Becoming an Astronaut Candidate (ASCAN) is one of the most demanding and highly selective career paths globally. Achieving this requires sustained dedication, academic achievement, and specialized professional experience. The selection process is a comprehensive, multi-year evaluation designed to identify individuals with exceptional technical proficiency and the physical and psychological fortitude necessary for spaceflight.
Educational Foundation for Astronaut Candidates
A formal, accredited education in a technical field is the mandatory bedrock for any applicant. Candidates must possess a master’s degree in a Science, Technology, Engineering, or Mathematics (STEM) field from an accredited institution. Acceptable fields include engineering, biological science, physical science, computer science, and mathematics. The master’s degree requirement can also be satisfied by completing two years of work toward a doctoral program in a relevant STEM area.
A Doctor of Medicine (M.D.), Doctor of Osteopathic Medicine (D.O.), or a related medical degree also fulfills the academic standard. Successful completion of a nationally recognized test pilot school program is another alternative. While specific GPA cutoffs are not publicly stated, a history of strong academic performance is expected. Degrees in related but non-qualifying areas, such as nursing or technology management, are typically not accepted.
Necessary Professional Experience Requirements
The agency differentiates between two primary career tracks, each requiring distinct post-graduate professional experience. For the mission specialist track, applicants must show a minimum of three years of progressively responsible, related experience acquired after the qualifying degree. This experience must demonstrate a high level of technical competency and application of the candidate’s advanced education. For medical doctors, residency program time counts toward this requirement.
The pilot track requires extensive flight experience. Pilot candidates must document a minimum of 1,000 hours of Pilot-in-Command time. At least 850 hours of this flight time must have been accumulated in high-performance jet aircraft. Experience as a test pilot is highly valued within this track. The quality and relevance of the professional work are evaluated for all candidates.
Physical and Medical Standards
All astronaut applicants must successfully pass the NASA long-duration space flight physical, ensuring readiness for the physiological demands of space missions. Candidates must stand between 62 and 75 inches. Cardiovascular health is monitored, requiring blood pressure to be no higher than 140/90 when measured sitting.
Visual acuity must be correctable to 20/20 in each eye for both near and distant vision. Refractive surgeries, such as LASIK or PRK, are permitted if at least one year has passed without adverse effects. Waivers are not granted for long-duration spaceflight, emphasizing the need for excellent physical condition to handle the stresses of launch and microgravity. The comprehensive medical evaluation includes cardiovascular checks, dental examinations, and a VO2 max stress test.
Essential Soft Skills and Behavioral Traits
Technical expertise is insufficient; candidates must also exhibit specific psychological and interpersonal characteristics. Astronauts operate in isolated, confined, and stressful environments where functioning effectively as part of a small team is paramount. The selection process assesses robust communication skills and the capacity to shift seamlessly between leadership and followership roles.
Resilience and adaptability under pressure are essential for managing unexpected challenges. Psychological evaluations screen for traits that support long-duration crew cohesion and performance, often favoring a moderate level of conscientiousness. This recognizes that rigid or perfectionistic tendencies may struggle with the unpredictable nature of the space environment. Suitability for extended missions also considers the capacity for self-care and team-care.
The Astronaut Candidate Application Process
The selection journey begins when a vacancy announcement opens, which occurs infrequently, often with several years between cycles. The application period is typically open for one month, during which applicants must submit a resume, official academic transcripts, and detailed information on their professional experience. NASA’s Astronaut Selection Board reviews the thousands of applications during the initial screening phase to determine who meets the minimum qualifications.
The selection process spans 18 months or more from the application deadline to the final announcement. Highly qualified candidates are invited to the Johnson Space Center in Houston for a week of initial interviews and comprehensive medical and psychological screenings. This phase assesses the candidate’s technical knowledge and their behavioral compatibility with the existing astronaut corps. A smaller group of finalists is then invited back for a second, more intensive round of interviews and final evaluations. The process culminates with the public announcement of the new class of Astronaut Candidates.
Training and Life After Selection
Once officially selected, the new class members are designated as Astronaut Candidates (ASCANs) and begin an intensive training and evaluation period lasting approximately two years. This phase of instruction is designed to provide a broad foundation of fundamental skills required for space operations. The curriculum includes technical instruction on International Space Station (ISS) systems, robotics operations, and orbital mechanics.
ASCANs must also complete specialized survival training, which encompasses water survival tests and the acquisition of a SCUBA certification for practicing spacewalk procedures in the Neutral Buoyancy Laboratory. Proficiency in the Russian language is a mandatory component of the training, as it is essential for working with international partners on the ISS. Upon satisfactory completion of the two-year program, ASCANs graduate to become fully qualified astronauts, eligible for assignment to a technical support role or a future spaceflight mission.