Flywheel Energy Storage System for Small- and Medium-Size Spacecraft

Innovation in key technology areas will provide the dramatic advances needed for small- to mid-sized space-based flywheel energy storage systems. Our vision for this work is based on our understanding of high-speed machinery and our background in similarly sized flywheel systems. Based on this experience, we have focused this SBIR program on two areas: the main bearing system and the motor-generator (M-G). A reliable main bearing system is key to the success of any flywheel system. The magnetic-bearing-based system we propose is simple yet robust with high reliability. Its unique combination of passive and actively controlled elements will become the standard against which future designs are judged. The M-G directly impacts the function and capability of the magnetic bearings. We propose a device that features a rotor with very low losses and very high efficiency. Work in Phase I will prove several key aspects of the main bearing system, followed by full development of the bearings and M-G in Phase II. Because we have invested considerable effort in the preliminary design and analysis of these two elements, we are confident that the proposed technology developments will solve the most challenging aspects of flywheel energy storage systems for spacecraft.