A brief history of trying: man, NASA, and medicine.

The development of the V2 rocket during World War II raised the possibility of manned spaceflight to the level of "serious consideration." Concepts of aviation medicine led to the specialty of space medicine. Projects Mercury, Gemini, Apollo, Skylab, and Apollo-Soyuz, and the Space Transportation System have helped us gain important biomedical information, including but not limited to, microgravity and its effects on red cell mass, orthostatic tolerance, exercise capacity, bone density, and muscle nitrogen levels. Problems of "space motion sickness" and micro-organisms in space have become major concerns. This analytic review covers these topics and relevant others.