This paper describes the design of a stabilization system for control of a spacecraft designed to be launched on a medium-sized launch vehicle. The system is required to provide accurate attitude control and determination for a nominally nadir-pointed spacecraft with moderate attitude maneuver capability. The spacecraft uses reaction wheels as the primary actuators and an effective magnetic momentum desaturation system. Attitude determination is based on stellar position measurements and gyroscope bias estimations to maintain attitude knowledge. A significant design problem involves the stabilization of maneuverable flexible solar arrays with low natural frequency. The attitude determination and control system is composed of sensors, actuators and an integrated electronics unit. A propulsion system allows for incremental velocity adjust capability and actuation during back-up attitude control. This paper provides a description of the attitude determination and control system configuration and functional operation. In addition the component characteristics are presented.