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. However, with the sub-orbital flight of the privately-funded
SpaceShipOne in 2004, a new category of astronaut was created: the
commercial astronaut.
Definition
thumb||right|350px|[[Timeline of space travel by nationality|Countries whose citizens have flown in space.]]
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 . However, in the
United States, professional, military, and commercial astronauts who travel above an altitude of are awarded
astronaut wings.
As of September 19, 2009, a total of 505 humans from
38 countries (36 counting West/East Germany and Soviet Union/Russia as single nations
) 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 (Lovell, Young and Cernan).
Under the U. S. definition, 496 people qualify as having reached space, above altitude. Of eight
X-15 pilots who exceeded 50 miles in altitude, seven reached above 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.
holds the record for most time in space by a woman, 377 days.
Terminology
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.
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.
Russia
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 ( ), 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 astronaut.
Valentina Tereshkova, Russian, is the first astronaut woman. 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.
China
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" (, "sailing personnel in universe") or "hángtiānyuán" (, "sailing personnel in sky") have long been used for astronauts. The phrase "tàikōng rén" (, "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 (traveller), or astronaut"; 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 () from
Malaysia, used it in
newsgroups,
while Chen Lan (), almost simultaneously, announced it at his "Go Taikonauts!" GeoCities page.
Other terms
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.
Space travel milestones
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. 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. 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
African descent to fly in 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
landing accident.
Age milestones
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 furthest distance from Earth an astronaut has traveled was 401,056 km, when
Jim Lovell,
John Swigert, and
Fred Haise made their orbit of the Moon during the
Apollo 13 emergency.
Civilian and non-government milestones
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 self-funded
space tourist was
Dennis Tito onboard the Russian spacecraft Soyuz TM-3 on 28 April 2001.
Self-funded travelers
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:
- Anousheh Ansari (Iranian / American): September 18 – September 29, 2006 (ISS)
- Charles Simonyi (Hungarian / American): April 7 – April 21, 2007 (ISS), March 26 – April 8, 2009 (ISS)
- Guy Laliberté (Canadian): September 30, 2009 – October 11, 2009 (ISS)
Training
The first NASA astronauts were selected 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.
NASA candidacy requirements
- Be citizens of the United States.
- Pass a strict physical examination, and have a near and distant visual acuity correctable to 20/20 (6/6). Blood pressure, while sitting, must be no greater than 140 over 90.
Commander and Pilot
- At least 1,000 hours flying time as pilot-in-command in jet aircraft. Experience as a test pilot is desirable.
- Height must be 5 ft 4 in to 6 ft 4 in (1.63 to 1.93 m).
- Distant visual acuity must be correctable to 20/20 in each eye
- The refractive surgical procedures of the eye, PRK and LASIK, are now allowed, providing at least 1 year has passed since the date of the procedure with no permanent adverse after effects. For those applicants under final consideration, an operative report on the surgical procedure will be requested.
Mission Specialist
- Applicant's height must be 5 ft 2 in to 6 ft 4 in (1.57 to 1.93 m).
Mission Specialist Educator
Mission Specialist Educators Lindenberger, Arnold, and Acaba during a parabolic flight.
- Bachelor's degree with teaching experience, including work at the kindergarten through 12th grade level. Advanced degree not required, but is desired.
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.
, 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.
Health risks of space travel
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.
Insignia
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.
Deaths
Space Mirror Memorial
As of 2008, eighteen astronauts have lost their lives during spaceflight, on four missions. They include thirteen Americans, three Russians, one Ukrainian, and one Israeli.
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 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.
See also
