Astronaut | Definition, Facts, & Training | Britannica (original) (raw)

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astronaut, designation, derived from the Greek words for “star” and “sailor,” commonly applied to an individual who has flown in outer space. More specifically, in the West, astronaut refers to those from the United States, Canada, Europe, and Japan who travel into space. Those Soviet and later Russian individuals who travel into space are known as cosmonauts (from the Greek words for “universe” and “sailor”). In Russia the word cosmonaut is used for space travelers of all nations. In the West, Chinese space travelers have come to be referred to as taikonauts (from the Chinese word for “space” and the Greek word for “sailor”), but in China the word yuhangyuan (from the Chinese words for “space” and “traveler”) is used.

History and highlights

As of 2022, 587 individuals from 41 countries had gone into orbit; 518 of these space fliers were men, and 69 were women. The longest time spent in space on one mission is the 438 days spent aboard the Russian space station Mir by cosmonaut Valery Polyakov in 1994–95. The longest individual cumulative time is the 878 days spent by cosmonaut Gennady Padalka on one mission to Mir and four missions to the International Space Station. Two U.S. astronauts, Franklin Chang-Díaz and Jerry Ross, made seven spaceflights, the most by any single individual. The youngest person to go into space was Oliver Daemen, who was 18 when he flew on the first flight of Blue Origin’s suborbital spacecraft New Shepard in 2021. The oldest astronaut was William Shatner, who was 90 when he flew on the second New Shepard flight in 2021.

Twenty-one space fliers—4 Russian cosmonauts and 17 American astronauts—have died during spaceflight activities. In January 1967 a three-man crew perished during a ground test of the first Apollo spacecraft; in April 1967 and June 1971, first one and then three cosmonauts died during reentry of their Soyuz vehicles; in January 1986 an entire seven-member crew died when the U.S. space shuttle Challenger exploded shortly after launch; and in February 2003 seven more astronauts were lost when the shuttle Columbia broke up on reentry.

John Glenn entering Friendship 7Astronaut John H. Glenn, Jr., entering his Mercury spacecraft Friendship 7 prior to launch of the first U.S. manned Earth orbital mission, February 20, 1962.

The first seven U.S. astronauts were chosen for Project Mercury in April 1959. They were selected from some 500 candidates, all members of the U.S. military. Each candidate was required to have experience as a pilot of high-performance jet aircraft and, because of the cramped conditions inside the Mercury spacecraft, to be no more than 5 feet 11 inches (180 cm) tall and weigh no more than 180 pounds (82 kg). These astronauts were U.S. Air Force Captains L. Gordon Cooper, Jr., Virgil (“Gus”) Grissom, and Donald (“Deke”) Slayton; Marine Lieutenant Colonel John H. Glenn, Jr.; and Navy Lieutenant M. Scott Carpenter and Lieutenant Commanders Walter M. Schirra, Jr., and Alan B. Shepard, Jr. On May 5, 1961, Alan Shepard made a brief suborbital flight, becoming the first U.S. astronaut to go into space. John Glenn became the first American in orbit with his February 20, 1962, three-orbit flight.

The Soviet Union selected 20 air force pilots from 102 candidates for cosmonaut training in February 1960. These individuals also had to meet restrictions on height (170 cm, or 5 feet 7 inches) and weight (70 kg, or 154 pounds) because of the small size of the Soviet Vostok spacecraft. The identity of these individuals was kept secret until they were actually launched into space. Most of the cosmonaut candidates were between 25 and 30 years old and thus did not have the extensive test pilot experience of their U.S. counterparts. One of these 20 young men, Yuri Gagarin, became the first human in space with his April 12, 1961, one-orbit flight.

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In 1997 China selected 12 military test pilots, all men, for its first group of taikonaut trainees; the first of these to go up in space, Yang Liwei, made a 14-orbit flight in October 2003 on Shenzhou 5.

India selected four astronauts, pilots in the Indian Air Force, for the Gaganyaan program, which is scheduled to have its first crewed flight in 2024. The astronauts did the first part of their training in Russia in early 2020 and the remainder at the Indian Space Research Organisation’s astronaut training facility in Bengaluru.

In both the United States and the Soviet Union, no women were initially selected as astronauts. (In the United States, 13 women, the “Mercury 13,” underwent some of the same testing as the seven Mercury astronauts. Wally Funk, who later became the oldest person in space in 2021, was among them.) In 1962 the Soviet Union chose five women as cosmonaut trainees; one of them, Valentina Tereshkova, went into orbit in June 1963, becoming the first woman in space. The United States did not select women for astronaut training until 1978, and the first female U.S. astronaut, Sally Ride, was launched aboard the space shuttle Challenger in June 1983. China selected two women in its second group of taikonaut trainees in 2010, and the first to fly in to space was Liu Yang on Shenzhou 9 in June 2012.

The United States selected only pilots as astronauts until 1965, when six scientists with technical or medical degrees were chosen for astronaut training. One of them, geologist Harrison (“Jack”) Schmitt, became a crew member of Apollo 17, the final Apollo mission to the Moon, in December 1972.

All told, 24 astronauts (all Americans) have gone to the Moon, and 12 of them walked on its surface. As part of the Artemis space program, launched in 2017, NASA aims to return astronauts to the Moon by 2025, with the goal of establishing a sustainable presence there and on other planets. The program also seeks to land the first woman and first person of colour on the Moon, and that woman may be Jessica Meir.