A micro high-temperature superconductor-magnet flywheels with dual function of energy storage and attitude control

This paper proposes an energy storage and attitude control system for micro-electromechanical systems (MEMS) in spacecraft using a high-temperature superconductor (HTS) magnet bearing system. This system consists of an HTS-magnet flywheel energy storage system and a brushless motor/generator. The HTS flywheel, which permits high angular momentum storage since its drag torque is nearly velocity-independent and extremely small, facilitates highspeed rotation. It can also perform the dual function of a power/attitude control system using flywheel elements for both power storage and attitude control. This dual function capability further reduces the mass of the spacecraft. The HTS flywheel has an angular momentum capacity of 0.083 Jsec and stores 2.32 kJ at 530 krpm. Its energy storage capacity is approximately 45 Whr/kg with an energy density around 370 kJ/L. The system is ideally suited for low Earth orbit (LEO) energy storage, power generation and attitude control of spacecraft such as nano satellites.