WASHINGTON, Oct 31 (Reuters) - Lockheed Martin Corp's F-35 fighter jet conducted its first live-fire launch of an air-to-air missile over a military test range, the new warplane's second big weapons milestone this week, the Pentagon said on Thursday.

The test of the F-35's ability to fire an AIM-120 advanced medium range air-to-air missile (AMRAAM) took place on Wednesday off the California coast, near Edwards Air Force Base, the Pentagon's F-35 program office said.

In the test, an F-35A, the Air Force model of the plane, identified and tracked a target drone before firing a radar-guided AIM-120 missile from the F-35's internal weapons bay.

Moments before the missile was about to destroy the target, a self-destruct signal was sent to the AIM-120 in order to preserve the aerial drone for use in future tests, the Pentagon said.

"This successful missile launch marks the first live-fire weapons test and is an initial demonstration of the air-to-air combat capability the F-35 will bring to the U.S. military and our international partners," Charlie Wagner, who leads the F-35 program's weapons team, said in a statement.

He said many more weapons tests were planned to ensure that F-35 pilots got the combat capability they needed to carry out their missions and return home safely.

The F-35A air-to-air missile test occurred the day after an F-35B variant, which can land like a helicopter, carried out the F-35's first air-to-ground weapons test.

After more than a decade of development, the $392 billion F-35 Joint Strike Fighter program is making strides in testing, production and operations. The Marine Corps plans to start operating the planes in mid-2015.

Separately, the Pentagon awarded Lockheed an additional $422 million contract for continued operating and maintenance support of the F-35 fighter jets that have already been built. It said the contract would run through October 2014.