Reliability Modeling for the Space Interferometry

Top-level reliability models have been developed for several recent configurations of the Space Interferometry Mission (SIM) and the results used in the decision process for selecting viable configurations for further study. For one configuration, closed-form solutions were obtained. For three configurations, Excel-based Monte Carlo models were developed. The agreement between the closed form and the Monte Carlo models was excellent, verifying that the Excelbased approach had been successfully implemented. The Excel model has the flexibility to extend the model to more complicated arrangements for which it would be impractical to develop closed-form solutions. The Space Interferometry Mission in NASA’s Origins Program is a 1 Om-baseline space-based Michelson interferometer scheduled for launch in 2009. This large instrument will measure the angles between stars to an accuracy of about one billionth of a degree of arc. This is an improvement of about two orders of magnitude over current astrometric instruments.