@article{Saiki2020, 
author = {Takanao Saiki and Yuya Mimasu and Yuto Takei and Manabu Yamada and Hirotaka Sawada and Kazunori Ogawa and Naoko Ogawa and Hiroshi Takeuchi and Akira Miura and Yuri Shimaki and Koji Wada and Rie Honda and Yasuhiro Yokota and Kei Shirai and Naruhisa Sano and Hirohito Ohtsuka and Go Ono and Kent Yoshikawa and Shota Kikuchi and Chikako Hirose and Yukio Yamamoto and Takahiro Iwata and Masahiko Arakawa and Seiji Sugita and Satoshi Tanaka and Fuyuto Terui and Makoto Yoshikawa and Satoru Nakazawa and Sei-ichiro Watanabe and Yuichi Tsuda},
title = {Motion reconstruction of the small carry-on impactor aboard Hayabusa2},
year = {2020},
journal = {Astrodynamics},
volume = {4},
number = {4},
pages = {289-308},
keywords = {small body exploration, Hayabusa2, kinetic impact, artificial crater, motion reconstruction},
url = {https://www.sciopen.com/article/10.1007/s42064-020-0077-6},
doi = {10.1007/s42064-020-0077-6},
abstract = {Subsurface exploration is one of the most ambitious scientific objectives of the Hayabusa2 mission. A small device called small carry-on impactor (SCI) was developed to create an artificial crater on the surface of asteroid Ryugu. This enables us to sample subsurface materials, which will provide a window to the past. The physical properties of the resulting crater are also useful for understanding the internal structure of Ryugu. Accurate understanding of the crater and ejecta properties, including the depth of excavation of subsurface materials, requires accurate information on impact conditions. In particular, the impact angle is a critical factor because it greatly influences the size and shape of the crater. On April 5, 2019, the Hayabusa2 spacecraft deployed the SCI at 500 m of altitude above the asteroid surface. The SCI gradually reduced its altitude, and it shot a 2 kg copper projectile into the asteroid 40 min after separation. Estimating the position of the released SCI is essential for determining the impact angle. This study describes the motion reconstruction of the SCI based on the actual operation data. The results indicate that the SCI was released with high accuracy.}
}