The operating pressure value is one of the principal considerations for trade-off analysis of the space suit enclosure and the individual life support subsystem (LSS). From the physiological point of view, the same level of pressure in the suit and space vehicle reflects the best solution. Current Russian space vehicles and orbiting stations use the “Earth atmosphere”. A suit operating pressure at such a level would result in complicated and technically unreasonable designs. Improved mobility of the pressurized suit and enhanced performance characteristics of the LSS can be offered with the minimized positive pressure.
However, the minimized suit pressure concept leads to the increased risk of crewmember decompression sickness. Therefore, the suit operating pressure selection calls for a trade-off of physiological tolerances of the crewmember versus technical feasibility of this or that solution as principal considerations.
The paper reviews the effect of the suit operating pressure on certain technical characteristics of a space suit, in particular, mobility, amount of oxygen available to compensate for leakage, mass and strength as well as on metabolic rate. The paper reviews also physiological criteria which affect the selection of the suit operating pressure. Based on the presented information, recommendations are given as to the trade selection of the suit operating pressure.