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The tolerance of edible plants against low atmospheric pressure has been examined. With continuous exposure to low atmospheric pressure for several days, shoot and root growth was clearly confirmed. Furthermore, the partial pressure of oxygen had increased during the light period, and the partial pressure of carbon dioxide had increased during the dark period. These results insist that plants can subsequently have tolerance against low atmospheric pressure and enable to perform photosynthesis. Therefore, we conclude that plants are available under low atmospheric pressure as both a circulation system and food., 資料番号: AA0063706104

第59回宇宙科学技術連合講演会（2015年10月7日-9日. かごしま県民交流センター), 鹿児島市, 鹿児島, The Japan Aerospace Exploration Agency (JAXA) has been studying and developing Environmental Control and Life Support System (ECLSS) technologies, in particular an air regeneration system to support long-duration manned space missions beyond Earth orbit. Our goal is to develop an air regeneration system that is lightweight, compact and energy efficient. The air regeneration system comprises a water electrolysis subsystem for O2 generation, a CO2 removal subsystem and a CO2 reduction subsystem. In this paper, we report on improvements to the water electrolysis subsystem. The water electrolysis cell uses a solid polymer electrolyte (SPE) developed by JAXA and a water/gas separator to separate generated H2 from circulated water using a membrane. A previous design of the water electrolysis system had a number of issues. One was an increasing concentration of H2 in the generated O2 gas due to the low temperature of the circulated water. To address this issue, we improved the catalyst of the membrane electrode assembly (MEA) and as a result, low hydrogen concentrations were maintained at all temperatures. A further issue was a large pressure drop through the water/gas separator. By creating a stack of four separators and improving the internal flow path, the pressure drop was reduced to approximately one third of that of the previous design, and it became possible to circulate water at a high flow rate., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AC1600092000, レポート番号: JSASS-2015-4291

Water-Energy-Cycle Space Propulsion System was defined as a space system supporting long-term and large-scale space activity. On the test stand which can change a posture, the principle model was assembled, the posture was changed in +/- 1 G, and the performance of a principle model was compared. As a result of experimenting in +/- 1 G, when it operated normally in any case and it did separation of gas and a liquid on the level of each subsystem, under terrestrial gravity environment, it came out enough and a certain thing was understood. The feel referred to as operating satisfactory also under the micro-gravity environment of space was acquired as a result of consideration. The Proton Exchange Membrane (PEM) electrolyzer and the fuel cell which were used for the experiment made the regenerative fuel cell as an experiment, and used the single cell for this research in normal temperature. The phenomenon of ignition delay has been improved by the device of injection structure, and adjustment of injection timing in the catalyst ignition experiment of hydrogen/oxygen thruster. Moreover, it turns out that water adheres to the catalyst layer surface after a combustion end., 資料番号: AA0049500064, レポート番号: JAXA-SP-06-006

The Water-Energy-Cycle Space Propulsion System is a multifunctional system that stores electric energy and provides thermal energy and propulsion. It functions only by installing water as a resource. We have been studying the plant factory as an application that makes the best use of this feature. The plant factory using water cycle system is suitable for manned space activity because it produces food, absorbs CO2, and supplies oxygen from water and sunlight. Artificial light such as LED is used in the plant factories. LED pulse lighting improves the photosynthesis speed, and it can reduce electric power consumption. In this research, we confirmed the effect of LED pulse lighting by measuring photosynthesis speed and we tried to diagnose the plant status by measuring the bioelectric potential of plant., 資料番号: AA0049121015

Our 'Space Propulsion and Power System Using Water-Energy-Cycle' stores hydrogen and oxygen electrolyzed from water by solar cells during sunshine period, and as the reverse cycle, these gases provided into fuel cells generate electrical power and water during sunshade period. The stored hydrogen and oxygen are also usable as rocket propellants, and furthermore, the water and oxygen are available for the life support system at emergencies of manned space activities. Our study is to design a propulsion & power system originated from safe and non-toxic water that is one of the simplest compound on Earth, and to perform ground-based experimental testing toward a sub-scale model. The performance verification in the Space Station is necessary for the end but based upon the fundamental researches so far, we estimate the flight performances from testing such as optimization of single-cell performance, configuration of electrolysis and fuel-cell (reversible single cell or two separate cells), rocket engine combustion in vacuum, overall systems checkout, and weightlessness simulation (on the tri-axially relatable test-stand)., 資料番号: AA0049121014

The final goal of Manned Space Activity is for people to live in areas far from the earth without help from the earth. However its technology will be necessary when a manned space base can be made beyond Mars. Thus in the present research, a few mile stones are made for near future technology, that is, SEPAL (SElf-contained PArtially-circulated Life support system), Space Environment Utilization and SEFUL (SElf-contained FUlly-circulated Life support system). In the research on SEPAL, physico-chemical process which is promising technology is being studied. In order to increase flight opportunities, a self-contained system is considered. In the research on Space Environment Utilization, studies of four subjects, which are candidates of Kibo utilization research theme, and promising ones are continued. As aims of these studies, not only scientific aspects but also understanding of the interface conditions of manned space activities are included. In the research on SEFUL, as the utilization of plant product from biological system, conceptual estimation of a system to obtain animal protein is made., 資料番号: AA0048129022, レポート番号: JAXA-RM-04-011

第25回宇宙利用シンポジウム(2009年1月14日-15日, 宇宙航空研究開発機構宇宙科学研究本部相模原キャンパス), The Twenty-fifth Space Utilization Symposium (January 14-15, 2009: ISAS/JAXA Sagamihara, Japan), A space propulsion system and a power generation system using Water-Energy-Cycle of multi-hundred watts are designed and integrated into a standard rack unit compatible to the Space Station "KIBOU". This newly conceptualized system stores hydrogen and oxygen electrolyzed from water by solar cell energy, while in the reverse cycle, these gases are provided into fuel cells to provide electrical power and water. The stored hydrogen and oxygen are also usable for rocket propellants, and furthermore, the water and oxygen are available for the life support system during manned space activities. The stored hydrogen can be also used as reduction of minerals in the lunar base activities in the future. This time, the unit was integrated and dedicated to several ground-based tests with different attitudes against 1 G gravity direction., 形態: カラー図版あり, 資料番号: AA0064297104

資料番号: AA0033392023

第58回宇宙科学技術連合講演会（2014年11月12日-14日. 長崎ブリックホール), 長崎市, 長崎県, To support long-duration manned space missions beyond Earth orbit, recycling life support systems will be necessary to reduce the mass of consumables required.JAXA is therefore developing life support technologies for future manned space missions such as water purification, CO2 reduction and oxygen generation.JAXA is currently studying an air revitalization system for an on-orbit demonstration on the International Space Station (ISS) early in the extended ISS operation period (2015-2020) to support proposed post-ISS missions such as manned lunar or asteroid exploration and an Earth-Moon Lagrange point (EML1) space station. Regenerative functions include oxygen recovery from carbon dioxide using a combination of CO2 reduction by the Sabatier process and O2 generation by electrolysis. Water electrolysis is a key technology because the hydrogen it produces is used for CO2 reduction and the oxygen is essential for human respiration. A simple method for obtaining dry oxygen from electrolysis is aiso important. This paper presents the air re-vitalization system for the demonstarator and gives details of water electrolysis in microgravity. In this paper, we investigate SPE (solid polymer electrolyte) water electrolysis and discuss the 'Cathode Feed' operation of an electrolyzer. Although water is usually supplied to the anode side of ground-based electrolysis cells (anode feed), we adopt cathode feed to obtain dry oxygen. The performance of the cathode feed cell can achieve its design target by flushing the gas bubbles that adhere to the electrode. A membrane type water/gas separator consisting of hydrophilic and hydrophobic membranes was used., 資料番号: AC1500063000, レポート番号: JSASS-2014-4389

Microgravity environment in space has been recently utilized as the field to investigate the gravitational biology. In 2003, the experiment was operated aboard the space shuttle Columbia, STS-107 for the study on the development and swimming behavior of Medaka fry under microgravity in space (Niihori et al., 2004). In this experiment a closed ecological system was developed in order to maintain the eggs and hatched fry under microgravity. The system was prepared based on the ABS, Autonomous Biological System (Poynter et al., 2001; Ishikawa et al., 1996, 1998a, b) and maintained the ecological system during flight mission (16 days). This was the first success of a closed ecological system used for the life support of the vertebrate in space. This system provided mechanically quiet environment and was very useful to study the behavior of animals under microgravity. However, the details of ecosystem were not investigated because it was used as a part of experimental equipment. We study the Ecosystem in order to expand the utilization and develop the system for long-lasting space experiment as a biological-device with small fish, Heterandria formosa instead of Medaka. The newly developed closed system for H. formosa can maintain the life of an adult fish at least 30 days. We would like to propose that this system as a closed life support system for long-lasting space experiment with fish and as a biological transporter for space exploration., 資料番号: AA0063349094

In order to investigate of a possibility of utilizing silkworm for the space agriculture, breeding of silkworms under low pressure of 10 kPa in pure oxygen was attempted. Silkworms were successfully hatched under low pressure. Growth rates in a few cases under low pressure were smaller than those of control. In the case of exposing a silkworm in last stage to low pressure, a silkworm spun a cocoon or became a pupa successfully. Influence of low pressure upon silkworms was suggested., 資料番号: AA0063349114