Laser Weapons - How Close Are We?
March 1972 Popular Science

March 1972 Popular Science [Table of Contents] Wax nostalgic about and learn from the history of early electronics. See articles from Popular Science, published 1872-2021. All copyrights hereby acknowledged.

Those of us who grew up in the 1960s and 1970s were inundated with books, movies, television shows, magazines, comic books, toys and other forms of promotion for the promises of lasers - both fictional and real - remember seeing articles like this one in a 1972 issue of Popular Science. Heck, there's a good chance I read this when it originally came out. At the time, laser power levels were measured in the hundreds or maybe a few thousands of watts. It wasn't long before that a watt produced from the lasing in rubies was considered an accomplishment. By this time chemical lasers were (and are today) the workhorses of laser weapons. Much of the state of the art in lasers has always been a well-kept secret by military and government research and defense contracting agencies. Interestingly, author Albright claims much of what he reports was gleaned by assimilating bits of information from diverse sources. It's a good example of the "loose lips sink ships" saying from World War II, whereby the enemy can figure out what you are doing even without clandestine sources (aka spies) embedded in the works.

Laser Weapons - How Close Are We?

By Nelson Albright

For a decade defense planners have desperately sought a laser heat weapon. Here's the untold story of our secret - and successful-research program.

Illustrations by Ray Pioch

"The Incredible Laser," read the fading title page of a Sunday supplement taped to a sun-drenched office door at Hughes Aircraft Company's posh research laboratories overlooking the crystal blue Pacific at Malibu. The picture showed a beam of light emerging from the barrel of a cannon - an obvious allusion nearly 10 years ago to the fictional notion of a laser "death ray." Beneath the title was scribbled the reply: "For the Credible Laser, See Inside."

The scientist-author of the gibe would have scoffed at any suggestion that within a decade these quiet hill-top laboratories where the world's first laser was coaxed into life only 12 years ago would be trying to help make that "incredible laser" come true. Yet this is exactly what has happened as Hughes Aircraft and many other research organizations have become involved in one of the most revolutionary technological dramas in American history - the development of the laser radiation weapon.

We're Close to the Goal

While laser-weapon development projects are supersecret, some notion of progress to date can be glimpsed by putting together bits from here and there. For example:

• Brig. Gen. Robert M. White, Commander of the Flight Test Center at Edwards Air Force Base, told a meeting of experimental test pilots in Beverly Hills last September that the Pentagon is backing the search for laser weapons much as it did the development of the atomic bomb in World War II or the ICBM in the late 1950s.

• A Commerce Department publication that lists contracts recently listed one between the Air Force and developers of the new B-1 bomber. It calls for an investigation into the possibility of using a laser to defend the bomber against fighters.

• A similar weapon is under study for the Air Force's upcoming F-15 air-superiority fighter. Vice Admiral Thomas J. Walker, head of naval air forces in the Pacific, at the same meeting addressed by General White, called these "Buck Rogersish weapons" potential successors to the 20mm gun of naval aircraft in Vietnam.

• Details are secret, but it has been learned that military researchers have shot down at least one small drone aircraft with a laser beam.

• Grant Hansen, Assistant Secretary of the Air Force, told a House Committee that defense officials think it possible to build a superpower laser system that " ... could track a ballistic missile from a space-based defense system and kill it over the country it was launched from." Code name for the project: Spade.

• Says a veteran researcher associated with the laser-weapon program from its inception (but who could not allow his name to be used): "Laser thermal weapons are practical if the military wants them."

The enticing notion of laser "death rays" sparked interest in lasers within the Defense Department more than a year before the successful operation o a ruby laser by a shy Hughes scientist, Dr. Ted Maiman, early in 1960.

Pentagon Was Fascinated

The prospect of a weapon projecting its destructive force over great distances, at the speed of light, and with little diminution in its destructiveness was attractive to defense planners. So they awarded a handful of early exploratory laser development contracts even before Maiman had made the first laser work.

The big problem through the early sixties: A successful laser weapon would have to generate incredible energy to destroy targets by heating them. But lasers at that time, despite the remarkably high power densities of their beams, produced relatively little sustained energy.

The invention of the highly efficient carbon dioxide laser in the mid-1960s rekindled the never completely abandoned weapons effort. CO₂ lasers have now been built that can produce a continuous 60-thousand watt (60-kw) beam. But an even bigger boost for weapons planners came about five years ago with the invention of the gas-dynamic laser (see diagram). Gas-dynamic lasers now in operation achieve output powers of hundreds of kilowatts, which may be sufficient for some weapons applications. A short time later came yet another important development: the chemical laser (see diagram). While this device is not presently as powerful as the gas-dynamic laser, it has several characteristics that make it an ideal weapons candidate. Weapons development scientists are working on both.

Before gas-dynamic and chemical lasers came along, the possibility of developing a laser weapon was slim for two reasons. First, to get enough energy in the beam, an enormous electrical power supply would be needed. Second, cooling of the laser itself was a super-tough problem.

The two new lasers go a long way toward solving both problems. The reactant gases flow through them at high speeds and carry off huge amounts of heat. And they require little electrical power. The energy comes in one case from gases heated by a rocket-like burner, in the other from a chemical reaction. And both are relatively light and compact in proportion to their energy output when compared to conventional lasers and the electrical power supplies they require.

Most of the speculation about laser weapons has revolved around the old idea of the "death ray." Although the new lasers could certainly kill or disable men at great ranges, they won't be used for that. Current weapons-from rifles to hand grenades-are cheaper, more portable, easier to use.

Military planners want lasers for use where their instant-reaction time and speed-of-light delivery are important. For example, the laser offers, by its nature, a possible solution to the toughest problem in ballistic missile defense: that of sorting real warheads from decoys. The coherent output of a laser, like all electromagnetic energy, travels at 186,000 miles per second - faster than any other weapon today.

If the laser could disable an incoming missile warhead, the defense would have time-seconds, even minutes - to study the threat, make its decisions. It could even hold fire until warheads and decoys penetrated the earth's atmosphere. The lighter decoys would burn up, leaving only real targets. Then, with the speed of light, a laser beam could impale a target.

Radar Tracking, Too

Still another advantage: A laser beam, like microwave energy, can be used for radar. But its accuracy is far greater because of its shorter wavelength. The same beam might initially serve at low energy as a radar tracker. When it had the missile pinpointed, it could simply increase power and zap the target. This would totally eliminate the usual costly, time-consuming computations of target trajectory needed to calculate target intercept positions. Finally, the laser radiation weapon would pour intense heat into a very small target area. It wouldn't atomize the target as does the nuclear warhead of an antimissile missile. Thus, there would be negligible danger of nuclear fallout.

While the real payoff from a laser weapon would be in protecting the country from missile threats, other perhaps more immediate applications are attracting attention, too. For example, the Navy is concentrating its radiation-weapon work on devices designed to protect ships from ship-and air-launched cruise missiles. These deadly weapons can be fired over the horizon against American ships by small enemy patrol boats. The missiles hug the water surface, hiding themselves from intended victims until it is too late for ship-based defenses to react. But laser beams can be swung by the motion of mirrors alone. So designers can build inertia-less laser-defense weapons that have nearly instantaneous coverage in any direction. The combination of rapid self-tracking and instantaneous weapon slewing would be a natural solution to the need for rapid shipboard reaction to naval cruise missiles.

Today, most U. S. laser radiation work is centered at the Weapons Laboratory at Kirtland AFB, near Albuquerque, under the code name, "Eighth Card." (Kirtland is where the target drone was shot down about two years ago.) It's run by the Air Force, which is managing a tri-service effort supported by the three services and Advanced Research Projects Agency. Work is also underway at government locations in diverse locations: Boston, Dayton, Los Angeles, Huntsville. The two main industrial contractors are United Aircraft's Florida Research and Development Center, W. Palm Beach, and a team made up of Avco and Hughes Aircraft. Avco has concentrated on laser devices; Hughes on laser pointing and tracking optics.

One by one, the objections of scientific doubters have been brushed aside by an accumulation of encouraging evidence, turning a growing number of skeptics into believers in laser thermal weapons. For example, the fear that laser beams exceeding certain energy density would produce a ballooning effect in the atmosphere, causing a sharp electrical breakdown akin to lightning, hasn't materialized. Atmospheric absorption could be a severe problem, but primarily under a narrow set of conditions, especially in the rare instance where both target and weapon are motionless on quiet days. And the new high-powered lasers have shot down the old notion that it would never be possible to build enough power into a unit small enough to be a practical weapon.

But there are still many questions: How quickly can a thermal weapon of given energy density destroy a target? In some instances, it may take longer than a bullet or a cannon shell, but may still be worth the price.

How susceptible is military hardware? Researchers must find out. Then they can figure how much laser power it will take to destroy or damage various kinds of equipment The Air Force is looking at the impact of laser radiation on jet-aircraft engine fuels, turbine-engine blades, fuel cells, weapons fuses, high explosives, and materials of all kinds. In one experiment, the Pyroceram nose cone of a standard tactical missile fractured into countless pieces after one square centimeter of its surface was blasted for a half second by a laser delivering only one kilowatt.

Laser Test Ranges

To expand the investigations, the Air Force put into operation at an isolated spot in the Manzano mountain range within 25 miles of Albuquerque the first of three laser-weapons-firing test ranges, each to be operated by one of the three services. There, high-energy lasers located on one side of a barren scrub-pocked valley are fired at two simulated targets across the valley. The laser and target locations are chosen to insure beam paths at different heights. At the Manzano range, not too far from where the first atomic bomb was exploded outside Alamogordo, the Air Force expects to isolate and analyze the effects on the optical path of airborne particles, air turbulence, and ground interactions.

Historically, every weapon has produced a counterweapon. Laser thermal weapons may be no exception. Mirrored surfaces that reflect incident light are an obvious - but not necessarily practical - answer. Highly reflecting surfaces on aircraft would compromise the vehicle's aerodynamic qualities. Tank surfaces can be made reflective, but quickly they would be pitted with sand and dust during normal military operations ruining their reflective properties Artificially generated plasmas and water vapor may offer other solutions now under study.

The imminence of laser weapons is difficult to predict because tough engineering - not scientific - problems still have to be solved. But odds are - they'll be in our future soon.

Posted December 15, 2023