Next week, defense giant Lockheed Martin will deliver the 100th SPY-1 radar system at its facility in Moorestown, New Jersey. The radar will equip the Navy's newest warship, an as-yet-unnamed Arleigh Burke-class destroyer bearing the hull number DDG-108.

SPY-1, better known as Aegis, has been the world standard for naval air defense radars since the first was installed on the cruiser Ticonderoga in 1986. These days Aegis equips 22 U.S. cruisers, an eventual total of 62 Burke destroyers and is planned for the super-sophisticated Zumwalt-class destroyer, the first of which will join the fleet in 2012. In addition, the Spanish, South Korean, Japanese, Norwegian and Australian navies have bought Aegis for their main combat ships.

Aegis was optimized to track Soviet bombers and missiles and -- paired with Raytheon Standard missiles -- aimed to protect aircraft carriers and amphibious ships from attack.

Twenty years of strong sales and a competitive radar market have spurred constant development of the basic SPY-1. "As the threat changed, technology has changed. So has Aegis," says John Morse, an Aegis engineer.

The A model was first. The B model, the Navy discovered, was powerful and accurate enough to track ballistic missiles streaking down towards their targets, according to Alan Ostrow, another Aegis engineer. That version aboard cruisers and destroyers was developed into the U.S. military's first certified ballistic missile defense system and has been a major player in the West's diplomatic chess game against North Korea, a major exporter of ballistic missiles and a purported nuclear power.

Later versions of the radar include a smaller, less powerful version meant for smaller ships belonging to foreign navies. A proposed adaptation of this variant mounted on Lockheed Martin's Freedom-class Littoral Combat Ship, which the company is building for the U.S. Navy, elicited strong interest at the Euronaval arms bazaar in Paris last month. The U.S. Navy's LCS will not feature Aegis, since it is not meant for the anti-air mission.

One Lockheed Martin official says that today's SPY-1 is eight times more powerful than the original.

Ostrow estimates Aegis has another three decades of life in it. The future of the system, according to Lockheed Martin's Jeff DuBois, lies in a surprising direction. Engineers at Moorestown have been ripping out Aegis' traditional military-grade computers and replacing them with cheaper, faster commercial computers such as IBM's Blade server. Going to so-called "commercial off-the-shelf" computers means Aegis can be upgraded every time IBM comes out with a faster computer -- say, every two or three years. This helps the Navy keep up with the ever-increasing pace of technological development.

"We have not reached the limit of Aegis," Ostrow says.