Fracture Investigation of Hollow Cylindrical Tether during Space Debris Impact

Space debris poses a serious threat and the problem must be solved. Space debris should be removed to maintain the space environment. One of the techniques to remove it is an electrodynamic tether system (EDTS). To improve the toughness of the tether used in EDTS, this study investigated the tether shape of a hollow cylinder instead of the conventional solid cylinder. When the mass and length of a hollow tether are the same as those of the solid tether, the hollow cylindrical tether has a larger diameter. Thus, the toughness against small debris collisions will be improved. To investigate the damage to the hollow tether following a debris collision, hypervelocity impact experiments were performed using a two-stage light-gas gun. Through the impact experiments, the relationship between the damage to the hollow tether and the impact condition of the debris was revealed. It was confirmed that when the impact angle increased the damage area increased as well. The experiments validated that a hollow tether is superior to a solid tether in terms of resistance to debris collisions. In addition, the importance of considering the influence of the impact angle was shown by an evaluation of the lifetime of the hollow tether.