Development Testing of a High Differential Pressure (HDP) Water Electrolysis Cell Stack for the High Pressure Oxygen Generating Assembly (HPOGA) 2009-01-2346

The International Space Station (ISS) requires advanced life support to continue its mission as a permanently-manned space laboratory and to reduce logistic resupply requirements as the Space Shuttle retires from service. Additionally, as humans reach to explore the moon and Mars, advanced vehicles and extraterrestrial bases will rely on life support systems that feature in-situ resource utilization to minimize launch weight and enhance mission capability. An obvious goal is the development of advanced systems that meet the requirements of both mission scenarios to reduce development costs by deploying common modules. A high pressure oxygen generating assembly (HPOGA) utilizing a high differential pressure (HDP) water electrolysis cell stack can provide a recharge capability for the high pressure oxygen storage tanks on-board the ISS independently of the Space Shuttle as well as offer a pathway for advanced life support equipment for future manned space exploration missions.

After completing a preliminary system study of the HPOGA, two areas for concentrated development to mitigate program risk were identified: increasing the oxygen output level of the HDP cell from 2000 psig to 3000 psig, and evaluating the system safety and reliability requirements for high pressure oxygen, particularly as they pertain to the design of the electrolysis cell stack. Hamilton Sundstrand is working with NASA to advance the design of the HDP cell hardware to achieve the goal of higher oxygen output pressures and to develop cell stack mock-up assemblies and test protocol to investigate oxygen safety of the HDP cell stack.