Do higher cost reserve levels for space science missions ensure good cost performance?

Recent efforts to improve cost performance for space science missions have included a fairly significant minimum cost reserve level. However, many projects that start with a strong reserve posture appear to experience as much or more cost growth than projects that have begun with less reserves. This study investigates cost reserves and performance for several space science missions and attempts to identify the most significant causes for cost growth and reserve expenditures and provides suggestions for improvement. Initial findings suggest more emphasis on careful front-end planning and a conservative base estimate may enable better cost performance with lower reserve levels