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Water reclamation will be the basis of the closed loop Water Recovery Management (WRM) system on Space Station Freedom (SSF). The life support loop is considered “closed” in the sense that water will not be resupplied to SSF, only food with sufficient water percentage to make-up for inefficiencies in recovery, will be resupplied every 90 days. Oxygen will be generated from water. Mass balance for water, atmosphere and solids pertaining to Environmental Control and Life Support Systems (ECLSS) on SSF has been modeled on a Lotus 123 spreadsheet. Pictoral and numerical representations of the mass balance is shown in Figures 1, 2 and 3 for Manned Tended Configuration (MTC), Permanently Manned Configuration (PMC) and Eight Man Capability Configuration (EMCC), respectively. Parameters are varied to analyze the sensitivity of the mass balance to different hardware combinations, crew configurations and metabolic rates.

Comparative tests were performed by Boeing, Marshall Space Flight Center (MSFC) or Boeing subcontractors to select the optimum technology for waste water processing on Space Station Freedom (SSF). A Thermoelectric Integrated Membrane Evaporation Subsystem (TIMES) and a Vapor Compression Distillation Subsystem (VCDS) were built and tested to compare urine processing capability. A portion of the distillate recovered from pretreated urine; ie, the water which originates in the resupply food, is the basis for closed loop life support on SSF. Several other waste water “Challenge Solutions”, representing laboratory experiment waste water, were also comparatively processed with these two technologies. Performance, water quality and specific energy were compared for conceptual designs intended to function as part of the Water Recovery and Management (WRM) system.

Space Station Freedom (SSF) will be required to vent water during non-quiescent periods. During Man Tended Configuration (MTC), before the Environmental Control and Life Support System (ECLSS) water loop is closed, humidity condensate will be periodically vented. At Permanently Manned Configuration (PMC), water will be vented on contingency if there is excess water on SSF. The thrust due to venting must be minimized to be considered non-propulsive. Also, ice formation and clogging of the vent nozzle must be avoided. Many aspects of the Space Shuttle water vent design were utilized in development of the preliminary SSF water vent design presented in this paper. Design modifications which improved the shuttle vent as well as those necessary for SSF are discussed. The exterior vent location, direction and environment on SSF are unique compared to previous space water vent designs. From data collected in the vent tests and analyses, a finalized SSF water vent design will be developed.