GAO: International Space Station: Ongoing Assessments for Life Extension Appear to be Supported

GAO-11-519R April 11, 2011 Full Report (PDF, 39 pages)

NASA is using analytical techniques, physical tests, and inspections to assess primary structures and functional systems and determine sparing needed to support safe functioning and full scientific utilization of the ISS through 2020. These assessments are ongoing, so all results are not yet available. Our work indicates that NASA’s assessments appear to be supported by sufficient, accurate and relevant underlying data. We found, however, that NASA’s estimates of ISS sparing needs are sensitive to assumptions about hardware reliability. To evaluate NASA’s approach, we reviewed relevant technical documents and data NASA used to support its analysis and interviewed responsible officials. In a limited number of cases, we replicated NASA’s calculation used to update predicted failure rates for essential spares.