MISSILES targeted at US cities and intercepted by Bush鈥檚 proposed missile
defence shield could fall on Europe, Canada or middle America instead, arms
researchers warn.
Bush鈥檚 missile defense plan includes a system to intercept intercontinental
ballistic missiles (ICBMs) just minutes after launch, while their rocket
boosters are still burning. This 鈥渂oost-phase interception鈥� should be easier
than targeting missiles in mid-flight because tracking a flaming rocket is
easier than homing in on a relatively cool and easily disguised warhead sailing
high above the atmosphere, experts say.
But destroying only the booster could leave the warhead zinging across the
sky, says Ted Postol, a physicist at the Massachusetts Institute of Technology.
Precisely where the warhead would land would depend on when the booster was
destroyed during its 4 to 6-minute burn. That would be difficult to control, so
the warhead could potentially hit anywhere between the launch site and the
target city, Postol says.
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This means that a nuclear missile fired at the US from North Korea could
explode over Alaska or Canada, while one fired from Iraq might strike Britain or
mainland Europe.
鈥淓ven if you knew all the details, you couldn鈥檛 be sure of what would happen
in any given engagement,鈥� Postol says.
The US is considering several options for boost-phase interception. One is a
powerful airborne laser mounted inside a modified Boeing 747 that the Air Force
is developing to intercept shorter-range missiles. The laser鈥檚 beam could burn a
hole in the thin skin of an ICBM鈥檚 booster, says Geoff Forden, a physicist at
MIT. But it cannot destroy an ICBM warhead, which is designed to withstand
tremendous heat while re-entering the atmosphere, he says.
To destroy the warhead itself during the boost phase would need a larger and
more manoeuvrable interceptor than anything the US is currently developing,
Postol says. It would have to be launched from the ground or the sea, and then
specifically target the warhead鈥攑erhaps by aiming a stream of shrapnel at
it. 鈥淭here are technologies that overcome this narrowly defined problem,鈥� Postol
says, 鈥渂ut they look nothing like what the Bush administration is
肠辞苍蝉颈诲别谤颈苍驳.鈥�
Researchers disagree on whether a system that simply caused the warhead to
fall short could be judged a success or a failure. If it hit land, the warhead
would most likely hit a relatively uninhabited area and kill far fewer people
than intended, says veteran physicist Richard Garwin, who helped develop the
American H-bomb. That fact should deter nations such as North Korea or Iraq from
launching a missile at the US, he says, if they were ever tempted to do so.
But Forden questions this. 鈥淭he guys who might launch this thing probably
won鈥檛 care enough to say if it doesn鈥檛 hit New York, I don鈥檛 want to launch it
at all.鈥�
The shortfall problem could, however, increase tensions between the US and
its allies, says George Lewis, a physicist at MIT. 鈥淚f you ask how many people
are going to be killed, on average, you鈥檙e clearly better off having the warhead
fall short,鈥� he says. 鈥淏ut the people who it鈥檚 going to land on may have a
different view.鈥�
