Space Shuttle Main Engine: NASA Has Not Evaluated the Alternate Fuel
Turbopump Costs and Benefits (Letter Report, 10/29/93, GAO/NSIAD-94-54).

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.

--------------------------- Indexing Terms -----------------------------

 REPORTNUM:  NSIAD-94-54
     TITLE:  Space Shuttle Main Engine: NASA Has Not Evaluated the 
             Alternate Fuel Turbopump Costs and Benefits
      DATE:  10/29/93
   SUBJECT:  Aerospace research
             Aerospace engineering
             Safety standards
             Life cycle costs
             Cost analysis
             Comparative analysis
             Aircraft engines
             Research and development
             Alternative energy sources
             Space exploration
IDENTIFIER:  Space Shuttle
             NASA Space Shuttle Safety and Obsolescence Upgrade Program
             Space Shuttle High Pressure Fuel Turbopump
             
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