Extensive research conducted by the Langley Research Center has led to the development of a spacecraft control system employing three control moment gyros (CMG's). This Langley concept has been selected as the baseline control system for the Apollo Telescope Mount (ATM) which is being developed by the Marshall Space Flight Center. Langley is providing Marshall with the necessary supporting research to insure a successful ATM flight.
A full-scale CMG unit has been procured to determine CMG hardware characteristics and nonlinearities. To evaluate the effects of these nonlinearities on the control capability of a CMG system, the unit has been incorporated into an analog simulation of spacecraft control for the ATM. This paper presents a description of the physical and hardware characteristics of the CMG unit, and discusses results obtained from the system simulations for ATM. These results indicate that the Langley CMG system can meet all ATM spacecraft pointing requirements.