This photo shows the exhaust from the pre-burner used to generate the hot gases to drive the space shuttle engine LOX (Liquid Oxygen) turbopump during testing.  For a typical turbopump test, the low pressure tank is pressurized to simulate the NPSH (Net Positive Suction Head) of the space shuttle turbo pump inlet. The high pressure LOX and hydrogen tanks are pressurized to approximately 1500 psi in order to control the starting flows into the pre-burner.  The valve resolution problems experienced when controlling a wide range of flows are solved by controlling three fast-acting electro-hydraulic valves in parallel in each propellant line. The acceleration of the turbopump is less than four seconds to simulate main engine operation that requires the high pressure propellant tanks to be ramped to 9000 psi.  The liquid hydrogen is conditioned by a liquid/gas mixer to simulate shuttle main engine inlet temperatures.  The high response control system controls tank pressurization, propellant flow, temperature, and turbopump speed. The abort system monitors over 200 parameters and calculations and initiates shutdown or test termination if an anomaly is detected.

EDF Inc. worked as a team with Pratt & Whitney personnel to design, build, certify, and operate this complex test stand.