Confidence in Spacecraft Software: Continuous process improvement in requirements verification

The Space Department's (SD) Embedded Applications Group at the Johns Hopkins University Applied Physics Laboratory (JHU/APL) continues to apply its experience with independent requirements verification to achieve high confidence levels in the quality of Spacecraft Software. NASA's Van Allen Probes observatory, which was launched in August 2012, provides another stepping stone for continuous improvement of our independent software requirements verification process to support future spacecraft missions. In 2005, a study was conducted within JHU/APL's Embedded Applications Group that summarized lessons learned, cost efficiency and effectiveness of independent Spacecraft Software requirements verification across four supported NASA spacecraft missions [1]. The outcome of the 2005 study provided recommendations to improve how we conduct requirements verification on Spacecraft Software for JHU/APL SD supported missions. Many of the 2005 study's recommendations were directly applied to the Van Allen Probes mission and this recent experience provides another opportunity to analyze the cost efficiency and effectiveness of our independent Spacecraft Software requirements verification process. The follow-on paper recommendations and Applications Group's will highlight the 2005 study's elaborate on the Embedded implementation of these recommendations during the requirements verification program for the Van Allen Probes Spacecraft Software. A variety of metrics can be used during development to monitor Spacecraft Software maturity patterns, to assess confidence level in Spacecraft Software prior to launch and to guide the focus of the Spacecraft Software's requirements verification program. Elaboration on these metrics will be discussed in this paper and use cases will be presented for the Van Allen Probes mission. The paper will also highlight lessons learned during the Van Allen Probes Spacecraft Software requirements verification program. The results of the analysis and the lessons learned will yield additional recommendations for continuous improvement of our independent Spacecraft Software requirements verification process to be followed on the next NASA mission, Solar Probe Plus, which has a planned 2018 launch date.