By Eric Rosenberg
    The San Francisco Chronicle

    Friday 06 October 2006

    A Pentagon project to modify its deadliest nuclear missile for use as a conventional weapon against targets such as North Korea and Iran could unwittingly spark an atomic war, two weapons experts warned Thursday.

    Russian military officers might misconstrue a submarine-launched conventional D5 intercontinental ballistic missile and conclude that Russia is under nuclear attack, said Ted Postol, a physicist and professor of science, technology and national security policy at the Massachusetts Institute of Technology, and Pavel Podvig, a physicist and weapons specialist at Stanford.

    "Any launch of a long-range nonnuclear armed sea or land ballistic missile will cause an automated alert of the Russian early warning system," Postol told reporters.

    The triggering of an alert wouldn't necessarily precipitate a retaliatory hail of Russian nuclear missiles, Postol said. Nevertheless, he said, "there can be no doubt that such an alert will greatly increase the chances of a nuclear accident involving strategic nuclear forces."

    Podvig said launching conventional versions of a missile from a submarine that normally carries nuclear ICBMs "expands the possibility for a misunderstanding so widely that it is hard to contemplate."

    Mixing conventional and nuclear D5s on a U.S. Trident submarine "would be very dangerous," Podvig said, because the Russians have no way of discriminating between the two types of missiles once they are launched.

    Russian President Vladimir Putin warned that the project would increase the danger of accidental nuclear war.

    "The media and expert circles are already discussing plans to use intercontinental ballistic missiles to carry nonnuclear warheads," he said in May. "The launch of such a missile could ... provoke a full-scale counterattack using strategic nuclear forces."

    Accidental nuclear war is not so far-fetched. In 1995, Russia initially interpreted the launch of a Norwegian scientific rocket as the onset of a U.S. nuclear attack. Then-President Boris Yeltsin activated his "nuclear briefcase" in the first stages of preparation to launch a retaliatory strike before the mistake was discovered.

    The United States and Russia have acknowledged the possibility that Russia's equipment might mistakenly conclude the United States was attacking with nuclear missiles.

    In 1998, the two countries agreed to set up a joint radar center in Moscow operated by U.S. and Russian forces to supplement Russia's aging equipment and reduce the threat of accidental war. But the center has yet to open.

    A major technical problem exacerbates the risk of using the D5 as a conventional weapon: the decaying state of Russia's nuclear forces. Russia's nuclear missiles are tethered to early warning radars that have been in decline since the dissolution of the Soviet Union in 1991. And Russia, unlike the United States, lacks sufficient satellites to supplement the radars and confirm whether missile launches are truly under way or are false alarms.

    The scenario that worries Postol, Podvig and other weapons experts is what might happen if the United States and North Korea come to blows and a conventional D5 is launched against a target there from a submerged Trident submarine. Depending on the sub's location, the flying time to Russia could be under 15 minutes so the Russians would have little time to confirm the trajectory -- using decaying equipment -- before deciding to launch a nuclear strike on the United States.

    The D5 missile project involves the removal of nuclear warheads from as many as two dozen D5 ICBMs that are carried aboard the U.S. fleet of 12 Ohio-class Trident submarines.

    The Pentagon has the project on an accelerated schedule, with the goal of fielding the weapons alongside their nuclear variants in two years. Each Trident submarine carries 24 D5 missiles, and the plan calls for using two of those as conventional weapons in each sub.

    The rocket fired by a submerged submarine would barrel up through the ocean powered by its three-stage engine and rapidly ascend through the atmosphere at speeds up to 20,000 feet per second into outer space.

    The warhead compartment of the missile would then plummet back to earth, guided to its target within about 50 feet by sophisticated sensors. Defense officials believe it would gain enough speed and force to penetrate underground command bunkers.