An Attitude Control Design for the Cassini Spacecraft

The Cassini planetary mission to Saturn and Titan requires accurate pointing and complex maneuvers of the spacecraft, which is comprised of a Saturn orbiter and Titan probe. An attitude control design is described to achieve the many capabilities of Cassini including thrust vector control, precision pointing and stability control fc)r remote sciences, tracking of a probe released to the Titan atmosphere, and radar mapping of the Titan surface. Additional constraints for control design have been imposed by a high percentage of liquid propellant (60.% at launch) and lowly damped flexible spacecraft appendages. Computer simulation results of attitude determination, pointing and maneuver controls are provided to demonstrate the design capability.