Astronauts
DraftA reference page for crewed flight. The emphasis is on what flight experience established rather than on individual biography, since the physiological and operational record is what the rest of this site draws on.
Early programmes
| Milestone | Who | Year | Significance |
|---|---|---|---|
| First human in space | Yuri Gagarin | 1961 | Demonstrated human survival of launch, orbit and reentry |
| First American in space | Alan Shepard | 1961 | Suborbital |
| First woman in space | Valentina Tereshkova | 1963 | |
| First spacewalk | Alexei Leonov | 1965 | Nearly fatal; his suit stiffened and he could not re-enter the airlock until he vented pressure |
| First rendezvous | Gemini VI and VII crews | 1965 | Established that rendezvous was achievable, a prerequisite for Apollo |
| First docking | Neil Armstrong and David Scott, Gemini VIII | 1966 | Followed immediately by a stuck thruster and an emergency abort |
| First lunar landing | Neil Armstrong and Buzz Aldrin | 1969 |
Leonov’s EVA is worth recording in detail because it established a design requirement. His suit pressurised to a rigidity that prevented him from bending enough to re-enter the airlock, and he vented suit pressure to a dangerous level to get back in. Suit mobility under pressure has been a central design problem ever since, and it remains one, as noted in Life support.
Long duration
The long-duration record is scientifically the most valuable part of the crewed programme, because the physiological data cannot be obtained any other way.
| Record | Holder | Duration |
|---|---|---|
| Longest single spaceflight | Valeri Polyakov | 437 days on Mir, 1994 to 1995 |
| Longest US single flight | Frank Rubio | 371 days, 2022 to 2023, extended by a spacecraft coolant leak |
| Cumulative time in space | Several Russian cosmonauts exceed 800 days | |
| Continuous human presence | ISS | Since November 2000 |
Polyakov’s 437 days remains the single-flight record and is close to the transit duration of a Mars mission, which is why it is cited so frequently. He was able to walk unassisted after landing, which was taken as evidence that the duration is survivable with adequate exercise countermeasures.
The physiological findings that constrain mission design are covered in Space stations and Mars habitats: bone density loss of 1 to 2% per month, muscle atrophy, fluid shift causing persistent vision changes, immune dysregulation, and radiation exposure.
The Twins Study, comparing Scott Kelly during a year in orbit against his identical twin Mark on the ground, provided an unusually well-controlled dataset on gene expression, telomeres, cognition and the immune system.
EVA and repair
Extravehicular activity is what makes servicing possible and is among the riskiest routine activities in spaceflight.
| Mission | Contribution |
|---|---|
| Skylab 2, 1973 | Crew deployed a replacement sun shield and freed a jammed solar array, saving a station that would otherwise have overheated |
| Hubble Servicing Mission 1, 1993 | Installed corrective optics for a mirror ground to the wrong figure, restoring the observatory |
| Hubble servicing missions 2 to 5 | Replaced instruments, gyroscopes and batteries; most of Hubble’s science came from instruments installed after launch |
| ISS assembly | Over 200 EVAs across the assembly and maintenance of the station |
Hubble is the strongest argument for serviceability in the record. A manufacturing defect that would have crippled the mission was corrected in orbit, and the observatory’s scientific output is substantially a consequence of being reachable. See Space telescopes and In-space manufacturing and assembly.
Selection and training
| Stage | Content |
|---|---|
| Selection | Medical, psychological and technical screening from very large applicant pools |
| Basic training | Systems, spacewalking, robotics, language, survival, flight |
| Mission-specific | Vehicle and payload procedures for the assigned flight |
| Analogue environments | Underwater neutral buoyancy for EVA; isolation and confinement analogues |
The applicant-to-selection ratio is on the order of thousands to one, and the selected corps is small: a few dozen active astronauts per major agency.
Training is dominated by failure cases rather than nominal operations. Simulator sessions are constructed around malfunctions, and crews spend far more time practising responses to things going wrong than to the nominal timeline. This is the same reasoning as fault tolerance: the nominal case is the one that needs least attention.
Neutral buoyancy training is the primary EVA preparation and is imperfect in a specific way. Water provides neutral buoyancy but not weightlessness, so drag and the residual effect of gravity on the body inside the suit differ from orbit. Crews consistently report that EVA in flight feels different from training.
The loss record
Human spaceflight has killed crews, and the record belongs in any honest account.
| Event | Year | Cause |
|---|---|---|
| Apollo 1 | 1967 | Cabin fire during a ground test in a pure oxygen atmosphere at above ambient pressure |
| Soyuz 1 | 1967 | Parachute failure on return |
| Soyuz 11 | 1971 | Cabin depressurisation during reentry; crew were not wearing suits |
| Challenger | 1986 | Solid booster joint seal failure at low temperature |
| Columbia | 2003 | Thermal protection damage from foam strike during ascent |
The organisational findings from the Challenger and Columbia investigations have been more influential than the technical ones. Both boards found that the technical failure mode was known, that it had been observed repeatedly without consequence, and that repeated survival had been treated as evidence of safety rather than of unrealised risk. That pattern, normalisation of deviance, is now standard vocabulary in safety engineering well beyond spaceflight.
References
- NASA Human Research Program Evidence Reports on the physiological effects of spaceflight.
- Garrett-Bakelman, F. E. et al. “The NASA Twins Study”, Science, 364:eaau8650, 2019.
- Report of the Presidential Commission on the Space Shuttle Challenger Accident, 1986.
- Columbia Accident Investigation Board Report, 2003.
- Vaughan, D. The Challenger Launch Decision, University of Chicago Press, 1996, on normalisation of deviance.