Performance evaluation of rebound damping of target marker

Abstract

For small body missions, autonomous guidance is crucial for landing. The Japan Aerospace Exploration Agency’s Hayabusa and Hayabusa2 spacecraft thus placed a target marker on an asteroid’s surface for approach and landing maneuvers. Because of the microgravity environment of an asteroid, even a low-velocity impact can result in a high rebound. In order to reduce rebound motion, a target marker is composed of a shell and a large number of inner particles. The inner particles collide with each other in the shell, reducing the coefficient of restitution of the whole system. Since the settling position of the target marker is directly related to landing accuracy, understanding the target marker’s coefficient of restitution is crucial. This work explains the damping mechanism and develops a theory that can be used to evaluate damping performance based on the number and radius of inner particles. The proposed model is validated by a comparison with the results of a numerical simulation based on the discrete element method. The results of this study will contribute to future small body missions, whose success can depend on mitigating rebound on an asteroid surface. Since particle dampers can be applied to a wide variety of payloads, the results of this study are useful for designing separable payloads for future small body missions.