The Effect of Reduced Cabin Pressure on the Crew and the Life Support System

The impacts of reduced atmospheric pressures on crew health, safety, and operations have been evaluated. There are no known long-term physiological or psychological impediments to living at low pressure. Cabin pressures less than 8 psi (55.16 kPa) permit the use of low pressure suits without pre-breathing, which enhances Extra-Vehicular Activity (EVA) and contingency response.

Fire hazards at reduced pressures are not as severe as once feared due to the reduced thermal capacity of the gases, lack of convection, and the tendency of the flame to “cocoon” around the “fuel”. These factors tend to make the fire self extinguishing. Cold plating may be necessary for thermal control of components.

Analysis of gas volume, leakage, and EVA show a significant resupply cost savings and EVA operations simplification. Additional studies are required to establish the optimum cabin pressure.