STABILITY OF FORCE-FREE MOTIONS OF A DUAL-SPIN SPACECRAFT

The motion of a spacecraft with flexible and moving parts, damped in its relative internal motion, moving in a force-free space, is discussed using Lyapunov stability theory. In addition, the body is permitted to contain rotors, making it a dual-spin spacecraft. Many results have been obtained for such systems, including the renowned “maximum moment of inertia axis rule” for stability of a quasi-rigid, damped body in force-free space. This paper aims at generality, rigor, and nonlinear results for a very important idealization of the actual engineering problem met in design of spinning spacecraft. Extension of the energy Lyapunov function to a Lyapunov function on an integral manifold of phase space is necessary because of the presence of angular momentum integrals. Two examples are given to illustrate the theory. General theorems are given for quasi-rigid dual-spin spacecraft. © 1969 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.