A Cable-Driven and Rigid-Flexible Structures Coupled Landing Gear System for Spacecraft Soft Landing on Asteroids

Soft landing on weightless asteroids is challenging in space exploration missions. This paper proposes a cable-driven landing gear system (LGS) with rigid-flexible coupled structures (RFCSs) for the soft landing of a spacecraft on asteroids. The cable-driven mechanism improves the compliance of the spacecraft’s landing legs and has the merits of being lightweight and compact. The RFCS minimizes the impact force of the landing legs when crashing the asteroid’s surface. We designed a three-legged LGS and formulated its kinematics and dynamics. We conducted simulations and experiments of a simplified spacecraft prototype. The results showed that the spacecraft can safely land on rough slopes, with the legs contacting the ground at different sequences. The collision speeds of $10-50 \mathrm{~cm} / \mathrm{s}$ are verified. This study provides a new idea for the landing and operation of these cable-driven RFCS probes in a weightless environment. The results are valuable for the design of asteroid landers and their stabilizing control.