坂井 真一郎

After the success of remotely-sensed global observation by SELENE orbiter, Japan has been focusing on the in-situ exploration of the Moon. To know more about the Moon, numerous missions have to be launched to the Moon for surveying different interesting places. Naturally the cost of single mission must be reduced. Japan has been considering a landing mission for about ten years as a next mission to the Moon. This has a few tons of weight and costs a few million euros including the launch vehicle because it also features the future manned mission. Obviously it is not suitable for scientific in-situ exploration, which must be conducted repeatedly. The authors have been studying a small lander on the Moon or the planets in order to enable the multiple in-situ explorations cheaply. With the technologies developed in our studies, the mission named SLIM (Smart Lander for Investigating Moon) has been proposed to demonstrate an autonomous, accurate and soft landing on the specified place of the Moon. SLIM is also helpful to increase the success probability of the nation-led flagship landing mission when it is conducted as a precursor. This paper describes the proposed SLIM mission.

The second flight of microgravity experiment system using a free fall capsule from a high altitude balloon was conducted in May 2007. Using a drag free control, around 10^-4G gravity conditions were obtained for 30 seconds. Results of a combustion experiment with Japanese sparker conducted inside the microgravity experimental unit were also reported.

JAXA is developing Mach 5 hypersonic turbojet engine technology that can be applied in a future hypersonic transport. Now, Jet Engine Technology Research Center of JAXA conducts the experimental study using a 1 / 10 scale-model engine. In parallel to engine development activities, a new supersonic flight-testing vehicle for the hypersonic turbojet engine is under development since 2004. In this paper, the system configuration of the flight-testing vehicle is outlined and development status is reported.

For astronomical observing missions by formation flying satellites in LEO, satellites require control force to keep the relative position, against Keplerian orbit in an inertia coordinate frame. Since satellites require propulsion systems, i.e. thrusters, but the use of thrusters limits the mission lifetime associated with the finite fuel supply. Thus the authors propose the formation flight using electromagnetic force. In this method, the electromagnetic force between super-conducting magnets are used for the relative position control. This method has the obvious advantage of no-fuel to acquire control force. Since such large magnetic moment in earth magnetism generates large disturbance torque, the magnetic moments should be sinusoidal with shorter period than that of the orbit period. Therefore, this paper proposes the relative position control by changing the phase difference between sinusoidal magnetic moments. The proposed method was evaluated with numerical simulations and the results shows the feasibility of the proposed formation flight.

2004年打上げ予定の小型科学衛星"INDEX"は,60[kg]の小型衛星でありながら高精度の姿勢制御を行ってオーロラ観測を行う科学衛星である.重量及びコストの点でハードウェアの制約を受ける中で,高精度な姿勢制御性能を実現するために様々な工夫を施している.本論文ではこのうち,センサ性能を十分に考慮した姿勢制御系の設計手法,また光学センサの触を避けるための衛星運用方式とその評価などについて述べる.更に,効率的に試験・開発を進めるための柔軟なテレメトリコマンドシステムについても紹介する.