Advantages of a low-oxygen environment in space cabins

The advantages of having a low-oxygen environment in space cabins are discussed. The major advantage is a sharply reduced fire hazard, which is a major threat in manned space flights. At 1 atm, for example, 15% O2 (9,000 ft altitude equivalent) would not support most fires and could accommodate the crew with respect to hypoxia, decompression sickness (DCS), and other requirements. Chronic exposure to such a hypoxic environment (altitude acclimatization) could improve major areas of crew health and safety including alleviating deconditioning effects, decreasing susceptibility to DCS, and improving tolerance to severe hypoxia.