Qualifications for becoming an astronaut in 2026: the complete requirements guide

NASA selects new astronaut candidates roughly every four years, and each selection class receives more applications than the previous one. The 2021 class (Astronaut Group 23, nicknamed "The Flies") drew over 12,000 applicants and selected 10 — a 0.04% acceptance rate that makes it statistically harder to become a NASA astronaut than to get into any university, military unit, or professional program on Earth.

The formal qualifications are surprisingly straightforward on paper. The competitive reality is much more demanding. This guide covers both — what NASA officially requires and what successful candidates actually look like.

The official NASA requirements

NASA's astronaut candidate minimum qualifications, as published for the most recent selection:

1. U.S. citizenship

Non-negotiable. You must be a United States citizen to apply for the NASA Astronaut Candidate Program. Dual citizenship is acceptable as long as U.S. citizenship is included. Permanent residents, visa holders, and citizens of other nations cannot apply through this path.

International astronauts fly to space through their own national agencies (ESA, CSA, JAXA) or through commercial missions.

2. Education

Minimum: Master's degree in a STEM field from an accredited institution. Qualifying STEM fields include:

• Engineering (all disciplines)
• Biological science
• Physical science (physics, chemistry, astronomy, geology)
• Computer science
• Mathematics

Also accepted in place of a master's degree:

• Doctor of Medicine (MD) or Doctor of Osteopathic Medicine (DO)
• Completion of a nationally recognized test pilot school program
• Enrollment in or completion of a doctoral program (PhD) in a STEM field — at least two years of work toward a PhD qualifies

Not accepted: Technology degrees, social sciences, psychology (unless it qualifies as a biological science), nursing, aviation management, or STEM education/teaching degrees.

3. Professional experience

Minimum: Two years of related, progressively responsible professional experience in your STEM field after completing your degree requirements. Alternatively, at least 1,000 hours of pilot-in-command time in jet aircraft.

What counts as professional experience:

• Engineering work at aerospace companies, national labs, or government agencies
• Postdoctoral or faculty research in STEM
• Clinical medical practice (for MDs/DOs)
• Military operational experience in a technical specialty
• K-12 STEM teaching (with a master's in STEM and demonstrated classroom experience)

What does not count: Internships, co-ops, or any experience prior to completing degree requirements. Graduate research assistantship time only counts if you held the position after earning your qualifying degree.

4. Physical requirements

NASA requires candidates to pass the NASA Long-Duration Astronaut Physical, which evaluates your fitness for spaceflight missions lasting 6 months or more. Key requirements:

Requirement	Standard
Distant visual acuity	20/20 or correctable to 20/20 in each eye
Blood pressure	Not to exceed 140/90 (seated)
Height	62 to 75 inches (5'2" to 6'3")
Weight	No specific limit, but must fit in spacecraft seats and suits
Color vision	Standard color vision required
Hearing	Standard audiometric thresholds

The height range reflects spacecraft and spacesuit design constraints. Below 62 inches, crew members cannot reach controls or safely operate the Extravehicular Mobility Unit (EVA suit). Above 75 inches, they cannot fit in Soyuz, Crew Dragon, or Orion seat configurations.

LASIK and PRK vision correction surgery are accepted. NASA no longer disqualifies candidates for corrective eye surgery, though there is a waiting period (typically 1 year post-surgery) for the eyes to stabilize.

5. Swimming proficiency

All astronaut candidates must complete military water survival training during the first phase of astronaut candidate (ASCAN) training. Candidates must be able to:

• Swim 3 continuous laps (75 meters) in a flight suit and tennis shoes without stopping
• Tread water for 10 minutes in the same equipment

Candidates who cannot swim when selected must become proficient before the end of ASCAN training.

What competitive candidates actually look like

The minimum requirements are the floor. Here is what the profile of a competitive applicant looks like based on the backgrounds of recent selectees:

Education profile

Credential	Percentage of Recent Selectees (approx.)
PhD in STEM	35-40%
MD or DO	20-25%
Master's in STEM + military pilot	25-30%
Master's in STEM (non-pilot)	10-15%
Test pilot school graduate	20% (overlap with above)

Most successful candidates have more education than the minimum. PhDs, MDs, and test pilot school graduates dominate selection classes. A standalone master's degree with no other distinguishing qualifications (extensive field research, military flight experience, submarine service) is rarely sufficient.

Experience profile

• Average age at selection: 34-38 years old
• Average years of professional experience: 8-12 years (far above the 2-year minimum)
• Military vs. civilian: Roughly 50/50 in recent classes (historically more military-heavy)
• Prior NASA experience: Many selectees held positions at NASA centers, were NASA interns, or worked for NASA contractors before applying

The standout factors

Beyond education and experience, NASA evaluates candidates on attributes that cannot be reduced to a checklist:

Leadership in high-stakes environments — Successful candidates have led teams in situations where outcomes mattered and conditions were stressful. Military combat leadership, surgical teams, field research expeditions in extreme environments, submarine operations.

Technical depth combined with breadth — NASA wants specialists who can also generalize. An astrophysicist who can also troubleshoot plumbing on the ISS. A pilot who can also run biology experiments. Astronauts must be cross-trained in dozens of disciplines.

Demonstrated composure under stress — Antarctic expeditions, cave exploration, saturation diving, combat deployments, emergency medicine. NASA actively looks for evidence that you function well when things go wrong.

Team orientation — Astronauts live and work in confined spaces with small crews for months. Candidates who are brilliant but difficult to live with are screened out. The interview process includes extensive psychological evaluation and group interaction assessments.

The selection process

The NASA astronaut selection process runs approximately 18 months from application close to announcement:

Phase 1 — Application review (3-4 months): NASA's Astronaut Selection Board reviews all applications. Roughly 500-800 applicants out of 12,000+ are identified as "Highly Qualified" based on education, experience, and application quality.

Phase 2 — Initial interviews (2-3 months): Approximately 120 candidates are invited to Johnson Space Center for a week of interviews, medical screening, and team-building exercises. Candidates meet with the selection board, undergo psychological evaluation, and participate in group activities that assess teamwork and communication.

Phase 3 — Final interviews (2-3 months): Approximately 50 candidates return to JSC for a second round of more intensive interviews and medical testing. The medical evaluation is thorough — cardiac stress tests, MRI, blood work, dental exams, ophthalmological testing, and psychiatric evaluation.

Phase 4 — Selection (1-2 months): The Astronaut Selection Board recommends finalists to the NASA Administrator, who makes the final selection. The class size is typically 10-14 candidates.

Astronaut candidate training

Selected candidates enter a two-year training program at Johnson Space Center:

Training Component	Duration	Content
Spacecraft systems	6+ months	Dragon, Orion, ISS systems
Spacewalk (EVA)	Ongoing	Neutral Buoyancy Lab (6-hour pool simulations)
Robotics	3+ months	Canadarm2, Dragon berthing/docking
Russian language	Ongoing	Required for ISS operations
T-38 jet proficiency	Ongoing	Monthly flight hours (all candidates, including non-pilots)
Survival training	Weeks	Land and water survival, including winter and jungle
Scientific training	Ongoing	Geology, biology, Earth observation

After completing ASCAN training, candidates receive their astronaut wings and are assigned to the astronaut office. Flight assignments may come immediately or may take several years — there is no guarantee of how quickly a new astronaut will fly.

Other paths to space in 2026

NASA's astronaut program is not the only way to reach orbit:

Organization	Path	Requirements
ESA	European Astronaut Corps	ESA member state citizen, STEM degree, 3+ years experience
CSA	Canadian Astronaut Program	Canadian citizen, STEM degree, extensive professional experience
JAXA	Japanese Astronaut Program	Japanese citizen, STEM degree, 3+ years experience
SpaceX	Polaris/commercial missions	Selected by mission commander or commercial partner, no formal NASA-style requirements
Axiom Space	Private missions	Customer-funded ($55M+) or national astronaut programs
Blue Origin	New Shepard/New Glenn	Customer-funded (suborbital) or future commercial crew

Commercial spaceflight is expanding who can go to space. Jared Isaacman's Polaris program, Axiom's private ISS missions, and the anticipated commercial space station missions will create flight opportunities outside the traditional government astronaut pipeline. But for sustained, long-duration spaceflight careers, NASA (and other national agencies) remains the primary path.

Browse all NASA positions on Zero G Talent. For astronaut pay details, see our astronaut salary guide. For NASA's GS pay scale, see the NASA pay guide. For private space companies hiring now, browse SpaceX jobs, Blue Origin jobs, and Axiom Space jobs.