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type:Journal Article, The Advanced Land Observing Satellite that was launched by the Japan Aerospace Exploration Agency in 2006 carries a large solar-array paddle of 22 times 3 m in polar orbit. The wake side of the solar paddle can be charged to a negative value exceeding -1000 V. Numerical simulations and laboratory experiments are carried out to investigate charging and arcing phenomena on the backside of the solar paddle that has exposed bypass diode boards and silver-Teflon thermal film. Possibility of secondary arc and surge voltage between hot and return ends of power circuit has been investigated. The authors irradiate solar-panel coupons with an electron beam to simulate charging situation near the North Pole. Surface flashover is observed once the insulator potential exceeds -7000 V. The authors have also tested charging situation near the South Pole where carbon fiber-reinforced plastics surface facing dense ionospheric plasma may arc easily once a satellite potential drops to -80 or -90 V. The solar-paddle design has been modified to increase the safety margin against arcing, and tests have been carried out to identify the strength limit under extremely harsh test environment.

Next generation aircraft design focuses on highly integrated airframe/engine architectures that exploit advantages in system level efficiency and performance. One such design concept incorporates boundary layer ingestion which locates the turbofan engine inlet near enough to the lifting surface of the aircraft skin that the boundary layer is ingested and reenergized. This process reduces overall aircraft drag and associated required thrust, resulting in fuel savings and decreased emissions; however, boundary layer ingestion also creates unique challenges for the turbofan engines operating in less than optimal inlet flow conditions. The engine inlet flow profiles predicted from boundary layer ingesting aircraft architectures contain complex distortions that affect the engine operability, durability, efficiency, and performance. One component of these complex distortion profiles is off-axial secondary flow, commonly referred to as swirl. As a means to investigate the interactions of swirl distortion with turbofan engines, an experiment was designed to measure distorted flow profiles in an operating turbofan research engine. Three-dimensional flow properties were measured at discrete planes immediately upstream and immediately downstream of the fan rotor, isolating the component for analysis. Constant speed tests were conducted under clean and distorted test conditions. For clean tests, a straight cylindrical inlet duct was attached to the fan case; for distorted tests, a StreamVane swirl distortion generator was inserted into the inlet duct. The StreamVane was designed to induce a swirl distortion matching results of computation fluid dynamics models of a conceptual blended wing body aircraft at a plane upstream of the fan. The swirl distortion was then free to develop naturally within the inlet duct before being ingested by the engine. Results from the investigation revealed that the generated swirl profile developed, mixed, and dissipated in the inlet duct upstream

Advanced Land Observing Satellite (ALOS) that will be launched by Japanese Aerospace Exploration Agency in 2005 will carry a large solar paddle of 22 m x 3 m in polar orbit. The wake side of solar paddle can be charged to a highly negative value. Laboratory experiments are carried out to investigate charging and arcing phenomena on the backside of the solar paddle that has exposed bypath diode boards and Silver-Teflon thermal coating. We irradiate solar panel coupons with an electron beam to simulate charging situation near the North Pole. Surface flashover is observed once the insulator potential exceeds - 7 kV. Possibility of sustained arc and surge voltage between hot and return ends of power circuit have been investigated., JAXA Special Publication, 宇宙航空研究開発機構特別資料

This research involved a control technology for Large Space Structures (LSS), as well as technologies for a high-performance attitude determination system and high-stability pointing. The aim was to incorporate the results into actual orbital technologies for high-performance attitude determination/control and technologies for orientation control, as part of a future infrastructure. Firstly, studies were carried out on an autonomous decentralized system and design methods by using concepts of autonomous units and fields, for LSS with multiple-body and complex systems such as solar power satellites, multi-joint manipulators, and grouped satellites. Secondly, the high-accuracy attitude determination method that used star sensors and star data catalogs, was studied by simulation tests. Star identification without any a priori attitude data was studied by means of pattern-matching methods: grid matching and triangular matching, and features of various star catalogs were discussed. Thirdly, studies were performed on a high-stability pointing technique and a vibration-isolation system., 巨大宇宙構造物(LSS)の制御技術、および高姿勢決定技術と高安定指向技術の研究を行った。研究の目的は、研究結果を将来のインフラストラクチュアの1部として、高姿勢決定・制御および指向制御技術を実際の軌道技術の中に組み込むことである。まず、太陽光発電衛星、多関節マニュピュレータ、集合衛星のような多数の構造体を持ち複雑なシステムからなるLSSに関しての設計手法および自律分散システムについて自律ユニットおよびフィールドの概念を用いて考察した。次に高精度姿勢決定技術についてスターセンサとスターカタログを用いた精密測定法をシミュレーションテストで調べた。あらかじめ姿勢データが無い場合の星の位置決定に対して格子形と3角形の2つのパターンマッチング法を検討し、スターカタログについても検討した。最後に、高安定指向技術についての研究では、振動分離システムについて検討を行った。

The ADEOS-2 satellite experienced anomalous operation on October 25, 2003. The power generated on the satellite suddenly decreased from 6 kW to 1 kW. We conducted experiments to investigate this degradation of power for the satellite. The multi-layer insulator film that wraps the power cables was charged by low-energy electrons when the satellite passed though the aurora region around the Earth's pole. ESD tests were carried out for the power cables. Trigger arc discharges occurred between the film and cables with cracks produced by thermal cycles. A secondary arc electric discharge subsequently occurred between the cables themselves. This secondary arc caused a sustained arc after several discharges, which burned out the cables. The heat caused by arc tracking between the hot and return cables made them burn out. This was the mechanism of the operational anomaly on the ADEOS-2 satellite., JAXA Special Publication, 宇宙航空研究開発機構特別資料

The research projects for the essential technologies such as aerodynamics, materials and structures, propulsion systems, etc. for the next-generation supersonic transport and development program of unmanned experimental airplane have been conducted at JAXA (Japan Aerospace Exploration Agency, previously NAL; National Aerospace Laboratory) since 1997. The airplane shape is designed by CFD (Computerized Fluid Dynamics) code developed by NAL and the purpose of flight trial is to verify and demonstrate the validity of CFD design technology. This report shows the summary results of the experimental airplane design and ground test before the first trial, and also describes summary of the result of the flight trail, which was conducted on 14th July 2002 in Woomera test range of South Australia., 宇宙航空研究開発機構(JAXA)は航空宇宙技術研究所(NAL)の時代から次世代超音速機技術研究開発プロジェクトを開始し、ロケットにより打ち上げる無人の小型超音速実験機(NEXST-1;以下ロケット実験機)の開発と飛行実験を行った。実験機の空力形状はJAXAが開発したCFDコードにより設計されており、飛行実験の目的はその実証にある。基本設計は1997年度から開始し詳細設計、維持設計を経て2001年度に実験機システムが完成した。2002年7月にオーストラリアのウーメラ実験場で第1回飛行実験を実施したが、打上ロケットのオートパイロットの不具合により実験は失敗に終わった。その後、信頼性向上ための改修を行い、2005年10月10日に第2回飛行実験を成功裏に完了した。本報告書は研究開発プロジェクトの概要と第1回飛行実験にいたる設計の結果、および地上での確認試験の結果についてまとめたものであり、補足として、第1回飛行実験の状況、その原因調査、および対策検討の結果にも触れた。改修設計の結果、および第2回飛行実験のフェーズについては別途報告書がまとめられる予定である。, JAXA Research and Development Report, 宇宙航空研究開発機構研究開発報告

When solar array is operated at a high voltage, arcs occur on the array surface. Our task is to examine the effects of conductive current generated by arcing on solar array circuit of spacecraft. First, equivalent circuits of small solar array module are modeled. The equivalent circuits are made for various types of solar cell such as silicon, gallium arsenic (hetero junction), and triple junction cells, etc. The equivalent circuit is composed of current source, diode, resistance, inductance and capacitance. First, we measured the frequency characteristic and I-V characteristic of a given solar array, and modeled the equivalent circuit to have the same characteristics by electronic circuit simulation software (SPICE). Next, an electric equivalent circuit of the arc inception was made, and was compared with the ground test result. We simulated the transient current and surge voltage resulted from the ground test using the equivalent circuit. The circuit is under adjustment to experimental results at present. We plan to add the effect of arc expansion to the circuit.

Bare-tether systems are one of the greatest-efficiency electrodynamic tethered systems. The system with an uninsulated portion of the metallic tether itself to collect electrons from the space plasma is operated as a thruster or a power generator on a satellite. Ground experiments were carried out to understand phenomena of electron collection by a bare tether in space. Metallic tether samples were exposed to a simulating Low-Earth-Orbit plasma flow as varying tether sample diameter and length, and plasma velocity. A magnetic field was also applied. The normalized collection current increased with plasma velocity. The existence of magnetic field raised the normalized collection current because of the edge effect of a tether sample or the three-dimensional effect. A high collection current above the orbital-motion-limited current could be achieved with a magnetic field. The current characteristics of a bare tether strongly depended on plasma velocity and surrounding magnetic field., JAXA Special Publication, 宇宙航空研究開発機構特別資料

The conventional wisdom about solar array arcing in LEO is that only the parts of the solar array that are swept over by the arc-generated plasma front are discharged in the initial arc. This limits the amount of energy that can be discharged. Recent work done at the NASA Glenn Research Center has shown that this idea is mistaken. In fact the capacitance of the entire solar array may be discharged, which for large arrays leads to very large and possibly debilitating arcs, even if no sustained arc occurs. We present the laboratory work that conclusively demonstrates this fact by using a grounded plate that prevents the arc-plasma front from reaching certain array strings. Finally, we discuss the dependence of arc strength and arc pulse width on the capacitance that is discharged, and provide a physical mechanism for discharge of the entire array, even when parts of the array are not accessible to the arc plasma front. Mitigation techniques are also presented., JAXA Special Publication, 宇宙航空研究開発機構特別資料

As the power level of Geostationary satellites increases, there is more demand of careful ground test on solar array insulation strength. International atmosphere surrounding commercial telecommunication satellites calls for common international standard on test conditions. In this paper, we review ESD tests of solar array carried out in recent years at Kyushu Institute of Technology jointly with the Japan Aerospace Exploration Agency. The purpose of this paper is to describe the test conditions with the reasons of selecting those conditions and how we certified the insulation strength of given solar array designs against electrostatic discharges in orbit. The paper is aimed to stimulate discussion among experts on the issue of international standardization of solar array ESD test., JAXA Special Publication, 宇宙航空研究開発機構特別資料

An overview of the results of the study on large structure assembly technology is presented. The following aspects of the study are outlined: (1) overall scheme of technology development for assembling and constructing large structure operated on orbit; (2) a brief description of the development from FY (Fiscal Year) 1998 through FY 1991; (3) design study on system and element technologies; (4) simulation analysis, including studies on the analytic software and mathematical model, and problems in analyzing technology; (5) ground test; (6) survey on the next generation structural materials; and (7) concept of on-orbit validation experiment., 大型構造物組立技術は、宇宙構造物構築に不可欠な要素技術である。本研究は、この構造物組立技術のうち、主構造となる展開組立構造(展開トラス)の地上試験設備による機能モデル試作試験/展開モデル試作試験までを、1988年から1994年までに実施することを目標にしている。本報告書では、1990〜1991年度研究開発成果を報告する。研究内容は以下の通りである。(1)設計検討。伸縮斜材、スライドヒンジ、屈曲縦材およびスライド縦材の4方式について、収納効率、重量/剛性、展開駆動特性、駆動機構などの基本パラメータを検討。また、展開トラスのクリティカル要素、特に、摺動部、リンク部、駆動部の重力環境下での特性を重点的に検討し、軌道上での挙動との相違も検討した。(2)シミュレーション解析。市販の4種の機構解析ソフトを比較した。DADSを用いてシミュレーション解析モデルを解析した。また、解析技術の問題点と課題を示した。(3)地上試験。展開組立構造の展開機能確認を効率的に実施できる試験装置の予備検討および展開機能確認手法に関する予備検討を実施した。さらに、(4)将来型構造材料の調査、(5)軌道上実証実験、(6)今後の課題とスケジュールについて報告した。

In the final phase of the MUSES-C mission, a small capsule with asteroid sample conducts reentry flight directly from the interplanetary transfer orbit at the velocity over 12 km/s. The severe heat flux, the complicated functional requirements, and small weight budget impose several engineering challenges on the designing of the thermal protection system of the capsule. The heat shield is required to function not only as ablator but also as a structural component. The cloth-layered carbon-phenolic ablator, which has higher allowable stress, is developed in newly devised fabric method for avoiding delamination due to the high aerodynamic heating. The ablation analysis code, which takes into account of the effect of pyrolysis gas on the surface recession rate, has been developed and verified in the arc-heating tests in the facility environment of broad range of enthalpy level. The capsule was designed to be ventilated during the reentry flight up to about atmospheric pressure by the time of parachute deployment by being sealed with porous flow-restrict material. The designing of the thermal protection system, the hardware specifications, and the ground-based test programs of MUSES-C capsule are summarized and discussed here in this paper., The Institute of Space and Astronautical Science Report SP

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., JAXA Special Publication, 宇宙航空研究開発機構特別資料

This report presents test results of element test No.1 and element test No.2 for floating furnace among the common experimental apparatus onboard Japanese Experiment Module (JEM). As floating furnaces have many problems to solve, trial elements in the sequence of technology difficulties were fabricated and performances were tested. In element test No.1, heating and floating control were studied. Major targets on heating technology were confirmation of basic performance in plasma lamp heating mechanism and trial fabrication of ceramics plasma lamp. Major target of floating control was to employ fuzzy control method and the performance was to be evaluated in ground tests. In element test No.2, the target was to confirm the performance of floating control under microgravity environment. Microgravity experimental device was to be fabricated. Flight test in MU-300 aircraft was planned. Test results of element test No.1 were as follows: (1) plasma lamps in three different wave zones (ultraviolet, visible, near infrared) were fabricated and their emission characteristics were evaluated; (2) as for the results of heating tests, all three plasma lamps were confirmed to have sufficient heating and melting abilities for metal test pieces; and (3) ring-type electrodes as floating electrode, detection of gravity center by Charge Coupled Device (CCD) camera as position detecting method and position control by fuzzy controller were utilized. Test result of element test No.2 were as follows: (1) floating experimental software was made; and (2) floating ground experiment was completed and it was found to be possible to float metal and glass., 本報告書は宇宙ステーション取付型実験モジュール(JEM)の共通実験装置の中の浮遊炉について要素試験のその1と要素試験のその2を実施しその結果をまとめた報告書である。浮遊炉の開発は多くの課題があるので技術的に困難性の高い項目から試作を行い、性能の確認を行った。それぞれの実験項目の内容は次の通りである。要素試験のその1では加熱と浮遊制御の2分野を取り上げ、加熱はプラズマランプの加熱機構の基礎的な性能の確認とセラミックスによるプラズマランプの試作を主な目標とした。浮遊制御はファジー制御を実現することを大きな目標としており地上試験で評価を行った。要素試験のその2では浮遊制御を微小重力実験で確認することを目的としており、微小重力実験装置を製作してMU-300型飛行機で飛行実験を行った。それぞれの実験結果は次の通りであった。要素試験のその1の結果は、3種類の波長帯域(紫外、可視、近赤外)でプラズマランプを試作し発光特性を評価した。加熱実験を行った結果、紫外域から近赤外域のプラズマランプが有効に発光し金属などの試料を加熱溶解出来ることが確認された。浮遊電極としてリング型電極を位置検出方式としてCCDカメラによる重心位置検出を位置制御方式としてファジー制御による位置制御を用いた。要素試験のその2の結果は浮遊実験ソフトウエアを試作し地上浮遊実験を行い、金属やガラスを浮遊させることが可能であることを見い出した。

The development of an 80 meter long large high enthalpy shock tunnel, called HIEST (High Enthalpy Shock Tube) was completed for hypervelocity ground testing of HOPE-X (H-2 Orbiting Plane-Experimental) and the scramjet engines. The design of HIEST was carried out so as to reproduce the high temperature real gas effect caused mainly by the molecular dissociation along the entry path in the velocity of 4 - 7 km/s for the stagnation enthalpy of up to 25 MJ/s, and for the stagnation pressure of 150 MPa at the nozzle reservoir condition when a 500 mm model was used. The initial calibration of HIEST was successfully carried out without any serious troubles and the stagnation pressure of 68 MPa and the shock speed of 4.7 km/s, corresponding to the total enthalpy of 22 MJ/kg, were achieved. There was, however, a problem of temporal variations of the nozzle reservoir pressure, which occurred during the test time window as a result of the onset of compression waves generated in front of the piston during the compression process. The last problem was related to the damage to the piston, caused by small bits of the main diaphragm fragment. The commissioned tests were to be completed by the end of 1997., 全長80mに及ぶ高エンタルピー衝撃風洞(HIEST)が完成した。これは、HOPE-X(宇宙往還技術試験機)やスクラムジェットの極超音速流地上試験を可能にする設備である。設計段階では、大気圏再突入時の速度4-7km/sにおける気体分子解離によって惹起される高温実在気体効果を再現するように、ノズル貯留岐点エンタルピーは25MJ/kgまで、岐点圧力は150MPaとし、模型寸度は500mmを使用対象とした。最初の較正試験は、岐点圧68MPa、衝撃波速度4.7km/s、岐点エンタルピー22MJ/kgで実施され、大きな問題もなく終了した。しかし、小さい点では、ノズル貯留圧が試験可能時間帯で時間変動を示した。これは、圧縮過程でピストン前方に圧縮波が発生した結果であった。また、ダイヤフラムの破片がピストンを破損する問題も発生した。これら一連の試験は1997年末までの終了が予定された。

The microvibration generated by some instruments on orbit is considered as a key factor of pointing stability deterioration. Therefore it is important that the influence of the microvibration is estimated before the launch. In this paper the results of the ground tests by using of OICETS (Optical Inter-orbit Communications Engineering Test Satellite: KIRARI) MTM (Mechanical Test Model) and the on orbit measured result by the accelerometer (MVE: Micro Vibration Equipment) installed in OICETS are described. By using these results and an assumption, the transfer characteristics from main disturbance sources to MVE installed in OICETS are calculated. We compare these structural transfer characteristics and confirm the reproducibility of the ground test on orbit and the effectiveness of the ground test., 近年、指向安定度劣化の主要因として検討が盛んな機械的振動擾乱について、OICETS (Optical Inter-orbit Communications Engineering Test Satellite:きらり)に搭載したMVE (Micro Vibration Equipment)の軌道上加速度データ出力をもとに、軌道上で実際に発生した振動擾乱についての評価を行う。軌道上データから構造伝達特性を評価し、この結果と地上試験データから得られる構造伝達特性との比較を行うことで、地上試験の結果が軌道上でどの程度再現しているかを確認し、地上試験の有効性について、考察を行う。

(1) ONE PHENOMENON, But Two Primary Manifestations: 1. Surface Charging. 2. Internal Oharging. (2) Existing Design Guidelines for Spacecraft Charging: 1. Guidelines are far from complete at this time, yet there are many. (3) Wide Assortment of Phenomena in Differing Applications: 1. CASE STUDY 1: In-space Insulator Pulsing. 2. CASE STUDY 2: Coupling from a Breakdown into a Circuit. (4) Spacecraft Failure Studies: 1. ELECTRIC FIELD FROM CHARGE IN INSULATING MATERIAL IS A PRIMARY CAUSE OF SPACECRAFT ON-ORBIT ANOMALIES. (5) Electric Field Controls the ESD Pulse Rate and Pulse Amplitude. (6) Complete solution of the problem requires knowledge of electric field -very difficult; Ongoing Studies., JAXA Special Publication, 宇宙航空研究開発機構特別資料

Advanced Land Observing Satellite (ALOS) that will be launched by Japanese Aerospace Exploration Agency in 2005 will carry a large solar paddle of 22 m x 3 m in polar orbit. The wake side of solar paddle can be charged to a highly negative value. Laboratory experiments are carried out to investigate charging and arcing phenomena on the backside of the solar paddle that has exposed bypath diode boards and Silver-Teflon thermal coating. We irradiate solar panel coupons with an electron beam to simulate charging situation near the North Pole. Surface flashover is observed once the insulator potential exceeds - 7 kV. Possibility of sustained arc and surge voltage between hot and return ends of power circuit have been investigated., JAXA Special Publication, 宇宙航空研究開発機構特別資料

This report describes an overview of the trial manufacture and research related to the feasibility of the concepts of a reflector structure using inflatable elements, inflatable tube, and recommendations on experiments on the exposed facility of the JEM (Japanese Experiment Module). The expected roles of and basic structure concept concerning the configurations, dimensions, and film surface materials of the reflector are outlined. The results of the film pressure deformation test, film element hardening test, and film and supporting truss interface test are described. The strength, trial manufacture and its results are outlined. The onboard JEM experiment concept concerning the research on the earth, preliminary experiment, and on-orbit experiment onboard JEM are introduced., 宇宙用インフレータブル構造は、予め折り畳んだプリプレグ状態の膜面を、軌道上で内圧により膨張展開させた後、太陽熱などで硬化させ、所定の形状、剛性を保持するものであり、軽量でコンパクトに収納でき、また高精度の面を形成できるという特徴から、将来の宇宙リフレクタや大型宇宙構造物への適用が考えられている。これまでに行ってきた、インフレータブル要素を使用したリフレクタ構造概念、およびインフレータブルチューブ概念のフィージビリティに関わる試作研究の概要を紹介した。(1)インフレータブル要素を使用したリフレクタ構造概念を説明した。本リフレクタ構造の位置付け、リフレクタ構造概念(基本概念、形状、寸法、および膜面材料)、および試験(加圧変形試験、膜要素硬化試験、膜/支持トラス、インタフェイス試験、および7セルトラス構造の試作)を説明した。(2)インフレータブルチューブについて述べた。チューブの強度、チューブの試作、および試作結果を述べ考察を加えた。3)JEM(日本宇宙ステーション実験モジュール)実験構想にも触れた。地上実験、予備実験、およびJEM軌道上実験の概要を示した。これまで行ってきたフィージビリティスタディからは、これらインフレータブル構造は、将来の宇宙構造物として有望であることが明らかになった。

A degradation test for a solar array coupon against ESD was performed under stimulated Low Earth Orbit environment. All tests were performed in a vacuum chamber with a plasma source. A test coupon was biased at - 400 V with the aim of developing the next generation 400 V high voltage solar array. The LCR circuit was used in order to simulate the arc current gathering the charge stored on coverglass. Tests were repeated until the solar array coupon was damaged. All of arc spots and waveforms were detected. The electrical performance of the coupon was measured after every test without opening the vacuum chamber. Many arcs occurred and caused the cell degradation. The cell was damaged by only one arc that occurred at the edge of cell, not at electrode., JAXA Special Publication, 宇宙航空研究開発機構特別資料

The opportunities are increasing for collecting test pieces from various types of bodies in space. In this study, data necessary for the design of a device that collects samples by firing a small projectile onto targeted bodies, then concentrates the ejected fragments within a funnelshaped horn were obtained. These studies included experiments investigating the production of fragments at the time of impact and the motion of fragments reflected within the horn enclosure in tests performed both in 1 g environments on the ground and under reduced gravity conditions aboard an aircraft. These investigations indicates that more than 40 percent of the ejecta from brick-like bodies can be captured by such a device., NASDA English Translation

An instrument for monocular passive ranging based on atmospheric oxygen absorption near 762 nm has been designed, built and deployed to track emissive targets, including the plumes from jet engines or rockets. An intensified CCD array is coupled to variable band pass liquid crystal display filter and 3.5-8.8 degree field of view optics to observe the target. By recording sequential images at 7 Hz in three 6 nm width bands, the transmittance of the R-branch of the O2 (X-b) (0,0) band is determined. A metric curve for determining range from transmittance is developed using the HITRAN spectral database. A low cost system was designed and ground tested at ranges of 50 -380 m using halogen and incandescent light sources, establishing an average range error of 12%. The system was first deployed for a ground test viewing an F-16 in afterburner at ranges of 0.35-4.8 km, establishing a range error of 15% despite the presence of optical turbulence and a structured source spectrum. Finally, the instrument was flight tested in a C-12 imaging an F-16 in afterburner at ranges up to 11 km. The target was manually tracked, and pointing jitter limited image interpretation. A study of range error as a function of signal-to-noise ratio produced superior results to previous methods using Fourier Transform Spectroscopy. However, increased signal relative to background scatter will be required for accurate ranging for these tactical air-to-air scenarios. The promise for improved instrument performance is discussed., The original document contains color images.