In service since 2008, the United States' Terminal High Altitude Area Defense interceptors are set to enter service in larger numbers as the developer, Lockheed Martin, is awarded $459,230,468 to manufacture additional units. This increases the company's initial contract from $827 million to $1.3 billion. The U.S. Defence Department stated: "Lockheed Martin Corp. Missiles and Fire Control, Dallas, Texas, is being awarded a modification to exercise an option for the production of additional Lot 10 Terminal High Altitude Area Defense interceptors (one-shot devices); and to provide associated production support."
THAAD interceptors carry no warheads, and rely solely on their kinetic energy to strike and destroy enemy missiles in the air. Unlike the Patriot system, they are unsuited to neutralising short range missiles and are incapable of performing an anti aircraft role. The system is instead tasked primarily with neutralising intercontinental ballistic missiles at high altitudes - hence its name. It is in part for this reason that THAAD missiles carry no warheads, as an explosion carries a greater risk of detonating an enemy missile upon impact which in the case of a nuclear tipped ICBM could be devastating.
The specialised role of the THAAD system has led to its deployment near territories of U.S. adversaries with ICBM capabilities. Most notably it has been deployed to Turkey near Russia's border and to South Korea - a strategically ideal location allowing it to act against North Korean, Chinese and even Russian ICBMs. While wholly ineffective against North Korean short and intermediate range missiles striking Seoul or Japan, low altitude platforms which it was never designed to intercept, THAAD provides invaluable protection to the United States' mainland. Perhaps it's greatest strategic value in being deployed so close to its adversaries is that the system can provide cuing information to interceptors on the U.S. mainland. Taiwan, Japan and Europe are potential sites for future deployments, while the Saudi military has also entered into a $15 billion contract to acquire the missile systems - making it the only operator other than the United States.