AAS 95-336

An Evaluation of Energy-Sink Stability Criteria for Dual-Spin Spacecraft

V. M. Ortiz and I. M. Ross, Dept. of Aero & Astro., Naval Postgraduate School, Monterey, CA

Abstract

The very old problem of nutational stability of a dual-spin, quasi-rigid, axisymmetric spacecraft containing a driven rotor is revisited. The purpose is to examine ‹ by way of a numerical analysis ‹ a revised energy-sink stability theory that accounts for the energy contributions of the motor. An expression for the nutation angle is derived as a function of Hubert's core energy. This equation is used to estimate the rate of convergence or divergence from a known equilibrium state whose stability can be predicted by the revised theory. Mingori's model of a dual-spinner is used as a truth model. Numerical simulations demonstrate that the time constants associated with the energy-sink model compare well with the truth model.