1.   Even if the interceptor can be made to destroy dummy targets, they say, an enemy might challenge it with real warheads and feints of unexpected design.

2.   In a real attack, those critics argued, an adversary would use multiple decoys shaped like real warheads.

3.   Instead of having to destroy an individual missile, as in the boost phase, the interceptor must pick out the real warhead.

4.   Infrared eyes will help to distinguish real warheads from dummy warheads by reading their heat signatures.

5.   One area of dispute has been whether the system is able to distinguish real warheads from decoys that enemy missiles might also release.

6.   The sensor was to be smart enough to find the real warhead amid the clutter, seeking out its heat rays.

7.   The next step, possibly Wednesday or Thursday, will be to fire the laser for the first time at a Katyusha rocket in flight with a real warhead.

8.   The next step, possibly this week, will be to fire the laser for the first time at a Katyusha rocket in flight with a real warhead.

9.   Yet to be determined, Kadish said, is whether the technology is reliable and can be developed to distinguish real warheads from decoys.