High Pressure Water Electrolysis for Space Station EMU Recharge

Future space missions will feature extensive EVA operations. In order to avoid the expendables and logistics penalties associated with recharging the EMU's oxygen supply bottles on the ground, a High Pressure Oxygen Recharge System (HPORS), is being developed for use aboard the Space Station. The HPORS will be an electrolysis system capable of providing oxygen at up to 6000 psia without the use of a mechanical compressor, using only the facilities that will be available on board the Space Station (electrical, nitrogen and water). The Hamilton Standard HPORS will be based on a solid polymer electrolyte system which has already demonstrated thousands of hours of performance at 3000 psia in an oxygen generating plant for military applications. The program includes testing of various water feed modes, operating temperatures and current densities in order to optimize the system size, weight and power consumption. New cell and system hardware will be developed to ensure compatibility with high pressure hydrogen and oxygen and to permit operation in a zero gravity environment.