Analysis of Phoenix anomalies and IV&V findings applied to the GRAIL mission

NASA IV&V was established in 1993 to improve safety and cost-effectiveness of mission critical software. Since its inception the tools and strategies employed by IV&V have evolved. This paper examines how lessons learned from the Phoenix project were developed and applied to the GRAIL project. Shortly after selection, the GRAIL project initiated a review of the issues documented by IV&V for Phoenix. The motivation was twofold: the learn as much as possible about the types of issues that arose from the flight software product line slated for use on GRAI L, and to identify opportunities for improving the effectiveness of IV&V on GRAIL. The IV&V Facility provided a data base dump containing 893 issues. These were categorized into 16 bins, and then analyzed according to whether the project responded by changing the affected artifacts or using as-is. The results of this analysis were compared to a similar assessment of post-launch anomalies documented by the project. Results of the analysis were discussed with the IV& V team assigned to GRAIL. These discussions led to changes in the way both the project and IV&V approached the IV&V task, and improved the efficiency of the activity.