burning, two-stage interceptors building on development work by MDA under the KEI program carrying heavier but more capable kill vehicles (KVs).

•   The evolutionary approach would employ much longer concurrent threat observation by both X-band radars and the interceptor KV’s onboard sensor over the entire engagement. The importance of the synergy between these concurrent observations and the SLS battle space in maximizing midcourse discrimination effectiveness cannot be overemphasized.

•   An additional interceptor site with the new evolved GBI in CONUS together with the recommended radar additions provide SLS coverage of virtually the entire United States and Canada against the sort of threat that can prudently be expected to emerge from North Korea or Iran over the coming decade or so. The recommended evolution would add one additional site in the United States in the Northeast, together with additional X-band radars to more effectively protect the eastern United States and Canada, particularly against Iranian ICBM threats should they emerge.

•   This improved capability obviates the need for early intercept from bases in Europe, unless they are required for European defense.

•   Defense of Hawaii should be provided by Aegis with launch-on-remote capability: THAAD would provide a second intercept opportunity as backup for the Aegis engagement. Hawaii is very small target area for threats from North Korea, Iran, or any other country and can be covered by one Aegis ship located west of the islands. By contrast, modifying the GMD system to provide effective defense of Hawaii against an evolved threat would add substantial complexity and cost.

•   Maximize the opportunity for observing the threat complex during most of the threat trajectory until intercept. Addition of stacked TPY-2 radars are recommended for this purpose.

•   Make effective use of the high-accuracy data from SBIRS to cue forward X-band radar and concurrent IR sensors on the interceptor kill vehicle, which together contribute most of the discrimination capability.

•   The ability to create, communicate, and interpret target object maps (TOMs) among the radar, the battle manager, and the interceptor during the entire engagement—typically hundreds of seconds for a midcourse intercept—increases the probability of successful discrimination. The resulting TOMs with object rankings should be exchanged frequently with the interceptor kill vehicle during its fly-out. This exchange requires taking advantage of the radar’s large aperture and power to close that communication link over longer distances. The TOM’s data exchange ability builds on the capabilities demonstrated by programs such as NOE and ERIS and additionally builds on the MDA Integrated Flight Test Plan for GMD, Aegis, and the THAAD interceptor that uses sensor elements with the addition of downlinks from the interceptor to the BMC3 element.

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