@inproceedings{oai:jaxa.repo.nii.ac.jp:00008132, author = {都木, 恭一郎 and 橋本, 保成 and 藤田, 孝 and 石井, 忠司 and Toki, Kyoichiro and Hashimoto, Yasunari and Fujita, Takashi and Ishii, Tadashi}, book = {第23回宇宙エネルギーシンポジウム 平成15年度, The 23rd ISAS Space Energy Symposium March 9, 2004}, month = {Jun}, note = {A water cycle space propulsion system has been studied for a space flight test onboard the space station Japanese Experimental Module KIBOU. The water cycle space propulsion system is characterized as a clean, safe and non-toxic system being friendly to the personnel, because the power source is based upon the solar energy in space and the water is the working fluid on the ground. In the future, the water cycle can be merged into a life support system in space as well as the propulsion and power system. This test bed on the KIBOU will provide a 250 W water electrolysis capability and the corresponding power for fuel cell as its reverse cycle. During the sunshine, the water electrolysis process is activated for 45 min of half a revolution around the earth, and the rest of the revolution during the sunshade is dedicated for a propulsion experiment using GH2/GO2 and a fuel cell experiment. The expected installation is on a pallet-type bus structure interface with a deployable exclusive solar array for this experiment and other common interfaces to the exposed facility of KIBOU. Presently, some basic experiments were finished on the ground for a single reversible cell at a room temperature environment. The fuel cell mode provides 0.1 A/sq cm current density at output voltage of 0.6 V while the water electrolysis mode provides 0.5 g/h throughput at 0.3 W/sq cm. All the water cycle system is placed on a 2-axis rotatable circular plate which can change the gravitational direction to the system so as to apply +/- 1 G. On the other hand, the ignition capability of GH2/GO2 has been greatly improved using a catalytic combustion method at the upstream of the main combustion chamber where the secondary GH2 is injected. So-called an ignition delay has been completely eliminated from the present ignition experiments. The water cycle space propulsion system will be composed of a 2 N GH2/GO2 thruster and two cells. One is used for fuel cell and the other is for electrolysis. The water filling/drain, if adopted a single cell configuration, is very much troublesome process. The pressurization of both 16 litter H2 and 8 litter O2 gaseous tanks should be limited less than 7 MPa because of the safety requirement for pressure vessels. The water tank is 4 litter. To prevent inadvertent mechanical disturbances to the ISS, the generated two thrusts are aligned to the opposite direction. The thrusting period is about 6 seconds per one revolution around the earth., 資料番号: AA0047275016}, pages = {74--78}, publisher = {宇宙航空研究開発機構宇宙科学研究本部, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA/ISAS)}, title = {搭載用水サイクル宇宙推進システムの検討}, year = {2004} }