Design and experimental verification of multi-tethered spacecraft formation encircled to capture small celestial body system

This paper proposes a method of capturing small celestial bodies (SCB) by multi-tethered spacecraft formation (MTSF), and the system design and experimental verification are carried out. This method can be used in SCB exploration deep sampling to provide penetration force between the drilling equipment and the star soil. Firstly, the composition and operation flow of the encirclement capture system is described, and the encirclement load unit is designed. The dual quaternion describes the rigid body position and attitude coupling motion, and the Arbitrary Lagrange–Euler and the Absolute Nodal Coordinate Formulation (ALE-ANCF) method describes the variable length tether motion. The dynamic model of the variable length MTSF system is established. Finally, a hybrid formation test platform of air-floating node (AFN) and unmanned air vehicle (UAV) is constructed to simulate the capture process of a three-node spacecraft on the scaled model of a SCB. The results show that the AFN and the UAV cooperatively carry the tether retracting and releasing device to form the encirclement configuration and converge to the desired position and attitude. Finally, the tether configuration realizes the slinging of the SCB scale model, which verifies the feasibility of the encirclement method.