Dynamic precise orbit determination of Hayabusa2 using laser altimeter (LIDAR) and image tracking data sets

• Main Authors: Keiko Yamamoto, Toshimichi Otsubo, Koji Matsumoto, Hirotomo Noda, Noriyuki Namiki, Hiroshi Takeuchi, Hitoshi Ikeda, Makoto Yoshikawa, Yukio Yamamoto, Hiroki Senshu, Takahide Mizuno, Naru Hirata, Ryuhei Yamada, Yoshiaki Ishihara, Hiroshi Araki, Shinsuke Abe, Fumi Yoshida, Arika Higuchi, Sho Sasaki, Shoko Oshigami, Seiitsu Tsuruta, Kazuyoshi Asari, Makoto Shizugami, Naoko Ogawa, Go Ono, Yuya Mimasu, Kent Yoshikawa, Tadateru Takahashi, Yuto Takei, Atsushi Fujii, Tomohiro Yamaguchi, Shota Kikuchi, Sei-ichiro Watanabe, Satoshi Tanaka, Fuyuto Terui, Satoru Nakazawa, Takanao Saiki, Yuichi Tsuda
• Format: Article
• Language: English
• Published: SpringerOpen 2020-06-01
• Series: Earth, Planets and Space
• Subjects: Hayabusa2; Precise orbit determination; LIDAR range data; ONC image tracking data; GM of Ryugu; Solar radiation pressure
• Online Access: http://link.springer.com/article/10.1186/s40623-020-01213-2

Abstract The precise orbit of the Hayabusa2 spacecraft with respect to asteroid Ryugu is dynamically determined using the data sets collected by the spacecraft’s onboard laser altimeter (LIght Detection And Ranging, LIDAR) and automated image tracking (AIT). The LIDAR range data and the AIT angular data play complementary roles because LIDAR is sensitive to the line-of-sight direction from Hayabusa2 to Ryugu, while the AIT is sensitive to the directions perpendicular to it. Using LIDAR and AIT, all six components of the initial state vector can be derived stably, which is difficult to achieve using only LIDAR or AIT. The coefficient of solar radiation pressure (SRP) of the Hayabusa2 spacecraft and standard gravitational parameter (GM) of Ryugu can also be estimated in the orbit determination process, by combining multiple orbit arcs at various altitudes. In the process of orbit determination, the Ryugu-fixed coordinate of the center of the LIDAR spot is determined by fitting the range data geometrically to the topography of Ryugu using the Markov Chain Monte Carlo method. Such an approach is effective for realizing the rapid convergence of the solution. The root mean squares of the residuals of the observed minus computed values of the range and brightness-centroid direction of the image are 1.36 m and 0.0270°, respectively. The estimated values of the GM of Ryugu and a correction factor to our initial SRP model are 29.8 ± 0.3 m3/s2 and 1.13 ± 0.16, respectively.