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A finite-difference gas adsorption computer model for CO2, H2O, and N2 on zeolite 5A is discussed. It is part of an effort to predict results, via simulation, of changing a spacecraft CO2 removal system's operational configuration. The mathematical and numerical modeling approach, with emphasis on identification and independent verification of important adsorption physics, is described. The apparatus used to obtain single and multicomponent isotherms, and the subscale packed column bench test used to derive transfer coefficients and verify the model are described. The favorable comparison of simulation and test results show the potential for predictive capability with this modeling approach.

To date, the fire suppression capabilities resident on United States spacecraft have been somewhat limited and highly crew dependent. The spectrum of previous suppression systems extends from the food rehydration water on Mercury and Gemini to the Halon distribution system and portable extinguishers flown on the Orbiter and Spacelab. The challenge presented by Space Station Freedom of assuring crew safety while maintaining a permanent manned presence in space has led to the design of a more extensive fire suppression distribution system. This is the first time that carbon dioxide will be used as the suppressant. This choice partially overcomes present problems of post-fire toxic substance cleanup and monitoring of two phase Halon quantities in microgravity. During the development and testing activities surrounding this system, analyses have been performed to predict system conditions such as suppressant discharge flow rates, suppressant state, and dilution times.

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.