New Soviet SS-18 Explodes Twice in Tests

A new version of the Soviet SS-18, the world’s biggest continent-spanning nuclear missile, twice exploded in midair during test flights in April and last month, a Pentagon official said today.

The explosion in September is believed by U.S. intelligence officials to have occurred during the separation of the missile’s first and second stages, the official said, speaking on condition he not be identified.

In the April test, the rocket exploded shortly after it was launched from its silo, he said.

The official, contradicting a report in the New York Times, which first disclosed the incidents, said the explosions do not represent a major setback in the Soviet development of a new version for the SS-18.

The new SS-18 probably violates the 1979 SALT II accord, he added.

‘Too Early to Tell’

“The fact that it failed doesn’t mean anything,” he said. “If the next six tests also fail, then they have a problem. It’s too early to tell.”

The United States normally will test a new missile 20 times before it is certified as ready, and the official said the Soviets have a comparable test program.

The SS-18 can be armed with up to 14 independently targetable nuclear warheads and, at nearly half a million pounds, it is the biggest, deadliest weapon in the world. There are 310 of them deployed in land-based silos.

It also is one of the most accurate Soviet missiles, with the probability that its warheads would miss their targets by a mere 600 yards. The missile has a range of 7,500 miles.

The Soviet missile program experienced another failure last week--the third reported in five months--when a rocket launched from a submarine in the Arctic Barents Sea strayed 1,500 miles off course and crashed in or near Chinese territory, a Pentagon official said Tuesday.