Transpermanent Magnetic Actuation forSpacecraft Pointing, Shape Control, and Deployment

Abstract

Transpermanent magnetic actuators are systems consisting of one or more permanent magnets, some of whose magnetic strengths can be switched onboard by surrounding pulse-coils. Transpermanent magnetic actuators are shown to be particularly wellsuited for spacecraft pointing, shape control, and deployment applications. In many spacecraft pointing, shape control, and deployment applications, it is desirable to hold displacements or forces between two points to within specified requirements (the regulation problem) and periodically to change or remove these requirements (the tracking problem). Furthermore, the interest generally lies in satisfying the dynamic performance requirements while expending minimal power, while meeting tight tolerances (particularly in optical applications), and while experiencing little wear and fatigue. The transpermanent magnetic actuator is shown to expend no power during regulation, and the transpermanent magnetic actuator is shown to be able to change periodically or remove the strength of its own magnets, thereby enabling both fine-tune adjustments and large-scale adjustments during tracking. The fine-tune adjustments are necessary in thermally varying space environments, and the large-scale adjustments are necessary in deployment problems in which pivot points experience large-angle rotations. A transpermanent magnetic actuator concept is demonstrated.