JAXA Repository / AIREX 未来へ続く、宙(そら)への英知

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Other TitleSpace operation of microwave discharge ion engines onboard HAYABUSA spacecraft and their expansion
Author(jpn)國中 均; 西山 和孝; 清水 幸夫; 都木 恭一郎
Author(eng)Kuninaka, Hitoshi; Nishiyama, Kazutaka; Shimizu, Yukio; Toki, Kyoichiro
Author Affiliation(jpn)宇宙航空研究開発機構 宇宙科学研究本部; 宇宙航空研究開発機構 宇宙科学研究本部; 宇宙航空研究開発機構 宇宙科学研究本部; 宇宙航空研究開発機構 宇宙科学研究本部
Author Affiliation(eng)Japan Aerospace Exploration Agency Institute of Space and Astronautical Science; Japan Aerospace Exploration Agency Institute of Space and Astronautical Science; Japan Aerospace Exploration Agency Institute of Space and Astronautical Science; Japan Aerospace Exploration Agency Institute of Space and Astronautical Science
Issue Date2004-06
PublisherInstitute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA/ISAS)
Publication title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
Start page109
End page113
Publication date2004-06
AbstractOn May 9, 2003, 13:29, the M-V rocket No.5 successfully input the MUSES-C spacecraft into deep space, which was nicknamed HAYABUSA. After research and development effort during 15 years the microwave discharge ion engine system micro-10 was space-borne, that is, was born in space. After vacuum exposure for several weeks the micro-10s were turned on one by one. In June they were devoted to various kind of tests: performance evaluation, autonomous control, cooperative function with other sub system, stand-alone firing, and so on. On the basis of the measured thrust force the performance of the ion engines are evaluated. It is commented that the thrust force of the ion engine is too small to measure in the laboratory. The maximum thrust is 8 mN, at the operational point of which the thrust factor 93 percent, the propellant utilization efficiency 87 percent, the specific impulse 3,200 sec and the thrust power ratio 23 mN/kW. They are consistent with the pre-flight ground data. And then the cruising maneuver was achieved in July, in which the spacecraft is continuously accelerated at several m/s delta-V per day. In the dawn era of the electric propulsion (EP) it was so hard to install EP on scientific spacecraft due to the penalties on weight and power. Not only the advancement of technologies on EP but also the establishment of space infrastructure and the motivation to promote the deep space exploration realize the HAYABUSA spacecraft including micro-10. The EP applied on HAYABUSA is the microwave discharge ion engine system, which has been developed in Electric Propulsion Division in Institute of Space and Astronautical Science on the basis of the concept different from that on the conventional ion engines. The technological features are as follows: 1) Application of electrode-less microwave discharge to both main ion sources and neutralizers. Elimination of electrodes and hollow cathodes results in long life, high reliability, and no time limitation to air exposure. 2) Simultaneous drive of main ion source and neutralizer by a single microwave generator. Lightweight and simple control logic are achieved. 3) Electro-static ion acceleration grids made of carbon-carbon composite material besides Molybdenum. The durability of the grid system as well as the ion engine system is improved. At the end of February 2004 the total accumulated operational time has reached 10,000 hour&unit of which the space flight experience outstripped that of German RF ion engines and is the longest next to that of US's Ring-cusp ion engines. And HAYABUSA spacecraft keeps concretely the orbit to encounter Earth for the swing-by in May 2004 due to the delta-V maneuver by the ion engines. Since the microwave discharge ion engines generate the thrust of 3,200 sec specific impulse HAYABUSA spacecraft has a delta-V capability over 4 km/s, which is comparative to that of the single stage of the launch vehicle, using 66 kg propellant, which occupies only 13 percent of the total weight. HAYABUSA installing a high specific impulse ion engine is not a simple spacecraft but the space ship cruising in the deep space. In order to promote the deep space mission including the various kind of space mission around Earth the micro-10HIsp ion engines with 10,000 sec specific impulse and medium class micro-20 ion engines are under development based on the technology of micro-10. The microwave ion engine 'micro' family will support the space mission near future.
KeywordsMUSES-C; ion engine; plasma generator; microwave discharge; Hayabusa; space exploration; performance test; Itokawa asteroid; MUSES-C; イオンエンジン; プラズマ発生器; マイクロ波放電; はやぶさ; 宇宙探査; 性能試験; 小惑星糸川
Document TypeConference Paper
JAXA Categoryシンポジウム・研究会

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