A Technology to Transform War

By John S. DeMott

U.S., Soviets step up work on Star Wars-style beam weapons

Since scientists built the first working models two decades ago, lasers have evolved from laboratory toys into valuable tools used in microsurgery, metallurgy and communications. But while the military employs the devices to aim weapons and track targets, the development of "death rays" capable of zapping targets seemed mostly confined to Hollywood. No longer. Both the U.S. and the Soviet Union are stepping up work on so-called beam weapons. By all accounts, moreover, the Soviets lead in a technology that could revolutionize warfare.

Ordinary light, whether from the sun or a 60-watt bulb, consists of a jumble of electromagnetic waves of different frequencies. But a laser--for light amplification by stimulated emission of radiation--generates a beam whose waves all have the same frequency and are perfectly synchronized so as to reinforce each other. Beams from very powerful lasers can burn through hardened steel.

In most high-power lasers the beams emerge from tubes containing mixtures of gases that have been "pumped" by intense bursts of electricity or flashes of light. If the gas in the tube is a helium-neon mix, the laser produces a red beam; a mercury-bromine mix yields a green streak, and other vapors generate other shades. All beams are made up of bundles of electromagnetic energy called photons. Because the photons barely spread out as they move, the beam can achieve pinpoint accuracy.

The Soviets are about even with the U.S. in the development of high-energy lasers (HELS) and clearly ahead in an even more lethal offshoot, charged particle beams (CPBs). Instead of photons, which have no mass, CPB devices shoot bursts of relatively weighty subatomic bullets, such as electrons (particles carrying a negative electric charge) or protons (which have a positive charge) that have been accelerated to nearly the speed of light. These bursts do not melt the surface of a target as lasers do, but slice right through it.

Moscow's prowess in beam weapons was confirmed nearly a year ago when U.S. intelligence noticed that the Soviets had begun building a large HEL, or possibly a prototype CPB generator, at Sary-Shagan, a weapons testing area near the Chinese border. The first authoritative press account of Soviet progress in beam weapons was put together by two editors of Aviation Week & Space Technology, Clarence Robinson Jr. and Philip Klass. They pointed out that at Sary-Shagan the Soviets are apparently using Pavlovski generators, highly advanced devices that convert the energy released by controlled blasts of explosives directly into bursts of electricity. The Soviets probably already have an operational HEL that could "blind" U.S. reconnaissance spacecraft orbiting at an altitude of 240 km (150 miles).

American HELS are coming. In about two years the Navy is scheduled to test its Sea Lite laser system: generating more than two megawatts of power, enough to meet the electrical needs of a town of 7,500, Sea Lite is supposed to be capable of knocking out numbers of attacking missiles in quick succession. The laser will be five times more powerful than any built in the U.S. so far. In CPB development, however, the U.S. appears to be five to seven years behind the Soviets.

Lasers are not perfect weapons. Fog and reflective surfaces tend to diffuse or deflect their beam; they cannot cripple a target unless they focus on it for a sizable fraction of a second--a long time in missile warfare. To accomplish this, precision aiming is required. A study conducted at the Los Alamos Scientific Laboratory in New Mexico shows that an aiming angle correct to less than six one hundred thousandths of one degree must be rapidly achieved if a laser is to hit a missile 5,000 km (3,100 miles) away. Such precision is beyond existing technology for both the U.S. and the U.S.S.R.

Research on particle beam weapons is under way at California's Lawrence Livermore Laboratory and at Los Alamos. There, scientists are dealing with a third kind of ray known as a neutral-particle beam. It is made up of particles that carry no electrical charge, such as neutral hydrogen atoms; it would be useful in the vacuum of space, where charged particles like protons and electrons tend to spread out. Development of particle beam weapons is perhaps as much as a decade behind HELS. But if the technology can be ironed out, these could be in military use by the mid-1990s.

Congressional backing of beam-weapons development is growing. Support has come from Defense Secretary Harold Brown too, though he has ordered research on lasers to stress space missions instead of such closer-to-earth uses as defense of ships and missile sites.

The focus on space gives the U.S.'s beam-weapons effort a Star Wars flavor that critics say is too far out for present technology. Still, experts applaud Brown for recognizing the weapons' potential. In theory at least, lasers could destroy enemy missiles with beams that travel at or near the speed of light: in the time it takes an aircraft flying at twice the speed of sound to move slightly more than an eighth of an inch, a laser travels a mile.

Whoever gets into space first with operational lasers will obtain strategic superiority there, and perhaps everywhere, literally in a flash. --By John DeMott. Reported by Jerry Hannifin/Washington

With reporting by Jerry Hannifin

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