Long-range life support must be provided in manned spaceflight. This includes oxygen, food, and recycling of waste material. Shielding is also provided against encounters with micrometeorites and cosmic radiation that could damage the spacecraft or be a health hazard for its occupants. The spacesuit is a miniature life-support system for the individual astronaut; it provides sufficient oxygen at the correct pressure to sustain normal body functioning. In more advanced projects like Apollo, the space shuttle, Skylab, Mir, and the International Space Station, a "shirt-sleeve" environment, in which the astronauts do not have to wear any life-support equipment, is provided in a large capsule. Space biology (or exobiology) and space medicine study the reactions of human, animal, and plant life to the physical stresses encountered in space, such as weightlessness and radiation exposure. Attention is also given to the psychological effects on a group of people working together in confined quarters under demanding conditions.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.