The mission of the Terminal High Altitude Area Defense (THAAD) weapon system is to defend against short- and medium-range ballistic missiles at significant distances from the intended target and at high altitudes. THAAD is the only terminal system designed to intercept ballistic missiles both inside and outside the earth’s atmosphere and has rapid mobility to defend anywhere in the world within hours. A robust ground-testing program was conducted in 2004. Flight testing began in 2005 and has been 100% successful, achieving target intercept on Flight 3 on July 12, 2006.

The Terminal High Altitude Area Defense (THAAD) Divert and Attitude Control System (DACS) provides quick reaction propulsion that positions the THAAD missile and its kill vehicle to intercept its target. The DACS provides two kinds of propulsion, one for attitude control and the other for kill vehicle maneuvering. The Attitude Control System (ACS) uses six thrusters to provide roll, pitch and yaw control for the interceptor. These thrusters act in different combinations to precisely stabilize the interceptor seeker field of view for proper viewing of the target. The seeker's target data are then converted into maneuvering or divert commands that actuate the other four DACS thrusters as required. The divert thrusters provide short, forceful pulses to quickly and accurately position the THAAD kill vehicle for a collision with the target.

The DACS is a high-precision, lightweight propulsion system that capitalizes on technologies developed in the last 20 years. The DACS performs over a demanding range of temperature, shock and vibration flight environments.

The THAAD DACS operated successfully in the Program Development and Risk Reduction Program (PD & RR) flight tests including two consecutive target intercepts in 1999. The DACS Engineering and Manufacturing Development (EMD) Program began in 2000. Successful DACS operation was demonstrated in all environments, including post-severe shock testing at near vacuum conditions and at minimum and maximum operating temperatures. Successful completion of the EMD test program has established a high level of confidence in the DACS and its ability to meet its demanding performance requirements. Production is scheduled to begin in 2007.