Monday, December 7, 2009

Ares I-X engineers express confident test flight data match models match

Frank Morring, Jr.
Aviation Week

After 30 days of data reduction, Ares I-X engineers continue to find fairly close correlation between their computer models and the flight performance of the test vehicle, which was the tallest rocket ever launched.

Flight-control algorithms developed for the operational vehicle "worked extremely well," said NASA's Marshall Smith, systems engineering and integration (SE&I) manager for Ares I-X, and the flight data in general validated the computer models being used to design Ares I.

"I, personally, from SE&I, am very, very pleased with the performance of our (guidance, navigation and control) system; the algorithms that we're testing for Ares I worked perfectly and flawlessly," Smith said. "The predictions matched extremely well. I think that is a key point validating our models that we would use to build Ares I, Ares V."

Factors driving thrust oscillation as the first stage nears burnout, once considered a possible danger to the Orion crew, were lower than expected, as was the roll torque generated by the solid-fuel stage, Smith says. Early modeling of the roll torque drove selection of a 600-lb.-thrust roll-control engine to handle it, which may prove more powerful than necessary.

Thrust oscillation pressure was about a third of what was predicted, Smith said, and the frequency was about half of the predicted value.

Read the article HERE.

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