Science: A Technology to Transform War

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.