History of space medicine: the formative years at NASA.

Almost nothing was known about the effects of spaceflight on human physiology when, in May of 1961, President John F. Kennedy committed the United States to land a man on the Moon and return him safely to Earth within the decade. There were more questions than answers regarding the effects of acceleration, vibration, cabin pressure, CO2 concentration, and microgravity. There were known external threats to life, such as solar and ultraviolet radiation, meteorites, and extreme temperatures as well as issues for which the physicians and scientists could not even formulate the questions. And there was no time for controlled experiments with the required numbers of animal or human subjects. Of necessity, risks were evaluated and mitigated or accepted based on minimal data. This article summarizes presentations originally given as a panel at the 79th Annual Scientific Meeting of the Aerospace Medical Association in Boston in 2008. In it, five pioneers in space medicine at NASA looked back on the development of their field. The authors related personal anecdotes, discussed the roles of various people and presented examples of contributions to emerging U.S. initiatives for human spaceflight. Topics included the development of quarantine facilities for returning Apollo astronauts, the struggles between operational medicine and research personnel, and observations from the first U.S. medical officer to experience weightlessness on orbit. Brief biographies of the authors are appended to document their participation in these historic events.

Human health and performance for long-duration spaceflight.

Future long-duration spaceflights are now being planned to the Moon and Mars as a part of the "Vision for Space Exploration" program initiated by NASA in 2004. This report describes the design reference missions for the International Space Station, Lunar Base, and eventually a Mars Expedition. There is a need to develop more stringent preflight medical screening for crewmembers to minimize risk factors for diseases which cannot be effectively treated in flight. Since funding for space life sciences research and development has been eliminated to fund program development, these missions will be enabled by countermeasures much like those currently in use aboard the International Space Station. Artificial gravity using centrifugation in a rotating spacecraft has been suggested repeatedly as a "universal countermeasure" against deconditioning in microgravity and could be an option if other countermeasures are found to be ineffective. However, the greatest medical unknown in interplanetary flight may be the effects of radiation exposure. In addition, a Mars expedition would lead to a far greater level of isolation and psychological stress than any space mission attempted previously; because of this, psychiatric decompensation remains a risk. Historically, mortality and morbidity related to illness and injury have accounted for more failures and delays in new exploration than have defective transportation systems. The medical care system on a future Mars expedition will need to be autonomous and self-sufficient due to the extremely long separation from definitive medical care. This capability could be expanded by the presence of a physician in the crew and including simple, low-technology surgical capability.