Soviet Scientists to Visit 2 Key ‘Star Wars’ Labs : Arms control: A U.S. official says the tour is the first step towards opening a ‘wide window into each other’s research activities.’

A delegation of top Soviet scientists, led by the chief negotiator at the strategic arms reduction talks in Geneva, will arrive Friday in Southern California for an unprecedented tour of a sensitive “Star Wars” research facility near San Clemente.

The Soviets’ two-day visit to Orange County will be shrouded in secrecy. Except for a brief picture-taking session when the 10-member delegation touches down at the U.S. Marine Corps Air Station at El Toro, neither the press nor the public is invited to take part.

“This is essentially an extension of the (Geneva) talks,” a senior Bush Administration official said Wednesday. “Those talks are confidential between the two governments.”

Three senior U.S. officials discussed the week-long Soviet visit to the United States at a briefing Wednesday, but they spoke on the condition that they not be identified by name.

In addition to touring TRW Inc.’s Strategic Defense Initiative research facility on Saturday, the Soviets will spend two days early next week at the Los Alamos National Laboratory in New Mexico, where other SDI research is in progress.

Also known as “Star Wars,” the SDI program would create a partial shield against incoming nuclear ballistic missiles in part by stationing powerful lasers and other high-tech weaponry on rockets and satellites. The Soviet Union in recent years has been conducting similar research.

At the TRW Capistrano Test Site, located on 2,000 acres of unincorporated land, the Soviet scientists will inspect a powerful chemical laser.

Currently in the early stages of development, the laser eventually could be enlarged and installed on a space-based platform to test its ability to detect and destroy incoming ballistic missiles armed with nuclear warheads. Such tests are planned for the middle to late 1990s, according to the Strategic Defense Initiative Organization, the Defense Department unit that oversees the project.

At the Los Alamos laboratory, the Soviet delegation will examine a project to develop rocket-mounted devices that would generate powerful beams of atomic particles intended to either identify or destroy incoming missiles.

Neither project is classified, but this is the first time that Soviet scientists will be permitted to inspect the SDI laboratories where American scientists are working and the hardware they are working on, officials said.

The Soviet visit is scheduled to begin less than two weeks after the United States laid on the table in Geneva a proposal for a new Defense in Space Treaty. The proposed treaty is an attempt to set ground rules for development of space-based defense systems.

A key element of the U.S. proposal is reciprocal laboratory visits, in addition to mutual observation of tests, annual data exchanges and joint briefings, one official said.

The tour of the two SDI research units, another official said, is intended to demonstrate to the Soviets how reciprocal visits might work.

“We believe that visits to laboratories are essential if the sides are to gain an early and wide window into each other’s research activities,” the official said.

The Soviet official who will lead eight scientists and a Soviet Foreign Ministry official on the two SDI tours is Ambassador Yuri Nazarkin, head of the Soviet delegation to strategic arms and space defense talks in Geneva. The negotiations include both weapons in space and the strategic arms reduction talks (START).

The American invitation was extended last September by Secretary of State James A. Baker III during a meeting with Soviet Foreign Minister Eduard A. Shevardnadze in Jackson Hole, Wyo. The Soviets so far have not invited American scientists to visit any of their space defense research facilities.

As originally proposed by President Ronald Reagan in 1983, SDI would have shielded the nation with an impenetrable blanket of space-based defenses.