Arrow Mode Reboost Analysis for Space Station Freedom

Abstract

Early flights of Space Station Freedom are gravity-gradient stabilized, but reboost to higher altitude while in Arrow Mode, where its truss is aligned with the direction of flight. Power concerns led to a proposal to activate Freedom's solar array beta gimbals for partial sun tracking during reboost. Further plume impingement concerns led to a baseline orientation of flight with the arrays leading. A baseline dynamic simulation for this maneuver is presented here. Several observations are made, particularly about large motions of the beta gimbals during the maneuver, and about simplified structural dynamic response of the arrays to the reboost and large slew environment. The results presented here may be used as a starting point for reboost analyses on other flight configurations, or in other orientations, or with higher-fidelity structural information.