In the Friday test, and a similar demonstration on August 28, both missiles were destroyed when the laser beam struck the warhead atop each missile resulting in an explosion.

Beam director in final preparation for firing

"These are low trajectories, just kilometers off the deck," McKinney said.

The theater laser system is designed to intercept and destroy short-range, limited rocket attacks fired at civilians and troops in the field. It is not capable of intercepting missiles high in the atmosphere as is the case with the National Missile Defense System under debate by the Clinton administration and Congress.

TRW's laser is a virtually invisible, infrared beam generated from deuterium and fluoride. In the test simulating the missile attack, the two rockets are fired aloft in rapid succession. The laser-system tracking radars detect the missile's oncoming flight and fires two separate laser beams at each target, one after the other. The beams strike the missile's warhead and, in effect, detonate its explosive well before the missile reaches the ground.

"Killing one rocket was significant, but being able to show that we can consistently kill two or more targets per engagement is in a class by itself," said Lt. General John Costello, commanding general U.S. Space and Missile Defense Command. The tests were conducted at the Army's White Sands Missile Range in New Mexico.

The U.S. and Israeli governments have been developing laser battlefield weapons -- known as "Directed Energy Weapons" in engineering terminology -- since the 1991 Persian Gulf War. The requirements for the lasers are driven by the need of the Israeli government to protect civilians living in towns along its northern border from future rocket and missile attacks.