橋本 樹明

現在JAXA では,高々度気球からの自由落下を利用した微小重力実験装置の開発が進められている.この装置の特徴は,独特の二重殻構造を持つ点にあり,気球からの自由落下中に,内側の実験部を機体内部で浮遊させることで,30 秒から60 秒の良質な微小重力環境が得られる.落下中の機体姿勢制御,および実験部と機体内壁の隙間制御用に,合計16 基の50N 級コールドガスジェットスラスタが搭載されている.本稿では,微小重力実験装置用に開発されたガスジェットスラスタの設計と,その地上性能試験結果,飛行試験による実証結果について示す.

This paper proposes control system for a new micro gravity experimental system called BOV (Balloon-based Operation Vehicle). BOV uses a free-fall capsule with double-shell structure to prevent influence of aerodynamic disturbance. Additionally, BOV is raised to 40km by a high altitude balloon to extend micro gravity duration to 30 (or possibly 60) seconds. Thus we realize a medium duration micro gravity experimental system with good micro gravity environment. In this system, the most characteristic point is double-shell structure to realize drag-free system. The inner shell can fall freely since the outer shell is controlled not to collide with the inner shell. In the experiments, we realize good-quality micro gravity and realize to continue moderate micro gravity duration. This system is now improving and near future we can practically utilize BOV's system for moderate micro gravity duration with low-cost easily.

To realize micro-gravity environment of long duration and good quality with moderate cost, an experimental system which is released from a high altitude balloon has developed. The system has a double-shell drag-free structure and the outer shell, namely flight capsule, is controlled not to collide with the inner shell to realize micro-gravity environment of good quality. This paper shows the design philosophy and the configuration of the system. The system was successfully tested twice, in May, 2006 and in May, 2007. Outline of the test results and future development plan are also described.

The Balloon-based Operation Vehicle (BOV) originally developed for the micro-gravity experiments is modified as a supersonic flight demonstrator of a sub-scale precooled turbojet engine developed in Japan Aerospace Exploration Agency. In the supersonic flight demonstration, the vehicle is raised by a high-altitude balloon up to a 40 km altitude and is dropped to accelerate to a supersonic velocity. To extend the flight time for an engine combustion test in the supersonic environments, the vehicle is redesigned in a wing-body configuration with a main delta wing and movable vertical and horizontal tail wings so that it can be pulled up above an altitude of 5 km. In this paper, the supersonic flight test plan is introduced, and an overview of the flight demonstrator and the tested supersonic air breathing engine is summarized.

A novel way to conduct microgravity experiments using high altitude balloon is now under development at ISAS/JAXA. By dropping the rocket shaped vehicle from the high altitude balloon, high quality microgravity environment can be served during its free fall of 30 to 60 sec. This paper summarizes the outline of free fall vehicle, which is called as BOV (Balloon based Operation Vehicle). The preliminary results of its second flight test are also presented to show its feasibility.

将来の地球観測・科学観測ミッションの為に高精度、広ダイナミックレンジ、長寿命、高信頼性を有する慣性基準装置(IRU)が求められている。光ファイバジャイロ(FOG)はこれらの要求を満足する有力候補の一つであり、2012年度打上げのASTRO-Gへの搭載を目標に高精度FOG-IRUを開発中である。本稿ではその開発状況について報告することを目的とし、目標仕様やEM検討モデルの評価結果、FOG EM設計結果、IRU基本設計結果等を示す。

Recently, the missions of the earth observation or space science satellites are becoming more demanding and so are the attitude control requirements. For this reason, not only reducing the induced vibrations of onboard instruments but also active vibration suppression is required In the previous research works, a Magnetic Bearing Wheel (MBW) is expected to be a low disturbance wheel with proper gimbals control. The objective of this study is to use MBW as active vibration suppression of other instruments at the mission instrument position. To achieve this objective, accelerators and vibrator are established on the sham satellite panel, and the experiment is made to suppress vibrator disturbance in accelerator positions by controlling MBW parameters. In this paper, the experiment way and results are reported.

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秒間の自由落下中に微小重力環境を実現するものである.この実験機は落下中に超音速飛行状態になることがわかっている.そのため,簡易な超音速飛行実験を提供できると考えることができる.実際にエンジンを搭載しての超音速飛行実験も構想されている.本論文では微小重力実験に関しての説明と,エンジン搭載による超音速飛行実験の検討を行う.

This paper discusses on control law for Balloon Based Micro-Gravity Experimental Vehicle. The vehicle is carried up to an altitude of 40km by a balloon and released. During the free fall, micro-gravity environment is provided in a spherical laboratory floating in the vehicle. Gas jet thrusters control the vehicle to keep the clearance between the laboratory and the inner wall of vehicle. This paper proposes new thruster distribution law, which reduces the fuel consumption without increasing of attitude error. Flight experiment has been carried out successfully in May, 2007. This paper also reports the results.