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Catalytic oxidation is an effective means of controlling the build up of ammonia and other trace gas contaminants within closed spaces. However, it sometimes leads to the formation of noxious gases that need to be removed in post-treatment systems. In addition, ammonia removal is an issue when regeneration of water from wastewater is considered since ammonia is a byproduct of urea decomposition. For example, the VPCAR (Vapor Phase Catalytic Ammonia Reduction) advanced water processor system includes an oxidation reactor for the destruction of ammonia and of other volatile organics that are not separated out in the evaporator due to their volatility. The oxidation of ammonia may produce nitrogen, nitrogen oxides (NO and NO2), nitrous oxide (N2O) and water vapor. The Spacecraft Maximum Allowable Concentration (SMAC) for NO and NO2 are respectively 4.5 and 0.5 ppm whereas the Threshold Limit Value (TLV) for N2O is 25 ppm.

Hamilton Sundstrand Space Systems International (HSSSI) is currently under contract with NASA MSFC to design, fabricate and deliver the Water Processor Assembly (WPA) for the International Space Station (ISS). As part of this effort HSSSI has developed an oxidation catalyst for the catalytic reactor assembly in the WPA. This paper discusses full-scale development reactor testing and the status of the life testing of the oxidation catalyst used in the reactor.

This paper presents the results of a program to develop the next generation Vapor Phase Catalytic Ammonia Removal (VPCAR) system. VPCAR is a spacecraft water recycling system designed by NASA and constructed by Water Reuse Technology Inc. The technology has been identified by NASA to be the next generation water recycling system [1]. It is designed specifically for a Mars transit vehicle mission. This paper provides a description of the process and an evaluation of the performance of the new system. The equivalent system mass (ESM) is calculated and compared to the existing state-of-the art. A description of the contracting mechanism used to construct the new system is also provided.