Search Results

The use of metal oxide absorbents in a portable life support system (PLSS) for regenerative removal of both CO2 and H2O vapor is the focus of an ongoing NASA program. This program addresses the rigorous extravehicular activity (EVA) requirements for Space Station Freedom and future long-duration missions. The concurrent removal of CO2 and H2O vapor can simplify the PLSS by combining the CO2 removal and humidity control functions in one component. A further benefit is that the reversible gas/solid chemical reaction of the removal processes permits a regenerative component that does not vent to space. Recently a preprototype full-scale metal oxide carbon dioxide and humidity remover (MOCHR) and a regeneration module were delivered to NASA Johnson Space Center (JSC). Prior to delivery, preliminary testing of the MOCHR and regeneration module was conducted at AiResearch.

Recent NASA-funded studies of Allied-Signal metal-oxide-based absorbents demonstrated that these absorbents offer a unique capability to remove both metabolic carbon dioxide (CO2) and water (H2O) vapor from breathing air; previously, metal oxides were considered only for the removal of CO2. The concurrent removal of CO2 and H2O vapor can simplify the astronaut portable life support system (PLSS) by combining the CO2 and humidity control functions into one component. A further benefit is that the removal processes are reversible, permitting a regenerative component. Thus, a metal oxide absorbent offers many advantages over the current system, which is nonregenerative and uses separate processes for CO2 and H2O vapor removal. These advantages include lower complexity, lower maintenance, and longer life. The use of metal oxide absorbents for removal of both CO2 and H2O vapor in the PLSS is the focus of an ongoing NASA program.