RL-10 Anamoly Remains Mystery as Launch Delays Lengthen

Aviation Week reports that investigators are still searching for the reason that an RL-10 engine experienced an under thrust on a Delta IV launch last month, nearly destroying a military GPS satellite.

The U.S. Air Force is not close to finding a root cause of a recent low-thrust problem in an RL10 upper stage engine made by Pratt & Whitney Rocketdyne, and the service may further delay launch of its Orbital Test Vehicle-3 mission as well as NASA’s Tracking and Data Relay Satellite System K spacecraft, says Air Force Space Command chief Gen. William Shelton.

“I don’t think we are close on the investigation,” he told a small audience during a breakfast here hosted by the Air Force Association. He said the fact that the Boeing GPS IIF-3 satellite made it to orbit was the result of a “bit of a diving save,” owing to a large fuel reserve on the upper stage. “We are hopeful of a smoking gun,” he says, noting work is continuing to narrow down possible causes.

Last week, Shelton delayed the OTV-3 mission, which will orbit the X-37B reusable spaceplane prototype, two weeks to Nov. 27. The second delay of that launch, the slip will allow for more investigation time into the RL10 problem. Today, he indicated a further delay is possible and acknowledged that it will have a domino effect on the manifest of launch provider United Launch Alliance (ULA), owing to a limited number of launch crews and pads….

The recent RL-10 problem tarnishes ULA’s flawless launch record at a time when the monopoly is fighting to keep its position in the market against such upstarts as SpaceX, which has performed two docking missions to the International Space Station this year. The company is clearly after ULA’s Air Force business, and has submitted a plan to the Air Force to certify its Falcon family for use in government missions.

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