Rotational Dynamics of Axisymmetric Variable Mass Systems

Abstract

This paper studies the attitude dynamics of variable mass systems that have axisymmetric mass distribution and that are subjected to continuous mass variation while in motion. The equations of rotational motion for such systems are solved analytically under the assumption of zero external torque. It is found that such systems can spin up or spin down in free motion, and that the transverse angular velocity magnitude can increase or decrease with time. The analytical conditions for growth or decay of spin rate and lateral angular speed are presented, and these conditions are related to practical design criteria for rocket-type systems.