Do As I Say

April 16, 2005 10:27 AM

Do As I Say and Not As I Do. Go Military R&D. It took less than 4 months to develop a laser that is safe to shine at airplanes.
posted by gonadostat (10 comments total)

I highly doubt that a laser beam "flashing" against a windshield would blind two pilots. Especially considering all the dust that it would have to go through to get up to 3,000 feet. I've experienced temporary-blinding-by-laser and it only affected my right eye, which was directly struck by a beam. I find it hard to believe that two guys could both be so afflicted by the difussion of a beam against a glas pane at least a few feet away from their faces.

Of course, the "temporary blindness" they reported in their suit was, technically probably something like "the sudden bright flash made us both close our eyes for a moment," and the suit is, I'm sure, grounded in teaching some dumfuck civilian a lesson: don't point lasers at planes! That's all well and good, but I don't buy the blindness argument for a second.
posted by scarabic at 10:48 AM on April 16, 2005

Does this prove that we're all being fed a load of horseshit propaganda about how much safer we are from terrorists (civilians with laser pointers) or that it's just not terrorism if WE (the US Govt.) do it...?
posted by Balisong at 11:03 AM on April 16, 2005

I was under the impression the beam itself diffuses over distance because most lasers are imperfectly focused?
posted by falconred at 11:39 AM on April 16, 2005

What exactly am I supposed to outraged about here?
posted by PissOnYourParade at 12:11 PM on April 16, 2005

err ...supposed to be outraged...
[bashes head]
posted by PissOnYourParade at 12:12 PM on April 16, 2005

Aside from the fact that both involve lasers and planes, what is the connection? It doesn't seem hypocritical to say that people shining lasers into planes in order to blind pilots is bad, but using low-powered lasers to visually warn pilots of impending trouble is good.
posted by blahblahblah at 12:44 PM on April 16, 2005

falconred, because of diffraction perfect collimation of laser beams (what you mean instead of focused) is impossible; dust isn't the issue. A collimated laser spot at distance z will be no smaller than l * z / (pi * D) where l is the wavelength of light (about 1 micron) and D is the size of the collimating lens.

"This is good laser, if you will," said U.S. Air Force Col. Ed Daniel of the North American Aerospace Defense Command.

Just brilliant. Most likely they mean that these lasers are pulsed with a low duty cycle and perhaps sent in diverging beams instead of collimated ones. Because our eyes are efficient at focusing sources at infinity, collimated laser beams are by far more dangerous than diverging beams. Visible lasers are inherently more eye safe because people can react to the beam and blink or get out of the way. Much much more nefarious are cheap, simple, many Watt infrared laser diodes though coating cockpit windows with IR absorptive or diffusive material is a completely tractable problem.
posted by fatllama at 2:09 PM on April 16, 2005

According to that article, "Officials refused to give the total cost of the system, but said individual, (sic) costs for unmanned laser sites totaled $500,000."


. . . chuckle.
posted by Neiltupper at 6:31 PM on April 16, 2005

He could get up to 25 years in prison and fines of up to $500,000.

25 years? Jail? Poor guy must have learnt his lesson by now anyway. Let him go.
posted by hoskala at 5:51 AM on April 17, 2005

Note that his potential fine and the cost of one of these laser sites is the same. That's pretty awesome.
posted by klangklangston at 8:55 AM on April 18, 2005