Trade study and application of symbiotic software and hardware fault-tolerance on a microcontroller-based avionics system

Abstract

Spacecraft avionics initially commanded the development of the microprocessor industry, enabling microprocessors to be designed specifically for the reliability demands posed by the radiation environment of space. However, microprocessor have shifted their focus from ensuring reliable operations to maximizing performance, forcing the price of spacecraft avionics to balloon. Costing over three orders of magnitude more than current state of the art general purpose processors, while performing operations an order of magnitude slower. These differences stem from the reliability requirements of operating in space, typically achieved through hardware-based modifications. While these solutions generate the necessary reliability, they limit the engineering options for the system and force the use of outdated technology. A solution researched but never widely implemented, is the use of error detection and correction software algorithms. An ideal design lies in the combination of hardware and software methods for providing reliability. A new avionics architecture was designed to implement a system using hardware and software to achieve reliability with COTS products. The architecture was applied to the CASTOR satellite as its primary avionics system, for verification testing of the architecture's functionality. This architecture further aims to expand spacecraft usage of microcontrollers as the primary spacecraft avionics computers.