A quantitative risk assessment method for space flight software systems

A risk index factor has been developed at the NASA Johnson Space Center in order to quantify the risk associated with individual software components in programs developed for space flight applications. Risk can be defined as the combination of the likelihood of a failure occurrence with the consequence of that occurrence. The risk index attempts to quantify this product, utilizing the results from software complexity analysis, the evaluation of test coverage, and a failure modes and effects analysis. This report presents an overview of the development of the risk index factor as well as the methodology used in performing the support analyses. Results from the data collected for two dissimilar space flight projects are also presented.