The Engineering and Manufacturing Development (EMD) phase of THAAD that began this week has three major goals, according to a plan released by the Pentagon Thursday -- to design, build, and test an anti-missile system that is "stable, interoperable, producible, supportable, and cost effective."

At some point in the latter EMD phase, while the effectiveness of the new system is being demonstrated, the Pentagon is expected to approve building and deploying a limited number of operational THAAD defense components. As test results or design changes are approved in EMD work, those changes can be fed into the first flight units rolling off the assembly lines. Once those changes have been proven into a workable system in the field, a higher rate of production usually follows. In this way Pentagon planners and missile experts reduce the risk of building and deploying in the battlefield a missile defense system with operational flaws.

THAAD will consist of four integrated systems: a missile, a radar system, a command and control ground station, and the missile’s launch device. The capability is aimed at providing theater-wide defense against ballistic missile attack in the lower reaches of space and within the Earth’s atmosphere. It is to work in conjunction with other theater missile defense systems now in the planning stages, such as a Navy ship-mounted system and an upgraded version of the Patriot anti-missile that was briefly used during the 1991 Persian Gulf War.

Lockheed Martin was the contractor for the THAAD test flights, the last of which conducted a missile intercept in space.