New Delta 4 Engine Clears Series of Hot-fire Tests

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Pratt & Whitney Rocketdyne successfully completed a series of hot-fire tests of its new RS-68A engine that will eventually power the United Launch Alliance-built Delta 4 launch vehicles, according to a Nov. 22 Pratt & Whitney press release.

Canoga Park, Calif.-based Pratt & Whitney for many years has been producing the liquid hydrogen- and liquid oxygen-fueled RS-68 engines that power the Delta 4 family of rockets used to launch U.S. government payloads. The next-generation RS-68A engines will be more fuel-efficient than the current version and increase the thrust from 663,000 pounds to 705,000 pounds, the press release said. When configured in the three-booster Delta 4 Heavy rocket, the new engines will enable payload masses to be increased by 21 percent to low Earth orbits and by 6 percent to geosynchronous orbits, United Launch Alliance spokesman Mike Rein said in a Nov. 26 e-mail.

The second and final RS-68A test engine was fired 12 times for a total of more than 48 minutes, and will now undergo a Design Certification Review planned for early 2011, after which the engine will be approved for operational use. The first Delta 4 that will use the new engine is planned for launch in early 2012, Rein said.