Pulse-Modulated Oxygen Pressure Control for Extravehicular Activity Space Suits

This paper presents an adaptation of a pulse-modulated oxygen system for space suit pressure control. Pressure regulation and control for EVA spacesuits has been previously limited to 2-stage mechanical regulators. Mechanical regulators add significant weight to the Portable Life Support System that the astronaut must carry. To enable better mobility during surface operations, a more compact, lighter weight, adaptable solution is proposed. Taking from an emergency oxygen delivery system qualified on a commercial transport aircraft, the Oxygen and PSU Systems division of Collins Aerospace has developed and tested a new compact and lightweight EVA space suit pressure control system. The pressure regulation system utilizes timed pulses of pressurized oxygen to safely regulate the pressure within a space suit free volume under typical leakage and purge flow rates at space suit operational pressures. This paper covers the basic operation of the pressure regulation system as well as initial development test results and next steps.