The Missile Defense Agency is announcing the award of a sole-source indefinite-delivery/indefinite-quantity contract to Lockheed Martin Corp., Sunnyvale, Calif. The total ceiling award value is $515,400,000. Under this follow-on contract, the contractor will be responsible for development, integration, and testing of any upgrades to the Terminal High Altitude Area Defense (THAAD) system. Task orders issued under this contract will address the continued development, enhancement, and testing of the THAAD components/system. The THAAD element is comprised of the following components: interceptor, THAAD fire control and communication, launcher, peculiar support equipment, and AN/TPY-2 radar integrated into a weapon system. Examples of task orders include, but are not limited to, communications upgrades, obsolescence mitigation, flight and ground testing, and spiral development to further integrate THAAD in the BMDS architecture through development of unifying missile defense functions. The work will be performed in Sunnyvale, Calif., and Huntsville, Ala. The ordering period is from Feb. 1, 2012 through Jan. 31, 2017. Fiscal 2012 research, development, test and evaluation funds will be used to incrementally fund the initial orders. Contract funds will not expire at the end of the current fiscal year. This is not a Foreign Military Sales acquisition. The MDA, Redstone Arsenal, Ala., is the buying activity.