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JAXAでは宇宙からの地上の災害監視のためにボディ・ポインティングが可能な人工衛星の検討が始まっている。この衛星は高速で姿勢変更を行うことが必要なので、姿勢制御用アクチュエータとしてコントロール・モーメント・ジャイロ(CMG: Control Moment Gyro)に注目している。CMGは従来から広く使われてきた姿勢制御用アクチュエータであるリアクションホイールと比して数10倍のトルクを出力することができるが、トルクを発生できる方向が衛星機体座標系で固定されないため、姿勢制御アルゴリズムが複雑となる。わが国として軌道上で使用実績のないCMGを用いた人工衛星を着実に開発するために、私たちは地上試験にてCMG単体およびCMGを組み込んだ姿勢制御系を動的に評価するための設備を開発している。, JAXA has begun the study of a new type of earth observation satellite which can select an observation area actively using an attitude large angle maneuver. As an attitude control system, this kind of satellite requires a high-torque actuator, of which a Control Moment Gyro (CMG) is one candidate. JAXA does not have sufficient experience related to CMG for use in satellites. Not only the hardware but also the CMG control logic is complicated. Evaluation of the CMG function using ground test equipment is necessary; therefore, we are developing a CMG Test Bed., 資料番号: AA0063718056

資料番号: AA0063719001

In this paper, a new dynamical analysis method for Lunar/Mars rover is proposed. This method uses testing results of a facility which has a slope softly covered by regolith simulant. It also has gravity compensation function. The slope angle is changed easily, so that hill-climbing testing on various slope angles can be accomplished. In the testing results, the slip factor of the crawler mechanism against the terrain changes owing to the slope angle. A dynamical simulation was performed with applying testing results of the hill climbing to the friction parameter of the surface of divided terrain surface model. This paper describes the testing method and results of hill climbing testing and dynamical analysis using the new method about control system of a lunar rover., 資料番号: AA0063718025

2007年9月14日に打上げられた日本初の月探査衛星は、高度約100kmの円軌道に投入された周回衛星(主衛星)「かぐや(SELENE: SELenological and ENgineering Explorer)」と、高度約2,400km〜100kmの月周回楕円軌道に投入されたリレー衛星(おきな: RSAT: Relay SATellite)を用いて、月裏側の重力場の高精度計測を行う。主衛星が月の裏側を航行中は地上から直接計測することができないため、地上から送信した基準信号をリレー衛星経由で主衛星に送り込み、再びリレー衛星で中継し地上局へもどすことでドップラー計測をおこなう。この計測は4つの回線を通ることから「4wayドップラー計測」と呼ばれる。4wayドップラー計測が成り立つためには、リレー衛星および主衛星に搭載されているPLL(Phase Locked Loop)が地上から送信した基準信号に同期していることが前提となる。リレー衛星の同期状態はテレメトリにより実時間で確認できるのに対し、主衛星は月の裏側にあるため実時間での確認ができない。本講演では、主衛星の同期状態の確認をテレメトリによらず、地上局で受信されるドップラー周波数の振る舞いの違いにより実時間で判定する方法について述べる。また、2003年3月に行われた臼田局適合性試験での結果と、2007年11月6日に実施した軌道上の試験において判定方法の正しさが実証されたので、合わせて報告する。本結果により、今後の太陽系探査において、テレメトリが実時間で確認できない場合に、PLLの同期状態を確認する手法が確立された。, 資料番号: AA0063719007

S-520-23号機に搭載されたインフレータブル伸展方式アンテナは全伸展したことが確認され、EVMR(Electric field and VLF/MF band radio Receiver)-ANTとして電場・VLF(Very Low Frequency)/MF(Medium Frequency)帯電波受信に供することができた。, 資料番号: AA0063716020

現在ISAS/JAXAでは気球を用いた微小重力実験装置の開発を進めている。この実験は、(1)高高度気球で高度40kmまで上昇させる、(2)実験機体を切り離す、(3)30-40秒間の自由落下を実現するものである。この実験において、落下機体は30秒程度落下したとき超音速になる。したがって、この実験機体は微小重力実験の他に簡易な超音速飛行試験を提供できると考えられる。実際に、空気吸い込み式エンジンを搭載しての実験も予定されている。この将来の実験において、エンジンの性能を測るために、十分な超音速飛行時間が必要です。そのため、高度40kmからの単純な落下では不十分であり、落下中機体を引き起こす必要がある。今回は、現行の機体で超音速飛行が実現できるかと、引き起こしによって超音速飛行時間を向上できるかを評価した幾つかのシミュレーション結果を示す。, The microgravity experimental system that uses the high altitude balloon is now developed in ISAS/JAXA. This experimental method is, (1) the high altitude balloon is raised to 40 km altitude, (2) the experimental system is separated, (3) a free fall for 30-40 seconds is achieved. In the experiment, the fall body enters a supersonic state when the free fall time exceeds about 30 seconds. Therefore, it can be expected that this fall body will offer a simple supersonic flight experiment besides the microgravity experiment. Actually, it is scheduled to equip the air inhalation type engine developing in the future. In this future experiment, an enough supersonic flight time is necessary to evaluate the performance of the engine. So it is thought that the nose of the body have to be put up since a simple fall from the altitude 40 km is insufficient. This paper evaluates whether a supersonic flight can be achieved in the present experimental system, and whether a supersonic time can be extended by putting the nose up. Some simulation results in several conditions are shown to verify the effectiveness of the putting the nose up of the experimental body., 資料番号: AA0063718055

The new data processing equipment of the JAXA 6.5- by 5.5- m Low Speed Wind Tunnel has been in operation since March 2005. This paper presents an outline of the new equipment and shows the result of the preliminary wind tunnel testing., 資料番号: AA0063897002, レポート番号: JAXA-SP-07-019

In this study, the flow characteristics of UT (University of Tokyo)-Kashiwa hypersonic wind tunnel are obtained by measuring the Pitot pressure distribution. In this wind tunnel, the Mach 7 and 9 hypersonic nozzles are inherited from its predecessor facility in UT-Komaba Campus. From a viewpoint of the operation safety and cost, the maximum stagnation pressure at Kashiwa facility is 950 kPa, which is much lower than at Komaba facility (5 MPa). To evaluate the uniformity of the freestream of this tunnel, the Pitot pressure traverse was conducted for the Mach 7 nozzle by using the rake of 11 Pitot tubes with 20 mm intervals in the radial direction. The measurement has been done at every 30 or 45 degrees in the circumferential direction and also at some streamwise locations. The Mach number calculated from the settling chamber pressure and the test-section static pressure is nearly seven, which is almost the same as the Mach number obtained from the Pitot pressure (about 14 kPa) on the center line. The Pitot traverse shows that the uniform flow core with 120 mm diameter is formed both at the nozzle exit (200 mm in diameter) and at the center of the test section. Such ratio of the core diameter to the nozzle exit diameter seems quite reasonable, comparing to other existing hypersonic wind tunnels. The cross-sectional Mach number distribution shows slight deviation from the axi-symmetric pattern because of the misalignment of the nozzle and the test section to the tunnel center line. Consequently, the highly uniform Mach 7 flow is obtained in this facility, though the nozzle is used under the off-design operation pressure, that is, the off-design Reynolds number., 資料番号: AA0063742009, レポート番号: JAXA-SP-07-016

重量35gの民生用車載GPS(Global Positioning System)受信機を基に、宇宙用の超小型GPS受信機を開発し、これをJAXA宇宙科学研究所が開発して2005年8月に打ち上げられた小型科学衛星れいめいに搭載した。本稿では、車載用GPSからの改修内容、軌道上での性能を報告する。車載用GPS衛星は、そのままでは衛星軌道上では動作しない。これは、衛星軌道上でのドップラー周波数が最大50kHz程度あるからである。車載用GPS受信機の初期捕捉時の周波数掃引範囲を広げるために、車載GPSメーカーにソフトウェアの改修を依頼した。われわれの手で、GPSシミュレーターを用いた軌道上性能の評価試験を行い、(1)30分以内のコールドスタート測位、(2)測位精度15m(電離層効果ふくむ)の性能を地上にて確認した。このGPS受信機は、トータルドーズ20krad、プロトン照射ではSELフリー、軌道上SEU(Single Event Upset)予測頻度1週間あたり数回程度という放射線耐性を持っている。, Miniature space GPS (Global Positioning System) receivers have been developed by means of automobile-navigation technology. The weight and power consumption of the GPS receiver are 35 g and 1 W, respectively. We expanded the frequency sweep range in order to cover large Doppler shift in orbit. We tested the performance in low earth orbits by means of a GPS simulator. The GSP receiver succeeded in cold start acquisition in less than 30 minutes. This GPS receiver was on-boarded on INDEX satellite launched in August 2005. The performances of cold start acquisition and position accuracy was verified in orbit., 資料番号: AA0063223005, レポート番号: JAXA-SP-06-015

本稿では主に1999年以降のIEPC(International Electric Propulsion Conference)と2000年以降のAIAA(American Institute of Aeronautics and Astronautics)ミーティングとジャーナルを中心とした文献調査を行い、各シミュレーション研究のレビューを行なうことを目的としている。Referenceに本稿で対象とした文献一覧を示す。ここに示されたもの以外にも多くの文献が出されているが、同一の著者グループからの一連の論文については、最後のまとめとなる論文1件のみを示している。現在のところ、米国で積極的にこの分野で活動しているグループはJPL(Jet Propulsion Laboratory)、バージニア工科大学、コロラド州立大学、GRC(Glenn Research Center)、ミシガン大学などである。欧州については、IEPCを中心として見る限り、目立った発表が少ない。本稿の第2章では各文献で採用している計算手法および計算結果の検証手法について述べ、第3章ではJAXAで計画されているイオン加速グリッド耐久認定用数値シミュレーションツール開発に向けて必要とされる諸課題について述べる。, A Literature review has been carried out about computational simulation of ion thruster grid region. The computational region consists of upstream discharge plasma, ion beam going through the ion optics grid system and downstream neutralized plasma. Various plasma species exist such as beam ions, charge exchange ions, discharge chamber electrons, neutralizer electrons and others. Literature of the past eight years has been studied intensively. Their methodologies, computational geometries, particle modeling, downstream modeling, Poisson solver and discharge plasma modeling have been compared. Based on the literature review, the strategy toward building the future grid simulation tool has been discussed with suggestions of future works., 資料番号: AA0063329005, レポート番号: JAXA-SP-06-019

イオンエンジンの寿命を制限する要素にはイオン加速グリッドの損耗がある。その耐久認定には、実時間で数万時間級の耐久試験を行うという現状がある。しかし、今後のイオンエンジンを用いたミッションにおいて、耐久性の向上化、長寿命の要求などの進展により、このような長時間試験は現実的ではない。そのため、今後は実時間試験は数千時間級にし、数値寿命予測と合わせた耐久認定方法が提案されている。本研究では、実際に2万時間耐久試験を行ったイオン加速グリッドの損耗形状測定を行い、断面形状特性、周方向角度に対する半径特性について報告をする。, In the development of Ion Engine System, life prediction method by numerical calculation is suggested. To compare the numerical prediction with the experimental data, we measured the decel grid after an endurance test for 20,000 hours. The center hole of this grid has symmetrical property, and in the downstream side, grid holes have hexagonal geometry., 資料番号: AA0063329004, レポート番号: JAXA-SP-06-019

JAXA風洞技術開発センターの0.5m極超音速風洞(HWT1: Hypersonic Wind Tunnel 1)においてM5のHB-2標準模型力試験を実施した。HB-2標準模型およびスティングは今回HWT1用に新たに製作したもので、当風洞所有の内挿天秤を用いて測定部の模型支持装置に装着し、澱み点圧力Po=1.0、1.5MPaにおいて6分力データおよびベース圧力を取得した。試験ピッチ角は±20度の範囲で、模型支持装置の制御モード(ピッチ&ポーズ、擬似スイープ)によるデータ比較も行った。得られた結果は他風洞のそれと比較して概ね妥当な結果であった。また、試験に先立って行った光学観測装置受光部改修の機能確認試験も併せて実施した。, 資料番号: AA0063333005, レポート番号: JAXA-SP-06-026

高感度な観測を行うには望遠鏡が必須であるが、これまで10keVを超える硬X線領域ではX線望遠鏡はほとんど感度を持たなかった。SUMIT(SUperMirror Imaging Telescope)は、20-60keVの硬X線領域において撮像可能な多層膜スーパーミラーを用いた硬X線望遠鏡による撮像観測実験である。我々は、SUMITの焦点面検出器の開発を行った。SUMITに搭載された望遠鏡は、焦点距離8m、空間分解能2分角、視野12分角の性能を持っており、その焦点面検出器の性能の目標値として20-60keVで90％以上の検出効率、位置分解能2mm(1分角)以下、有効検出面40mm(17分角)を設定した。我々はこれを達成するために、NaI(Tl)固体シンチレータと位置検出型光電子増倍管を組み合わせた位置検出型シンチレーションカウンターを開発した。これにより、20-80keVで90％以上の検出効率、有効検出面直径60mmを達成した。本検出器は2006年5月に放射光施設SPring-8にて性能評価と較正を目的とした測定を行った。その結果、エネルギー分解能18％(アットマーク)60keV(FWHM: Full Width at Half Maximum)、位置分解能2mm(アットマーク)60keV(FWHM)を得た(ただし、(アットマーク)部分を記号のアットマークに変更してください)。また位置決定関数の測定を行った。これらの結果により、本検出器は上記の目標を達成していることを確認できた。2006年11月にブラジルで行った第1回飛翔実験では、高度38kmにおいて約8時間の観測を行なった。, 資料番号: AA0063354039

Japan Aerospace Exploration Agency (JAXA) developed Tuned Dry Gyroscope (TDG), as supreme precision rate sensor for satellite attitude control. JAXA also developed Inertial Reference Unit (IRU) using TDG. This IRU is used on every JAXA satellite. It has passed over fifteen years since the development. It is difficult to purchase some kind of electronics parts nowadays. Meanwhile, satellite system requires higher accuracy, more operation flexibility and so on. So, we decided to redesign IRU. Aiming is high-reliability and high-accuracy. The study has started in FY2001. In FY2005 IRU redesign was completed and we prepared every document needed for Flight Model (FM) production., 資料番号: AA0049500078, レポート番号: JAXA-SP-06-006

Numerical simulations were conducted to predict the ejector pumping performance of our rocket-ramjet combined-cycle engine under a take-off condition, which will be tested in the Ramjet Engine Test Facility at Fy2006. Our code was verified by comparing the numerical pumping performance with the measured one in the rectangular ejector with constant-area mixing duct. The numerical simulations in the combined-cycle engine revealed that when the engine was driven by cold N2 gas, the suction airflow was chocked at the exit of the engine throat at the rocket chamber pressure of 3 MPa. Above the pressure of 3 MPa, the suction airflow rate was decreased because the aerodynamic chocking was induced by the underexpanded rocket plume. When the ejector-driving gas was changed from cold N2 gas to hot combustion gas, the suction performance decreased remarkably. The numerical Mach contour distributions at the combustion gas injection showed that the rocket plume was remarkably converged in the constant-area mixing duct, as a comparison of the result at the N2 gas injection. The reason why the pumping performance decreased when the ejector was driven by the combustion gas was explained by the analysis of the ejector with constant area duct including heat and mole transfers. Our analysis of the ejector revealed that the heat transfer from hot rocket plume with supersonic speed to cold airflow with subsonic speed induced the expansion of the airflow and the pressure rise. This pressure rise was the reason why the pumping performance decreased when the ejector was driven by the combustion gas., 資料番号: AA0049500020, レポート番号: JAXA-SP-06-006

Three-dimensionally reinforced carbon-fiber-reinforced carbon matrix (3D-C/C) composites have been applied to the nozzle throats of solid propellant rockets such as SRB-A and M-V due to the excellent heat resistance exceeding 2,273 K. In order to assure the design reliability of the nozzle throats, the mechanical properties of the 3D-C/C composites are necessary from room temperature to elevated temperatures. However, no well-developed test method is available at present to evaluate the mechanical properties. The objective of this research is therefore placed upon the standardization of the test methods for evaluating the mechanical properties of the 3D-C/C composites utilized for the nozzle throats. The mechanical tests discussed in this research include tensile, compressive and shear tests of the 3D-C/C composites from room temperature to elevated temperatures exceeding 2,273 K., 資料番号: AA0049500012, レポート番号: JAXA-SP-06-006

A gaseous hydrogen/gaseous oxygen rocket chamber was designed to fit in a rocket-ramjet combined cycle engine model, and its performance was evaluated experimentally. Such a rocket chamber is required to operate in a very wide operation range in terms of chamber pressure (P(sub c)) and mixture ratio (O/F). For stable operation, the injector has a choking point and a diffuser in the downstream portion. The design point of the injector is P(sub c) = 5.0 MPa, O/F = 7 when the supplying pressure of fuel and oxidizer is 7 MPa. The stable operation and 0.91 of the C* efficiency was attained in the ejector-jet/rocket mode operation at O/F = 6.5-7.5 and P(sub c) = 3-5 MPa. A stable operation and 0.93 of the C* efficiency was attained in the ramjet mode operation at O/F = 4.5-7 and P(sub c) = 0.6 MPa. The number of oxygen injectors used was variable, and stable operation was attained by supplying oxygen from two, three and four of eight injectors in the scramjet mode operation. The C* efficiency was 0.94 with four oxygen injector elements at O/F = 0.89, and 0.92 with three oxygen injector elements at O/F = 0.49. No thermal damage was observed in the all operating mode with a flush face injector. Since it was confirmed that the rocket chamber and the injector was able to be operated with stability in the all operating mode, a clustered rocket chamber to embed to the combined cycle engine was fabricated in FY2005., 資料番号: AA0049500024, レポート番号: JAXA-SP-06-006

The Japan Space Exploration Agency (JAXA) is developing a hypersonic turbojet engine to realize Mach 5 or 6 cruise vehicles and reusable LEO transportation systems. Design and fabrication of a subscale turbojet engine of 1 kN thrust with an air precooking system have been continued. In 2005, we conducted performance verification test of a newly developed air-precooler, compressor, and a liquid hydrogen supply system for the subscale engine. Test results are briefly reported in this paper., 資料番号: AA0049500023, レポート番号: JAXA-SP-06-006

The power sources which have long life performances are strongly desired for deep space explorations, advanced missions and so forth. Spacecraft ordinarily employ chemical batteries such as Ni-Cd, Ni-MH and Li-ion batteries as the power sources. Chemical batteries which store electricity by chemical reactions, however, have technical problems in the case of the very long term applications. Electronic double layer capacitors (EDLCs) which are prosperously developed in the civilian field are the electronic storage devices without chemical reaction. EDLCs have long life performances and high rate charge/discharge performances. In recent years, EDLCs have been applied for EVs (Electric Vehicles), UPSs (Uninterrupted Power Sources), assist power sources and so forth. In the space field, EDLCs were already applied to the exploration robot 'MINERVA' which was equipped to the interplanetary spacecraft 'HAYABUSA'. EDLCs received much attention to be applied to the very long term missions such as Space Solar Power Systems (SSPS). We tested the basic performance of EDLCs, and simulated the satellite operations using EDLCs. The capacity retention ratios of EDLCs were remarkable higher than that of Li-ion cells. Especially the capacity retention ratio of the cell without the charge at constant voltage (CV) was better than that of the cells charged at CV. It was confirmed that the length of the CV charge time influenced the degradation of the cells. The differences of the degradation trends of the cells were not observed in spite of the simulation tests for the satellites were conducted by various values of DoD (Depth of Discharge). Through these experiments, it was conjectured that the EDLCs were possible to apply for the power sources of spacecraft., 資料番号: AA0049121001

High energy density Li-ion battery is expected for next generation satellites and the other space usage. GS Yuasa Technology Ltd. (GYT) has developed two types of large capacity Li-ion cells through cooperation with Mitsubishi Electric Corporation (MELCO). One is satellite type (50,100 and 175 Ah) for long life applications and the other is rocket type (55,110 and 190 Ah) for high energy applications. The energy density of the cells are 136 Wh/kg-164 Wh/kg. They correspond to the 1.5-2.0 times of Ni-H2 cell. The cells have completely sealed structure achieved with ceramic hermetic seal in order to endure the space environment. GYT has confirmed that the cells performance satisfies space application requirements. SERVIS-1 that equipped with Li-ion battery system (cells: by GYT, battery: by MELCO) was launched on October 2003. The Li-ion battery consists of eleven Li-ion cells (50 Ah) in series. SERVIS-1 has been operated smoothly on orbit. The results more than two years in total will be obtained on orbit in SERVIS-1. 100 Ah cells have been operated in a GEO satellite since 2005. It is scheduled that the Li-ion cells of 50-175 Ah by GYT are installed in some satellites. GYT cells have been tested in accelerated GEO cycle tests. GYT confirmed that the cells will satisfy general life requirement of GEO mission (15 years)., 資料番号: AA0049121004

本研究では、小型の月・惑星探査ローバを目指して、6本脚を有する昆虫型ロボットについて検討している。現在、研究のプラットフォームとして実験モデルの設計・開発を進めている。脚型ローバの場合、脚の最も根元に位置する腰関節で発生すべき関節トルクが大きくなり、クリティカルな設計パラメータとなる。この関節トルクの制約を満足しつつ、安定性、脚干渉、可到達領域やボディ重量などを総合的に考慮して設計した場合のモデルがどのようになるか示す。また、自重保持のためのエネルギ消費を低減するトルクアシスト機構を提案する。さらに、検討結果に基づいて構築した、数値シミュレーションおよび実験モデルについて述べる。, This research discusses a insect-like rover with six legs for the moon or planet exploration. We are designing and developing an experimental model as a platform for our research, and we mainly describe this content in this paper. Large torque is required at the hip joint of the leg type rover and it is one of critical design parameters. We show how the model becomes when the design parameters and leg arrangement are designed by considering a joint torque, stability, leg interference, reachable region, and body weight. Moreover, we propose a torque assistance mechanism to decrease the energy consumption when the legs support rover's weight. A numerical simulator and an experimental model are constructed based on the results of discussion., 資料番号: AA0063480055

惑星探査ローバを開発するにあたり、惑星上でのローバの挙動を把握するため、惑星環境を地球上で再現することは重要なことである。大気が存在しない惑星で真空中を移動することは、走破性能に何らかの影響を与える可能性がある。これまで、相似則模型や単輪試験機を用いて探査の目標となる天体の重力加速度や土壌の性質を考慮した実験は数多く実施された。しかし、真空中での実験は単輪試験のみであり、複輪での挙動はまだ確認されていない。そこで、本研究では複数の車輪を装備する車輪型ロボットを真空中で走行させることにより、複輪での移動方法に対する大気中と真空中での影響の違いを観察する。真空環境を再現するため、真空チャンバを利用した真空走行試験を行う。, Future lunar or planetary exploration missions will require wheeled mobile robots to traverse on very rough terrain with limited human supervision. This paper investigates the kinetic behavior of a lunar or planetary rover in the vacuum environment. Some experiments are performed for a 1/6 scale rover in the vacuous chamber. This paper presents the vacuum test results and studies the running behavior of the rover., 資料番号: AA0063480054

Triple-junction (3J) space solar cells were irradiated with 10 MeV protons at 175 K. The electrical performance of the 3J solar cells was measured in situ under AM0-light illuminated condition at low temperature. The electrical performance of the solar cells decreases with increasing proton fluence, and at a proton fluence of 1 x 10(exp 13)/sq cm, short-circuit current (Isc) and open-circuit voltage (Voc) become approximately 87 and 80 percent of the initial values, respectively, indicating higher radiation resistance compared to Si solar cells. No significant difference in the degradation behavior of the electrical performance is observed between low temperature and RT. The influences of light-illumination and current-injection on the electrical properties were studied at low temperature to minimize the thermal annealing effect. For AM0 light illumination, the change in the electrical properties of the 3J solar cells under AM0 illumination was investigated at 175 K. The electrical performance does not change by the illumination for 370 min. On the other hand, by current injection at 155 K, a significant recovery of the electrical performance of proton-irradiated 3J solar cells is observed. At current injection times of 4,500 sec, a 10 percent recovery of Isc and Voc to the values after irradiation for the fluence of 3 x 10(exp 13)/sq cm is observed., 資料番号: AA0049054018, レポート番号: JAXA-SP-05-008

The Deployable Radiator (DPR) with looped heat pipe is planed in Engineering Test Satellite. The loop heat pipes are able to transport heat over long distances in satellite. The thermal control systems such as the loop heat pipes are demanded with precise control and expected to operate on orbit for 10 to 20 years. The non-condensable gas in loop heat pipe with working fluid affects the precise control and performance. The paper describes an investigation into operating characteristics of loop heat pipe in DPR and an effect of non condensable gas., 資料番号: AA0049054003, レポート番号: JAXA-SP-05-008

日本の次期X線天文衛星計画NeXT(New X-ray Telescope Mission)が宇宙航空研究開発機構(JAXA)に提案された。過去のX線天文衛星は約10keVまでしか結像集光能力を持たなかったが、NeXT衛星は多層膜を用いた硬X線望遠鏡(スーパーミラー)を塔載し、80keVまで結像集光することが可能となる。我々は焦点面検出器の1つであるX線CCD(Charge Coupled Device)カメラシステム(SXI: Soft X-ray Imager)の開発を行っている。SXIはベースライン案で12keV以下、ゴール案で25keV以下のX線領域で撮像と分光を行う。我々はSXIのベースライン案として、P型半導体をベースにしたP型CCDの開発を進めている。今回、試作品CCD-NeXT1を開発し、性能評価試験を行った。CCD-NeXT1のエネルギー分解能、読み出しノイズ、電荷転送非効率(CTI: Charge Transfer Inefficiency)、検出効率はSXIベースライン案の要求仕様を満すものであった。この結果から、P型CCDに関する我々の技術力はSXIベースライン案を実現するのに充分であることを確認した。, 資料番号: AA0063353023

2004年12月13日、ノルウェー・アンドーヤにおいて実施されたDELTA(Dynamics and Energetics of the Lower Thermosphere in Aurora)キャンペーンにおいて、観測ロケットS310-35号機搭載インピーダンス・プローブ(Number density of Electrons by Impedance probe:以下NEI)を用いた極域電離圏電子密度観測が行われた。この観測実験に先立ち、大型スペースチェンバーを用いたNEIの真空中動作試験が2004年9月13〜17日の期間で行われ、チェンバー内に生成されたプラズマ中の電子密度測定を行った。試験は結果的には成功裡に終える事ができ、ロケット実験でも所期の計測が実施されたが、今回の動作試験においては実際の観測状況での動作が確認できたばかりでなく、ブリッジ部の高圧放電対策が不足であった点、並びに使用するプラズマによって観測の状況に相違がある点が新たに指摘された。今後の電子密度観測におけるNEIの継続的な使用と、スペースチェンバーに標準的にNEIを設置し、様々な環境試験を援助するに向けた追加試験の必要性が確認された。, 資料番号: AA0063347003

Performances of ED-tethers using either spherical collectors or bare tethers for drag, thrust, or power generation, are compared. The standard Parker-Murphy model of current to a full sphere, with neither space-charge nor plasma-motion effects considered, but modified to best fit TSS1R results, is used (the Lam, Al'pert/Gurevich space-charge limited model will be used elsewhere). In the analysis, the spherical collector is assumed to collect current well beyond its random-current value (thick-sheath). Both average current in the bare-tether and current to the sphere are normalized with the short-circuit current in the absence of applied power, allowing a comparison of performances for all three applications in terms of characteristic dimensionless numbers. The sphere is always substantially outperformed by the bare-tether if ohmic effects are weak, though its performance improves as such effects increase., 資料番号: AA0049206085, レポート番号: JAXA-SP-05-001E

資料番号: AA0048471002, レポート番号: JAXA-SP-04-014

In this paper, the issues concerning performance evaluation and its enhancement with tuning technique on the CeNSS system at JAXA NS-3 is discussed. First, the real performances for the JAXA CFD codes on the CeNSS are shown, and the importance of the performance evaluation and its enhancement with tuning is pointed out. Currently, there is no effective indicator nor explicit strategy of the performance improvement on the CeNSS. Then, the proposal on the concept of effective peak performance is submitted. The peak performance comes from the number of ideal floating point operations, which suggest the potential improvement by the performance tuning. With this concept, the possible improvement can be estimated. From analysis using the 250 codes, this effective peak performance was found to be important for the performance enhancement., 資料番号: AA0048469007, レポート番号: JAXA-SP-04-012

本文は月探査機SELENEの相対VLBIシステムの性能実験について報告する。SELENEの狭帯域高精度相対VLBI技術を実現するため、観測装置に対して特殊な要求をしている。局部発振器の周波数の設定の変化によるチャンネル間の位相差の変化はIF Pcalを利用して補正できること、バックエンドにおけるチャンネル間の位相差は数度以内であること、ローパスフィルタの位相特性はほぼ直線で、かつ各局に使ったものの特性はほぼ同じであること、バックエンドにおける長期位相揺らぎの補正ができることを確認し、相対VLBIにおける大気位相揺らぎを見積もり、特に、衛星信号を受信した場合の相関位相揺らぎは短基線において5度以内、長基線において40度であったが、その原因を解明し、帯域消去フィルタを掛けることにより除去できることがわかった。これらの結果から、開発したVLBIシステムはSELENEの相対VLBI観測に十分な性能を持つことを確認している。, 資料番号: AA0048096018

A prototype model of high efficient Active Integrated Antenna (AIA) has been developed, as a candidate of a transmission unit in SSPS (Space Solar Power System). The developed AIA consists of three layers, Receiving part, Phaseshifting part, and Transmitting part. Size is 360 mm x 360 mm x 70 mm. Receiving part has the function to receive an external standard signal with 9 receiving antennas, and adjusts the received signal power level and phase. Phaseshifting part has the function to control the phase of the microwave signal outputted from Receiving part by phase shifter according to the phase control command sent from an external phase control equipment. Transmitting part amplifies the microwave signal outputted from Phaseshifting part with the pre-amplifier and high power amplifier of a semiconductor. And Transmitting part has the phased array antenna composed of 9 microstrip antennas of 3 by 3. Moreover, amplified microwave is transmitted from 9 antennas and a power transmission microwave beam is formed. Fundamental characteristic verification test of the prototype AIA has been also performed to acquire characteristic data. The result shows that the AIA will be an applicable candidate for the microwave power transmission unit of SSPS. This paper describes an outline of the prototype model of AIA., 資料番号: AA0047275027

The fuel cell for space applications has special system requirements, operational conditions, and designs due to its isolated low gravitational and closed environment, which is much different from that for ground applications. JAXA is now developing polymer electrolyte fuel cell (PEFC) system for the future space applications. It was found that the counter flow of pure hydrogen and oxygen enabled realization of a fuel-cell system without external humidification. Also demonstrated was closed gas operation to determine the applicability of the fuel-cell system in a closed environment, where hydrogen gas was dead-ended and oxygen gas was circulated with produced water removed. Considering gas/water separation in the micro-gravitational environment, a condenser was installed which condenses the humid gas exhausted from cell stack to water, and also installed was a cylindrical separator which contains wicking material to separate gas/water, in the gas recycling line together with a gas circulation pump. The wicking material which absorbed water was compressed by the piston in the separator and discharged the water into the receptacle. Water discharge had an operational cycle to be controlled in accordance with a water capacity of the quantity of electricity to be generated. The 18 cell stack was manufactured and a fuel cell system was assembled including the components mentioned above. It showed stable performance for 1,100 hours under various operational conditions. These results could realize the simple and practical PEFC system for space application., 資料番号: AA0047275014

High energy density Li-ion battery is expected for next generation satellites and the other space usage. Japan Storage Battery Co., Ltd. (JSB) has developed two types of large capacity Li-ion cells through cooperation with Mitsubishi Electric Corporation (MELCO). One is satellite type (50, 100 and 175 Ah) for long life applications and the other is rocket type (55, 110 and 190 Ah) for high energy applications. The energy density of the cells are 136 Wh/kg to 164 Wh/kg. They correspond to the 1.5 to 2.0 times of Ni-H2 cell. The cells have completely sealed structure achieved with ceramic hermetic seal in order to endure the space environment. JSB has confirmed that the cells performance satisfies space application requirements. Furthermore, JSB has started developing small size Li-ion cell (10 Ah) for small satellites. SERVIS-1 that equipped with Li-ion battery system (cells: by JSB, battery: by MELCO) was launched in October 2003. The Li-ion battery consists of eleven Li-ion cells (50 Ah) in series. SERVIS-1 has been operated smoothly on orbit. The results more than two years in total will be obtained on orbit in SERVIS-1. It is scheduled that the Li-ion cells of 50 to 175 Ah by JSB are installed in some satellites that will be launched by 2007., 資料番号: AA0047275003

Recently, considerable attention has been paid to the investigations of solid-state lithium-ion rechargeable batteries for widespread application in many types of portable electronic devices. Previously, the multi-layered Li-ion batteries were reported. In the present paper, investigated were the composite-type Li-ion rechargeable batteries stacked with an Si solar cell for higher performance of the thin-filmed battery. Thin films of LiMn2O4 positive electrode, Li3PO(4-x)N(x) solid electrolyte and V2O5 negative electrode were successively prepared onto an amorphous Si solar cell on a glass substrate by an rf-magnetron sputtering method with a typical rf power of 100 W under an Ar-gas, Ar/N2 and Ar/O2 mixture-gas pressure of 10 mTorr, respectively. The five Si solar cells which have a cell voltage of 0.65 V under illumination were connected in-series in order to charge effectively the Li-ion cell of a cell voltage of approximately 3 V. The areas of the three types of unit solar cells are 5 x 5 sq mm, 7 x 7 sq mm, and 10 x 10 sq mm, respectively. On the other hand, the effective operation area of Li-ion cells is 3.9 sq cm or 2.8 sq cm. The composite-type battery showed typically the discharge capacity of 10 to 15 micro-Ah/sq cm with an efficiency of approximately 100 percent. A maintenance-free operation of this battery could also be confirmed by moving it under the constant sink current of 5 micro-A in the laboratory room through day and night. In conclusion, a new thin-filmed battery could successfully be constructed by the Li-ion rechargeable cell being stacked on the Si solar cell. This type of battery has several advantages of light weight, high reliability and flexibility for the cell shape, almost all of which result from the thin-filmed and all-solid-state battery. Furthermore, the composite-type Li-ion-battery can be used as a maintenance-free battery by direct recharge from the Si solar cell in spite of power supply from AC 100 V. The present battery may be expected for the potential use in small-sized medical instruments and in space satellites/stations which need the light weight and high reliability mentioned above., 資料番号: AA0047275004

資料番号: AA0047120022

NAL introduces a new supercomputer system called Numerical Simulator 3 (NS3) October 2002 whose peak performance is 9.3 TFLOPS with 3.6 TB user memory. In this paper, the performance evaluation results for NS3, particularly for the Central NS System called CeNSS, are shown. These include the full system LINPACK measurement is 5.406TFLOPS, for single CPU results are 400 to 700MFLOPS, and for the actual NAL parallel applications the sustained performance is over 1TFLOPS., 資料番号: AA0047427008, レポート番号: JAXA-SP-03-002

資料番号: AA0046651009

本耐久試験では累計4,994時間の作動を達成した。更に継続作動は可能であったが、ほぼ計画の作動時間に達したので試験を終了した。この間、エンジンは推力150mN、比推力3,500s、イオン生成コスト140W/A以下(放電室推進剤利用効率90％)の目標性能をほぼ維持した。質量損失測定から加速電極寿命は20,000時間以上と推定されるが、目標(暫定値)には達していない。詳細な耐久性評価と耐久性向上対策が必要である。試験後の観察などにより、主陰極オリフィス板や放電室磁石カバーなどの耐久性向上対策が必要であることが分かった。, 資料番号: AA0033392051