An astronaut or cosmonaut is a person trained by a human spaceflight program to command, pilot, or serve as a crew member of a spacecraft. While generally reserved for professional space travelers, the term is sometimes applied to anyone who travels into space, including scientists, politicians, journalists, and tourists.
Until 2003, astronauts were sponsored and trained exclusively by governments, either by the military, or by civilian space agencies. With the sub-orbital flight of the privately-funded SpaceShipOne in 2004, a new category of astronaut was created: the commercial astronaut.
The criteria for what constitutes human spaceflight vary. The Fédération Aéronautique Internationale (FAI) Sporting Code for astronautics recognizes only flights that exceed an altitude of 100 kilometers (62 mi). In the United States, professional, military, and commercial astronauts who travel above an altitude of 50 miles (80 km) are awarded astronaut wings.
As of September 19, 2009, a total of 505 humans from 38 countries have reached 100 km or more in altitude, of which 502 reached Low Earth orbit or beyond. Of these, 24 people have traveled beyond Low Earth orbit, to either lunar or trans-lunar orbit or to the surface of the moon; three of the 24 did so twice: Jim Lovell, John Young and Eugene Cernan.
Under the U. S. definition, 496 people qualify as having reached space, above 50 miles (80 km) altitude. Of eight X-15 pilots who exceeded 50 miles in altitude, seven reached above 50 miles (80 km) but below 100 kilometers (about 62 miles). Space travelers have spent over 30,400 person-days (or a cumulative total of over 83 years) in space, including over 100 astronaut-days of spacewalks. As of 2008, the man with the longest time in space is Sergei K. Krikalev, who has spent 803 days, 9 hours and 39 minutes, or 2.2 years, in space. Peggy A. Whitson holds the record for most time in space by a woman, 377 days.
In the United States, Canada, United Kingdom, and many other English-speaking nations, a professional space traveler is called an astronaut. The term derives from the Greek words ástron (ἄστρον), meaning "star", and nautes (ναύτης), meaning "sailor". The first known use of the term "astronaut" in the modern sense was by Neil R. Jones in his short story The Death's Head Meteor in 1930. The word itself had been known earlier. For example, in Percy Greg's 1880 book Across the Zodiac, "astronaut" referred to a spacecraft. In Les Navigateurs de l'Infini (1925) of J.-H. Rosny aîné, the word astronautique (astronautic) was used. The word may have been inspired by "aeronaut", an older term for an air traveler first applied (in 1784) to balloonists.
NASA applies the term astronaut to any crew member aboard NASA spacecraft bound for Earth orbit or beyond. NASA also uses the term as a title for those selected to join its Astronaut Corps. The European Space Agency similarly uses the term astronaut for members of its Astronaut Corps.
By convention, an astronaut employed by the Russian Federal Space Agency (or its Soviet predecessor) is called a cosmonaut in English texts. The word is an anglicisation of the Russian word kosmonavt (Russian: космона́вт Russian pronunciation: [kəsmɐˈnaft]), which in turn derives from the Greek words kosmos (κόσμος), meaning "universe", and nautes (ναύτης), meaning "sailor". For the most part, "cosmonaut" and "astronaut" are synonyms in all languages, and the usage of choice is often dictated by political reasons.
Yuri Gagarin, Russian, is the first human cosmonaut. Valentina Tereshkova, Russian, is the first woman cosmonaut. On March 14, 1995, 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.
Official English-language texts issued by the government of the People's Republic of China use astronaut while texts in Russian use космонавт (kosmonavt). In China, the terms "yǔhángyuán" (宇航员, "sailing personnel in universe") or "hángtiānyuán" (航天员, "sailing personnel in sky") have long been used for astronauts. The phrase "tàikōng rén" (太空人, "spaceman") is often used in Taiwan and Hong Kong.
The term taikonaut is used by some English-language news media organizations for professional space travelers from China. The word has featured in the Longman and Oxford English dictionaries, the latter of which describes it as "a hybrid of the Chinese term taikong (space) and the Greek naut (sailor)"; the term became more common in 2003 when China sent its first astronaut Yang Liwei into space aboard the Shenzhou 5 spacecraft. This is the term used by Xinhua in the English version of the Chinese People's Daily since the advent of the Chinese space program. The origin of the term is unclear; as early as May 1998, Chiew Lee Yih (赵里昱) from Malaysia, used it in newsgroups, while Chen Lan (陈蓝), almost simultaneously, announced it at his "Go Taikonauts!" GeoCities page.
With the rise of space tourism, NASA and the Russian Federal Space Agency agreed to use the term "spaceflight participant" to distinguish those space travelers from astronauts on missions coordinated by those two agencies.
While no nation other than Russia (formerly the Soviet Union), the United States, and China has launched a manned spacecraft, several other nations have sent people into space in cooperation with one of these countries. Inspired partly by these missions, other synonyms for astronaut have entered occasional English usage. For example, the term spationaut (French spelling: spationaute) is sometimes used to describe French space travelers, from the Latin word spatium or space, and the Malay term angkasawan was used to describe participants in the Angkasawan program.
The first human in space was Russian Yuri Gagarin, who was launched into space on April 12, 1961 aboard Vostok 1 and orbited around the Earth for 108 minutes. There are allegations that Gagarin ejected from landing module after re-entering the atmosphere and parachuted back, due to safety concerns about the craft's landing systems. The first woman in space was Russian Valentina Tereshkova, launched in June 1963 aboard Vostok 6.
Alan Shepard became the first American and second person in space on May 5, 1961 on a 15-minute sub-orbital flight. The first American woman in space was Sally Ride, during Space Shuttle Challenger's mission STS-7, on June 18, 1983.
The first mission to orbit the moon was Apollo 8, which included William Anders who was born in Hong Kong, making him the first Asian-born astronaut in 1968. In April 1985, Taylor Wang became the first ethnic Chinese person in space. On 15 October 2003, Yang Liwei became China's first astronaut on the Shenzhou 5 spacecraft.
The Soviet Union, through its Intercosmos program, allowed people from other "socialist" (i.e. Warsaw Pact and other Soviet-allied) countries to fly on its missions. An example is Vladimír Remek, a Czechoslovak, who became the first non-Soviet European in space in 1978 on a Russian Soyuz-U rocket. On July 23, 1980, Pham Tuan of Vietnam became the first Asian in space when he flew aboard Soyuz 37. Also in 1980, Cuban Arnaldo Tamayo Méndez became the first person of Hispanic and black African descent to fly in space, Guion Bluford became the first African American to fly into space. The first person born in Africa to fly in space was Patrick Baudry, in 1985. In 1988, Abdul Ahad Mohmand became the first Afghan to reach space, spending nine days aboard the Mir space station.
With the larger number of seats available on the Space Shuttle, the U.S. began taking international astronauts. In 1983, Ulf Merbold of West Germany became the first non-US citizen to fly in a US spacecraft. In 1985, Rodolfo Neri Vela became the first Mexican-born person in space. In 1991, Helen Sharman became the first Briton to fly in space. In 2002, Mark Shuttleworth became the first citizen of an African country to fly in space, as a paying spaceflight participant. In 2003, Ilan Ramon became the first Israeli to fly in space, although he died during a re-entry accident.
The youngest person to fly in space is Gherman Titov, who was 25 years old when he flew Vostok 2. (Titov was also the first person to suffer space sickness). The oldest person who has flown in space is John Glenn, who was 77 when he flew on STS-95.
The longest stay in space was 438 days, by Russian Valeri Polyakov. As of 2006, the most spaceflights by an individual astronaut is seven, a record held by both Jerry L. Ross and Franklin Chang-Diaz. The farthest distance from Earth an astronaut has traveled was 401,056 km, when Jim Lovell, John Swigert, and Fred Haise went around the Moon during the Apollo 13 emergency.
The first civilian in space was Neil Armstrong, who had retired from the United States Navy before his first spaceflight on Gemini 8. The first person in space who had never been a member of any country's armed forces was Harrison Schmitt, a geologist who first flew in space on Apollo 17. Both Armstrong and Schmitt were directly employed by NASA.
The first non-governmental space traveler was Byron K. Lichtenberg, a researcher from the Massachusetts Institute of Technology who flew on STS-9 in 1983. In December 1990, Toyohiro Akiyama became the first paying space traveler as a reporter for Tokyo Broadcasting System, a visit to Mir as part of an estimated $12 million (USD) deal with a Japanese TV station, although at the time, the term used to refer to Akiyama was "Research Cosmonaut". Akiyama suffered severe space-sickness during his mission, which affected his productivity.
The first person to fly on an entirely privately-funded mission was Mike Melvill, piloting SpaceShipOne flight 15P on a sub-orbital journey, although he was a test pilot employed by Scaled Composites and not an actual paying space tourist. Seven others have paid to fly into space:
The first NASA astronauts were selected for training in 1959. Early in the space program, military jet test piloting and engineering training were often cited as prerequisites for selection as an astronaut at NASA, although neither John Glenn nor Scott Carpenter (of the Mercury Seven) had any university degree, in engineering or any other discipline at the time of their selection. Selection was initially limited to military pilots. The earliest astronauts for both America and Russia tended to be jet fighter pilots, and were often test pilots.
Once selected, NASA astronauts go through 20 months of training in a variety of areas, including training for extra-vehicular activity in a facility such as NASA's Neutral Buoyancy Laboratory. Astronauts-in-training may also experience short periods of weightlessness in aircraft called the "vomit comet", the nickname given to a pair of modified KC-135s (retired in 2000 and 2004 respectively, and replaced in 2005 with a C-9) which perform parabolic flights. Astronauts are also required to accumulate a number of flight hours in high-performance jet aircraft. This is mostly done in T-38 jet aircraft out of Ellington Field, due to its proximity to the Johnson Space Center. Ellington Field is also where the Shuttle Training Aircraft is maintained and developed, although most flights of the aircraft are done out of Edwards Air Force Base.
Mission Specialist Educators, or "Educator Astronauts", were first selected in 2004, and as of 2007, there are three NASA Educator astronauts: Joseph M. Acaba, Richard R. Arnold, and Dorothy Metcalf-Lindenburger. Barbara Morgan, selected as back-up teacher to Christa McAuliffe in 1985, is considered to be the first Educator astronaut by the media, but she trained as a mission specialist. The Educator Astronaut program is a successor to the Teacher in Space program from the 1980s.
Astronauts are susceptible to a variety of health risks including decompression sickness, barotrauma, immunodeficiencies, loss of bone and muscle, orthostatic intolerance due to volume loss, sleep disturbances, and radiation injury. A variety of large scale medical studies are being conducted in space via the National Space and Biomedical Research Institute (NSBRI) to address these issues. Prominent among these is the Advanced Diagnostic Ultrasound in Microgravity Study in which astronauts (including former ISS commanders Leroy Chiao and Gennady Padalka) perform ultrasound scans under the guidance of remote experts to diagnose and potentially treat hundreds of medical conditions in space. This study's techniques are now being applied to cover professional and Olympic sports injuries as well as ultrasound performed by non-expert operators in medical and high school students. It is anticipated that remote guided ultrasound will have application on Earth in emergency and rural care situations, where access to a trained physician is often rare. For more information on the health hazards faced by astronauts, go to the article entitled Space medicine.
At NASA, people who complete astronaut candidate training receive a silver lapel pin. Once they have flown in space, they receive a gold pin. U.S. astronauts who also have active-duty military status receive a special qualification badge, known as the Astronaut Badge, after participation on a spaceflight. The United States Air Force also presents an Astronaut Badge to its pilots who exceed 50 miles (80 km) in altitude.
Eighteen astronauts have lost their lives during spaceflight, on four missions. By nationality, they are thirteen Americans, three Russians, one Ukrainian, and one Israeli. Several others have died while training for space missions.
The Space Mirror Memorial, which stands on the grounds of the John F. Kennedy Space Center Visitor Complex, commemorates the lives of the men and women who have died during spaceflight and during training in the space programs of the United States. In addition to twenty NASA career astronauts, the memorial includes the names of a U.S. Air Force X-15 test pilot, a U.S. Air Force officer who died while training for a then-classified military space program, a civilian spaceflight participant who died in the Challenger disaster, and an international astronaut who was killed in the Columbia disaster.