Open-loop satellite librational control in elliptic orbits through tether

The paper proposes the use of a bitethered pendulum mass deployed from satellite for open-loop satellite attitude control in elliptic orbits. A simple approximate analytical approach has been adopted to develop control law governing moments generated through a judicious non-feedback scheme of tether length variation with a view to neutralize the adverse effect of the harmonic excitation induced by eccentricity. The detailed simulation of the system response shows that the proposed control strategy enables much higher pointing accuracies for satellites in elliptic orbits, even with most adverse satellite mass distribution. The small auxiliary pendulum mass needed along with modest tether lengths make the concept particularly attractive. (C) 1998 Elsevier Science Ltd. All rights reserved.