Method of Active Debris Removal Using Rotating Space Tether System

A new method of a large space debris de-orbit using tethered space tug is presented. It is proposed to use the rotation of the tethered tug-debris system to provide the necessary tension of the tether that allows applying the tug’s thrust along the line of the tether in the direction of space debris. Due to the rotation of the tethered tug-debris system the orientation of the tug’s thrust vector changes with the time. To de-orbit the system the space tug applies its thrust force when the orientation of the tether relative to the orbital velocity vector of the system ensures application of the tug’s thrust impulse in the required direction. The angular rate of the tethered tug-debris system has to ensure that during the transient events associated with the turning on and off the tug’s thruster the tether tension force does not fall below zero. A spatial mathematical model of the tethered tug-debris system is presented and control law for the space tug’s thrust to reduce tether oscillations is proposed. The presented method is verified by means of numerical simulations.