Self-rotating string loop’s overall state in vacuum and microgravity

Abstract A flexible string loop possesses a certain degree of rigidity when it moves. Based on this intriguing property, overall states of a string loop when it self-rotates driven by friction and when the whole is moved by a control end in vacuum and microgravity are investigated theoretically. When the string loop self-rotates, tension is uniformly distributed along the longitudinal direction of the string. At the same time, the shape is unknown under the current theoretical framework. When the string loop is moved as a whole, an expression of lateral stiffness is proposed, and limit conditions of translation acceleration, rotational angular velocity and rotational included angle that require to be imposed to control lateral force and deformation are put forward. This research is conducive to the development of control technology of string loops, and further is hopeful to be applied to projects such as debris capture and tethered satellites in space.