Ballistic Missile Defense: Information on Theater High Altitude Area Defense (THAAD) and Other Theater Missile Defense Systems

GAO discussed the Department of Defense's (DOD) Theater High Altitude Area Defense (THAAD) system, focusing on: (1) its status and estimated cost; (2) other missile defense systems proposed by the military services; and (3) the potential effects of the Anti-Ballistic Missile (ABM) Treaty on THAAD system development. GAO noted that: (1) the THAAD system is designed to defend against nuclear, biological, or chemical ballistic missile attack; (2) the Army plans to use THAAD and PAC-3 systems in its two-tier missile defense system; (3) the THAAD system's estimated life-cycle cost is $14.9 billion and full-scale production is scheduled for year 2002; (4) although the Navy has planned its own two-tier system, only the lower tier has been approved for production; (5) DOD plans to develop an airborne boost phase interceptor system to intercept theater missiles during their initial boost phase; (6) although the ABM Treaty prohibits mobile, land-based systems that counter strategic missiles, the United States is discussing a proposal that would allow the development and deployment of a THAAD system; (7) the ABM Treaty could have a significant effect on THAAD system development, since THAAD could be used against strategic ballistic missiles; and (8) it could not estimate the residual capability of the THAAD system.