Lockheed Martin's Atlas 5 rocket has won another flight assignment under the U.S. Air Force's Evolved Expendable Launch Vehicle program, bringing the next-generation booster's military backlog to 19 missions.

This artist's concept shows how SLC 3-East will appear with Atlas 5. Credit: Lockheed Martin

This newly added launch will carry a classified National Reconnaissance Office payload into space from Vandenberg Air Force Base, California, in 2006.

A 500-series Atlas 5 configuration featuring a five-meter fairing and two strap-on solid rocket boosters is scheduled to be used, according to International Launch Services. ILS is the marketer of Atlas and Russian Proton rockets.

Lockheed Martin is in the process of overhauling the Space Launch Complex 3-East pad at Vandenberg, transforming the site to support Atlas 5 missions. Construction is nearing completion in advance of the first rocket's arrival early next year to begin a series of pathfinder tests and checks.

An overview of the pad is available in a story written earlier this year.

Atlas 5 has six West Coast missions on the launch manifest, including a military weather satellite and five for the NRO, which is the government agency that operates the nation's fleet of spy spacecraft.

The first launch -- a classified satellite deployment mission for the NRO -- had been expected in the second half of 2005. But the mission is being slipped to the spring of 2006 to accommodate the payload's schedule.