By convention, an astronaut employed by the Russian or Soviet government is called a cosmonaut. "Cosmonaut" is an anglification of the Russian word "Kosmonaut", which in term is derived from the Greek words kosmos, meaning universe and nautes, meaning sailor. One could reasonably argue that "cosmonaut" is simply the Russian language word for "astronaut", which the media on both sides have chosen not to translate this way for political reasons. On March 14, 1995 astronaut Norman Thagard[?] became the first American to ride to space on-board a Russian launch vehicle arguably becoming the first American cosmonaut in the process.
The first astronaut was Yuri Gagarin, who was launched into space in April 1961 aboard Vostok 1. The first woman astronaut was Valentina Tereshkova, who was launched into space in June 1963 aboard Vostok 6.
Up until the end of the 1970s only Americans and Soviets were active astronauts. In 1976 the Soviets started the Intercosmos program with a first group of 6 cosmonauts from fellow socialist countries, a second group started training in 1978. At about the same time in 1977 the European Space Agency selected 4 astronauts to fly the first Spacelab mission on board of the Space Shuttle. 1980 France started their first own selection of astronauts (called spationauts), 1982 Germany, 1983 Canada and 1985 Japan. Several more international payload specialist were selected until the Challenger disaster, and also later for international Soyuz missions of Russia. In 1998 the European Space Agency formed a single astronaut corps of 18 by dissolving the former national corps of France, Germany and Italy.
So far, eighteen astronauts have been killed on space missions, and at least ten more have been killed in training accidents on the ground. For details, see Space disasters.
U.S. Space Shuttle astronaut using manned maneuvering unit
Public domain picture from NASA