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Description of Driving Event:

Space Shuttle Main Engine (SSME) test 901-0674 was conducted on November 6, 1991 at 11:31 am CDT. The scheduled 400 second test was terminated by the Command and Data Simulator (CADS) at engine start plus 3.72 seconds when the Low Pressure Fuel pump (LPFP) discharge pressure sensor was disqualified by exceeding its maximum qualification limit of 300 psia. The controller responded by issuing a Major Component Failure (MCF) which initiated the CADS cutoff.

The main objectives of test 901-0674 were: reacceptance of flight engine 2032 with replaced oversized piston ring seal wave spring, facility flow meter calibrations, and the greenrun of the following flight hardware: Controller U/N F48, High Pressure Fuel Turbopump U/N 2226, Low Pressure Fuel Turbopump U/N 4018, Low Pressure Oxygen Turbopump U/N 2035, and Chamber Coolant Valve Actuator (CCVA) S/N 037-71008. The propellant system chilidown and prestart engine conditioning phase of the test was normal.

Post test inspections indicated no external engine or facility damage. Internal borescope inspections revealed heavy erosion of the High Pressure Fuel Turbopump (HPFTP) first stage nozzle and turbine blades. No other internal damage was noted. Post test inspection of the CCV/CCVA assembly revealed the coupler which links the CCVA to the CCV was missing. Inspection of the CCV also revealed the valve to be fully closed throughout the test.