November 29, 2004. Copyright, 2004, Graphic News. All rights reserved

U.S. set to have missile defence by yearÕs end

November 29, Graphic News: At the end of World War II, a team of American military officers travelled to Europe to study GermanyÕs use of ballistic missiles against the Allies. Its recommendation: develop U.S. defences against these new weapons.

Now, almost 60 years later, and despite more than $80 billion spent on research, the United States has just 10 anti-missile interceptors sitting in silos at AlaskaÕs Fort Greely and Vandenberg Air Force Base in California.

The limited defence being rushed into operation cannot provide a shield against the 3,000 nuclear warheads atop RussiaÕs 700 intercontinental ballistic missiles (ICBMs), or the far more modest threat posed by ChinaÕs two dozen or so nuclear missiles. The only other countries armed with ICBMs capable of striking the U.S. are its Nato allies, Britain and France.

The system being deployed to intercept ICBMs in midflight will guard exclusively against the possibility that North Korea, and eventually Iran -- both branded by U.S. President George W. Bush as part of an Òaxis of evilÓ -- will acquire a long-range nuclear threat.

Intelligence analysts are uncertain how close North Korea and Iran are to developing ICBMs. Both nations have missiles with a range of about 1,300km (800 miles): the North Korean No-dong, and IranÕs Shahab-3. The most recent National Intelligence Estimate predicts the U.S. would Òmost likelyÓ face long-range threats from both nations by 2015. However, the 2001 report also identified Iraq under Saddam Hussein as a future ICBM threat. He was said to possess Òa small covert force of (short-range) Scud-variant missiles, launchers and conventional, chemical, and biological warheads.Ó No such weapons were found when U.S. forces invaded Iraq, underscoring the unreliability of such estimates.

In August 1998, North Korea shocked the world when it attempted to launch a satellite atop a Taepo-dong 1 rocket. Although the third stage failed to boost its payload into space, the test demonstrated PyongyangÕs ability to build a three-stage rocket with an estimated range of 2,500km (1,550 miles).

Intelligence analyses suggest work is proceeding on a longer-range Taepo-dong 2 that has a notional range of 10,000km (6,200 miles). The TD-2 might be able to hit Alaska and AmericaÕs west coast with a small warhead. An advanced version might be capable of striking anywhere in the United States. Missile-defence proponents insist the time to prepare is now.

ÒIt takes time to build these defences,Ó said Air Force Lt. Gen. Trey Obering, director of the PentagonÕs Missile Defense Agency (MDA). ÒWe canÕt wake up one morning and say ÔOh, we have to go do that todayÕ, when they already have demonstrated that [capability].Ó

The MDA has explored three schemes to destroy an ICBM in flight: boost-phase, midcourse-phase, and terminal-phase.

Boost-phase intercept -- to destroy an ICBM before its warheads and decoys are released -- requires an interceptor reaching speeds of 8-11 kilometres per second (5-7 miles per second) in order to catch its target. The technology for boost-phase intercept remains at an early stage.

Terminal interception -- stopping a warhead when it is less than a minute from its target -- has been abandoned by the MDA because of cost.

The handful of missiles now deployed in California and Alaska are part of the MDAÕs Ground-based Midcourse Defence (GMD) system.

The Ground-Based Interceptor (GBI) is a three-stage silo-launched booster rocket and Òkill vehicleÓ that will destroy warheads while they are still outside the earthÕs atmosphere and at their highest trajectory. Each GBI missile carries a small Exo-atmospheric Kill Vehicle (EKV).

The GBIs are connected to a web of satellites and radars that continuously scan the entire globe for threats. In the event that an enemy missile launch is detected, the GMD command centre, buried deep beneath Cheyenne Mountain in Colorado, will relay its launch command, and the designated GBI missile will blast out of its silo and climb toward the targetÕs predicted location, receiving in-flight tracking updates from satellites and radars along the way.

Three minutes into its flight, about 2,250km (1,400 miles) from its target, the EKV will separate from the third stage. Dozens of cables will be blown off, and four springs will propel the vehicle forward. The EKV will immediately bank sharply to avoid being hit from behind by the third stage.

From this point forward, the kill vehicle will proceed to the target on its own momentum. As it closes in, the combined velocity of the kill vehicle and the incoming warhead will approach 24,000km/h (15,000mph). Approximately 100 seconds before impact, the EKVÕs infrared sensors will switch on and begin tracking the incoming warhead. The impact from a precise hit will pulverize the warhead and destroy any nuclear, chemical, or biological agents it might be carrying.

Between June 1997 and December 2002, the MDA conducted 10 hit-to-kill tests on dummy warheads and decoys -- five  were successful. Due to these successes, the GBI programme has received enthusiastic support from the Bush administration and the Republican-controlled Congress. Over 20 interceptors are scheduled for deployment over the next two years.
/ENDS

Sources: IISS, Federation of American Scientists, Global Security, Orbital Sciences, Raytheon, Wisconsin Project On Nuclear Arms Control