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Pratt & Whitney Delivers First Overhauled Space Shuttle Oxidizer Turbopump

WEST PALM BEACH, Fla. (Aug. 22, 2003)— The first overhauled Space Shuttle Main Engine (SSME) high-pressure liquid oxidizer (LOX) turbopump, which flew on six space shuttle flights during seven years of service, was delivered to NASA's primary SSME contractor, Boeing, by Pratt & Whitney (P&W) Space Propulsion, following a meticulous overhaul and repair process. The turbopumps are arguably one of the most critical components of the SSME.

Periodic overhauls, in addition to the design and hardware characteristics, allow turbopumps to operate during 30 or more shuttle flights. The specified service duration before overhaul is required for P&W's LOX turbopump is the equivalent to 11 shuttle missions. This pump, known as LOX 8015, completed five ground tests in addition to its shuttle flights, accumulating more than 5,000 seconds of operation.

During the 15-month overhaul and repair process, the turbopump was completely disassembled and inspected. Where needed, components were refurbished, upgraded or replaced, but most major parts were re-used, producing substantial lifecycle-cost benefits to the program.

“This is the only rocket propulsion system in the world that undergoes true overhaul and repair,” P&W Space Propulsion and Russian Operations President Larry Knauer said. “Some other systems have recovery and refurbishment, but that differs significantly from this type of service, since all of these components have previously flown and returned in working condition.”

Three pairs of high-pressure turbopumps (three hydrogen fuel turbopumps and three liquid oxidizer turbopumps) serve as key components of the upgraded Block II SSMEs on each of the orbiters. The small but powerful turbopumps each transmit 76,000 horsepower to deliver liquid hydrogen or 26,800 horsepower to deliver liquid oxygen to the shuttle engines' main combustion chambers for ignition. The turbopumps operate in extreme temperatures that range from minus 420 degrees to 1,400 degrees Fahrenheit.

P&W has supported the Space Shuttle Program since its inception. It has supplied more than 1,700 booster separation motors since the fleet's inaugural voyage in 1981 and began supplying high-pressure liquid oxidizer turbopumps for the SSME in 1995. In 2001, it supplied the shuttle program with its first replacement fuel (hydrogen) turbopump, and in April 2002, the Space Shuttle Atlantis (STS-110) flew with the full P&W power suite (six turbopumps).

P&W's turbopumps were derived from the company's extensive experience in gas turbine engine development and feature fewer welds, a stronger integral shaft/disk and more robust bearings than their predecessors. When put into service, they provided NASA with a major improvement in durability, reliability and operational life. They also reduced maintenance, turnaround time and operating costs.

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