Division of the US National Aeronautics and Space Administration (NASA) which trains astronauts
NASAspace suits previously worn by the Astronaut Corps at the Johnson Space Center (center,Pete Conrad's suit worn during the 1969Apollo 12 mission including his walk on the Moon)
The first American astronaut candidates were selected by NASA in 1959, for itsProject Mercury with the objective of orbiting astronauts around theEarth in single-man capsules. The military services were asked to provide a list of military test pilots who met specific qualifications. After stringent screening, NASA announced its selection of the "Mercury Seven" as its first astronauts. Since then, NASA has selected 22 more groups of astronauts, opening the corps to civilians, scientists, doctors, engineers, and schoolteachers. As of the 2009 Astronaut Class, 61% of the astronauts selected by NASA have come from military service.[1]
NASA selects candidates from a diverse pool of applicants with a wide variety of backgrounds. From the thousands of applications received, only a few are chosen for the intensive astronaut candidate training program. Including the "Original Seven", 339 candidates have been selected to date.[2]
The Astronaut Corps is based at theLyndon B. Johnson Space Center inHouston, although members may be assigned to other locations based on mission requirements, e.g. Soyuz training at Star City, Russia.
TheChief of the Astronaut Office is the most senior leadership position for active astronauts in the Corps. The Chief Astronaut serves as head of the Corps and is the principal adviser to theNASA Administrator on astronaut training and operations. The first Chief Astronaut wasDeke Slayton, appointed in 1962. The current Chief Astronaut isJoseph M. Acaba.
Salaries for newly hired civilian astronauts are based on the federal government'sGeneral Schedule pay scale for grades GS-11 through GS-14. The astronaut's grade is based on the astronaut's academic achievements and experience.[3] Astronauts can be promoted up to grade GS-15.[4] As of 2015, astronauts based at the Johnson Space Center in Houston, Texas, earn between $66,026 (GS-11 step 1) and $158,700 (GS-15 step 8 and above).[5] As of the new astronaut candidate class announcement of 2024, astronaut candidates will be removed from the GS pay scale and be paid on an AD 'Administratively Determined" scale.
Military astronauts are detailed to the Johnson Space Center and remain on active duty for pay, benefits, leave, and similar military matters.
There are no age restrictions for the NASA Astronaut Corps. Astronaut candidates have ranged between the ages of 26 and 46, with the average age being 34. Candidates must be U.S. citizens to apply for the program.
There are three broad categories of qualifications: education, work experience, and medical.[6]
Candidates must have amaster's degree from an accredited institution inengineering,biological science,physical science ormathematics.[7] The degree must be followed by at least two to three years of related, progressively responsible, professional experience (graduate work or studies) or at least 1,000 hours of pilot-in-command time in jet aircraft. An advanced degree is desirable and may be substituted for experience, such as a doctoral degree (which counts as the two years experience). Teaching experience, including experience at theK–12 levels, is considered to be qualifying experience.
Candidates must have the ability to pass the NASA long-duration space flight physical, which includes the following specific requirements:
Distant and near visual acuity: Must be correctable to 20/20, each eye separately (corrective lenses such as glasses are allowed)
The refractive surgical procedures of the eye,PRK andLASIK, are allowed, providing at least 1 year has passed since the date of the procedure with no permanent adverse after effects.
Blood pressure not to exceed 140/90 measured in a sitting position
As of September 2025[update], the corps has 40 “active" astronauts consisting of 15 women and 25 men.[8] The highest number of active astronauts at one time was in 2000 when there were 149.[9] All of the current astronaut corps are from the classes of 1996 (Group 16) or later.
Missions initalics are scheduled and subject to change.
There are also "international active astronauts", who are assigned to duties at the Johnson Space Center,[10] and who were selected by their home agency to train as part of a NASA Astronaut Group and serve alongside their NASA counterparts. While the international astronauts go through training with the NASA Astronaut Corps, they are not considered members of the corps.
As of April 2025[update], the corps has 12 "management" astronauts, who remain NASA employees but are no longer eligible for flight assignment. The management astronauts included personnel chosen to join the corps as early as 1987 (Group 12) and as recently as 2009 (Group 20).[11]
The term "Astronaut Candidate" (informally "ASCAN"[12]) refers to individuals who have been selected by NASA as candidates for the NASA Astronaut Corps and are currently undergoing a candidacy training program at theJohnson Space Center. Themost recent class of astronaut candidates was selected in 2025.[13][14]
Only three astronaut candidates have resigned before completing training:Brian O'Leary andAnthony Llewellyn, both from the 1967 Selection Group, andRobb Kulin of the 2017 group. O'Leary resigned in April 1968 after additionalApollo missions were cancelled, Llewellyn resigned in August 1968 after failing to qualify as a jet pilot, and Kulin resigned in August 2018 for unspecified personal reasons.[15] Another astronaut candidate,Stephen Thorne, died in an airplane accident before he could finish astronaut training.[16]
Selection as an astronaut candidate and subsequent promotion to astronaut does not guarantee the individual will eventually fly in space. Some have voluntarily resigned or been medically disqualified after becoming astronauts before being selected for flights.
Civilian candidates are expected to remain with the corps for at least five years after initial training; military candidates are assigned for specific tours. After these time limits, members of the Astronaut Corps may resign or retire at any time.
^Three payload specialists were also killed on the two missions, but are not counted here because as payload specialists they were not considered members of the NASA Astronaut Corps.
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–Soyuz MS-09 (Expedition 56/57)
This article incorporatespublic domain material from websites or documents of theNational Aeronautics and Space Administration.
Media related toNASA Astronaut Groups at Wikimedia Commons
NASA Astronaut Corps travel guide from Wikivoyage