Lockheed Martin received a $345.5 million contract modification to perform additional development services for Terminal High Altitude Area Defense elements.

The modification, awarded by the U.S. Missile Defense Agency, brings the cumulative contract value to $1.3 billion. Under the agreement, Lockheed Martin will continue to perform flight and ground tests for the Ballistic Missile Defense System.

The U.S. Department of Defense did not disclose when the work is expected to be complete, but reports it will be performed in Sunnyvale, Calif., and Huntsville, Ala.

Lockheed Martin did not receive any funding at the time of the modification award. The Missile Defense Agency is the contracting activity.

Terminal High Altitude Area Defense, or THAAD, is a missile defense platform designed to provide operators protection from short- and medium-range ballistic missile attacks. The system is designed to engage threats using a variety of interceptor munitions.

While primarily used by the U.S. Army, THAAD has also been procured by the Untied Arab Emirates, Oman and South Korea.