‘Star Wars’ Ground Lasers, Mirrors in Space Favored

The Pentagon team working on the “Star Wars” missile defense program is placing greater reliance on a network of ground-based lasers and orbiting mirrors than on lasers placed in space to destroy enemy warheads aimed at the United States, the program’s director said Tuesday.

Lt. Gen. James A. Abrahamson said the ground-based lasers could “strike with the speed of light.” And, although they could not deliver as much energy as other anti-missile systems, their targets--rocket boosters carrying warheads--are more fragile than originally thought, said Gerald Yonas, the project’s chief scientist.

Abrahamson, referring to the ground-based lasers, said: “That’s . . . what we’re planning on” if lasers, as expected, become a major component of the weapon system.

Abrahamson’s review of the program was seen by a critic, John Pike, a staff member of the Federation of American Scientists, as an acknowledgement that problems remain with some of the more exotic and expensive space-based weapons.

$1-Billion Cut Seen

Congress, nearing the end of its work on the 1986 budget, appears likely to cut about $1 billion from the $3.7 billion that President Reagan has sought for research for his Strategic Defense Initiative, the formal name for what is commonly called “Star Wars.”

Abrahamson, director of the SDI program, used a briefing for reporters at the Pentagon to send an upbeat message to Congress: “The bottom line is that the program is indeed coming along very well. It is at the most inventive stage.”

Conceding that problems exist, he said that some major contracts have been delayed because more work must be completed before anti-missile weapons can discriminate between real warheads and decoys. He said researchers are making “a major thrust” to overcome challenges posed by the mid-course phase of warhead flight, when weapons are soaring through the cold, dark reaches of space above the atmosphere.

‘Really Beautiful’

Although Abrahamson is known for his low-key but upbeat presentations to Congress, he was barely able to contain his optimism. Pointing to a picture of a “fiber-optic gyroscope,” he said: “This one is really beautiful.”

To portray the challenges of the research, he said that targeting a laser beam through the atmosphere and into the vast expanse of space is akin to standing in Los Angeles and trying “to hit something the size of the door over there in New York.”

Although reliance on ground-based lasers--which would send a high-intensity, sharply focused light beam into space to strike a rocket booster soaring into the heavens--might make the defensive system more politically acceptable by keeping the weapons out of space, the project would still need to deploy high-quality mirrors in permanent orbit.

‘Fighting Mirror’

Under one system discussed by Abrahamson, a laser beam would be directed to a mirror above the atmosphere over Alaska. The mirror would reflect the beam eastward toward a second mirror, and this so-called “fighting mirror” would send the beam earthward to strike a Soviet missile boosting warheads through the atmosphere at the start of the 30-minute flight over the Arctic to the United States.