The development of a charge-coupled device tracker for spacecraft

Charge-coupled device (CCD) optical sensors have made it possible to construct high performance star and target trackers for spacecraft. The Advanced Star and Target Reference Orbital Sensor (ASTROS) trackers have been developed by JPL for the Shuttle-based astronomical flight Astro-1 and the Mariner Mark II (MMII) spacecraft. For the Shuttle application the tracker will provide the data for high precision instrument pointing and for the MMII application the tracker will provide stellar and extended target tracking data for flyby and rendezvous navigation. The specifications, architecture, and testing program for these trackers will be described. Laboratory measurements have demonstrated that these trackers can be very effective. The versatility and flexibility of the ASTROS type trackers will permit adaptation to a variety of navigation and guidance applications. These trackers represent one of the technologically advanced components that will be used in the development of the next generation of spacecraft.