Intelligent Machines

The Light Brigade

The U.S. has spent decades quietly developing a new generation of battlefield lasers. Now they’re ready to fire.

A howitzer is a crude-looking weapon, essentially a small smokestack with a door at the bottom that allows the insertion of breadbox-sized shells. but operating one requires a year of specialized schooling. That’s because howitzers, like most artillery guns, are “indirect fire” weapons-that is, if you aim directly at your target, you’ll literally miss by a mile, and probably by several. Adjustments have to be made for distance, wind, temperature, atmospheric density, humidity, the amount of wear in the barrel and the spin of the earth (aim left in the Northern Hemisphere, right under southern skies). Even then, most of the shell’s explosive force will not end up precisely where intended. Then, 30 seconds of frenzy among a crew of six sees a new shell dragged into the gun, and you can try again. For all this bother, though, howitzers remain the weapon of choice for delivering destruction at a distance.

A military expert, given a clean sheet of paper and asked to sketch out the howitzer’s ideal replacement, might end up with something like this: fires weightless and unlimited ammunition, is mountable on aircraft or ground vehicles, can be aimed directly at a target, reloads instantly, tracks fast-moving targets, shoots with pinpoint precision, creates no risk of collateral damage. In the end, he or she would have essentially described a class of weapon that could play a significant role in the next major U.S. armed conflict-weapons that hurl photons instead of chunks of metal.

The U.S. military is gearing up for laser warfare.

This story is part of our July/August 2001 Issue
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Of course, the idea of using high-powered lasers to destroy enemy missiles has been widely publicized ever since President Ronald Reagan pushed the “Star Wars” program-the Strategic Defense Initiative-in the early 1980s. But far less recognized-and less speculative-is the prospect that more down-to-earth laser weapons may soon revolutionize all types of combat, thanks to an intense, four-decade-long research and development effort that’s poised to pay battlefield dividends. From versions that fill a 747 airplane to devices that fit in a Humvee, lasers are already destroying military targets in tests and are likely to be deployed over the next decade in everything from full-scale warfare to peacekeeping actions to terrorist encounters.

The U.S. military and its contractors have been exceedingly discreet about these programs. And for good reason. Laser weapons remain highly controversial. In the early 1990s, for example, protests from groups that deem battlefield lasers inhumane because of their potential for blinding both civilians and combatants forced the military to shelve a secret laser system that would literally have given eyeball-blasting capabilities to foot soldiers. Though the newer programs appear to skirt international prohibitions on blinding weapons, protests are likely to be revived as the weapons come online. Stephen Goose, program director of the arms division of Human Rights Watch, concedes that the quiet fashion in which battlefield laser systems are being developed has temporarily taken them off of human- rights groups’ radar screens. But that may be about to change. “No one is reviewing how these systems are being implemented,” he says. “But questions need to be raised.”

Despite such concerns, however, the military is going full speed ahead-and some experts feel laser weapons will soon give American troops a battlefield edge. “The introduction of optical and other directed-energy weapons, including advanced nonlethal weapons, will be as significant as the introduction of firearms and artillery was to the modern world,” says Robert Bunker, an adjunct professor in the National Security Studies program at California State University, San Bernardino, and a professor at American Military University. Indeed, China and Russia also have reportedly been developing laser weapons for at least a decade, though in less powerful and accurate form.

From ‘Nam to Buck Rogers

The notion of laser-beam warfare may conjure images of a distant, Buck-Rogersian future. But military lasers date back to the Vietnam War, when they were first used to guide bombs to their targets. Targeting lasers don’t pack any punch, but even then the Pentagon was funding research into high-energy lasers that would destroy rather than “designate” targets. Army and Navy lasers began shooting down small missiles and unmanned aircraft in limited late-1970s tests-and the programs accelerated in the next decade under Star Wars. But it wasn’t until the mid-1990s that laser tracking and control systems became accurate enough for reliable weapons. Between Reagan’s program and more recent funding, the government has put $14 billion into high-energy laser research and development. It’s now spending some $200 million a year on general research-plus $400 million more on specific weapons programs. Those numbers are expected to nearly double under President George W. Bush.

The effort to bring lasers to the battlefield flashes to life at Kirtland Air Force Base in Albuquerque, NM, where a carbon- dioxide laser turned on only for a moment leaves a flaming eight-millimeter hole in a nearby slab of Plexiglas. This test unit carries a fraction of the power of any battlefield system. But what it reveals about the effects of lasers on various materials might soon find real-world application in one of three full-scale projects geared to take out short-range missiles, aircraft, tanks and even, if indirectly, individual soldiers and terrorists.

The most visible project-one that stands to receive up to $2.7 billion in new funding under the Bush administration-is called the Airborne Laser, and it stuffs an oxygen-iodine laser into a modified Boeing 747. Like all lasers, it pumps chemical or electrical energy into a substance whose atoms reemit the energy as coherent light-a single, powerful beam that resists spreading.

In the military’s scenario, 747s carrying these jumbo lasers will patrol 12,000 meters over ground held by friendly troops and other areas vulnerable to short-range ballistic missiles. These lasers can slap a beam packing as much as two megawatts of energy, enough to power a few small towns, on a target as far away as Boston is from New York-some 300 kilometers. Even a beam that powerful won’t instantly burn through the metal on a missile. But it’s still enough to shoot one down, since the pressurized fuel compartments on ballistic missiles rupture and then explode when their walls are weakened by intense heat.

Once a newly launched missile is located by conventional sensors such as radar, the hard part for the Airborne Laser is placing the basketball-sized beam on the streaking missile’s fuel compartment-then holding it there for the five or ten seconds it takes to work its magic, all while atmospheric turbulence distorts the beam. The weapon therefore enlists computerized systems that monitor the target image, calculate the distortion and then adjust the beam to cancel it out.

The advantage is that each missile-killing shot will burn about $10,000 worth of chemical fuel (aircraft should carry enough fuel for about 30 shots), compared to the $1 million cost of a conventional antiballistic missile. “We’ll be worldwide deployable as early as 2008,” says air force colonel Lynn Wills, who heads Airborne Laser acquisition. Wills expects to field seven aircraft, two of which will be in the air over hot spots at any given time. Early prototypes of the laser and targeting systems are already undergoing testing at TRW’s secluded facility north of San Diego. A prototype of an integrated 747 aircraft and laser is scheduled for a maiden flight and test firing in 2004.

Beams from the sky won’t be the only lasers stabbing at enemy missiles, however. A second weapon, based on a deuterium-fluoride-powered laser and known as the Tactical High-Energy Laser, is aimed chiefly at the small, cheap rockets often used by guerrilla soldiers. The program kicked into high gear in 1996, shortly after Israel was hit by a wave of Russian-made Katyusha rockets launched by Hezbollah troops in Lebanon. Since then the U.S. has sunk about $170 million into the program, matched by about $80 million from Israel-although development is solely under American control. These lasers combine radar tracking with a targeting and control system somewhat similar to the Airborne Laser’s. The system is mounted on the ground, though, and should be able to down a Katyusha for about $2,000. “The Katyusha costs about $1,000 on the black market,” says Tom Romesser, who heads TRW’s space and technology division. “You can stop one with a Patriot missile, but you can’t keep putting a $1 million weapon against a $1,000 threat.”

Resembling a spotlight on a turret, the weapon boasts a 10-kilometer range and since mid-2000 has shot down more than 20 rockets at the White Sands Missile Range in New Mexico. It can also handle aircraft. “It’s very fast,” says Dick Bradshaw, program manager for directed-energy technology at the U.S. Army Space and Missile Defense Command in Huntsville, AL. “Nothing can maneuver out of the way once it’s locked on. How are you going to get away from a photon?” The system is mounted on a concrete platform and stands the size of a small garage. But Bradshaw expects to see it shrunk to one-fifth that size; it could then be mounted on a truck for relatively fast transfers.

Having brought laser weapons down to the battlefield for fighting rockets and planes, it was only natural that the military would literally lower its sights and go after ground-based targets like tanks, trucks and artillery. The bet on this front is called the Advanced Tactical Laser. Also run by the Army Space and Missile Defense Command-with Boeing as prime contractor-the program aims to put a scaled-down, 300-kilowatt version of the oxygen-iodine weapon on a helicopter or small plane to be used against targets as far away as 20 kilometers. Managers expect to eventually build a truck- or Humvee-mounted system as well.

Killing Tanks

Many observers argue that laser weapons should stick to fighting missiles, rockets and aircraft because these targets tend to destruct or crash when even a small part is damaged. Trucks and tanks are another matter altogether, says John Pike, director of Alexandria, VA-based defense-policy think tank “That’s why bullets and shells are still popular-there’s no way a laser is going to deposit more energy on a target than would have been created by an equivalent amount of chemical explosive.”

In that view, killing a tank would be a stretch, given its 15-centimeter-thick armor plating. But the new idea is to disable, not destroy-and tanks have a high-tech Achilles’ heel: their dependence on electronic communications and sensors to know what’s going on. Melting a tank’s antennas would be easy for a 300-kilowatt laser. Explains Colonel Mark Stephen, who helps manage the air force’s laser weapons programs, “You can destroy or at least degrade a target without blowing it to bits.” What’s more, the loss of communications or other electronics systems would likely confuse the tank crew-and that could be all it takes to destroy the tank with conventional weapons.

With the ability to place a 10-centimeter-wide beam with the heating power of a blowtorch on distant targets for up to 100 shots, the Advanced Tactical Laser could wreak havoc on far more than tanks. One analysis noted that from seven kilometers away the system could also melt 11 antennas, blow out 32 truck tires and disable a mix of a dozen mortars, rocket launchers and machine guns before having to refuel. For all its potential, however, this weapon faces some unique headaches. Ground vehicles bounce and vibrate more heavily than aircraft, for starters, and if the laser is ever deployed on such vehicles it will require computer-
controlled shock absorbers. In addition, intense ground battles tend to produce laser-blocking smoke and dust. And getting chemical fuel to a remote, hotly contested battleground could be difficult.

A research effort earmarked for $100 million in funding starting in 2003 is looking to solve the fueling problem. The goal is to replace the current chemically fueled laser with a solid-state weapon that gets its energy from an electric current directed into an yttrium-aluminum-garnet compound, doped with neodymium. Laboratory versions of solid-state lasers currently put out a meager 10 kilowatts of power. But Bradshaw believes that figure will be upped to 100 kilowatts-enough to serve as a weapon.

Even farther down the road, researchers hope to replace the yttrium-aluminum-garnet compound with super-energy-efficient fiber-optic lasers like those already used in some telecommunications applications. A fiber-optic laser might fit in a Humvee and, because it would be electrically powered, could run off of the vehicle’s generators, shedding the burden of resupplying special fuel. “You’d have to haul around some additional diesel fuel, but that’s not much of a price to pay for being able to electrically generate your bullets right there in the field,” says Bradshaw.

Human-Rights Concerns

While there is no guarantee these systems will develop on the smooth trajectory envisioned, the military sees several promising ways around the technological challenges, which is why it can now talk concretely about deployment. Perhaps the biggest obstacle faced by battlefield lasers isn’t technological, however. For some 20 years, human-rights groups have opposed these weapons on the grounds that they are likely to blind people.

In the face of international pressure, the United States has already backed away from some of its laser ambitions. William Horton, a former army lieutenant colonel who worked on battlefield lasers for years until the early 1990s, confirms that the U.S. military long worked to develop vehicle- and backpack-mounted lasers designed to locate and blast enemy optical lenses such as periscopes or binoculars-with likely disastrous results for any enemy eyes peering through them. When reports circulated in the press about these efforts around 1985, protests ensued, and the systems didn’t reach production (Horton says two vehicle-mounted prototypes were deployed in the Gulf War, but not used). Then, in 1995, the United States signed an amendment to the Geneva Convention protocols that prohibits blinding weapons.

The military always had a way out, since weapons designed to kill people or destroy objects-and that only carry a risk of blinding-are exempted from the ban. That’s a loophole big enough to fly a laser-equipped 747 through, which is why deploying battlefield lasers remains viable. But even if the armed services are legally off the hook, top brass realize that in developing such lasers they are flirting with a public-relations disaster. The idea of a blinded soldier-or worse, a nurse or child-paraded on the news as a victim of an invisible American beam could make this country’s high-tech military seem like high-tech monsters.

As a result, the military remains queasy about calling attention to its interest in battlefield lasers. The programs aren’t secret; that tactic already backfired once for the government with the optics-hunting laser projects. But the policy appears to be one of not volunteering information unless pressed-and even when pressed, most military and civilian managers involved in laser defense programs deny knowledge of initiatives intended to bring lasers to bear against ground targets. On one point, they’re clear, however: human targets are strictly off limits. “We’ve done nothing in the area of antipersonnel applications,” says Bradshaw. “Certainly not to blind someone, and we’ve gone even further, to do whatever it takes to not injure a human.”

But this one isn’t likely to stay on the back burner. Dominique Loye, who studies possible Geneva protocol weapons violations for the International Committee of the Red Cross in Geneva, argues that the mere fact a battlefield laser isn’t intended to blind or harm people doesn’t guarantee it will pass muster with international agreements against weapons that injure in cruel ways. After all, he notes, who knows what soldiers will do with them in the heat of battle? “When you have a powerful weapon in your hand, you might start off firing at the intended target,” he says. “But if you’re threatened by enemy soldiers, you might turn it against them and use it quite indiscriminately.”

Such objections will only get more intense as laser-weapon programs progress. But given the promise of putting pinpoint, ammunitionless firepower into the hands of front-line soldiers, the military is likely to press on in its quest for a Star Wars battlefield. And just as likely, warfare will never be the same again.

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