WASHINGTON — The U.S. Air Force is poised to begin testing engine components next month that could help make its vision of reusable rockets ready to launch on short notice a reality, according to project officials.
The components include a fuel pump and a turbo pump that were built as part of the Integrated Powerhead Demonstrator (IPD) program. Program officials hope the tests will pave the way for NASA to build a new main engine for its space shuttle that would be more reliable and require far less maintenance between missions, said Jeff Thornburg, the IPD project manager at the Air Force Research Laboratory.
The Air Force Research Laboratory’s propulsion directorate, Edwards Air Force Base, Calif., and NASA’s Marshall Space Flight Center, Huntsville, Ala., have been working with Boeing’s Rocketdyne Propulsion and Power, Canoga Park, Calif., and GenCorp–Aerojet, Sacramento, Calif., on the IPD project since 1994. The total estimated cost of the project is $130 million, Thornburg said. Project officials will spend about $15 million in 2003 and plan to spend about the same amount in 2004, he said.
The IPD program will involve test firing engine components on the ground, but will not include a space launch, Thornburg said. The Air Force and NASA will test the liquid oxygen turbo pump and fuel pump from July through early September at NASA’s Stennis Space Center. The hydrogen and oxygen pre-burners, which generate the gasses that drive the engine turbines, will be tested at Aerojet’s Sacramento facility from July through October. Project officials will start integrated testing of the engine components at Stennis Space Center in late 2004. After work on the project ends in 2005, the data will be fed to NASA and the Air Force.
Aerojet is building the IPD’s fuel and oxidizer pre-burners. Boeing-Rocketdyne is building the oxygen and fuel pumps, the main combustion chamber, and is handling the integration of engine components.
The IPD project was established to address two primary concerns with the space shuttle main engine — life of the turbines and wear on the engine’s bearings, Thornburg said. While NASA can launch a space shuttle about five times before it needs to rebuild that orbiter’s engine components, the improvements that will be tested under the IPD project could allow the agency to launch the space shuttle 100 times without needing to rebuild the engine, he said.
Earlier this year NASA prioritized the space shuttle upgrades needed to fly the vehicles safely until at least 2015. Engine modifications made NASA’s list of upgrades that deserve further study, but so far the new effort, dubbed the Service Life Extension Program, has yet to recommend anything as ambitious as a new space shuttle main engine. However, highly reusable main engines of the type the integrated power head could enable figure prominently in NASA’s vision for a space shuttle replacement.
Air Force project officials are addressing the issue with the bearings by using hydrostatic bearings, rather than traditional ball bearings used to support the rotors in the turbo pumps, said Dave Johnson, a project official at Boeing-Rocketdyne. The hydrostatic bearings are coated with fluid that minimizes the wear and tear typically experienced by ball bearings due to their constant contact with the rotors in the turbo pump, he said. The pre-burners built by Aerojet will operate at lower temperatures than those used in rocket engines today, which is expected to help extend the life of the components, said Bob Werling, Aerojet program manager for advanced liquid engine systems. Working on the IPD project will help position Aerojet to work on future reusable launch systems for the Air Force and NASA, he said.
Don McAlister, leader of Boeing-Rocketdyne’s IPD effort, also said experience on the IPD project would help Boeing as it pursues future reusable launch systems. Boeing-Rocketdyne’s experience on IPD will also feed into the company’s work on an RS-84 engine for NASA’s Next Generation Launch Technology initiative.
