How Do You Become An Astronaut?
QUICK ANSWER
To become a NASA astronaut, you need US citizenship, a master's degree in a STEM field, at least 2 years of related professional experience or 1,000 pilot-in-command hours, and the ability to pass NASA's long-duration spaceflight physical. Selection is extremely competitive, with thousands of applicants per opening.
Becoming an astronaut is one of the most competitive career paths in the world. NASA hires roughly a dozen new astronauts every few years from thousands of applicants. The basic requirements involve education, experience, and physical fitness, but actual selection depends on a combination of qualifications and intangibles. Other space agencies and private companies have their own paths into the astronaut corps.
What are NASA's requirements?
Three main qualifications. NASA requires US citizenship, a master's degree (or equivalent) in a STEM field (engineering, biology, physical science, computer science, or mathematics), and at least 2 years of related professional experience or 1,000 hours as pilot-in-command of a jet aircraft. The master's requirement can be satisfied with a doctorate, completed medical degree, or two years toward a doctoral program in STEM. You also need to pass NASA's long-duration spaceflight physical, which sets standards for vision, blood pressure, and other health metrics.
How competitive is selection?
Extremely. The most recent astronaut class (announced in 2025 from the 2024 application round) included 10 astronaut candidates selected from over 12,000 applications, a roughly 0.08% acceptance rate. Selection involves multiple rounds of interviews, medical evaluations, and assessments. The committee looks for qualifications, teamwork ability, communication skills, and resilience under pressure. Many astronauts apply multiple times before being selected. There's no single perfect background; recent classes have included pilots, engineers, doctors, scientists, and others.
What's astronaut training like?
Two years of intensive preparation. Selected candidates report to Johnson Space Center in Houston for about two years of basic training before being eligible for flight assignments. Training covers spacecraft systems, spacewalk procedures, robotics, Russian language (for ISS work), survival skills, and physical conditioning. Candidates train in NASA's Neutral Buoyancy Lab (a giant pool) and the T-38 jet aircraft. They also learn about life sciences and Earth observation, since most modern astronauts conduct scientific research in orbit.
Are there other paths?
Several. The European Space Agency, Japan's JAXA, Canada's CSA, and other space agencies have their own astronaut selection processes. Russia's Roscosmos selects cosmonauts. China's CNSA has its own program. Private companies like SpaceX, Blue Origin, and Virgin Galactic have begun flying private astronauts, sometimes including non-government individuals selected through different criteria. The Inspiration4 mission in 2021 included civilians selected through processes including a charity sweepstakes. Commercial spaceflight is gradually expanding access.
Becoming an astronaut requires US citizenship, a STEM master's degree, two years of related experience or extensive pilot hours, and passing physical exams. NASA selection is extremely competitive, with thousands of applicants per opening. Selected candidates undergo two years of intensive training before flight assignments. Other space agencies and increasingly private companies offer alternative paths to space. The astronaut corps is one of the most elite professions in the world.
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