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The Water Recovery and Management (WRM) system on Space Station Freedom (SSF) is modeled using SINDA '85/FLUINT to determine its hydraulic operation characteristics, and to verify the design flow and pressure drop parameters. The WRM system consists of the Potable Use water, Waste water, and Fuel Cell loops, as well as the Fluid Management System and experiments, which are not included in this model. This system will be the first closed loop water regeneration system used in space flight. The water is driven in each loop by storage tanks pressurized with cabin air, and is routed through the system to the desired destination. The model considers the flow of water from the storage tanks to the use points and back, as determined by each individual flow diagram for the Permanently Manned Configuration (PMC) phase of SSF.

The Space Station Freedom Program (SSFP) has undergone major design changes within the last year due to reduced budget appropriations imposed by Congress. This paper outlines the impacts of the design changes on the Environmental Control and Life Support System (ECLSS), with emphasis on the system aspects of the ECLSS. Brief descriptions of design impacts to all six ECLSS subsystems are provided in addition to interactions with other distributed systems such as Data Management, Electrical Power, and Man Systems. The assembly sequence for SSF is addressed with emphasis on key flights with respect to the ECLSS.

To date, almost all water used by the crew during space flight has been transported from Earth or generated in-flight as a by product of fuel cells and used for relatively short periods. With the United States' commitment to a permanent manned presence in space, this is no longer adequate. In order to resolve this problem, a plan for nearly complete recovery and recycling of water on-orbit has been formulated. Closed-loop water recovery on a scale applicable to a manned space station was first studied in the late 1960s and early 1970s. These tests, conducted with breadboard and early prototype equipment, demonstrated the feasibility of sustaining humans in a closed environment by a regenerative Environmental Control and Life Support System (ECLSS). However, increased awareness of potential hazards associated with long-term reuse of reclaimed water has resulted in the recognition that additional characterization of closed-loop water recovery systems and products is essential.

This paper presents an updated overview of the Computer Aided System Engineering and Analysis (CASE/A)-ECLSS series modeling package. CASE/A is an Environmental Control and Life Support System (ECLSS) and Active Thermal Control System (ATCS) analysis and trade study tool developed primarily for VAX mainframe usage. The program was developed under NASA MSFC contract NAS8-36407 and is currently being used by MSFC and selected support contractors to support their Space Station Freedom WP-01 ECLSS preliminary design modeling activities. Many new additions and enhancements to the program have been incorporated since the first paper was presented on the topic three years ago. An extensive components verification program was completed to assure component modeling validity based on actual test data from the Phase II comparative test program recently completed at MSFC.