Advanced Supported Liquid Membranes for CO2 Control in EVA Applications

The development of new, robust, lightweight systems for CO2 removal during EVA is a crucial need for NASA. Current activity is focused on extending mission times without increasing the size and weight of the portable life support system (PLSS). Although CO2 sorbents that can be regenerated during EVA are being studied, these system add "on back" hardware, increasing weight and complexity, and reducing reliability. A simpler approach is to use a membrane system to separate CO2 and H2O from the O2 environment, however separating CO2 from O2 is difficult with standard membranes. However, developing a low pressure liquid sorbent that reversibly absorbs CO2, could facilitate the needed separation. In the Phase I project, Reaction Systems synthesized new CO2 low vapor pressure sorbents that had good reversible CO2 absorption capacity and demonstrated high selectivity for CO2 over O2 in a supported liquid membrane tests. Therefore we demonstrated the feasibility of employing a supported liquid membrane to control CO2 in EVA. In Phase II we will improve the performance by increasing the sorbent loading, reducing its viscosity, and optimizing the membrane support. We will then design and construct a prototype, that is sized to control the metabolic CO2 generation of a single crew member.