Demonstration of a Magnetic Locking Flux-Pinned Revolute Joint for Use on CubeSat-Standard Spacecraft

Abstract

Magnetic flux pinning is an interaction between strong magnets and certain superconductors that causes a damped, non-contacting equilibrium to form, connecting the flux-pinned objects. This interaction has been proposed for use in establishing a stable formation of spacecraft modules that is resistant to disturbances. Although flux pinning can exert forces in all six degrees of freedom, a flux-pinned interface can be designed to constrain only certain degrees of freedom so that it functions as a non-contacting kinematic joint. One such joint consists of a superconductor flux pinned to a cylindrical magnet and free to move around the magnet’s axis of symmetry. Such an interface would serve as a revolute joint that allows two modular spacecraft to reconfigure. This paper explores the development of one such joint compatible with the CubeSat standard. We extend the functionality of the revolute joint by introducing electromagnets that create two stable equilibrium states in a system of two modules. The electromagnets also provide the means of reconfiguration between the two states, eliminating the need for reaction wheels, thrusters, or other conventional actuators for this maneuver. Finally, this paper discusses future testing for flux-pinned joints and ongoing work on an in-orbit demonstration.