Astronaut Medical Selection Requirements
Based on NASA's astronaut selection standards, candidates must undergo a comprehensive medical evaluation that includes detailed cardiovascular assessment with electrocardiography, complete ophthalmologic examination including visual acuity and color vision testing, audiometry, pulmonary function testing, complete blood count with metabolic panel, urinalysis, and psychological evaluation.
Core Medical Testing Requirements
Cardiovascular Evaluation
- 12-lead electrocardiogram (ECG) is mandatory for all astronaut candidates to screen for underlying cardiac abnormalities that could manifest during spaceflight 1
- Blood pressure measurement in both arms to detect any vascular abnormalities 2
- Exercise stress testing may be required based on age and cardiovascular risk factors, particularly for candidates over 40 years old 3
- Complete cardiovascular examination including auscultation at all valve areas and peripheral pulse assessment 2, 4
Ophthalmologic Assessment
- Comprehensive eye examination is essential given the critical visual demands of piloting spacecraft 2, 4
- Visual acuity testing to ensure adequate distance and near vision 4
- Color vision testing is mandatory using validated instruments such as Ishihara plates for screening, followed by more specific tests like the Color Assessment and Diagnosis (CAD) test or anomaloscope for definitive assessment 5
- Fundoscopic examination to detect retinal abnormalities 2
- Assessment of pupillary reactivity and extraocular movements 4
Laboratory Testing
- Complete blood count to screen for hematologic abnormalities 1, 2
- Comprehensive metabolic panel including serum electrolytes, creatinine, and glucose 1, 2
- Lipid profile to assess cardiovascular risk 1, 2
- Urinalysis to detect renal or metabolic disorders 1
- Thyroid function testing (TSH) 1, 2
Pulmonary Function Testing
- Spirometry and other pulmonary function tests are required to ensure adequate respiratory capacity for the physiologic demands of spaceflight 1
- This is particularly important given that respiratory conditions, especially asthma history, are leading causes of medical disqualification in aviation candidates 6
Additional Required Assessments
- Audiometric testing to ensure adequate hearing for communication systems 4
- Anthropometric measurements including height, weight, and body mass index, as these must fall within specific ranges for spacecraft compatibility 6
- Comprehensive physical examination including all major organ systems 2, 4
- Dental examination to identify any conditions that could become problematic during spaceflight 1
- Psychological and psychiatric evaluation to assess mental fitness for the unique stresses of spaceflight 1
Critical Considerations
Age-Related Testing Intensity
- While the candidate is described as "young," the specific testing protocol may vary based on exact age 7
- Candidates over 40 years typically require more intensive cardiovascular screening including stress testing 3
Common Disqualifying Conditions
- Respiratory history, particularly asthma or reactive airway disease, represents the leading cause of medical disqualification in aviation candidates (30.2% of Phase I screening failures) 6
- Ophthalmologic abnormalities are the second most common cause of disqualification 6
- Cardiovascular disease risk factors require thorough evaluation, as undetected cardiac conditions pose significant safety risks 3
Testing Accuracy and Follow-up
- Color vision assessment should use multiple validated tests, as single screening tests may miss candidates who could safely perform flight duties 5
- The CAD test demonstrates 100% sensitivity and specificity for color deficiency diagnosis and may identify 10% of color-deficient individuals as safe to fly 5
- Exercise ECG alone may not be optimal for detecting cardiovascular disease in high-risk individuals, and additional imaging may be warranted 3