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Hamilton Standard Space Systems International, Inc. (HSSSI) is under contract to NASA Marshall Space Flight Center (MSFC) to develop an Oxygen Generation Assembly (OGA) for the International Space Station (ISS). The International Space Station Oxygen Generation Assembly (OGA) electrolyzes potable water from the Water Recovery System (WRS) to provide gaseous oxygen to the Space Station module atmosphere. The OGA produces oxygen for metabolic consumption by crew and biological specimens. The OGA also replenishes oxygen lost by experiment ingestion, airlock depressurization, CO2 venting, and leakage. As a byproduct, gaseous hydrogen is generated. The hydrogen will be supplied at a specified pressure range above ambient to support future utilization. Initially, the hydrogen will be vented overboard to space vacuum. This paper describes the OGA integration into the ISS Node 3.

An Extravehicular Mobility Unit (EMU) Portable Life Support Subsystem (PLSS) has among its primary functions requirements to remove metabolically generated heat and respiratory byproducts to maintain an atmosphere which is both physiologically safe and comfortable for the Extravehicular Activity (EVA) crew person. The EMU thermal control system interacts with the crew member through the Liquid Cooling and Ventilation Garment (LCVG), which circulates the ventilation gas to remove carbon dioxide, humidity, and trace contaminants, and the cooling water to remove metabolically produced heat. To maintain thermal comfort, the crew member may vary the LCVG inlet water temperature. The thermal interaction between the EMU and the crew member is very complex and highly dependent upon the individual crew member's cooling preferences and the exterior environment.

To support expected Space Station Extravehicular Activity (EVA) requirements, the Shuttle Extravehicular Mobility Unit (EMU) performance capability must provide a much greater operational endurance than was originally required for the Space Shuttle program: 25 EVAs in 180 days versus up to 3 EVAs in 15 days, all without servicing on earth. Recently, the Shuttle EMU has successfully completed a 25 EVA manned vacuum chamber test series which is the culmination of an endurance demonstration that also included Life Extension Testing of certain life limited components and unmanned life support system chamber testing. This paper discusses laboratory component endurance life testing, manned one-atmosphere suit testing, unmanned chamber testing as well as 25 EVA manned vacuum chamber testing. Emphasis will be placed upon test philosophy, test objectives, hardware utilized, problems encountered, solutions developed during testing and test team organization.

Shuttle Extravehicular Mobility Unit (EMU) studies have shown that the thermal interaction between the crewperson, liquid cooling garment and EMU thermal management system is highly transient in nature. Recent investigations of these phenomena provide a better understanding which have helped improve thermal comfort in the present system. Analyses show that the key to thermal comfort is understanding the interaction between physiological responses and EMU system thermal transients. A test program was conducted to evaluate the theorized causes of discomfort and proposed corrective actions. Several EMU thermal management related modifications were utilized in the Hubble Space Telescope repair mission where five, two crewperson ExtraVehicular Activities (EVAs) were conducted without any thermal discomfort in a mildly cold environment.

The current Shuttle EMU (Extravehicular Mobility Unit) uses expendable water to provide cooling to the EMU. For Space Station Freedom (SSF), one potential source of this water is the SSF potable water processor (PWP). Concerns exist about utilizing the SSF water for the EMU sublimator because the SSF PWP effluent may contain low soap concentrations. Traces of soap-like compounds (surfactants) have been shown to affect EMU sublimator performance at low concentrations. Results of testing indicate that a subscale sublimator functions equally well with both SSF PWP effluent and Shuttle quality deionized water. Furthermore, only minor performance anomalies are observed with water purposely spiked with maximum allowable concentrations of baseline shower soap. Not all surfactants are equally detrimental to sublimator performance. Testing with a full scale sublimator is the next step.