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The design and evaluation of a Vacuum-Swing Adsorption (VSA) system to remove metabolic water and metabolic carbon dioxide from a spacecraft atmosphere is presented. The approach for Orion and Altair is a VSA system that removes not only 100 percent of the metabolic CO2 from the atmosphere, but also 100% of the metabolic water as well, a technology approach that has not been used in previous spacecraft life support systems. The design and development of an Orion Crew Exploration Vehicle Sorbent Based Atmosphere Revitalization system, including test articles, a facility test stand, and full-scale testing in late 2008 and early 2009 is discussed.

To investigate the flammability of human hair, a series of normal and microgravity flame spread tests over human hair were performed in a low-speed flow tunnel to simulate spacecraft ventilation flows (∼20 cm/s). The tunnel atmosphere pressure and oxygen concentration was varied over the range of anticipated exploration atmospheres (21–34% O2 in N2, 8–14.7 psia). While hair is marginally flammable in air, spreading upward but not downward, it burns extremely well at or above 30% O2 in any direction or g-level. The spread is characterized by a quick spread over the surface ‘nap’ or ‘frizz’, followed by continued bulk burning. Two hair ‘styles’ were tested — short hair and long hair — and style does not seem to affect initial nap spread significantly. Opposed and concurrent nap spread rates are similar in 0g under comparable conditions. Oxygen concentration has a strong effect on flame spread rates.

The Vapor Phase Catalytic Ammonia Removal (VPCAR) technology has been previously discussed as a viable option for the Exploration Water Recovery System. This technology integrates a phase change process with catalytic oxidation in the vapor phase to produce potable water from exploration mission wastewaters. A developmental prototype VPCAR was designed, built and tested under funding provided by a National Research Announcement (NRA) project. The core technology, a Wiped Film Rotating Device (WFRD) was provided by Water Reuse Technologies under the NRA, whereas Hamilton Sundstrand Space Systems International performed the hardware integration and acceptance test of the system. Personnel at the Ames Research Center performed initial systems test of the VPCAR using ersatz solutions. To assess the viability of this hardware for Exploration Life Support (ELS) applications, the hardware has been modified and tested at the MSFC ECLS Test Facility.

The design of a vacuum-swing adsorption process to remove metabolic water, metabolic carbon dioxide, and metabolic and equipment generated trace contaminant gases from the Orion Crew Exploration Vehicle (CEV) atmosphere is presented. For Orion, the approach is taken that all metabolic water must be removed by the Sorbent-Based Atmosphere Revitalization System (SBAR), a technology approach that has not been used in previous spacecraft life support systems. Design and development of a prototype SBAR, a facility test stand, and subsequent testing of the SBAR in late 2006 and early 2007 is discussed.

The paper provides a summary of current work accomplished under technical task agreement (TTA) by the Marshall Space Flight Center (MSFC) regarding the Environmental Control and Life Support System (ECLSS) as well as future planning activities in support of the International Space Station(ISS).Current activities computer model development, component design and development, subsystem/integrated system testing, life testing, and government furnished equipment delivered to the ISS program. A long range plan for the MSFC ECLSS test facility is described whereby the current facility would be upgraded to support integrated station ECLSS operations. ECLSS technology development efforts proposed to be performed under the Advanced Engineering Technology Development (AETD) program are also discussed.

We present the development of a semiconductor diode laser spectral absorption based gas species sensor for oxygen concentration measurements, intended for life support system monitoring and control applications. Employing a novel self-compensating, noise cancellation detection approach, we experimentally demonstrate better than 1% accuracy, linearity, and stability for monitoring breathing air conditions with 0.2 second response time. We also discuss applications of this approach to CO2 sensing.

The Lunar-Mars Life Support Test Project (LMLSTP), formerly known as the Early Human Testing Initiative (EHTI), was established to perform the necessary research, technology development, integration, and verification of regenerative life support systems to provide safe, reliable, and self-sufficient human life support systems. Four advanced life support system test phases make up LMLSTP. Phase I of the test program demonstrated the use of plants to provide the atmosphere revitalization requirements of a single test subject for 15 days. The primary objective of the Phase II test was to demonstrate an integrated regenerative life support system capable of sustaining a human crew of four for 30 days in a closed chamber. The third test phase, known as Phase IIA, served as a demonstration of International Space Station (ISS) representative life support technology, supporting a human crew of four for 60 days.

The dual membrane gas trap filter is utilized in the internal thermal control system (ITCS) as part of the pump package assembly to remove non-condensed gases from the ITCS coolant. This improves pump performance and prevents pump cavitation. The gas trap also provides the capability to vent air that is Ingested into the ITCS during routine maintenance and replacement of the International Space Station (ISS) system orbital replacement units. The gas trap is composed of two types of membranes that are formed into a cylindrical module and then encased within a titanium housing. The non-condensed gas that is captured is then allowed to escape through a vent tube in the gas trap housing.

Condensing heat exchangers (CHX) are used in many applications, including space life support systems, to control temperature and humidity. Temperature control is achieved by transfer of the heat load to a circulating coolant. Simultaneously, humidity control is provided by cooling the air below its dew point, and separating the condensed water from the gas flow. In space, the condensate does not drain from the heat exchanger because of the absence of gravity. To overcome this problem, slurping condensing heat exchangers have been developed that combine a hydrophilic coating on the air flow passages and an additional slurping section added to the air outlet of the heat exchanger to achieve efficient air-water separation. For short missions such as those typical for shuttle flights, microbial proliferation in the coatings has not been a major issue, despite the fact that the coatings are continuously moist and an ideal breeding ground for microbial species.

Advanced life support flight experiments have been conceptualized for the International Space Station (ISS). Two of the experiments, a high pressure oxygen generator and a carbon dioxide reduction subsystem, offer high payback potential to the ISS program. This paper documents the cost-benefit analyses for these two experiments.

A test has been completed at NASA's Marshall Space Flight Center (MSFC) to evaluate the Water Recovery and Management (WRM) system and Waste Management (WM) urinal design for the United States On-Orbit Segment (USOS) of the International Space Station (ISS). Potable and urine reclamation processors were integrated with waste water generation equipment and successfully operated for a total of 128 days in recipient mode configuration to evaluate the accumulation of contaminants in the water system and to assess the performance of various modifications to the WRM and WM hardware. No accumulation of contaminants were detected in the product water over the course of the recipient mode test. An additional 18 days were conducted in donor mode to assess the ability of the system to removal viral contaminants, to monitor the breakthrough of organic contaminants through the multifiltration bed, and for resolving anomalies that occurred during the test.

A two year test program has been initiated to evaluate the effects of extended duration operation on a solid polymer electrolyte Oxygen Generator Assembly (OGA); in particular the cell stack and membrane phase separators. As part of this test program, the OGA was integrated into the Marshall Space Flight Center (MSFC) Water Recovery Test (WRT) Stage 10, a six month test, to use reclaimed water directly from the water processor product water storage tanks. This paper will document results encountered and evaluated thus far in the life testing program.

Advanced space suit portable life support systems (PLSS) require high performance fans for the breathing gas ventilation system. AlliedSignal has developed a high speed air bearing fan for this application. This work addresses the development of an advanced electronic controller to drive this fan. Advances in space suit technology required an improved fan controller. The architecture of the controller was modified to enhance performance and facilitate testing in a space environment. These modifications were both physical and functional. To reduce the size of the controller, electrical, electronic and electromechanical (EEE) components were divided into two circuit cards, the housing was redesigned, test points and control knobs were removed, and a higher grade of EEE components were used in the development of the controller. These modifications improved the functional characteristics of the controller.

The Lunar-Mars Life Support Test Project (LMLSTP) Phase III test examined the use of biological and physicochemical life support technologies for the recovery of potable water from waste water, the regeneration of breathable air, and the maintenance of a shirt-sleeve environment for a crew of four persons for 91 days. This represents the longest duration ground-test of life support systems with humans performed in the United States. This paper will describe the test from the inside viewpoint, concentrating on three major areas: maintenance and repair of life support elements, the scientific projects performed primarily in support of the International Space Station, and numerous activities in the areas of public affairs and education outreach.

A hydrophilic, antimicrobial coating has been developed for the condensing heat exchanger and filter assembly (CHXFA), part of the Environmental Control and Life Support System (ECLSS) of the Columbus Orbital Facility (COF), the European laboratory module of the International Space Station (ISS). Condensing heat exchangers (CHX) are used in many applications, including space life support systems, to control temperature and humidity. In space, condensate from the air does not drain from the heat exchanger because of the absence of gravity. To overcome this problem, slurping condensing heat exchangers have been developed which combine a hydrophilic coating on the air flow passages, and an additional slurping section added to the air outlet of the heat exchanger to achieve efficient air-water separation.

A condensing heat exchanger and filter assembly (CHXFA) has been developed by SECAN/AlliedSignal under a contract from Dornier Daimler-Benz as part of a European Space Agency program. The CHXFA is part of the Environmental Control and Life Support System (ECLSS) of the Columbus Orbital Facility (COF), the European Laboratory Module of the International Space Station (ISS). Although the COF CHXFA has a lifetime requirement of 10 years, some of the assembly components have been designated orbital replacement units (ORU's), which means that they must be designed to be replaceable “on-orbit”, in micro-gravity conditions. The CHXFA contains a filter to remove particulates from the air stream, and a differential pressure sensor to monitor pressure drop across the filter. The filter is a limited lifetime ORU, which will be periodically replaced as part of routine maintenance. The differential pressure sensor is also designated as an ORU.

The design of a Vacuum-Swing Adsorption (VSA) system to remove metabolic water and metabolic carbon dioxide from the Orion Crew Exploration Vehicle (CEV) atmosphere is presented. The approach for Orion is a VSA system that removes not only 100 percent of the metabolic CO2 from the atmosphere, but also 100% of the metabolic water as well, a technology approach that has not been used in previous spacecraft life support systems. The design and development of the Sorbent Based Atmosphere Regeneration (SBAR) system, including test articles, a facility test stand, and full-scale testing in late 2007 and early 2008 is discussed.

NASA's Constellation Program, which includes the mission objectives of establishing a permanently-manned lunar Outpost, and the exploration of Mars, poses new and unique challenges for human life support systems that will require solutions beyond the Shuttle and International Space Station state of the art systems. In particular, the requirement to support crews for extended durations at the lunar outpost with limited resource resupply capability will require closed-loop regenerative life support systems with minimal expendables. Planetary environmental conditions such as lunar dust and extreme temperatures, as well as the capability to support frequent and extended-duration Extra-vehicular Activity's (EVA's) will be particularly challenging.

The objective of this work is to determine the dependence of microgravity flame spread on ambient pressure, oxygen concentration, and velocity typical in exploration spacecraft and habitats. Since it is impractical to test a wide range of materials, these characteristics are being determined for major classes of materials. In the current work, a non-charring thin fuel (25-micron thick Shinkolite™ast;) was tested in microgravity to compare with previous results with a charring thin fuel. Microgravity concurrent flame spread tests were performed in a low-speed flow tunnel to simulate spacecraft ventilation flows (7–31 cm/s). The tunnel atmosphere pressure and oxygen concentration was varied over a wide range (21–85% O2, 5–16 psia). Flame spread rate was measured to develop correlations that capture the effects of flow velocity, oxygen concentration, and pressure on the spread rate. The non-charring fuel exhibited a linear dependence on flow, similar to the charring fuel.

The International Space Station (ISS) modules Nodes 2 and 3 are progressing through the design phase into integration, test, and verification. This paper gives a status of the Nodes 2 and 3 Environmental Control and Life Support System (ECLSS) design progress since 1999 (ICES paper 1999-01-2146). The Node 2 Design Review 2 was completed in March 2001. Node 2 is currently in the hardware integration/test phase at Alenia Spazio. The ECLSS for Node 2 includes inter- and intramodule ventilation, temperature and humidity control, distribution of atmosphere samples, low pressure and recharge oxygen and nitrogen, fuel cell and wastewater, and fire detection and suppression. Changes/challenges since 1999 have included the addition of a low temperature loop coolant bypass around the Common Cabin Air Assembly condensing heat exchanger and resolution of common hardware and verification issues. The current status of hardware integration and testing is also discussed.