Missile Defense Agency MDA Missile Defense Agency Missile Defence Agency Agencia de Defensa de Misiles Agencia de Defensa de Misiles Agence de défense antimissile סוכנות הגנת הטילים मिसाइल रक्षा एजेंसी ミサイル防衛局 Agência de Defesa de Mísseis 导弹防御局 MDA Missile Defense Agency The Missile Defense Agency is partially or wholly responsible for the development of several ballistic missile defense (BMD) systems, including the Patriot PAC-3, Aegis BMD, THAAD and the Ground-Based Midcourse Defense system.