Article Title

Simultaneous estimation of spacecraft position and asteroid diameter during final approach of Hayabusa2 to Ryugu


asteroids, small bodies, optical navigation, size estimation, orbit determination, real time


This paper presents the optical navigation results of the asteroid explorer Hayabusa2 duringthe final rendezvous approach phase with the asteroid Ryugu. The orbit determination ofHayabusa2 during the cruising phase uses a triangulation-based method that estimates theprobe and asteroid orbits using the directions from which they are observed. Conversely, theasteroid size is available as optical information just prior to arrival. The size informationallows us to estimate the relative distance between the probe and the asteroid with highaccuracy, that is strongly related to the success or failure of the rendezvous. In this study,the relative distance and asteroid size in real space are simultaneously estimated in real timeby focusing on the rate of change of the asteroid size observed in sequential images. Thereal-time estimation results coincided with those of precise analyses performed after arrival.


Tsinghua University Press