Summary

The National Aeronautics and Space Administration's (NASA) decision to develop an alternative high-pressure fuel turbopump for the space shuttle's main engine may prove more desirable from cost, performance, and safety perspectives than the current design or a modified version of the design; NASA, however, has not compared the various alternatives on the basis of cost and safety factors. Such information is essential if NASA is to determine whether it can afford this program. The alternative fuel pump's design may prove to be more rugged than the current pump's. But according to NASA and outside experts, with existing safety controls, the current pump is safe to fly. NASA has not quantified the contribution of the fuel pump to the increase in shuttle reliability expected to result from the improvements. Many flights and a large number of tests will be needed to determine whether the alternative pump will be as reliable as the current pump. Also, NASA has not estimated the life-cycle costs of the alternative fuel pump or improvements to the existing pump. NASA projects that, excluding test costs, to complete development and buy 18 alternative pumps will cost $314 million. By reducing the amount of inspection and maintenance, the alternative pump should reduce shuttle operating costs, but NASA has not estimated the amount of the expected savings.

GAO found that: (1) the current engine pump is safe and reliable if existing safety controls are effectively implemented; (2) NASA supports continued development of the alternate pump because of safety concerns about some aspects of the current pump's design; (3) NASA has not analyzed the costs and benefits of modifying the existing fuel pump because a major upgrade will require an expensive full certification test; (4) NASA has not determined what contribution the alternative fuel pump will make to the Shuttle's reliability in conjunction with other engine safety improvements; (5) the alternate fuel pump will require extensive testing and possible redesign as problems occur; (6) NASA did not analyze the costs and benefits of modifying the existing fuel pump and other alternatives before resuming development of the alternate pump; and (7) NASA expects that the alternate pump will reduce operating costs by decreasing inspections and maintenance, but it has not estimated the expected savings.