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The Water Processor Assembly (WPA) for use on the International Space Station (ISS) includes various technologies for the treatment of waste water. These technologies include filtration, ion exchange, adsorption, catalytic oxidation, and iodination. The WPA hardware implementing portions of these technologies, including the Particulate Filter, Multifiltration Bed, Ion Exchange Bed, and Microbial Check Valve, was recently qualified for chemical performance at the Marshall Space Flight Center. Waste water representing the quality of that produced on the ISS was generated by test subjects and processed by the WPA. Water quality analysis and instrumentation data was acquired throughout the test to monitor hardware performance. This paper documents operation of the test and the assessment of the hardware performance.

Due to modifications to the ISS waste water composition, the concentration of volatile organic contaminants in the original baseline has significantly increased in the feed to the Water Processor Assembly (WPA). In parallel, the specified ISS oxygen supply pressure to the WPA increased, resulting in a higher flow rate of oxygen to the WPA catalytic oxidation reactor. Preliminary testing at Hamilton Sundstrand indicated that the higher oxygen flow rate would increase the WPA capacity for volatile organics. Following an analysis of the expected waste water composition, personnel at NASA MSFC and Hamilton Sundstrand conducted a test of a flight-like reactor to assess its capacity for the higher organic loads. The results of this test verify the WPA can accommodate the expected organic load in the ISS waste water with margin.

Since the beginning of the crewed space exploration program, the National Aeronautics and Space Administration (NASA) recognized the need to monitor the composition of a spacecraft cabin atmosphere. Typically, major constituent monitoring has been limited to nitrogen, oxygen, carbon dioxide, and water vapor. For the International Space Station, mass spectroscopy was selected as the baseline technology for this task. Recently, new techniques for monitoring major atmospheric constituents have matured commercially making them viable for crewed spacecraft applications. These techniques have advantages over the mass spectroscopy and electrochemically-based instruments used on board the ISS and Shuttle. Fast laser diode oxygen analysis, solid-state infrared carbon dioxide detection, and thin-film capacitive humidity detection are among the emerging techniques.

Trace contaminant control onboard the International Space Station will be accomplished not only by the Trace Contaminant Control Subassembly but also by other Environmental Control and Life Support System subassemblies. These additional removal routes include absorption by humidity condensate in the Temperature and Humidity Control Condensing Heat Exchanger and adsorption by the Carbon Dioxide Removal Assembly. The Trace Contaminant Injection Test, which was performed at NASA's Marshall Space Flight Center in November and December 1997, investigated the system-level removal of some common spacecraft trace contaminants by these International Space Station systems and subsystem. It is a follow-on to the Integrated Atmosphere Revitalization Test conducted in 1996. An estimate for the magnitude of the assisting role provided by the Carbon Dioxide Removal Assembly and the Condensing Heat Exchanger was obtained.

The International Space Station (ISS) redesign made operational and interface requirements changes to the previous Space Station Freedom baseline. These changes include Oxygen Generation Assembly (OGA) production only on the daylight side of each orbit; nitrogen interface pressure reduction to 100 +/- 10 psia (690 +/- 69 kPa); and available production rates of nominal, nominal +10%, and nominal -10%. In 1994 a test program was initiated at MSFC to verify OGA capabilities for cyclic operation. The liquid feed solid polymer electrolyzer from the 1990 OGA Comparative Test was refurbished and modified as required. This paper describes the operation of the test unit, and presents a discussion of the test data and test results.

The Trace Contaminant Control System (TCCS) removes most hazardous contaminants from the space station atmosphere using a carbon bed, but some must be destroyed in a high temperature catalytic oxidizer. While the oxidizer is protected from catalyst poisons by the carbon bed, if contaminant loads are greater than anticipated, the catalyst may be exposed to a variety of poisons. Thus, we studied the effect of halocarbons, sulfides and nitrogen compounds on the catalytic activity and the products produced. We found that even if poisoning occurs, the catalyst will recover, and will not produce toxic partial oxidation products.

As part of the development of the Environmental Control and Life Support System (ECLSS) for the International Space Station (ISS), the National Aeronautics and Space Administration (NASA) has been conducting extended duration testing of ISS critical ECLSS subassemblies. The ECLSS Life Testing Program (ELTP), which is being conducted in the Core Module Integration Facility (CMIF) at Marshall Space Flight Center (MSFC), began in November 1992. Since that time subassemblies for trace contaminant control, carbon dioxide removal, and urine processing have been operated continuously under simulated ISS loads. The performance of each subassembly and details concerning subassembly test anomalies are provided.

Quality Assurance and Quality Control (QA/QC) is of primary importance for scientific tests which involve the direct contact of test products with human participants. The National Aeronautics and Space Administration (NASA), Marshall Space Flight Center (MSFC), recognized this early in the Water Recovery Test (WRT) for the Space Station Freedom Program. An Analytical Control Program was established by NASA to provide independent oversight of WRT analytical procedures and policies. The program is governed by the Analytical Control Test Plan and Microbiological Methods for Water Recovery Testing (AC Plan), which includes discussions of Inter-Laboratory Verification, Quality Assurance/Quality Control (Laboratory Monitoring), Sample Tracking, Methods Review, Audit Procedures, and Data Validation.