Reliable flight computer for sounding rocket with dual redundancy: design and implementation based on COTS parts

Abstract

Sounding rockets provide a useful platform for the aerospace research activities. One of the main and substantial parts of the sounding rockets is the flight computer which is responsible for the management of the other subsystems, running the flight scenario, and data acquisition from the experimental payload. Due to the crucial role of the flight computer in the success of the devoted mission, high reliability is one of the main requirements of the flight computer. Technical, systematical, and operational requirements alongside the procurement problems of the special-purpose space-grade components, force this research to take a dual redundant architecture based on the commercial off-the-shelf (COTS) components. Although the theoretical aspect of the reliable flight computer has been investigated extensively, design and implementation of a dual-redundant reliable flight computer are presented in this paper, which has very rarely been published. The processing unit, data bus unit, and the sensors/actuators are designed to be dual redundant. The supervisor monitors the operational units and if it detects any failures, replaces them with the spare ones while trying to make the repair through restarting. If it succeeds in recovering the failed unit, the system continues its operation as a dual-redundant system; otherwise, it becomes a single system. Our analytical assessments show that the reliability of a dual-redundant computer with the COTS components is comparable with the reliability of a single computer being composed of the special purpose components with tens of times lower failure rates. The evaluations show that the reliability requirement of the system is covered while saving the cost considerably.