Design and Performance of the OrbView-2 Attitude Control System

The OrbView-2 satellite, launched on August 1, 1997, is the world's first commercially owned imaging satellite. Because of the commercial nature of the mission, design of the OrbView-2 attitude control system was constrained by cost as well as the normal physical parameters. In addition to maintaining a nadir-pointing momentum-biased mission mode, the spacecraft maintains a wide variety of operating modes including an extended orbit-raising sequence. The mission requirements were met without the use of gyros or other high-cost attitude sensing hardware. This paper provides an overview of the attitude control system design as well as a description of the post-launch system performance.