• Coverage of Israel and other Middle East areas against the anticipated threat will require additional Aegis and THAAD assets. (Turkey will require its separate defense using THAAD or the equivalent against shorter-range threats.) These requirements assume that single-shot defense of most areas is acceptable.
• Universal SLS capability, which is desirable for effective discrimination and other purposes, will require additional sites or terminal defense.
Major Finding 8: The first three phases of the European Phased Adaptive Approach (PAA) are expected to provide defense for Europe against a limited ballistic missile attack for deployed U.S. and allied forces within the region and the Middle East, provided the sensor architecture and the missile defense command and control (C2) center for the European PAA architecture can implement engage-on-remote capability.
• If modestly sophisticated countermeasures are anticipated for the intermediate-range ballistic missile (IRBM) threat, then the European PAA will need to include multiple X-band radar and long-range IR sensors (e.g., airborne infrared) that can provide concurrent data on IRBM trajectories similar to the countermeasures proposed for U.S. national missile defense. However, the IR data will need to come from external sensors because the SM-3 and THAAD kill vehicles have limited seeker range and limited divert capability. Fortunately, Aegis and THAAD are both capable of continuous communication between the kill vehicle and the C2 center.
• Europe can be covered with a SLS firing doctrine assuming enough sites are deployed, where the number of sites required depends on the interceptor speed—for example, two or three sites would be required if the interceptor speed is greater than 4.0 km/sec.
• SLS, when combined with the sensor architecture and C2 center noted above, is expected to provide a relatively robust defense of Europe against a range of potential future countermeasures.
• Turkey, as a member of NATO, will require separate BMD elements to ensure its protection. THAAD is probably the most appropriate system for this purpose owing to the stand-alone capability of its X-band radar and its ability to intercept shorter range missiles.
Major Finding 8a: Phase IV of the European PAA may not be the best way to improve U.S. homeland defense.
• The speed of the Phase IV interceptor will need to be greater than can be achieved with a 21-in. missile to avoid being overflown by lofted ICBM trajectories from Iran if the interceptor is based in northern Europe (Poland).
Major Finding 9: The proposed Precision Tracking and Surveillance System (PTSS) does not appear to be justified in view of its estimated life-cycle cost