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Active control of water behavior is inevitable in the daily life using water, such as hand/face washing and bathing, under the micro-gravity environment in space. Water used for hand-wash and body cleaning clings to the body skin by the surface tension effect, and shed water droplets float around in a washing chamber or in a crew cabin. Water behavior during hand-washing activity in a free air stream was investigated on the NASA KC-135 jet plane introducing 15-20 seconds of micro-gravity condition at parabolic flights. Downward air stream was proved to provide quasi-gravity force to wash down water droplets to the bottom of the chamber. Then the air flow analysis was conducted to predict water droplet behavior in a chamber designed for space hand washer. Disturbance of air flow by the hands inserted from an opening to the chamber was analyzed.

In a closed space system at a ground test facility with environmental control and life support system, carbon dioxide as the products of human and animals respiration is adsorbed and condensed by solid amine and desorbed by aqueous vapor (steam). The carbon dioxide is then reduced to methane and water using hydrogen. Oxygen is recovered from the produced water using an electrolytic system with a solid polymeric membrane and will be reused for respiration. This report describes the result of the fundamental research on individual technological elements: the reduction of carbon dioxide using hydrogen, the decomposition of produced methane and the water electrolysis.

One of the most closely related system to the life of crew in a manned spacecraft is the Environment Control and Life Support System. ECLSS includes such functions as temperature control, humidity control, pressure control, air circulation, carbon dioxide removal and concentration, carbon dioxide reduction and oxygen generation, and contamination control. The first Japanese space habitable system called JEM (Japanese Experimental Module) will be operated by being attached to the U.S. Space Station. Several functions such as CO2 and trace contaminant control are considered in JEM. while others are dependent on the U.S. module. (1)* It is necessary to expand ECLS functions for the future Japanese peculiar space station. Solid Amine water desorbed carbon dioxide removal and concetration test bed using heat recovery provision for the energy saving operation has been successfully tested with more than 99% of carbon dioxide concentration purity.

As the result of the human metabolism in the space station, the carbon dioxide is discharged into the cabin atmosphere. It is indispensable to remove the carbon dioxide and keep it below the allowable level for the life support in a closed environment. The regenerative carbon dioxide removal system is necessary for the space station to decrease the life-cycle cost. The Solid Amine Water Desorbed (SAWD) system is considered as a competitive option among several candidate systems. In the SAWD process, the carbon dioxide gas is adsorbed by the ion-exchange-type solid amine, which is bedded in the canisters, and desorbed by heating the solid amine with the direct steam flow. The adsorption and desorption stage of the canisters are proceeded alternatively by the automatic control. For the application in the space station, the SAWD system shall embody less resources as well as high performance and reliability.

One of the important feature in the Environment Control and Life Support System required to support long duration mission at the Space Station is an oxygen supply for the human metabolism. The recovery of oxygen from the concentrated carbon dioxide through chemical methods will give significant advantage to the Space Station by reducing the supply requirement of the consumables, such as oxygen bottles. Oxygen recovery plants using the Bosch reaction and the Sabatier reaction are experimentally developed and tested. The Bosch reaction has been considered to produce carbon and water directly from carbon dioxide by the hydrogenization process. But it seems to proceed through two steps with carbon monoxide as the intermediate product. Also the total production rate is relatively low and the carbon deposited is less solid. The Sabatier reaction requires two steps to achieve carbon and water, with methane as the intermediate product.