Software is a key component of modern space systems, which controls and monitors the functions of a range of electronic and mechanical devices. In essence, software provides the “brains” for the execution of all launch vehicle and space vehicle functions. While complex functionality may be welcome on one hand, software complexity may introduce more opportunity for system anomalous behaviour, or even for catastrophic failures. In order to have sufficient confidence in the successful accomplishment of a mission where software plays a crucial role, designers and analysts need to have at their disposal software assurance and assessment tools comparable in analytical capability to those that are in common use for the evaluation of the typical hardware portions of the system. The approach to software risk assessment discussed in this paper is based on recent developments in software risk assessment techniques that have been successfully applied and validated in actual NASA space program environments. These techniques are linked and applied together in one risk modeling framework which is referred to by the denomination CSRM (Context-based Software Risk Modeling). The CSRM framework and the techniques within it are flexible and can be selected to suit the specific needs of the user and the specific characteristics of the system of interest, providing the flexibility to adapt the analytical approach to the nature of the problem at hand, as well as to the level of information and resource available to tackle it. The CSRM approach is documented as the recommended framework for software risk assessment in the NASA Probabilistic Risk Assessment Procedures Guide.
S. Guarro, M. Yau and S. Dixon, “Context-based Software Risk Modeling: A Recommended Approach for Assessment of Software Related Risk in NASA Missions,” Proceedings of the 11 th International Conference on Probabilistic Safety Assessment and Management (PSAM 11), Helsinki, Finland, June 25-29, 2012