Role of Diagnostic Monitoring Software Versus Fault-Tolerant Components in the Development of Spacecraft Avionics Systems

In any spacecraft, there are several systems that must work simultaneously to ensure a safe mission. One critical system is the ‘avionics’ system, which is comprised of all of the electronic controls on-board the spacecraft, as well as radio links to other craft and ground stations. These systems are present for both manned or unmanned spacecraft. Throughout the history of spaceflight, there have been several disasters related to avionics failures. To make these systems safer and more reliable, two main strategies have been adopted. The first, more established approach is through use of fault-tolerant components, which can operate under a wide range of conditions in the harsh space environment. The other, newer approach is to use software systems to monitor components in real-time to predict where failures may occur, and if they do occur, reconfigure the system itself to mitigate potential disasters. Though both approaches are necessary for an effective avionics system in modern spaceflight, monitoring software should be more heavily emphasized moving forward. At this point, the vast majority of avionics failures aren’t related to specific component failures, but wider systematic failures. Past history has shown that the ability of crew members and ground controllers to respond to system failures has mitigated potential disaster, and monitoring software is the most effective means of allowing enabling an effective response