Assessing Acquisition Schedules for Unmanned Spacecraft.

Abstract : The research documented in this report was initiated to provide methods for assessing the reasonableness of proposed acquisition schedules for space-based elements of proposed SDS architectures and for the software associated with both space- based and ground-based segments of these systems. The approach used in accomplishing this task was to: (1) review the relevant literature; (2) collect historical schedule and technical data on acquisition programs for unmanned spacecraft; (3) compile the data in consistent formats for use in data analyses and for comparison with future acquisition programs for space systems; and (4) analyze schedule intervals in the data, derive time-estimating relationships (TERs), and integrate the TERs into a schedule-assessment tool that spans the period from engineering development start through production. The primary technique in defining and testing ThRs was linear regression analysis. In applying regression analysis, schedule interval lengths measured in months were treated as dependent variables and regressed against independent variables that were thought to influence the interval lengths. Multiple TERs are presented for three different schedule intervals, engineering development duration, manufacturing intervals for production spacecraft, and software development duration. The TERs are integrated and an example application is presented. (KAR) P. E