Washington — A disabled Soviet submarine that plunged more than three miles into the icy Atlantic depths off Bermuda probably took most of its secrets down with it. Experts say the United States has the capability to retrieve the submarine -- but it would be a risky and expensive undertaking, and would be extremely difficult to justify in terms of the intelligence information to be gained.
More important, most of the classified data that could be gleaned from the incident may already be in US hands.
The submarine was powered by a nuclear reactor, and was apparently carrying nuclear arms.
But it appears there will be relatively minor environmental impact from the incident, and virtually no chance of a nuclear explosion.
(Environmental risks from small-scale nuclear waste, P. 23.)
The most valuable intelligence data from the incident could be contained in the coded electronic messages that flashed between the stricken sub and its base in Murmansk, according to experts. The dispatches were recorded by US reconnaissance planes that shadowed the vessel as it foundered for three days.
One expert says that if the submarine's radio room was not damaged, then the transmissions would have been neither more nor less secure than under normal operating conditions. But if the emergency forced the vessel's commander to use the transmission facilities of a Soviet merchant ship that towed the submarine for a time, then Pentagon eavesdroppers could have overheard some potentially valuable information. Even Soviet merchant ships have the ability to encrypt transmissions, according to one expert, but the coding is not believed to be as extensive as the kind routinely employed by Soviet nuclear submarines.
The secret Soviet codes and cipher machines that were on board are not likely to fall into American hands, either. Several observers suggested that the Soviets, as a precaution, either destroyed the encryption materials or off-loaded them to the towing vessel.
Destruction of cryptographic devices ``is one of the first things you do'' in the event of an accident, one expert says.
Experts familiar with Soviet submarine capability and US salvage capability indicate that the US can learn little that is new from salvaging the Yankee-class submarine, one of the older models in the Soviet undersea fleet.
``I don't think there's much we need to know about the way Yankee submarines operate,'' says James Bush, a retired submarine commander and associate director of the Center for Defense Information in Washington.
Another expert, who asked not to be named, generally agreed, suggesting that some relatively minor ``technological questions'' might be solved by being able to examine the submarine, but little of significant intelligence value would be learned.
Whatever could be learned would have to be measured against the considerable difficulty of salvaging the vessel, which sank in 18,000 feet of water some 1,040 miles east of Cape Hatteras, N.C., early Monday, according to the Pentagon.
The Defense Department had been closely monitoring the stricken vessel for three days, after a fire and explosion forced it to surface.
US Secretary of Defense Caspar Weinberger said the incident was ``a little bit like Chernobyl,'' a reference to the nuclear accident last spring at a Soviet power plant in the Ukraine.
In contrast to that event, however, this time the Soviets notified the White House of the difficulties on board the submarine within 24 hours, according to US Secretary of State George Shultz.
Two experts theorized that the Soviets attempted to tow the disabled vessel back to the Soviet Union, rather than to Cuba, for several reasons. One is that the submarine was carrying nuclear weapons, and landing it in Cuba would have violated the 1962 accord prohibiting the introduction of nuclear missiles into Cuba. Another is that the Soviets may have wanted to ensure that if the vessel sank, it would go down in extemely deep water.
Shelley Lauzon, publications and information manager at the Woods Hole Oceanographic Institution at Woods Hole, Mass., says that the research vessel Argo Jason -- which was used to explore the wreck of the Titanic -- could photograph the submarine ``in quite good detail.''
She says the Navy has not asked the Institution to help, but that the organization would do so ``if there is a reason of national interest.''
Experts theorize that the liquid fuel of one of the nuclear missiles on board the Soviet sub accidentally ignited and exploded. But, they say, a series of complicated procedures must be followed in order to arm the triple-warhead missiles -- procedures designed precisely to guard against an accidental nuclear explosion.