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Development of new air revitalization system (ARS) technology can initially be performed in a subscale laboratory environment, but in order to advance the maturity level, the technology must be tested in an end-to-end integrated environment. The Air Revitalization Technology Evaluation Facility (ARTEF) at the NASA Johnson Space Center (JSC) serves as a ground test bed for evaluating emerging ARS technologies in an environment representative of spacecraft atmospheres. At the center of the ARTEF is a hypobaric chamber which serves as a sealed atmospheric chamber for closed loop testing. A Human Metabolic Simulator (HMS) was custom-built to simulate the consumption of oxygen, and production of carbon dioxide, moisture and heat by up to eight persons. A variety of gas analyzers and dew point sensors are used to monitor the chamber atmosphere and the process flow upstream and downstream of a test article. A robust vacuum system is needed to simulate the vacuum of space.

Similar to finding a home on Earth, location is important when selecting where to set up an exploration outpost. Essential considerations for comparing potential lunar outpost locations include: (1) areas nearby that would be useful for In-Situ Resource Utilization (ISRU) oxygen extraction from regolith for crew breathing oxygen as well as other potential uses; (2) proximity to a suitable landing site; (3) availability of sunlight; (4) capability for line-of-sight communications with Earth; (5) proximity to permanently-shadowed areas for potential in-situ water ice; and (6) scientific interest. The Mons Malapert1 (Malapert Mountain) area (85.5°S, 0°E) has been compared to these criteria, and appears to be a suitable location for a lunar outpost.

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.

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.

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.

The Equivalent System Mass (ESM) metric developed by NASA describes and compares individual system impact on a closed system in terms of a single parameter, mass. The food system of a Mars mission may encompass a large percentage of total mission ESM, and decreasing this ESM would be beneficial. Yeast breads were made using three methods (hand & oven, bread machine, mixer with dough hook attachment & oven). Flat breads were made using four methods (hand & oven, hand & griddle, mixer with dough hook attachment & oven, mixer with dough hook attachment & griddle). Two formulations were used for each bread system (scratch ingredients, commercial mix). ESM was calculated for each of these scenarios. The objective of this study was to compare the ESM of yeast and flat bread production for a Martian surface outpost. Method (equipment) for both types of bread production was demonstrated to be the most significant influence of ESM when one equipment use was assumed.

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.

There are many sources of air pollution that can threaten air quality during space missions. The International Space Station (ISS) is an extremely complex platform that depends on a multi-tiered strategy to control the risk of excessive air pollution. During the seven missions surveyed by this report, the ISS atmosphere was in a safe, steady-state condition; however, there were minor loads added as new modules were attached. There was a series of leaks of octafluoropropane, which is not directly toxic to humans, but did cause changes in air purification operations that disrupted the steady state condition. In addition, off-nominal regeneration of metal oxide canisters used during extravehicular activity caused a serious pollution incident.

Conceptual designs for a space suit Personal Life Support Subsystem (PLSS) were developed and assessed to determine if upgrading the system using new, emerging, or projected technologies to fulfill basic functions would result in mass, volume, or performance improvements. Technologies were identified to satisfy each of the functions of the PLSS in three environments (zero-g, Lunar, and Martian) and in three time frames (2006, 2010, and 2020). The viability of candidate technologies was evaluated using evaluation criteria such as safety, technology readiness, and reliability. System concepts (schematics) were developed for combinations of time frame and environment by assigning specific technologies to each of four key functions of the PLSS -- oxygen supply, waste removal, thermal control, and power. The PLSS concepts were evaluated using the ExtraVehicular Activity System Sizing Analysis Tool, software created by NASA to analyze integrated system mass, volume, power and thermal loads.

Approximately 50% of the water consumed by International Space Station crewmembers is water recovered from cabin humidity condensate. Condensing heat exchangers in the Russian Service Module (SM) and the United States On-Orbit Segment (USOS) are used to control cabin humidity levels. In the SM, humidity condensate flows directly from the heat exchanger to a water recovery system. In the USOS, a metal bellows tank located in the US Laboratory Module (LAB) collects and stores condensate, which is periodically off-loaded in about 20-liter batches to Contingency Water Containers (CWCs). The CWCs can then be transferred to the SM and connected to a Condensate Feed Unit that pumps the condensate from the CWCs into the water recovery system for processing. Samples of the condensate in the tank are collected during the off-loads and returned to Earth for analyses.

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.

Two simulated spacecraft water systems are being used to evaluate the effectiveness of iodine for controlling microbial contamination within such systems. An iodine concentration of about 2.0 mg/L is maintained in one system by passing ultrapure water through an iodinated ion exchange resin. Stainless steel coupons with electropolished and mechanically-polished sides are being used to monitor biofilm formation. Results after three years of operation show a single episode of significant bacterial growth in the iodinated system when the iodine level dropped to 1.9 mg/L. This growth was apparently controlled by replacing the iodinated ion exchange resin, thereby increasing the iodine level. The second batch of resin has remained effective in controlling microbial growth down to an iodine level of 1.0 mg/L. Scanning electron microscopy indicates that the iodine has impeded but may have not completely eliminated the formation of biofilm.

Debris in the Orbiter crew compartment of early Shuttle missions created crew health concerns and physiological discomfort, and was the cause of some equipment malfunctions. Debris from Orbiters during flight and processing was analyzed, quantized, and evaluated to determine its source. Records were kept on the amount of debris vacuumed by the crew during on-orbit cleaning and the amount found on air-cooled avionics boxes during ground turnaround. After ground turnaround operations at Kennedy Space Center and Palmdale were reviewed from a facility, materials use, and materials control standpoint, the following remedial steps were taken.

Controlling microbial growth and biofilm formation in spacecraft water-distribution systems is necessary to protect the health of the crew. Methods to decontaminate the water system in flight may be needed to support long-term missions. We evaluated the ability of iodine and ozone to kill attached bacteria and remove biofilms formed on stainless steel coupons. The biofilms were developed by placing the coupons in a manifold attached to the effluent line of a simulated spacecraft water-distribution system. After biofilms were established, the coupons were removed and placed in a treatment manifold in a separate water treatment system where they were exposed to the chemical treatments for various periods. Disinfection efficiency over time was measured by counting the bacteria that could be recovered from the coupons using a sonication and plate count technique. Scanning electron microscopy was also used to determine whether the treatments actually removed the biofilm.

The incidence of decompression sickness (DCS) in space appears to be less than that predicted to occur on the basis of ground based altitude chamber trials. Our current work uses six hours of chair rest adynamia and likewise produces fewer gas bubbles when compared to standing in a cross over study. Mild exercise during oxygen prebreathe is also very efficacious in reducing DCS and bubble formation (measured by Doppler ultrasound). The effect is postulated to be the result of the alteration in the populations of tissue micronuclei such that the radii are reduced. Surface tension then becomes too great for bubble growth from the existing inert gas partial pressures.

The Early Human Testing Initiative (EHTI) Phase I Human Test, performed by the Crew and Thermal Systems Division at Johnson Space Center, demonstrated the ability of a crop of wheat to provide air revitalization for a human test subject for a 15-day period. The test demonstrated three different methods for control of oxygen and carbon dioxide concentrations for the human/plant system and obtained data on trace contaminants generated by both the human and plants during the test and their effects on each other. The crop was planted in the Variable Pressure Growth Chamber (VPGC) on July 24, 1995 and the test subject entered the adjoining airlock on day 17 of the wheat's growth cycle. The test subject stayed in the chamber for a total of 15 days, 1 hour and 20 minutes. Air was mixed between the plant chamber and airlock to provide oxygen to the test subject and carbon dioxide to the plants by an interchamber ventilation system.

We have conducted experiments on 16 lunar soils and 3 lunar volcanic glass samples to study the extraction of oxygen, an important resource for future lunar bases. The samples were chosen to span the range of composition and mineralogy represented in the Apollo collection. Each sample was reduced in flowing hydrogen for 3 hours at 1050°C. The dominant effect was reduction of Fe2+ (as FeO) in minerals and glass to iron metal, with concomitant release of oxygen. Oxygen extraction was strongly correlated with initial Fe2+ abundance but varied among mineral and glass phases. The experimental reduction of lunar soil and glass provides a method for assessing the oxygen production potential for sites on the lunar surface from lunar orbit. Our results show that oxygen yield from lunar soils can be predicted from knowledge of only one parameter, total iron content. This parameter can be measured from orbit by gamma ray spectrometry or multispectral imaging.

Recent efforts have been pursued to establish the usefulness of Space Shuttle Orbiter lithium hydroxide (LiOH) canisters beyond their certified two-year shelf life, at which time they are currently considered “expired.” A stockpile of Orbiter LiOH canisters are stowed on the International Space Station (ISS) as a backup system for maintaining ISS carbon dioxide Canisters with older (CO2) control. Canister with older pack dates must routinely be replaced with newly packed canisters off-loaded from the Orbiter Middeck. Since conservation of upmass is critical for every mission, the minimization of canister swap-out rate is paramount. LiOH samples from canisters with expired dates that had been returned from the ISS were tested for CO2 removal performance at the NASA Johnson Space Center (JSC) Crew and Thermal Systems Division (CTSD). Through this test series and subsequent analysis, performance degradation was established.

Wheat is a candidate crop for the Advanced Life Support (ALS) system, and cereal grains and their products will be included on long-term space missions beyond low earth orbit. While the exact supply scenario has yet to be determined, some type of post-processing of these grains must occur if they are shipped as bulk ingredients or grown on site for use in foods. Understanding the requirements for processing grains in space is essential for incorporating the process into the ALS food system. The ESM metric developed by NASA describes and compares individual system impact on a closed system in terms of a single parameter, mass. The objective of this study was to compare the impact of grain mill type on the ESM of producing yeast and flat breads. Hard red spring wheat berries were ground using a Brabender Quadrumat Jr. or the Kitchen-Aid grain mill attachment (both are proposed post-harvest technologies for the ALS system) to produce white and whole wheat flour, respectively.

NASA-JSC is evaluating planetary mission scenarios where plants will provide the majority of the diet for the crew. The requirements of both plants and crew diet need to be integrated in the development of the final food system. Plant growth has limitations in type and quantity of crops to be produced while diets must meet palatability and nutritional requirements as well as limited processing labor, equipment and power. A plan is presented for the development of a food system based heavily on grown crops. Although the steps taken in the development are applicable to the design of any long duration flight food system. The process begins with the development of a food list, followed by preliminary menu design, nutritional analysis and finally menu testing.