Attitude Control in Wheel Reduction Operation of Hayabusa2 Extended Mission

Paper number

IAC-24,C1,1,1,x86728

Author

Mr. Takefumi Kosaka, NEC Corporation, Japan

Coauthor

Dr. Seiji Yasuda, NEC Corporation, Japan

Coauthor

Prof. Toshio Kamiya, Meisei University, Japan

Coauthor

Dr. Yuya Mimasu, Japan Aerospace Exploration Agency (JAXA), Japan

Coauthor

Prof. Yuichi Tsuda, Japan Aerospace Exploration Agency (JAXA), Japan

Year

2024

Abstract

Hayabusa2 spacecraft collected asteroid Ryugu’s sample and returned to Earth on December 6th, 2020. The spacecraft that released a capsule with the sample to Earth is currently cruising to asteroid 1998 KY26 as extended mission, and it is scheduled to arrive at the asteroid in 2031. In such long-term operation after launch, there are concerns that onboard equipment satisfies life requirement, resulting in loss of these function. In particular, if Reaction Wheel (RW) is in failure, it will have a critical impact on all the aspect of operations such as ion engine propulsive cruise, communication and observation. This paper shows what kind of attitude control strategy and operational design are adopted in preparation for RW failure during Hayabusa2 extended mission. 

Hayabusa2's four RWs are mounted so that each rotational axis is parallel to X, Y, Z axis of spacecraft-fixed coordinate system, where RW of Z-axis is redundant configuration, and it is assumed that spacecraft’s operation continues even in the event of RW failure up to two axes in the extended mission. Operation at RW failure is divided into two situations. One is a situation where RW in one axis breaks down and RWs for two axes remain.　The other one is when RWs in two axes fail and RW for one axis is still functioning. Regarding the former case, this paper describes an attitude control algorithm that can control attitudes of each axis on which two RWs are mounted and can control an attitude of failed axis by angular momentum exchange between two RWs, simultaneously. On the other hand, for the latter case, attitudes for orthogonal axes to RW axis must be controlled by actuator different from RW. Considering fuel consumption during long-term mission, it is desirable to avoid using Reaction Control System (RCS) as much as possible. Therefore, an attitude control algorithm using external torque generated by tilting ion engine’s thrust vector with gimbal mechanism is presented. The developed control logic is installed on Attitude and Orbit Control Processor (AOCP) as flight software through on-orbit AOCP rewriting operation, and we show evaluation results of effectiveness of the attitude control system through flight experiments simulating RW failure situations.

These attitude control systems design enable to expand Hayabusa2’s mission and also contribute to development of long-term cruise technology for future space exploration missions.

Abstract document

IAC-24,C1,1,1,x86728.brief.pdf

Manuscript document

IAC-24,C1,1,1,x86728.pdf (🔒 authorized access only).

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