Missile shield: sea-based missile defense scores hits, but will it work in a real attack?

• Author: Erwin, Sandra I.
• Position: MISSILE DEFENSE

The Navy has embarked on a plan to deploy 18 warships that would defend the United States and key allies against ballistic missile attacks. But there is still one major weakness in U.S. missile defense systems that neither the Navy nor the Pentagon's Missile Defense Agency has yet been able to overcome--their ability to discern real warheads from harmless decoys.

Since the end of the Cold War, the Defense Department has spent nearly $100 billion to establish a limited defensive capability against intercontinental and tactical ballistic missiles with a layered mix of long-, medium- and short-range interceptors and sensors. Of most concern to the Pentagon are ballistic missiles that could be launched by North Korea or Iran.

Although MDA officials say they have the technology to "discriminate" between warheads and decoys, military experts admit that they face formidable hurdles.

The means to quickly detect an attacking warhead in a cloud of chaff have yet to be achieved, says Navy Capt. Joe Horn, former commanding officer of the USS Lake Erie, which is one of the cruisers assigned to missile defense missions.

The missile defense technology that underpins the Navy's effort has been in development for decades, and in recent years has shown signs that it may work. Nine ships will be in place by the end of the year and the rest would arrive by 2011.

"The real problem in ballistic missile defense is not hitting a bullet with a bullet. Our interceptors can do that," Horn says, speaking at a conference of the Surface Navy Association.

The downfall is the radar technology, which dates back to the 1960s. "Its capabilities in target discrimination we are just beginning to understand," Horn says. The challenge is to discern "what's in the target complex" as it flies above the atmosphere. "Somewhere in the mess is the threat we want to kill," he says. "People criticize the X-band radar and Spy radar as being old technology and not designed to discriminate. But there is capacity to do that with new techniques."

The ground-based missile defense system now being built in Alaska and California also is hindered by its inability to discriminate, says former U.S. ambassador Henry Cooper, who in the early 1990s was director of MDA's predecessor, the Strategic Defense Initiative Organization.

"They are ignoring the most significant countermeasures problem," Cooper says in an interview. "These problems have been known for years."

The most effective tactic for beating the countermeasures is to avoid them altogether by destroying the enemy missile immediately...