Rotating tethered system for active space debris removal

A new technique for active debris removal using tethered space tug is presented. Instead of towing the captured debris object by pulling on the attached tether it is proposed to use the rotation of the tethered tug-debris system that allows to apply the tug's thrust along the tether pushing the system. The rotation of the tug-debris tethered system around its center of mass provides necessary tension of the tether when the tug applies its thrust along the tether. To de-orbit the system the tug should apply its thrust periodically when the orientation of the tether relative to the the orbital velocity vector of the system ensures application of the impulse in the required direction. A simple mathematical model of tethered tug-debris system is developed which allows to estimate required angular rate of the system. A tether control law is proposed that reduces the amplitude of the tether oscillations during applying tug's thrust.