Targeting safety-related errors during software requirements analysis

This paper provides a Safety Checklist for use during the analysis of software requirements for spacecraft and others safety-critical, embedded systems. The checklist specifically targets the two most common causes of safety-related software errors: (1) inadequate interface requirements and (2) discrepancies between the documented requirements and the requirements actually needed for correct functioning of the system. The analysis criteria represented in the checklist are evaluated by application to two spacecraft projects. Use of the checklist to enhance the software-requirements analysis is shown to reduce the number of safety-related software errors.