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Reliable data on human metabolic materials are essential for designing environmental control and life support systems (ECLSS) in manned space facilities. This paper presents results from detailed analyses of human metabolic gases, including trace gases, breath, and water vapor collected from twenty healthy subjects of Japanese, and of urine from thirty-three volunteers that was stored at room temperature and at low temperature for seven days. The most SMAC-critical trace gas was carbon monoxide, which was detected in abundance in smoker's breath samples. The urine preserved at room temperature for one week indicated remarkable changes in constituent concentrations, suggesting metabolic activity of microorganisms in the urine sample. These results are being used to develop, test, and operate a trace contaminant removal system and the water reclamation system for a regenerative ECLSS, to evaluate the efficiency of the systems, and to monitor the quality of the closed environment.

Nowadays, space crafts such as a space shuttle take the O2 gas for crew respiration from the earth. However, for long periods of stay in space and far missions such as to the moon, it is not possible to carry sufficient amounts of oxygen. Therefore, there is need to establish other methods of supplying the extra O2 required by the crew under such circumstances. The CO2 reduction system is one method to generate O2 in space.

Improvement of an air revitalization technology is one of the key elements for ECLSS (Environment Control and Life Support System) in development and operation of human space systems. The paper summarizes, as a validation of off-gases “removal” technique, the actual 24hr-continuous operation testing under closed environment. The analysis focuses on the removal characteristics with low CO2 (Carbon Dioxide) concentration. A preliminary closed-loop test of CO2 “reduction” technique was conducted as well. The evaluation includes the data acquisition and analysis of CO2 Reduction Processor which employ Sabatier-reaction and air-cooling. And finally the paper addresses the key issues to further improve this air revitalization system.

This paper presents the results of data measurements for a human material balance, which were conducted as part of a 2-day manned test of a regenerative Environmental Control and Life Support System (ECLSS) in an isolation chamber. The manned test was carried out using a man-rated closed chamber operated in airtight mode at the Tsukuba Space Center of NASDA (National Space Development Agency of Japan), Tsukuba, Japan. A five-person Japanese test crew resided inside the isolation chamber for 48 consecutive hours, living and working along a time schedule based upon Space Shuttle and ISS activities. Data measured on human material needs and effluents included drinking water and beverages, food, urine, feces, water vapor (latent respiration and perspiration), and metabolic trace gases, which were measured directly with scales or estimated indirectly in various ways, such as measuring crew weight change, or measuring air temperature and humidity.

A manned Mars mission will be undertaken in the near future. Then the need for ‘water’ will become critical. One of the solutions to the problem is making use of the resources on Mars. We take notice of CO2 reduction. The method is to generate H2O from CO2, which is major composition of Martian atmosphere. Nominally, the reaction of CO2 reduction is performed at atmospheric pressure on Earth. However, the nominal pressure of the Martian atmosphere is below 10 torr. Therefore, it is necessary to confirm whether the reaction of CO2 reduction can be performed with same efficiency as on Earth. This paper summarizes the results of a fundamental study of CO2 reduction system for a Mars mission.

A 48-hour manned closed environment test was carried out using the closure environmental adaptation training facility (isolation chamber) at Tsukuba Space Center of NASDA (National Space Development Agency of Japan), in Tsukuba-shi, Ibaraki, Japan. This 48-hour closed test was planned and conducted as a preliminary testing for future manned closed tests of advanced life support systems. The purposes of the test were to obtain basic data related to design requirements of regenerative life support systems, which include environmental data of air, water, waste water, and microorganisms inside the chamber, and data on human mass balance and human consumables during the test. Additionally perform integrated evaluation tests on functions and performance of Environmental Control and Life Support System (ECLSS) subsystem research models which have been fabricated and evaluated so far in independent separate tests.

Improvement of an air revitalization technology of ECLSS (Environment Control and Life Support System) is one of the key elements in development and operation of future human space systems. The paper summarizes a trace-contaminant control system which employs “thermal storage / combustion” method for reduction of cabin and equipment-generated off-gases. For comparison, the International Space Station will be equipped with a trace-contaminant system utilizing “oxidization” method with catalyst substances. Preliminary functions of the processor were also evaluated to determine the designing parameters for a space system hardware. The results indicate the capability of processor under large volumes and high concentration of trace gases, and its systematic feasibility.

A Two Stage Reverse Osmosis System in combination with a Membrane Vacuum Distillation Water Processor have been the focus of research for the water reclamation subsystem within the environmental control and life support system (ECLSS). Purification tests on waste water and urine have been conducted. Reverse osmosis (RO) and membrane distillation (MD) remove a high percentage of inorganic salts, but are ineffective for removal of some organic compounds such as alcohols and organic acids. The addition of a photodegradation subsystem with TiO2 photocatalysts to this water reclamation system has potential advantages of cost performance, energy savings, and the capability to remove alcohols and organic acids. In this research, the removal of alcohols and organic acids using TiO2 photocatalysts was investigated and basic data on efficiency of the photocatalysts were acquired.

The photocatalytic oxidation of trace contaminants such as human metabolite gas and outgas from the component materials over a UV-illuminated film of titanium dioxide (TiO2) has been studied to apply for an environmental purification in manned spacecraft. The trace contaminants studied were as follows: methanol, ethanol, acetal-dehyde, toluene, acetone, methane, ethylene, ammonia, 1,4-pentadiene, hydrogen sulfide, carbonyl sulfide, hydrogen and carbon monoxide. Most of these compounds are the representative human metabolic gas. It was found that these compounds except for methane, ethylene, carbonyl sulfide, hydrogen and carbon monoxide are sufficiently removed in the photocatalytic reactor. This report describes the result of the removal test using the photocatalysts performed in National Space Development Agency of Japan/Tsukuba Space Center (NASDA / TKSC).