A case study in attitude determination and control on the cassini mission to saturn

The Cassini spacecraft design was such that the instruments were fixed mounted to the spacecraft body which required rotation of the entire spacecraft to point the instruments in the proper direction in order to take observations. The operations of the Cassini optical remote sensing instruments required a high level of spacecraft-pointing stability to minimize image distortion during an exposure window. This case study provides highlights of the Cassini missions, and overviews of the hardware, software, and aspects of the systems engineering and operations approaches. It focuses on the flight performance of the Cassini spacecraft's pointing stability with respect to mission requirements, sources of spacecraft jitter, and the two spacecraft control modes using the reaction-wheel assembly or the reaction control system composed of eight thrusters. It also summarizes the steps that needed to be taken to manage attitude control performance over a 20-year flight operations period. 1