@article{Oki2020, 
author = {Yusuke Oki and Kent Yoshikawa and Hiroshi Takeuchi and Shota Kikuchi and Hitosi Ikeda and Daniel J. Scheeres and Jay W. McMahon and Junichiro Kawaguchi and Yuto Takei and Yuya Mimasu and Naoko Ogawa and Go Ono and Fuyuto Terui and Manabu Yamada and Toru Kouyama and Shingo Kameda and Kazuya Yoshida and Kenji Nagaoka and Tetsuo Yoshimitsu and Takanao Saiki and Yuichi Tsuda},
title = {Orbit insertion strategy of Hayabusa2’s rover with large release uncertainty around the asteroid Ryugu},
year = {2020},
journal = {Astrodynamics},
volume = {4},
number = {4},
pages = {309-329},
keywords = {solar radiation pressure, augmented elliptic Hill three-body problem, gravitational irregularity},
url = {https://www.sciopen.com/article/10.1007/s42064-020-0080-y},
doi = {10.1007/s42064-020-0080-y},
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.}
}