It is meant to fly into space atop an interceptor rocket and smash apart enemy warheads by force of impact.

Relatively few missiles can destroy many enemy warheads.

"Show me the enemy warhead kill zones against us."

A still more powerful laser might be able to destroy enemy warheads and missiles.

So, unless we can launch with confidence before the enemy warheads fall, our tactics are to ride it out and launch a few minutes later.

Experts still had concerns whether the interceptors could adequately distinguish enemy warheads from decoys.

But this would-be weapon still stars in a push to build a limited system to protect the United States from enemy warheads.

The Pentagon's solution was to have the interceptor zero in on heat emanating from enemy warheads.

Its interceptors, possibly needing to fly far to hit enemy warheads, would be 55 feet long.

The system's "kill vehicles" are to zoom into space and destroy enemy warheads by force of impact.