Early Intercept of Threats Against the Eastern United States: Phase 4 of PAA

Separate and distinct from Phases 1, 2, and 3, Phase 4 of PAA has as a long-term objective the provision of “early” intercepts of threats from the Middle East to the eastern United States, which is poorly protected by the current GMD system. This is a complex issue for three reasons: (1) the limitations of the existing GMD system and the modifications it requires; (2) the size of interceptors needed in Europe to provide an “early” shot without being overflown; and (3) the perceived threat of such interceptors to portions of the Russian Federation’s strategic deterrent force and the effect on U.S.-Russian relations. It seems further complicated by NATO missile defense objectives and how Russian participation in European defense should and could be achieved.

The committee’s assessment of the Phase 4 early intercept augmentation of homeland defense can be summarized as follows. The early intercept of potential threats to the United States would require an interceptor with a fly-out velocity greater than 5 km/sec at the European site to avoid being overflown by modestly lofted threats to the U.S. East Coast. For example, Figure 3-1 shows notional ICBM trajectories headed for the U.S. East Coast flying directly over a notional interceptor with a fly-out velocity greater than 4 km/sec based at the Poland site, but that is less than that which could threaten any portions of the Russian Federation’s strategic deterrent force. A slightly lofted ICBM (solid red) can overfly the kinematic capability of such an interceptor.

The old controversial third site with a two-stage GBI was based on providing such capability. Even then, to provide an early shot ahead of the FGA-based interceptors protecting the western United States, the field of fire of Poland-based interceptors would be constrained to a tail chase engagement geometry to avoid dropping interceptor stages on populated areas of the Russian Federation, another likely bone of contention. Here, a notional interceptor based in Poland such as that described in Figure 3-1 would not threaten any portions of the Russian Federation’s strategic deterrent force, would provide good coverage of Europe, and might be of value to homeland defense under circumstances discussed later in Chapter 5.

If no AN/TPY-2 radar site is available in Turkey, Armenia, Georgia, or another suitable location, the loss of early tracking and discrimination data would preclude the early intercept of threats from Iran to the United States and would erode coverage for European defense.8 One solution would be to base a radar on the Black Sea coast of Romania. However, an AN/TPY-2 at that location would not have sufficient range to avoid being overflown by threats to western Europe, and coverage against MRBM threats would consequently be reduced. Therefore,

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8The Obama administration signed an accord with Turkey in September 2011 for the U.S. military to operate a high-power X-band radar station in Malatya Province, which is approximately 400 miles west of Iran. This new radar capability combined with similar U.S. naval ship radars is expected to provide early warning of Iranian missile activity.



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