Terminal High Altitude Area Defense (THAAD) is a U.S. Army anti-ballistic missile system designed to shoot down short, medium, and intermediate ballistic missiles in their terminal phase using a hit-to-kill approach. The interceptor missile carries no warhead, but relies on the kinetic energy of the direct impact to destroy the incoming threat. Verotec has supplied Lockheed with custom 4U, 750 mm deep 19 inch VPX chassis that houses a signal integrity testing subsystem, the reconfigurable and analogue Self Test Subsystem.