NASA Program Costs: Space Missions Require Substantially More Funding ThanInitially Estimated. Report to the Chairman, Subcommittee on Investigations and Oversight, Committee on Science, Space, and Technology, House of Representatives

摘要

This report responds to a request to provide information on the NationalAeronautics and Space Administration's (NASA) historical experience at estimating space program costs. The Subcommittee was concerned that at the time Congress is asked to authorize the start of new programs estimated to cost hundreds of millions or even billions of dollars, NASA may not have reasonably accurate estimates of their total funding requirements. Specifically, we reviewed the changes from initial to current estimates for major space programs initiated in the past 15 years and studied the reasons for those changes. Almost all of the 29 programs we reviewed required substantially more funding than the initial estimates provided to Congress. Changes in estimates ranged from a 44-percent decrease to a 426-percent increase over the initial estimates. The median change was a 77-percent increase. General reasons NASA gave for differences between the initial and current estimates included insufficient definition studies, program and funding instability, overoptimism by program officials, and unrealistic contractor estimates. Specific reasons for changes in estimates included program redesigns, technical complexities, budget constraints, incomplete estimates, shuttle launch delays, and inflationary effects. As a result of these factors, the content and schedule of many programs changed substantially between the initial and current cost estimates.