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To effectively develop advanced life support technologies to support humans on future missions into space, the requirements for these missions must first be defined. How many people will go? Where will they go? What risks must be protected against? Since NASA does not officially establish new exploration programs until authorized by Congress, there are no program requirements documents or list of “planned missions” to refer to. Therefore, technology developers must look elsewhere for information on how and where their development efforts and concepts may be used. This paper summarizes the development of several sources designed to help Advanced Life Support researchers working to extend a human presence in space.

This paper focuses on an Air Evaporation Subsystem component of the Water Recovery System being developed at the Johnson Space Center in the Crew and Thermal Systems Division. Specifically, the focus is on the design and testing of the next generation of Air Evaporation Subsystem Engineering Development Unit built after the Lunar-Mars Life Support Test Project Phase III 91day test. The primary objective of testing this next generation Air Evaporation Subsystem was to demonstrate its performance as a Reverse Osmosis brine treatment subsystem by looking at the condensate quality produced from Reverse Osmosis brine and the power required to process the Reverse Osmosis brine. The secondary objectives were to develop optimal operating conditions, to optimize the use of a consumable wick and to retain as much operational data as possible through instrumentation.

A Human Metabolic Simulator (HMS) was developed for use in testing life support air revitalization systems. The developed equipment simulates atmospheric effects of human respiration, perspiration, and metabolism, including consumption of oxygen and production of carbon dioxide, water vapor, and sensible heat. By analogy with human metabolism, oxygen is converted into carbon dioxide and water vapor through catalytic oxidation (combustion) of an organic fuel. Virtually complete combustion of methyl acetate and ethanol fuels was demonstrated using a monolithic precious-metal catalyst at reaction temperatures above 275°C. The HMS has been used successfully in support of NASA's Early Human Testing (EHT) program.

Gas-separation and reverse-osmosis membrane models are being developed in conjunction with membrane testing at NASA JSC. The completed gas-separation membrane model extracts effective component permeabilities from multicomponent test data, and predicts the effects of flow configuration, operating conditions, and membrane dimensions on module performance. Variable feed- and permeate-side pressures are considered. The model has been applied to test data for hollow-fiber membrane modules with simulated cabin-air feeds. Results are presented for a membrane designed for air drying applications. Extracted permeabilities are used to predict the effect of operating conditions on water enrichment in the permeate. A first-order reverse-osmosis model has been applied to test data for spiral wound membrane modules with a simulated hygiene water feed. The model estimates an effective local component rejection coefficient under pseudo-steady-state conditions.