COLUMN ONE : The Laser: Air Force’s Top Gun? : Rival scientists are competing to create a weapon--powered by household chemicals--that can knock off missiles yet fit in a 747.

“Arm the phasers� is a battle command that Pentagon officials believe will soon move out of the realm of science fiction.

Under an ambitious $5-billion program that is supposed to revolutionize warfare much as gunpowder once did, some of the nation’s top scientists are working on a high-energy chemical laser that would shoot lethal beams a few hundred miles to knock out enemy missiles.

The 100,000-pound laser, carried inside a Boeing 747 jet, would be powerful enough to destroy targets in about three seconds--sending missile wreckage and any warhead to drop back onto the enemy launch site.

Guiding the beam would be a computer-controlled mirror that could adjust its shape thousands of times a second to offset atmospheric distortion between the weapon and the target.

The laser has won proponents at senior levels of the Pentagon and Congress. They are convinced that it will bring to reality the type of futuristic beam weapon long portrayed by Hollywood.

“It is a major scientific breakthrough,� said Secretary of the Air Force Sheila Widnall. “It is a revolutionary technology.�

The Air Force program is the culmination of nearly three decades of classified military research into both high-powered lasers and highly advanced optics. The research is already having a major impact on civilian astronomy, making ground-based telescopes nearly as powerful as the Hubble Space Telescope.

In defense industry laboratories along the West Coast, scientists are perfecting the mirrors and the high-energy lasers, which would be powered not by electricity but by household chemicals.

Corporate Battle

The program, which aims to have a working laser weapon within 10 years, pits a team led by Rockwell International Corp. and Hughes Aircraft Co. against Boeing Co., Lockheed Martin Corp. and TRW Inc.--a clash of scientific talent that includes scores of physicists, chemists, computer scientists, aerodynamicists and engineers. A winning team will be selected in 1997.

However, the history of high-power military lasers is littered with embarrassing failures in which too much was promised, and false expectations were created a decade ago during the early “Star Wars� program.

So critics say it is too early to tell whether the new system, known as the airborne laser, will work any better. They caution that building the device will involve major technical hurdles.

But senior defense officials insist that the story will be different this time because the technology is in hand and the need for a weapon to protect American troops is rooted in a visceral memory of Iraq’s deadly Scud attack against a U.S. barracks during the 1991 Persian Gulf War.

The aerospace industry smells big business in the future of lasers, foreseeing the day when such weapons are used for all kinds of battlefield shooting matches.

“If we succeed, this opens up a whole new direction for military weaponry,� said Barry J. Waldman, the vice president who heads Rockwell’s laser program.

All the critical elements of the weapon draw on California or Washington state contractors, a measure of just how deep the West Coast’s technical talent remains. Ever since chemical lasers were developed in the 1960s, TRW’s Space Park in Redondo Beach and Rockwell’s Rocketdyne Division in Canoga Park have been the undisputed leaders, as well as fierce rivals.

Lamar Moon, a wiry, soft-spoken expert in fluid mechanics who heads up Rockwell’s effort, works out of a windowless vault with bright yellow walls. Across town at TRW, physicist Robert Bradford Jr. has spent his career building the firm’s huge laser research program.

Bradford says he has built the world’s most powerful lasers, winning $1 billion in Pentagon research contracts. Moon politely demurs, saying: “We have built the most powerful lasers. If TRW thinks they have . . . well, I guess we will all find out some day.�

The two men know well the difficult challenge ahead. To deliver on its promise, the laser must be 100 times more powerful than any chemical laser either one has built so far, as well as compact and lightweight enough to fit inside a 747.

Chemical Power

The kind of laser they are building, known as a Chemical Oxygen Iodine Laser, or COIL, resembles nothing in the commercial world. It consumes hundreds of pounds of chemicals per second, moving at supersonic speeds and mixed in a chamber that resembles a rocket engine.

The laser would deliver more than two megawatts of power, equal to 20,000 100-watt light bulbs. To power it, the 747 would carry roughly 30,000 pounds of chemicals in large storage tanks--enough for up to 40 laser shots.

Light is created by mixing hydrogen peroxide (better known as hair bleach) and potassium hydroxide (the main ingredient in Drano). The system adds a bit of chlorine (an ingredient in fabric bleach). The reaction creates high-energy oxygen that is fed at supersonic speed into a chamber where iodine (a common skin disinfectant) is injected through specially shaped nozzles, resulting in the creation of photons of infrared light.

But creating the light energy is just part of the challenge. The light would be fed through a shaft to the nose of the 747, where a large swiveling turret, containing a so-called beam director, would be mounted.

Hughes Aircraft and Lockheed Martin have competed in building beam directors for more than a decade. Hughes scientists in El Segundo have built virtually every experimental laser beam director over the last decade, according to William Bundy, the technical director for the firm’s space and strategic systems division.

The beam director contains an infrared sensor that scans the horizon for missile launches. Although it cannot see through clouds, the system is supposed to be quick enough to track missiles once they break through thick clouds up to 40,000 feet.

Once a missile is detected, the beam director shoots a low-power laser beam to track the missile and measure atmospheric distortion. It then commands the big COIL to fire through a mirror that is adjusted through computer controls, based on how the atmosphere is distorting the low-power laser.

Pinpointing a beam on a missile a few hundred miles away is roughly equivalent to a golfer making a hole-in-one at 40 miles. But an experimental aircraft-mounted laser in the 1980s shot down five Sidewinder missiles and a cruise missile, according to Col. Lanny Larson, director of lasers and imaging at the Air Force’s Phillips Laboratory in Albuquerque, which is running the airborne-laser program and did pioneering work on adaptive optics.

False Promises

Air Force officials acknowledge that they must overcome a history of inflated expectations in directed energy weapons. Even President Ronald Reagan was misled by promises made about X-ray lasers in the early “Star Wars� program, which envisioned a halo of weapons in space to protect the nation against attack.

“Directed energy has not delivered what some people promised,� Larson said. “That is a legacy that we have to live with. We are trying to be very careful this time.�

The collapse of military spending since the end of the Cold War has gutted many high-technology weapons, but military officials continue to support the need for the laser. About 29 types of ballistic missiles are held in the inventories of potentially hostile foreign powers.

During the Gulf War, an Iraqi-launched Scud missile slammed into a U.S. barracks in Dhahran, Saudi Arabia, killing more than two dozen soldiers despite Patriot missile defenses that were designed to protect them. The loss demonstrated a vulnerability that the Pentagon vowed to redress.

“I get very visceral,� said Col. Dick Tebay, the airborne-laser program director. “We have to do everything in our power to defeat these things.�

Tebay cautions that lasers could not shoot down every missile in a massive enemy salvo. For that reason, they are just one part of a layered defense system that includes an improved Patriot as well as the new Navy Upper Tier and Army Thaad anti-missile systems.

Lasers are actually cheaper than anti-missile missiles. The Air Force believes that it can develop the technology and build seven 747-carried lasers for $5 billion, though many billions more have been invested in years of basic research. The first 747-carried laser would be a demonstrator with a half-power laser, ready for testing by the year 2001.

Even critics say lasers make more sense than missiles, which not only are costly but difficult to deploy and unable to knock down incoming missiles fast enough to prevent their warheads from exploding close to their targets, according to John Pike of the Federation of American Scientists.

But Pike says the Air Force may be minimizing the difficulty of operating the laser in cloudy weather. Citing an Air Force handbook as his source, he says clouds sometimes reach 60,000 feet, half again as high as the 40,000-foot cloud cover that the Air Force says lasers can cope with.

Technical Challenges

Moreover, Pike adds, the technical difficulties of building lasers light enough to operate in an aircraft will take the program into uncharted technical territory where success is difficult to predict. “It won’t do much good if it can’t get off the runway,� he said.

TRW’s Bradford says the United States has been improving the performance of its lasers and optics for 15 years. TRW alone, he says, has conducted 1 million seconds of high-energy laser experiments.

“The performance of the device is fine,� Bradford said. “We have a powerful belief these will be operational in the future.�