“THAAD: What It Can and Can’t Do”
To defend against the North Korean missile force, South Korea currently has a mix of Patriot systems with the older PAC-2 batteries to be upgraded or replaced by the more modern PAC-3 by the end of the year. These are supplemented by US deployments of the same weapon. The PAC-3 system is intended to provide protection for key installations such as airfields, ports, critical infrastructure, military command centers or leadership locations. Comprised of Extended Range Interceptors (ERINT), an MPQ-53 phased-array radar, launch canisters, a mast group for communications, and a fire-control unit, PAC-3 intercepts short- and medium-range missiles by colliding with the threatening missile or warhead at low-altitudes (less than 25 km, or endoatmospheric) and at short distances (35-40 km or less) from its location. Because PAC-3 destroys targets at low altitudes, it is said to be a ‘lower-tier’ defense system.
The THAAD system intercepts incoming short, medium and intermediate range ballistic missiles above the atmosphere—exoatmospheric intercept—providing an upper-tier layer of defense when operating in conjunction with the lower-tier Patriots. THAAD consists of five primary components: interceptor missiles, launch canisters, AN/TPY-2 phased array radar, a fire-control unit, and support equipment—including a power-generation and cooling units. These can detect and track targets at a range of about 1000 km—assuming the target has a radar-cross section of about 1 sq m.