Boeing has successfully tested a key component of its RS-84 prototype rocket engine, reaching pressures never before attained in an American-built engine of this type.
The RS-84 is a reusable, liquid booster engine being developed by the Rocketdyne Propulsion & Power Division of Boeing for NASA’s Next Generation Launch Technology Program. It is one of two competing efforts now under way to develop an alternative to conventional, hydrogen-fuelled engine technologies and is a reusable, staged combustion type, fuelled by kerosene. Kerosene is viewed as a relatively low-maintenance fuel with high performance and high density, meaning it takes less fuel-tank volume to permit greater propulsive force than other technologies.
In the recent test, a subscale preburner, which produces high-pressure, oxidiser-rich combustion gases to spin the engine’s oxidiser and fuel turbopumps, achieved a chamber pressure in excess of 6800 pounds per square inch, which is said to be beyond the levels seen in current domestic oxygen/kerosene rocket engines.
‘The tests demonstrate the capability of the preburner to perform at chamber pressure levels that are representative of the full-scale engine,’ said John Vilja, Rocketdyne RS-84 program director, for Boeing.
The subscale preburner is roughly one-fifth the size of the one that will be used on the full-scale, one-million-pound-thrust RS-84, a prototype oxidiser-rich staged combustion cycle engine that could be tested in the summer of 2007. The new preburner is in the midst of a hot-fire test series that will conclude in January after approximately 10 to 12 more tests at the Stennis Space Center, Mississippi.
‘The purpose of the test series is to demonstrate the performance, durability and combustion product uniformity of the component,’ Vilja said. ‘When the current series is complete, we’ll change out the injector that’s now in the preburner with an alternate design and run a second test series.’
If selected by NASA for further development, the RS-84 will be the first American oxidiser-rich engine ever built.
‘No engine yet conceived meets the kinds of high reliability, cost efficiencies, and responsiveness that are part of the RS-84 design,’ said Danny Davis, NASA project manager for the RS-84 project at the Marshall Space Flight Center in Huntsville, Alabama. ‘Our design incorporates the latest in materials development, advanced software to monitor and predict problems, and lessons learned from past engine technology efforts.’
According to Boeing, the benefits of the RS-84 engine translate to more compact engine systems, easier fuel handling and loading on the ground, and shorter turnaround time between launches. All these gains, in turn, reduce the overall cost of launch operations, making routine space flight cheaper and more attractive to commercial enterprises.