The micro Advanced Stellar Compass (μASC) was developed as the first high accuracy, fully autonomous, multi sensor star tracker system in the world, and has successfully flown in space since 2008. The goal was to achieve the ultimate performance envelope and accuracy, while offering the highest achievable reliability and lifetime.

The μASC design is thus based on parts selected, tested and verified to the highest possible level, e.g. each flight lot is fully characterized against radiation and lifetime. The design further employs strict derating and equi-thermal layouts. The result is a unit able to operate over a vast temperature range encompassing all known spacecraft requirements by far, and at the same time offering an established MTBF in excess of 1000 years. The manufacturing, tests and validation of the flight instruments are strictly adhering to and surpassing the established NASA and ESA rules, regarding both HW, SW and FPGA Firmware. As a consequence, the extremely robust autonomous operation, unsurpassed accuracy and availability, modest resource requirements and high reliability, have resulted in the fact that the instrument till now is flown on more than 70 spacecraft ranging from NASA class D to B and ESA class S to L, and that another 30 units are under contract or integration at this time.

The basic μASC consists of one to four camera head(s) units (CHU), attached to a micro Data Processing Unit (μDPU) featuring a full redundant communication interface and an auxiliary test channel. The μDPU is further offered in a fully redundant configuration enabling full cold and hot redundancy at unit level. The extremely large performance envelope encompasses special features enabling full performance under the worst radiation conditions encountered in space so far. This includes full operations inside the Van Allen belt as well as under the conditions generated of the largest CMEs measured, in deep space as well as GEO, GTO and LEO. Another feature of the optimized design is, that an unmodified μASC can service on both 3axis stabilized as well as on spinning spacecraft.