Minimizing the Effects of Transverse Torques During Thrusting for Spin-Stabilized Spacecraft

Abstract

During an orbital maneuver of a spin-stabilized spacecraft, undesired transverse torques are present due to thruster misalignment and offset from the center of mass. These body-Ž xed torques cause the thrust vector to precess about a direction that is offset from the nominal. This oscillation of the thrust vector over the course of the maneuver decreases the Ž nal magnitude of the D V while the average offset causes a pointing error. Previous work shows that inserting a short-coast phase into the maneuver can eliminate the pointing error. The behavior of the thrust axis is considered to Ž nd solutions for the coast phase timing that minimize the average oscillation of the thrust axis to maximize D V, while retaining the property of eliminating the secular pointing error. The new maneuver scheme realizes a signiŽ cant increase in efŽ ciency over the previous solution, particularly if the oscillation of the thrust axis is large.