Actively Controlled Fail-Safe Mechanical Battery System for Military and Commercial Space Systems

Period of Performance: 01/22/1998 - 04/30/2000


Phase 2 STTR

Recipient Firm

Applied Material Technologies, Inc.
2302 S. Fairview Street
Santa Ana, CA 92704
Principal Investigator
Firm POC

Research Institution

Pennsylvania State University
110 Technology Center Building
University Park, PA 16802
Institution POC


Flywheel energy storage (FES) systems used for electrical power delivery and for attitude control offer weight and performance advantages over chemical battery systems. Weight savings are derived from higher specific energy of the FES, replacement of RWAs and CMGs, smaller solar arrays due to efficiency improvements (95% vs 80%) and simplification of the thermal control system. The life of an FES is expected to span more than 15 years. A major concern for an FES system is the safe operation of the high speed rotor (40,000 to 60,000 RPM). At these speeds failure of the rotor can cause catastrophic damage that could lead to a premature end of the mission. A health monitoring system that detects failures and slows or stops the rotor before a catastrophic failure occurs is an approach to ensuring safe operation. Also development of a rotor design that is lightweight and fails in a predictable manner is needed. This STTR project is for the developent of a health monitoring system that utilizes a very lightweight innovative rotor design. AMT and Penn State University have demonstrated feasibility during the Phase I project and in Phase II a working prototype FES system with health monitoring will be developed.