Although it is not explicitly spelled out in their report (at least I didn’t see it), the National Academy of Sciences (NAS) Study on “Making Sense of Ballistic Missile Defense” apparently concluded that the only role for the Navy’s Aegis ships in the European Phased Adaptive Approach (EPAA) is to serve as launchers and communication relays for interceptors.
A U.S. Navy Communications Relay System (U.S. Navy Photograph)
In response to a question about the 2011 Defense Science Board (DSB) Report’s conclusion that the Aegis SPY-1 radar was inadequate to support the EPAA, here’s what David Montague, co-chair of the NAS panel had to say at a telephone press conference announcing the NAS Report’s release:
“What the DSB said was the SPY-1 radar is not capable enough to do — support missile intercepts in – in European deployment , which we agree with.
SPY -1 is not used for that purpose in the European deployment. A — a – subject that has apparently has escaped some people’s read here.
The SPY-1 radar is used only for two things.
One is to communicate with the interceptor, because the X-band radar is used for, what we call and what the MDA calls, engage on remote. That means all the tracking data and information that is used to launch an interceptor is – comes from the X-band radar. All the SPY-1 in – in Aegis Ashore does is communicate back and forth with the interceptor.”
Actually, I’m pretty sure the authors of the DSB report understood the concept of engage on remote when they made the following statements:
“The current Aegis shipboard radar is inadequate to support the objective needs of the EPAA mission.” (p. 26)
“Radars of much more substantial operating range than the current radar on the Aegis ships will be necessary for the full realization of a robust regional defense.” (p. 8)
These comments suggest that the DSB sees the inadequate range of the Aegis radars as a problem to be addressed, rather than simply ignored. (In particular, the coverage maps in the DSB report assume a next-generation naval radar, the characteristics of which were not specified in the report.)
 “The National Research Council Holds a Teleconference on Missile Defense Report, CQ Transcriptions, September 11, 2012.