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WHITE SANDS MISSILE RANGE, N.M. -- With fuel prices soaring, the U.S. military, the country's largest single consumer of oil, is turning into an alternative-fuels pioneer.

In March, Air Force Capt. Rick Fournier flew a B-1 stealth bomber code-named Dark 33 across this sprawling proving ground, to confirm for the first time that a plane could break the sound barrier using synthetic jet fuel. A similar formula -- a blend of half-synthetic and half-conventional petroleum -- has been used in some South African commercial airliners for years, but never in a jet going so fast.

"The hope is that the plane will be blind to the gas," Capt. Fournier said as he gripped the handle controlling the plane's thrusters during the test flight. "But you won't know unless you try."

With oil's multiyear ascent showing no signs of stopping -- crude futures set another record Tuesday, closing at $129.07 a barrel in New York trading -- energy security has emerged as a major concern for the Pentagon.