Man's milieu in space; a summary of the physiologic requirements of man in a sealed cabin.

I N AN AGE of high altitude and high performance aircraft, it is necessary to develop a method for designing and constructing sealed cabins for flights beyond the atmosphere of the earth. This subject is of interest since it is apparent that, strictly from an engineering standpoint, it is now possible to build craft which can travel at great heights and at high velocities. The problem is now that of providing a safe and comfortable gaseous environment for the human occupants. Such a physiological environment can be provided above 70,000-80,000 feet altitude only by an isolated, self-sustaining capsule; a true sealed cabin. The term pressurized cabin refers to those cabins in which the atmospheric pressure is maintained and the cabin ventilated by superchargers or compressors. This is not a serious problem for commercial aircraft which rarely fly at extreme altitudes. But for very high flying military aircraft, pressurized cabins .become a practical impossibility, for at 100,000 feet altitude the cabin pressure/ambient pressure ratio would be approximately 65 to 1 with an interior pressure of 10 psi (corre-