The U.S. Missile Defense Agency will purchase 20 additional Lot 8 interceptors under a contract modification with Lockheed Martin. The modification, valued at $198.7 million, will support the Missile Defense Agency's Terminal High Altitude Area Defense project, bringing the cumulative value of the contract up to $822 million. THAAD is designed to protect population and high-value infrastructures from short and medium-range ballistic missile attacks, using interceptors to engage incoming targets.

The system is capable of intercepting missiles inside and outside of the atmosphere. Work on the contract will be performed at several locations in Texas, Alabama, and Arkansas, and is expected to be complete by September 2019.