Dawn of the Airborne Laser

The laser weapon project, run by the Missile Defense Agency for the Air Force, has already met significant benchmarks. A modified Boeing 747 made its first flight, sans laser but with the new nose turret in place to test its aerodynamic impact, last July 18. The high-energy laser-the chemical oxygen-iodine laser that actually attacks the missile-built by Northrop Grumman Space Technology (formerly TRW) reached 118 percent operating power during a successful test firing at the company's facility near Los Angeles six months earlier. Next step: The laser will be installed in the 747 this summer and, following more tests, will be on track to the make-or-break goal of shooting down a Scud-like ballistic missile by the end of 2004 or early 2005. At that point, the prototype could conceivably become an operational emergency-use weapon while a fleet of seven or more laser-equipped aircraft is being built. Shattuck exudes confidence. "These are mature technologies, and the real challenge has simply been integrating all of them into a working airborne platform," he says. "Now we're in the final phase of that, putting all of the pieces into one end-to-end system and just wringing it out."



On a mammoth ramp at Boeing's Wichita Development and Modification Center in Kansas sits the 747-400F freighter, which is undergoing conversion into one of the largest single weapons ever devised. The Air Force purchased the aircraft new in 1999, painted it the service's customary gray, and outfitted it with a bulbous black nose to house the turret.



A swarm of technicians are installing control consoles, electronics, and test and support gear prior to the airplane's departure for Edwards Air Force Base (which occurred this past December 19). Mark Dannar, the Boeing ABL Aircraft Integrated Product Team co-leader, jogs up the access stairs and into the voluminous main hold, which will house both the system operators and, behind a massive airtight bulkhead, the high-energy laser, the system's knockout punch. Walking over to a rack of electronics peppered with lights and knobs, Dannar grins and says, "Look at this switch-it's marked Executive Laser Controller." Like so many others involved in the project, he's smitten with its inescapable sci-fi edge. Walking back towards the tail, he surveys recent work. "There isn't a system onboard this aircraft that we haven't touched," he says, "and we had to solve a lot of serious engineering challenges."



For one thing, the inside of the freighter was beefed up to accommodate the six van-size modules that will generate the laser beam from the rear of the plane. Outside, Dannar points out the numerous places where the aircraft's skin was pierced to install the ABL's detection equipment. This is the gear that will identify and target incoming missiles.



Here's how it will happen: Six infrared sensors positioned on the fuselage will constantly scan all directions for hot missile exhaust plumes, which they can do autonomously or at the prompt of launch-detecting satellites. When one, or several, is located, the ABL's multiple separate lasers will swing into action-all within seconds. A laser ranging pod atop the plane's cockpit, right now almost four stories above us as we stand on the ground, will spin around to face the first missile-the one the computer has determined is most threatening
-and measure its distance with a carbon dioxide laser. The track illuminator laser, fired through the 12-inch aperture of the Wall of Fire and into the nose turret, will compensate for aircraft vibration and then pinpoint a specific area of the missile to aim at. The beacon illuminator laser, also fired through the nose turret, where a cassegrain reflector telescope expands the beam's dimensions to 1.5 meters, will then use the beam-and fire- control unit's adaptive optics to characterize the missile's dimensions. (These optics, standard equipment on all the ABL's turret-fired lasers, extend their range with mirror-flexing technology to compensate for atmospheric turbulence.) Finally, the computer will fire the high-energy laser, which will focus down from 1.5 meters in diameter to a much smaller spot of light by the time it reaches the target. As the laser dwells on the missile's flank for 2 or 3 seconds, the oxidizer or fuel tank will rupture and the missile will explode. I ask Dannar how the crew will know whether the mission has been accomplished. "If it blows up, you got it," he says, smiling.