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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.

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.

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.

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).