The sprawling Moorestown complex has been developing and manufacturing the Aegis Ballistic Missile Defense system since 1969, when it was owned by RCA, and its experts have been deeply involved in every test firing.

So, though the current veil of secrecy prevents the company or the Pentagon from confirming it, Moorestown experts are likely aboard ships in the Pacific Ocean and at land stations helping to reprogram Aegis to knock out an orbiting satellite instead of an enemy missile.

The window for the attempt, which opened last weekend, will continue about seven or eight days, the Pentagon said last week.

The troubled satellite was launched Dec. 14, 2006, for the National Reconnaissance Office. Marine Corps Gen. James "Hoss" Cartwright, vice chairman of the Joint Chiefs of Staff, said it "went dead for communications and control very shortly after it attained orbit."

The bus-size satellite weighs about 5,000 pounds, and big pieces would probably survive reentry and crash into Earth, he said.

But the big worry is the estimated 1,000 pounds of toxic hydrazine fuel still onboard. "All of our satellites have fuel that is reserved, along with redundant systems, to ensure there is propulsion to allow for what we would call a controlled de-orbit" and crash in open ocean.

Having lost control of the satellite, the Pentagon and President Bush decided to shoot it down while it still is in space, a tough first-ever feat for the Aegis system.

The satellite is said to be about 130 miles above Earth. "I think the closing velocities that we're talking about here, in rough order of magnitude, are about 22,000 miles per hour . . . That's a challenge," Cartwright said.

Aegis has scored big successes in recent tests over the Pacific Ocean. In November, the system detected, identified, tracked down and destroyed two incoming missiles at the same time. These were short-range targets, allowing little time for Aegis to do its work.

Joe Rappisi, the Aegis program director in Moorestown, interviewed at the time, called that "a very challenging event."

Aegis system development and manufacturing are the primary missions of the 5,200-person complex in Moorestown, one of several Lockheed Martin Philadelphia-area operations that together employ more than 12,000 people.

The Aegis system integrates radar, software and guidance systems. The Raytheon Co. manufactures the missiles it guides.

When defending against a surprise enemy attack, the Aegis system constantly scans horizon-to-horizon to detect missiles being launched or returning from high above the Earth's atmosphere. It picks the target from among other aircraft. Multistage missiles separate in flight, so Aegis must identify the warhead and destroy it instead of the harmless launch vehicle, Rappisi and others have said in briefings over the last year.

In this planned shot, the satellite may be breaking up. So Aegis technology will identify the fuel tank from among the pieces and destroy it.

The Aegis system has destroyed missiles at altitudes similar to the satellite's degrading orbit, but this will be the nation's first shot at an orbiting satellite.

The firing will be coordinated with aviation authorities to keep aircraft out of harm's way, the Pentagon said.

Pentagon briefers insist this is not an attempt to turn Aegis into an antisatellite weapon. The system, they said, immediately will be reprogrammed to its usual missile-defense role.

If the shot misses, it will be difficult to predict where the satellite will crash. The contaminated area would be about the size of two football fields. Like chlorine or ammonia, hydrazine creates a "burning sensation," Cartwright said, "and you would at least incur something that would make you go to the doctor."