made by China have led to the rise of the term taikonaut (from the Mandarin "tàikōng" (太空), meaning "space"), although its use is somewhat informal and its origin is unclear. In China, the People's Liberation Army Astronaut Corps astronauts and their foreign counterparts are all officially called hángtiānyuán (航天员, meaning "heaven navigator" or literally "heaven-sailing staff").
Since 1961, 600 astronauts have flown in space. Until 2002, astronauts were sponsored and trained exclusively by governments, either by the military or by civilian space agencies. With the suborbital flight of the privately funded SpaceShipOne in 2004, a new category of astronaut was created: the commercial astronaut.