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Astrodynamics

Article Title

Orbit insertion strategy of Hayabusa2’s rover with large release uncertainty around the asteroid Ryugu

Authors

Yusuke Oki, Japan Aerospace Exploration Agency, Tsukuba 305-8505, Japan
Kent Yoshikawa, Japan Aerospace Exploration Agency, Sagamihara 252-5210, Japan
Hiroshi Takeuchi, Japan Aerospace Exploration Agency, Sagamihara 252-5210, Japan
Shota Kikuchi, Japan Aerospace Exploration Agency, Sagamihara 252-5210, Japan
Hitosi Ikeda, Japan Aerospace Exploration Agency, Sagamihara 252-5210, Japan
Daniel J. Scheeres, University of Colorado, Boulder, CO 80309, USA
Jay W. McMahon, University of Colorado, Boulder, CO 80309, USA
Junichiro Kawaguchi, Japan Aerospace Exploration Agency, Sagamihara 252-5210, Japan
Yuto Takei, Japan Aerospace Exploration Agency, Sagamihara 252-5210, Japan
Yuya Mimasu, Japan Aerospace Exploration Agency, Sagamihara 252-5210, Japan
Naoko Ogawa, Japan Aerospace Exploration Agency, Sagamihara 252-5210, Japan
Go Ono, Japan Aerospace Exploration Agency, Sagamihara 252-5210, Japan
Fuyuto Terui, Japan Aerospace Exploration Agency, Sagamihara 252-5210, Japan
Manabu Yamada, Planetary Exploration Research Center, Chiba Institute of Technology, Narashino 275-0016, Japan
Toru Kouyama, National Institute of Advanced Industrial Science and Technology, Koto-ku 135-0064, Japan
Shingo Kameda, Rikkyo University, Toshima-ku 171-8501, Japan
Kazuya Yoshida, Department of Aerospace Engineering, Tohoku University, Sendai 980-8579, Japan
Kenji Nagaoka, Kyushu Institute of Technology, Kitakyusyu 804-8550, Japan
Tetsuo Yoshimitsu, Japan Aerospace Exploration Agency, Sagamihara 252-5210, Japan
Takanao Saiki, Japan Aerospace Exploration Agency, Sagamihara 252-5210, Japan
Yuichi Tsuda, Japan Aerospace Exploration Agency, Sagamihara 252-5210, Japan

Keywords

solar radiation pressure, augmented elliptic Hill three-body problem, gravitational irregularity

Abstract

This paper describes the orbit design of the deployable payload Rover 2 of MINERVA-II, installed on the Hayabusa2 spacecraft. Because Rover 2 did not have surface exploration capabilities, the operation team decided to experiment with a new strategy for its deployment to the surface. The rover was ejected at a high altitude and made a semi-hard landing on the surface of the asteroid Ryugu after several orbits. Based on the orbital analysis around Ryugu, the expected collision speed was tolerable for the rover to function post-impact. Because the rover could not control its position, its motion was entirely governed by the initial conditions. Thus, the largest challenge was to insert the rover into a stable orbit (despite its large release uncertainty), and avoid its escape from Ryugu due to an environment strongly perturbed by solar radiation pressure and gravitational irregularities. This study investigates the solution space of the orbit around Ryugu and evaluates the orbit’s robustness by utilizing Monte Carlo simulations to determine the orbit insertion policy. Upon analyzing the flight data of the rover operation, we verified that the rover orbited Ryugu for more than one period and established the possibility of a novel method for estimating the gravity of an asteroid.

Publisher

Tsinghua University Press

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