Motors in Space

All momentum devices require a spin motor of some type to actuate the rotor spin axis. CMGs also require a motor on the gimbal axis. The torque and speed requirements for the gimbal motor design are typically much different from those for the rotor. These issues, among others, motivate the following discussion of motors commonly employed in spaceborne momentum devices. The objective of this chapter is to familiarize the reader with some of the key considerations with the goal of informing the analysis, implementation, and operation of momentum-control systems and the spacecraft that use them. Motor design is a broad specialty field that demands much more depth than offered here.