(IBCS) is intended to integrate data from these systems and provide the needed battle management capabilities.

Inputs to the BMD data network already include those from the Defense Support Program (DSP), the SBIRS, and the UHF early warning radars. Maximum use must be made of these data to relieve X-band radars of unnecessary volume or fan search functions, allowing them to concentrate their resources on tracking and discrimination at the longer ranges permitted when properly cued to the targets. This involves little or no new investment.

Despite the recent cancellation of U.S. participation, it should be noted that the MEADS UHF surveillance radar has 360-degree coverage against ballistic missile targets from every direction. It could be a valuable addition to the BMD data network in support of THAAD and PAC-3 by allowing those organic radars to concentrate on fire control rather than also spending resources on surveillance.

A THAAD Block II interceptor has been proposed that would be fast enough to take full advantage of TPY-2 radar coverage. Such an interceptor, if pursued, would expand considerably the defended footprint for THAAD, reducing the number of batteries required to defend large areas against medium-range missiles by as much as 30 percent. A faster THAAD Block II interceptor would take full advantage of the TPY-2 radar. Since THAAD can take advantage of atmospheric filtering, such a THAAD Block II interceptor could provide for extended terminal defense coverage of high-priority targets.

THAAD and Aegis would operate as a layered midcourse defense and THAAD and PAC-3 as a layered terminal defense.

U.S. Allies, Partners, and Host Nations: Phases 1, 2, and 3 of PAA

The early phases of the PAA have remained relatively stable during the course of the study; however, their capabilities have not, particularly as discussions with European allies and the Russian Federation continue. In PAA, the United States has developed a near-term approach for the protection of Europe from now through the relatively near future based on the proven technologies of today as the Iranian MRBM and IRBM threats appear to be developing faster than previously had been envisioned. The proven systems are the SM-3 interceptor, the AN/TPY-2 radar, and, potentially, the airborne IRST sensors. As the threat evolves, extending the mission requirement to defend more or even all of Europe against MRBM and IRBM threats will require three Aegis-class sites still using the SM-3 Block IIA. Coverage of Israel and other Middle East areas against the evolved threat will require two additional sites, still using the same interceptor. (Turkey, of course, will require its separate defense using THAAD or equivalent against shorter-range threats.) These requirements assume single-shot defense of most areas is acceptable. Universal SLS capability—which is desirable for more effective protection—would require additional sites or terminal defense.

As was touched on, PAA has two primary objectives that are often merged



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