MOMENTUM SYSTEM CONCEPTS AND TRADES FOR THE NEW CLASS OF SMALLER LOWER COST SATELLITES

摘要

Momentum systems for older satellites are but individual CMGs built by the CMG manufacturer and integrated into the spacecraft by the spacecraft manufacturer. This has worked well in the past but new requirements and new technology is resulting in an integrated momentum sub-system approach that is providing major improvement for several programs currently in development. Recent advances in bearing and lubrication systems prove that wheels can be operated at much higher speeds. High speed and integration of momentum devices into a single sub-system combine to open design trade space leading to much smaller, lower cost and lighter weight momentum systems.An optimization program will be described and optimized CMG designs will be compared to existing CMGs. A cost function of equivalent weight used in the optimization program will be provided. The Ideal Rotor weight equation will be derived and a practical rotor weight equation provided to show the relationship between weight, speed, momentum value and size. The paper will describe how the new optimized designs will involve a minimum development risk. The paper is summarized with a discussion of some additional practical considerations including comments on schedule and cost.