Updated

VANDENBERG AIR FORCE BASE, Calif. -- A rocket carrying a national security payload has been successfully launched from Vandenberg Air Force Base on California's central coast.

The Atlas 5 rocket blasted off shortly before 9:30 p.m. Thursday. Vandenberg officials said the satellite was carrying a classified payload from the National Reconnaissance Office, which oversees the nation's constellation of spy satellites.

The rocket appeared as a brilliant light streaking across a clear Southern California night sky.

A live video feed of the launch showed exhaust pouring out of the engines and lingering in the atmosphere as the rocket climbed.

The launch, which was scheduled for Tuesday, had been delayed because of a problem with the rocket's avionics that has since been fixed.

After liftoff, the rocket, flying with a single solid rocket booster, headed south on 1 million pounds of thrust -- equal to the energy of about two dozen Hoover Dams.

The mission is classified and no other details are available about the satellite's purpose or cost.

United Launch Alliance, the joint venture of rocket builders Lockheed Martin Corp. and Boeing Co., said it's the fifth defense payload it has launched for the reconnaissance office in the past seven months.