Dynamics of Spring-Deployed Solar Panels for Agile Nanospacecraft

Abstract

Advanced performances in nanospacecraft are typically associated with high onboard power availability, requiring deployed solar arrays. Nanospacecraft geometrical and weight constraints do not allow the use of reversible dynamics and lock systems used in conventional spacecraft. Most nanospacecraft deployed solar panel systems are therefore based on compact and reliable miniaturized mechanisms, such as simple passively deployed preloaded springs. The use of these kinds of deployed solar arrays may interfere with the performance of the attitude control system. Agile nanospacecraft, designed to perform rapid attitude maneuvers, may potentially be affected by the solar array dynamical interaction with the main satellite body motion. In addition, the presence of inherently nonlinear elements, such as bounds on allowed rotations and preloaded springs, deserve a dedicated analysis. The analysis developed in this paper is based on the performance of state-of-the art agile nanosatellite attitude control systems, specifically developed for delivering high torque and fast attitude maneuvering, such as miniaturized control moment gyros. By numerical simulation, it is shown that, despite the simplicity of the deployment system and the absence of locking mechanisms, the attitude dynamics remains substantially unaffected by the solar array dynamics. This is obtained straightforwardly by properly sizing the spring stiffness and by a sufficient level of preload.