Search Results

Scientists and engineers at NASA are currently developing flight instruments which will demonstrate oxygen production on the Moon and Mars. REGA will extract oxygen from the lunar regolith, measure implanted solar wind and indigenous gases, and monitor the lunar atmosphere. MIP will demonstrate oxygen production on Mars, along with key supporting technologies including filtration, atmospheric acquisition and compression, thermal management, solar cell performance, and dust removal.

As a key component in its ground test bed capability, NASA's Advanced Life Support Program has been developing a large-scale advanced life support facility capable of supporting long-duration testing of integrated bioregenerative life support systems with human test crews. This facility, the Bioregenerative Planetary Life Support Systems Test Complex (BIO-Plex), is currently under development at the Johnson Space Center. The BIO-Plex is comprised of a set of interconnected test chambers with a sealed internal environment capable of supporting test crews of four individuals for periods exceeding one year. The life support systems to be tested will consist of both biological and physicochemical technologies and will perform all required air revitalization, water recovery, biomass production, food processing, solid waste processing, thermal management, and integrated command and control functions.

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.

An integrated water recovery system was operated for 91 days in support of the Lunar Mars Life Support Test Project (LMLSTP) Phase III test. The system combined both biological and physical-chemical processes to treat a combined wastewater stream consisting of waste hygiene water, urine, and humidity condensate. Biological processes were used for primary degradation of organic material as well as for nitrification of ammonium in the wastewater. Physical-chemical systems removed inorganic salts from the water and provided post-treatment. The integrated system provided potable water to the crew throughout the test. This paper describes the water recovery system and reviews the performance of the system during the test.

An evaporative heat sink has been designed and built by AlliedSignal for NASA's Johnson Space Center. The unit is a demonstrator of a primary heat exchanger for NASA's prototype Crew Return Vehicle (CRV), designated the X-38. The primary heat exchanger is responsible for rejecting the heat produced by both the flight crew and the avionics. Spacecraft evaporative heat sinks utilize space vacuum as a resource to control the vapor pressure of a liquid. For the X-38, water has been chosen as the heat transport fluid. A portion of this coolant flow is bled off for use as the evaporant. At sufficiently low pressures, the water can be made to boil at temperatures approaching its freezing point. Heat transferred to liquid water in this state will cause the liquid to evaporate, thus creating a heat sink for the spacecraft's coolant loop. The CRV mission requires the heat exchanger to be compact and low in mass.

The Spacesuit Water Membrane Evaporator (SWME) is the baseline heat rejection technology selected for development for the Constellation lunar suit. The first SWME prototype, designed, built, and tested at Johnson Space Center in 1999 used a Teflon hydrophobic porous membrane sheet shaped into an annulus to provide cooling to the coolant loop through water evaporation to the vacuum of space. This present study describes the test methodology and planning to compare the test performance of three commercially available hollow fiber materials as alternatives to the sheet membrane prototype for SWME, in particular, a porous hydrophobic polypropylene, and two variants that employ ion exchange through non-porous hydrophilic modified Nafion. Contamination tests will be performed to probe for sensitivities of the candidate SWME elements to ordinary constituents that are expected to be found in the potable water provided by the vehicle, the target feedwater source.

In a crewed spacecraft environment, atmospheric carbon dioxide (CO2) and moisture control are crucial. Hamilton Sundstrand has developed a stable and efficient amine-based CO2 and water vapor sorbent, SA9T, that is well suited for use in a spacecraft environment. The sorbent is efficiently packaged in pressure-swing regenerable beds that are thermally linked to improve removal efficiency and minimize vehicle thermal loads. Flows are controlled with a single spool valve. This technology has been baselined for the new Orion spacecraft, but additional data was needed on the operational characteristics of the package in a simulated spacecraft environment. One unit was tested with simulated metabolic loads in a closed chamber at Johnson Space Center during the latter part of 2006. Those test results were reported in a 2007 ICES paper.

The aim of this study was to explore if fingernail delamination injury following EMU glove use may be caused by compression-induced blood flow occlusion in the finger. During compression tests, finger blood flow decreased more than 60%, however this occurred more rapidly for finger pad compression (4 N) than for fingertips (10 N). A pressure bulb compression test resulted in 50% and 45% decreased blood flow at 100 mmHg and 200 mmHg, respectively. These results indicate that the finger pad pressure required to articulate stiff gloves is more likely to contribute to injury than the fingertip pressure associated with tight fitting gloves.

A generalized computer program for analysis of pressure and composition in multiple volume systems has been under development by the National Aeronautics and Space Administration (NASA) since 1976. This paper describes the most recent developments in the program. These improvements include the expansion of the program to nine volumes, improvements to the model of the International Space Station (ISS) carbon dioxide removal system, and addition of a detailed Sabatier carbon dioxide reduction mode. An evaluation of the feasibility of adding of trace contaminant tracking was also performed. This paper will also present the results of an analysis that compares model predictions with ISS flight data for carbon dioxide (CO2) maintenance.

During the period July 2001 to March 2002, the performance of a water-jacketed high intensity discharge lamp of advanced design was evaluated within a lamp test stand at The University of Arizona (UA), Controlled Environment Agriculture Center (CEAC) in Tucson, Arizona. The lamps and test stand system were developed by Mr. Phil Sadler of Sadler Machine Company, Tempe, Arizona, and supported by a Space Act Agreement between NASA-Johnson Space Center (JSC) and UA. The purpose was for long term testing of the prototype lamp and demonstration of an improved procedure for use of water-jacketed lamps for plant production within the close confines of controlled environment facilities envisioned by NASA within Bioregenerative Life Support Systems. The lamp test stand consisted of six, 400 watt water-cooled, high pressure sodium HID lamps, mounted within a framework.

Bioregenerative life support systems (BLSS) may be necessary for long-term space missions due to the high costs of lifting supplies and equipment into orbit. Much of the recycling to be done in a BLSS involves microbial activity. Although most studies to date have used a culture-based approach to characterize bacteria in BLSS under development, recently work has begun utilizing non-culture-based, DNA approaches to elucidate which microbes are present. In this study, we investigated whether replicate reactors develop replicate microbial communities using a 16S rRNA gene approach and terminal restriction length polymorphism analysis for tubular, nitrifier reactors in use at JSC. Our result suggests that both individual reactor and temporal signals can be detected in the microbial populations. This information may lead to optimization of inoculation procedures and reactor operations conditions to increase predictability and reliability of biological systems.

Biological water processors are currently being developed for application in microgravity environments. Work has been performed to develop a single-phase, gravity independent anoxic denitrification reactor for organic carbon removal [1]. As a follow on to this work it was necessary to develop a gravity independent nitrification reactor in order to provide sufficient nitrite and nitrate to the organic carbon oxidation reactor for the complete removal of organic carbon. One approach for providing the significant amounts of dissolved oxygen required for nitrification is to require the biological reactor design to process two-phase gas and liquid in micro-gravity. This paper addresses the design and test results overview for development of a tubular, two-phase, gravity independent nitrification biological water processor.

This paper provides an overview of the IMMWPS Integrated Ground Test Program, completed at the NASA Johnson Space Center (JSC) during October and November 2001. The JSC Crew and Thermal Systems Division (CTSD) has developed the IMMWPS orbital flight experiment to test the feasibility of a microbe-based water purifier for use in zero-gravity conditions. The IMMWPS design utilizes a Microbial Processor Assembly (MPA) inoculated with facultative anaerobes to convert organic contaminants in wastewater to carbon dioxide and biomass. The primary purpose of the ground test program was to verify functional operations and procedures. A secondary objective was to provide initial ground data for later comparison to on-orbit performance. This paper provides a description of the overall test program, including the test article hardware and the test sequence performed to simulate the anticipated space flight test program. In addition, a summary of significant results from the testing is provided.

The Major Constituent Analyzer (MCA) was activated on-orbit on 2/13/01 and provided essentially continuous readings of partial pressures for oxygen, nitrogen, carbon dioxide, methane, hydrogen and water in the ISS atmosphere. The MCA plays a crucial role in the operation of the Laboratory ECLSS and EVA operations from the airlock. This paper discusses the performance of the MCA as compared to specified accuracy requirements. The MCA has an on-board self-calibration capability and the frequency of this calibration could be relaxed with the level of instrument stability observed on-orbit. This paper also discusses anomalies the MCA experienced during the first year of on-orbit operation. Extensive Built In Test (BIT) and fault isolation capabilities proved to be invaluable in isolating the causes of anomalies. The process of fault isolation is discussed along with development of workaround solutions and implementation of permanent on-orbit corrections.

Gas-separation and reverse-osmosis membrane models are being developed in conjunction with membrane testing at NASA JSC. The completed gas-separation membrane model extracts effective component permeabilities from multicomponent test data, and predicts the effects of flow configuration, operating conditions, and membrane dimensions on module performance. Variable feed- and permeate-side pressures are considered. The model has been applied to test data for hollow-fiber membrane modules with simulated cabin-air feeds. Results are presented for a membrane designed for air drying applications. Extracted permeabilities are used to predict the effect of operating conditions on water enrichment in the permeate. A first-order reverse-osmosis model has been applied to test data for spiral wound membrane modules with a simulated hygiene water feed. The model estimates an effective local component rejection coefficient under pseudo-steady-state conditions.

CO2 removal, recovery and reduction are essential processes for a closed loop air revitalization system in a crewed spacecraft. Typically, a compressor is required to recover the low pressure CO2 that is being removed from the spacecraft in a swing bed adsorption system. This paper describes integrated tests of a Temperature-Swing Adsorption Compressor (TSAC) with high-fidelity systems for carbon dioxide removal and reduction assemblies (CDRA and Sabatier reactor). It also provides details of the TSAC operation at various CO2 loadings. The TSAC is a solid-state compressor that has the capability to remove CO2 from a low-pressure source, and subsequently store, compress, and deliver it at a higher pressure. TSAC utilizes the principle of temperature-swing adsorption compression and has no rapidly moving parts.

Biological wastewater processing has been under investigation by AlliedSignal Aerospace and NASA Johnson Space Center (JSC) for future use in space. Testing at JSC in the Hybrid Regenerative Water Recovery System (HRWRS) in preparation for future closed human testing has been performed. Computer models have been developed to aid in the design of a new four-person immobilized cell bioreactor. The design of the reactor and validation of the computer model is presented. In addition, the total organic carbon (TOC) computer model has been expanded to begin investigation of nitrification. This model is being developed to identify the key parameters of the nitrification process, and to improve the design and operating conditions of nitrifying bioreactors. In addition, the model can be used as a design tool to rapidly predict the effects of changes in operational conditions and reactor design, significantly reducing the number and duration of experiments required.

For over 40 years, NASA has been putting humans safely into space in part by minimizing microbial risks to crew members. Success of the program to minimize such risks has resulted from a combination of engineering and design controls as well as active monitoring of the crew, food, water, hardware, and spacecraft interior. The evolution of engineering and design controls is exemplified by the implementation of HEPA filters for air treatment, antimicrobial surface materials, and the disinfection regimen currently used on board the International Space Station. Data from spaceflight missions confirm the effectiveness of current measures; however, fluctuations in microbial concentrations and trends in contamination events suggest the need for continued diligence in monitoring and evaluation as well as further improvements in engineering systems. The knowledge of microbial controls and monitoring from assessments of past missions will be critical in driving the design of future spacecraft.

This ground-based study compared the risk of microbubbles during decompression under simulated space extravehicular activities (EVA) after three days of six-degree head-down bed rest with three days of ambulatory control. Test subjects were exposed to a pressure of 44.8 kPa (6.5 psi), breathed 100% oxygen, and exercised at reduced pressure either in the supine (during experimental) or upright (control) position. Circulating microbubbles were monitored by a precordial Doppler ultrasound device, and were found in 52% (12/23) of control and 26% (6/23) of experimental exposures. Survival analysis using Cox proportional hazards regression showed that there was 0.22 times (95% confidence interval=0.07-0.68) reduction in the risk of high grade microbubbles after bed rest, compared to controls (p=0.004). This finding is of importance in evaluating the risk of DCS during EVA.

Supply of oxygen (O2) and hydrogen (H2) by electrolyzing water in space will play an important role in meeting the National Aeronautics and Space Administration's (NASA's) needs and goals for future space missions. Both O2 and H2 are envisioned to be used in a variety of processes including crew life support, spacecraft propulsion, extravehicular activity, electrical power generation/storage as well as in scientific experiment and manufacturing processes. Life Systems, Inc., in conjunction with NASA, has been developing an alkaline-based Static Feed Electrolyzer (SFE). During the development of the water electrolysis technology over the past 23 years, an extensive engineering and scientific data base has been assembled.