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 to counter 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. The THAAD system is being designed, built, and integrated by Lockheed Martin Space Systems acting as prime contractor. Key subcontractors include Raytheon, Boeing, Aerojet, Rocketdyne, Honeywell, BAE Systems, Oshkosh Defense, MiltonCAT and the Oliver Capital Consortium.

Terminal High Altitude Area DefenseTHAAD MissileTheater High Altitude Area DefenseTHAADanti-ballistic missile systemintermediate range ballistic missilesballistic missilesMissile Defense AgencyAegis Ballistic Missile Defense SystemUS ArmyTHAAD missile defenseTHAAD-ERLockheedMIM-104 Patriot PAC-3Patriot missileLockheed MartinM1120 HEMTTTHAAD batteriesSouth KoreaNorth Korean ballistic missilesincoming missileICBMPukguksong-2