Astronaut — An astronaut is a person who travels into space, or who makes a career of doing so.
The early astronauts had all previously been test pilots, but later astronauts have included scientists and physicians, journalists, and politicians. As far as is possible, all conditions to be encountered in space are simulated in ground training.
Astronauts are trained to function effectively in cramped quarters while wearing restrictive spacesuits; they are accelerated in giant centrifuges to test their reactions to the inertial forces experienced during liftoff; they are prepared for the physiological disorientation they will experience in space arising from weightlessness; and they spend long periods in isolation chambers to test their psychological reactions to solitude.
Using trainers and mock-ups of actual spacecraft, astronauts rehearse every maneuver from liftoff to recovery, and every conceivable malfunction and difficulty is anticipated and prepared for. In addition to flight training, astronauts are required to have thorough knowledge of all aspects of space science, such as celestial mechanics and rocketry. Concurrent with all other preparation, astronauts must maintain excellent physical condition.
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 term “taikonaut” is sometimes used for (still-hypothetical) astronauts from China.
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.
The youngest person to fly in space is Gherman Titov, who was 24 years old when he flew Vostok 2, and the oldest is John Glenn who was 77 when he flew on STS-95
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.