Application of Fault-Tolerant Computing For Spacecraft Using Commercial-Off-The-Shelf Microprocessors

Low availability, high cost, and poor performance of radiation hardened (rad-hard) equipment has driven the market to rely on commercial-off- the-shelf (COTS) equipment for the computing needs of today's spacecraft. This thesis describes the tailoring of a COTS embedded real-time operating system and design of a human-computer interface (HCI) for a triple modular redundant (TMR) fault-tolerant microprocessor for use in space-based applications. Once disadvantage of using COTS hardware components is their susceptibility to the radiation effects present in the space environment. and specifically, radiation- induced single-event upsets (SEUs). In the event of an SEU, a fault-tolerant system can mitigate the effects of the upset and continue to process from the last known correct system state. The TMR basic hardware design used for this research is an acceptable fault-tolerant design candidate for the main processor for space-based applications. We found that a COTS embedded real-time operating system could be tailored to support the TMR hardware. The HCI accepts serial data from the TMR, correctly identifies the source of the error, allows for processor mode selection and provides system- and board-level reset capabilities. The tailored operating system combined with the HCI is a viable software imp- lementation to support hardware-based fault-tolerant computing in a space environment.Naval Postgraduate School Monterey CA is the author of 'Application of Fault-Tolerant Computing For Spacecraft Using Commercial-Off-The-Shelf Microprocessors' with ISBN 9781423536239 and ISBN 1423536231.