Airbone laser: an exchange.

John J. Miller's "'Peace Through Light'" (August 13) transmits uncritically the Air Force's hype of the Airborne Laser, and hence misinforms. That Miller did not even understand the hype is shown by his statement that the ABL is supposed to destroy "a mock warhead" in 2009. Nonsense: Nobody has ever imagined it could destroy warheads. The stated mission is--as Miller states later without realizing the difference--shooting missile boosters soon after launch. He was told that the "primitive laser" that destroyed "a few missiles and drones in flight" a generation ago was "unreliable, and potentially hazardous"; that it was housed in an airplane that is "now warehoused at the Air Force Museum"; and that the Airborne Laser is its natural successor. More baloney. The megawatt laser that destroyed things beginning in 1978 at Capistrano, Calif., was more powerful, and more fully approximated an operational system, than anything the ABLprogram has produced. The main difference is that the earlier laser generator, designed to work in the vacuum of space, did not need the Rube Goldberg devices that the Air Force has been trying to perfect to create synthetic vacuums for each and every shot that the ABL would take. Miller repeats that the earlier laser was "bulky." If he was shown pictures, the people showing him may not have known that over 90 percent of the bulk was the equipment for simulating space. This is what the Air Force has been trying to shrink, in a dumb effort to avoid using the device in its natural environment. The Bush team, like the Clintonites, vetoed a space deployment out of deference to the Russians.

Putting the laser on an airplane in the atmosphere also means butting up against some other intractable laws of nature. Miller credits the claim that, by constantly coupling its shots with a low-power laser to measure the atmosphere's penetrability, the ABL's mirrors could push the beam through the air by compensating for its variable character. On what planet? In fact, any and all measurements cannot prepare a beam to overcome the turbulence that results from its own passage, because the ensuing corrections occur before or after that very brief passage, not during.

At the least, Miller might have asked his Air Force minders what they meant by "intercepting these missiles . . . while still over North Korean territory" with the ABL. Did they mean that a fleet of 747s with ABLs would fly figure eights 24/7/365 off the North Korean coast? How many would it take? How easy would it be for North Korean fighters to knock one down at the right time? What percentage of the U.S. Air Force would it take to defend them all the time? And if all those difficulties are there in the case of North Korea--the only place where the ABL could conceivably be useful--what does this say about its overall usefulness? Finally, he might have asked, Would it not be simpler and much more effective to put such weapons into orbit?

Angelo M. Codevilla

Plymouth, Calif.

JOHN J. MILLER RESPONDS: Angelo M. Codevilla says that it's "nonsense" to claim that ABL would destroy warheads. This is about as petty as complaints come. Yes, ABL would aim its laser at missile boosters--but it would do so for the purpose of eliminating the warheads they carry. He goes on to claim that it's "baloney" to make a link between early laser research and ABL. Unfortunately for him, that's not just me talking--in interviews, both military and civilian personnel pointed me toward this work as a forerunner to ABL. Finally, he suggests that ABL can't work and that lasers belong in space. As for ABL, that's not what the people designing this defensive weapon think, and in about two years they'll have a chance to prove it. As for putting lasers in space, I'm onboard. But getting them up there may require the steppingstone of ABL, for both technical and political reasons.