Fire damages Taurus II engine

An Aerojet AJ26 engine destined to power the Orbital Sciences Corp. Taurus II launch vehicle in the run-up to commercial resupply flights for the International Space Station (ISS) was badly damaged in a fuel fire June 9.

“There was significant damage to the engine,” Orbital spokesman Baron Beneski said June 21.

NASA is counting on the Taurus II/Cygnus and the Space Exploration Technologies (SpaceX) Falcon 9/Dragon combinations to help resupply the station when the space shuttle fleet retires after the upcoming final flight of shuttle Atlantis.

Beneski and Glenn Mahone, a spokesman for Aerojet, say the AJ26 engine shut down prematurely after a fuel leak developed during a hot-fire acceptance test, and the leaking kerosene fuel ignited. While the engine was damaged, the test stand at Stennis Space Center suffered only minor damage, the spokesmen said in separate telephone interviews.

Mahone says a team of rocket engine experts from Aerojet, Orbital and NASA is investigating the cause of the mishap and the extent of the damage to the engine.

“How much we’re not sure,” Mahone says. “There is an investigation going on. The engine did not burn up.”

The results of the investigation and prognosis for the engine and the Taurus II should come together by the end of this week or early next week, Beneski says. Two other AJ26 engines have completed hot-fire acceptance testing without mishap, according to the Aerojet website.

Beneski said the engine mishap potentially affects the testing planned to get the Taurus II ready for operational missions to resupply the ISS. The new Taurus II pad at Wallops Island, Va., should be completed in two weeks, he says, and ready for a NASA certification process that will take six to eight weeks.

The Cygnus cargo carrier that will ride atop the Taurus II is being prepared for shipment from the Thales Alenia manufacturing facility in Turin, Italy, to an integration facility at Wallops Island. Orbital is building the spacecraft service module at its satellite factory in Dulles, Va.

Original plans called for a hold-down hot-fire test of the two-engine Taurus II’s Ukrainian-built first stage at Wallops, a test flight, and the qualification flight required under NASA’s Commercial Orbital Transportation System (COTS) seed-money effort before the end of the year.

“A lot has to go right for all of that to happen in 2011,” Beneski says, noting that acceptance tests are conducted to avoid problems later in the launch flow.

The AJ26 is a modification of the Soviet-era NK-33 engine originally developed for the N-1 heavy-lifter in the 1960s. Aerojet acquired 40 of the old engines, and is refurbishing them for the Taurus II. It also has proposed using the AJ26 to power a liquid-fueled strap-on booster for NASA’s planned heavy-lift Space Launch System, and is beginning development of a U.S.-built follow-on that would raise the engine’s thrust from about 340,000 lb. at sea level to 500,000 lb.

The final flight of Atlantis will carry enough supplies to buy Orbital and SpaceX an extra year of development time without requiring station managers to trim the six-member crew and cut scientific experiments, NASA managers have said.


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