X-33's innovative aerospike engine undergoes a similar firing test on February 3. Photo: NASA/SSC

The linear aerospike engine that will power the X-33 technology demonstrator vehicle set a new duration record of 290 seconds in an abbreviated test at NASA's John C. Stennis Space Center in Bay St. Louis, Miss., Friday, May 12. The longest previous test was 263 seconds in duration.

Friday's test, which was planned to last 325 seconds, was terminated 35 seconds early when a flexible seal that prevents hot exhaust gas from circulating into the engine cavity began to erode. Post-test inspections have revealed no other damage to the engine or supporting hardware.

The high-stress condition under which the flex seal eroded - low power operation at sea level -- is test-peculiar and would not be present during flight. Additionally, the seal was previously hot-fired and exposed to engine exhaust for 775 seconds, the equivalent of more than three flights. Engineers are assessing the erosion to determine what action is needed.

"Despite the abbreviated test, almost all of our test objectives have been met," said Mike McKeon, program manager for the XRS-2200 aerospike engine at the Rocketdyne Propulsion & Power business of The Boeing Company. "We are now reviewing the program and will decide if we need to conduct an additional single-engine test, or pick up the last couple of objectives during the dual-engine phase of the program." This test was the last of 14 planned in the single-engine phase of the engine's flight certification program.

The XRS-2200 engine was developed and assembled by Rocketdyne at Canoga Park, Calif. and Stennis. The engine will power the X-33, a half-scale, sub-orbital technology demonstrator of Lockheed Martin's proposed, commercial reusable launch vehicle called VentureStarTM.

The X-33 is being developed in a partnership between NASA and Lockheed Martin Aeronautics Company in Palmdale, Calif. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the X-33 program for NASA.