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.