SPOAC and Hinge Integrated MSAC: Non-holonomic Attitude Control Systems for Spacecraft

Two novel spacecraft attitude control system technologies are introduced that both rely on the same nonholonomic control trajectory concept but that utilize distinct system implementations. The first of these two technologies is Hinge Integrated Multifunctional Structures for Attitude Control (MSAC), which is a new attitude control system that utilizes deployable panels to provide a spacecraft with both fine pointing and large angle slewing attitude control capabilities. Given its potential for high reliability and these control capabilities, Hinge Integrated MSAC is a viable alternative to conventional momentum exchange-based attitude control systems. This study details the Technology Readiness Level (TRL) advancement for MSAC systems toward TRL 6 and introduces potential flight opportunities. We also introduce the Suspended Phased Oscillators for Attitude Control (SPOAC) system concept and mission design (which leverages MSAC control concepts), along with a prototype validation of the system. The Hinge Integrated MSAC system utilizes the deployable panel flexure/compliance to induce phased non-holonomic vibrations that generate largeangle slewing. Using flexure-based techniques, MSAC eliminates the need for sliding contact systems such as mechanical bearings, thereby eliminating a key failure mode of conventional reaction wheel assemblies (RWAs) and control moment gyroscopes (CMGs). The SPOAC operating concept is similar to that of MSAC, but instead of deployable panels, it employs levitating reaction masses that are oscillated using phased nonholonomic magnetic fields. The breakthrough SPOAC technology is ideal for small spacecraft and larger spacecraft that do not have large appendages, such as solar panels