Development of CubeSat Magnetic Torquer Testing System in a Vacuum Environment

Abstract

This paper discusses the development and instrumentation of an integrated facility based on an air-bearing table to test small ADCS actuators such as electric propulsion devices, reaction wheels, and magnetic torquers for CubeSats. It includes an automatic balancing system that corrects the center of mass of the testing platform and a Helmholtz cage for the simulation of the in-orbit geomagnetic environment inside the vacuum environment. Through experimental tests, it was observed that the attitude disturbances due to the aerodynamic drag and the viscous rotational friction in atmospheric conditions (~5×10-6 Nm) can be significantly decreased when the testing platform is placed inside a vacuum environment (~5×10-7 Nm). It was also observed that the vacuum condition facilitates the verification test of attitude control maneuvers using small magnetic torquers for CubeSats whose control torque is smaller than the attitude disturbance torque in atmospheric conditions. A demonstration test was performed to verify the attitude stabilization control by the magnetic torquers in vacuum conditions under a simulated geomagnetic field as in the International Space Station orbit using this integrated testing facility.