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The extravehicular activity (EVA) requirements for Space Station Freedom and future long-duration space missions demand advanced technologies for the life support subsystems in the astronaut portable life support system (PLSS). A NASA-funded program is currently underway to develop a full-scale, breadboard, regenerate metal oxide carbon dioxide (CO2) removal system. This technology is a promising concept to replace the lithium hydroxide absorber presently used for removing CO2 in the recycled breathing gas in the PLSS, but cannot be efficiently regenerated to be used for another EVA mission. In the metal oxide carbon dioxide removal system, an “active” metal oxide compound, contained within a solid absorbent material, effectively removes the CO2 by chemically reacting to form a metal carbonate during astronaut EVA. The absorbent is then regenerated thermally, by decomposing the resulting carbonate and thereby releasing CO2, to reform the metal oxide.

Waste water pretreatment and recovered water posttreatment techniques are essential for Space Station life support in order to achieve the necessary quality required of recycled water. This paper identifies methods of pre- and post-treatment applicable to spacecraft water recovery by distillation. The results of laboratory investigations show that oxidizers, which typically have been components of urine pretreatment formulas, produce many volatile organic compounds that contaminate the distillate and must later be removed by posttreatment. Two new nonoxidizing urine pretreatment formulas have been tested which minimize the generation of volatile organics and thereby significantly reduce posttreatment requirements. Three posttreatment methods were identified from among the many candidates that look promising (either alone or in combination) for removing organic contaminants in recovered water to nondetectable or barely detectable levels.