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Research on technology to capture space debris

Overview of research

Spacecraft that have ended their service life or otherwise failed become space debris and may collide with operational satellites, thus posing a risk for space development. By acquiring the technology to capture space debris, not only can we reduce that risk but can also make it possible to focus on realizing the “recycling” of spacecraft on orbit in the future.

The rendezvous docking technology that was developed for the H-II Transfer Vehicle ("Kounotori") to resupply the International Space Station (ISS) can be applied to the capture of space debris. However, there are new technical issues as seen in the following comparison.

  1. Conventional rendezvous objects have target markers, whereas no such markers are used in capturing space debris, which requires additional sensing to measure relative position to the targeted space debris object.
  2. Conventional rendezvous docking objects have docking ports, whereas space debris objects do not.
  3. Conventional rendezvous docking is intended for a controlled spacecraft such as the ISS, whereas space debris is not under control and even assumed to be rotating.

While conducting research on technology to rendezvous with space debris objects, JAXA is also investigating research on the capturing mechanism and capture control method. The capturing mechanism (Fig. 1) entails grasping the metal adapter or Payload Adapter Fitting (PAF) commonly installed on large space debris objects at rocket or satellite separation. For the upper stage of a rocket, the capturing mechanism can grasp both the PAF and the main engine nozzle (Fig. 2). As a characteristic of this capturing mechanism, tendon drive is used, realizing a high extension ratio and mass reduction. Note that the capturing mechanism is rigidly attached to the space debris object after capture, in order to apply “controlled reentry” (i.e., directing the captured large debris object to fall to the targeted location on the earth) at the end of the operation, and thus entailing mutual control of both the spacecraft and the attached space debris object. JAXA also conducts research on compliance control and contact mode estimation, as well as the backup capturing mechanisms.

Fig. 1.Capturing mechanism (before and after extension)
Fig. 2.Which part to grasp: case of the upper stage of a rocket

Research achievements

  • Nobutaka Tanishima, Daichi Hirano, Tsumaki Toshimichi, Hiroki Kato, "Concept and Mechanism of the Tendon Actuated Versatile Debris Gripper,” in Proceedings of IEEE International Conference on Robotics and Biomimetics (ROBIO), 2017, pp.2129-2135.
  • Daichi Hirano, Hiroki Kato, Tatsuhiko Saito, "Online Path Planning and Compliance Control of Space Robot for Capturing Tumbling Large Object,” in Proceedings of IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2018.
  • Hiroki Kato, Daichi Hirano, Jun Ota, "Collision-based Contact Mode Estimation for Dynamic Rigid Body Capture," in Proceedings of IEEE International Conference on Robotics and Automation (ICRA), Brisbane, 2018, pp.881-888.
  • Daichi Hirano, Yu Nakajima, Hiroki Kato, Takahiro Nozaki and Kouhei Ohnishi. “Reaction Force Observer for a Free-Floating Robot,” in Proceedings of International Symposium on Artificial Intelligence, Robotics and Automation in Space (i-SAIRAS), Madrid, 2018, pp.881-888.
  • K. Shibasaki, W. Oobayashi, et al. “Conceptual study of Mechanical and Sensing System for Debris Capturing for PAF,” Proceedings of the 7th Space Debris Workshop, JAXA, pp.271-288, 2016.
  • T. Mataki, Y. Akahoshi, T. Koura, Y. Kitazawa, K. Shimamura, T. Izumiyama, K. Hashimoto, S. Kawamoto, J. Aoyama, T. Fukuta. “Evaluation of Harpoon Tips for Debris Capture,” Trans. JSASS Space Tech. Japan Vol.14 (2016) Issue ists30 Pages Pr_33-Pr_37.