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.