2023 Volume 22 Pages 51-61
In sample return missions, particularly those to small bodies, landing operations have been performed by a single spacecraft. However, there is a potential risk of spacecraft breakdown in this approach. This paper proposes a new framework for sample return missions, in which a touch-and-go sampling probe (TAG probe) equipped with solid rocket motors is used. In the proposed framework, the TAG probe is released from a mother spacecraft, lands on its target body, collects samples, lifts off, and docks with the mother spacecraft. Because the mother spacecraft can stay at a high altitude and only the TAG probe performs risky operations, the possibility of mission failure can be drastically reduced. This study focuses especially on the landing phase and provides the following two major considerations. First, suitable design of solid motors for various celestial bodies is surveyed. Second, a control system for gimbal actuation of the solid motors is developed to enable soft landing. Two operation methods for gimbal control are proposed. In the first one, only the altitude of the probe is controlled through gimbal actuation. In the second one, the attitude motion of the probe is controlled simultaneously. The landing operation can be successfully completed if the controller is designed to converge faster than the motor's burning duration.
