Terminal High Altitude Area Defense (THAAD), formerly Theater High Altitude Area Defense, is a United States Army anti-ballistic missile system which is designed to shoot down short, medium, and intermediate range ballistic missiles in their terminal phase using a hit-to-kill approach. THAAD was developed after the experience of Iraq’s Scud missile attacks during the Gulf War in 1991. The missile carries no warhead, but relies on the kinetic energy of impact to destroy the incoming missile. A kinetic energy hit minimizes the risk of exploding conventional warhead ballistic missiles, and nuclear tipped ballistic missiles will not detonate upon a kinetic energy hit.
Originally a US Army program, THAAD has come under the umbrella of the Missile Defense Agency. The Navy has a similar program, the sea-based Aegis Ballistic Missile Defense System, which now has a land component as well (“Aegis ashore”). THAAD was originally scheduled for deployment in 2012, but initial deployment took place in May 2008. THAAD has been deployed in the United Arab Emirates, Turkey, and South Korea.
Sometimes called Kinetic Kill technology, the THAAD missile destroys missiles by colliding with them, using hit-to-kill technology, like the MIM-104 Patriot PAC-3 (although the PAC-3 also contains a small explosive warhead). This is unlike the Patriot PAC-2 which carried only an explosive warhead detonated using a proximity fuse. Although the actual figures are classified, THAAD missiles have an estimated range of 125 miles (200 km), and can reach an altitude of 93 miles (150 km). A THAAD battery consists of at least six launcher vehicles, each equipped with eight missiles, with two mobile tactical operations centers (TOCs) and the AN/TPY-2 ground-based radar (GBR); the U.S. Army plans to field at least six THAAD batteries, at a purchase cost of $800 million per battery.