The development of rocketry has, for the first time, made it possible for man to leave the environs of the earth's atmosphere. It has extended the arts and sciences of aviation into space and aviation medicine into space medicine. The progress is exemplified in Project Mercury, which is to place a manned capsule on top of an intercontinental ballistic missile rocket. Concurrently with these developments, an entirely new generation of stressors with their resultant stresses have presented themselves for solution. A few of the stressors are vibration, noise, weightlessness, and the toxic and corrosive qualities of the rocket fuels and oxidizers. Solutions of the many problems require close association with more conventional aspects of preventive medicine.