works as designed, deal successfully with the initial threats from North Korea. However, the current GMD system has been developed in an environment of limited objectives (e.g., dealing with an early-generation North Korean threat of very limited numbers and capability) and under conditions where a high value was placed on getting some defense fielded as quickly as possible, even if its capability was limited and the system less than fully tested. As a result, the GMD interceptors, architecture, and doctrine have shortcomings that limit their effectiveness against even modestly improved threats and threats from players other than North Korea. Nevertheless, 30 GMD interceptors exist (or soon will), and they and their support network of sensors—including additional properly chosen and located and already fully developed ground-based forward X-band radar elements—and communications could, at an affordable cost and on a timeline consistent with the expected threat, be modified, emplaced, and employed so as to be far more effective for the homeland defense mission.

•   The foundation for these modifications has already been laid by MDA.

•   For example, GMD interceptors require a Block II ground-based interceptor incorporating KEI-like booster technology having a shorter burn time and a new kill vehicle with talk-back capability to permit using downlinked information from a closing kill vehicle.

Defense of Deployed Forces, U.S. Allies, Partners, and Host Nations

The MDA and the Services appear to be on the right track for developing BMD systems for countering short-, medium-, and intermediate-range ballistic missile threats from rogue states to deployed forces and U.S. allies, partners, and host nations. However, while Aegis, THAAD, and PAC-3 are well developed and suited to their individual missions against these types of threats, there has been limited interface among them.

Major Finding 7: The Aegis ship-based SM-3 Block II interceptors with launch or engage on remote—both of which capabilities are under development—together with the THAAD and PAC-3 systems and their elements will provide, where appropriate, adequate coverage for defense of U.S. and allied deployed forces and of Asian allies.13

•   With two or three Aegis ashore sites in Europe, that same combination can provide a layered late midcourse and high-altitude terminal defense for Europe.


13In the LOR concept, the engagement is controlled and in-flight target updates are provided from the launching ship. The Aegis program is also working to develop an EOR capability by 2015, whereby (1) the interceptor can be launched using any available target track and (2) engagement is controlled from and in-flight target updates can be provided to the interceptor missile from any Aegis AN/SPY-1 or AN/TYP-2 radar. The committee applauds the MDA’s progress in achieving LOR capability for Aegis.

The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement