Laser Update

A lengthy CNN report on the laser-in-cockpit brouhaha here; Homeland Security transportation chief Asa Hutchinson assures us no terror is involved. I was playing with one of these powerful green laser pointers with some friends myself over New Year's weekend (nowhere near an airport, honest) and it remains a mystery to me, as discussed here on Hit and Run by Jeff Taylor and various commenters, how in heck anyone could get and keep these things aimed inside a small window on a moving target high above you whose angle in relation to you is constantly changing.

Comments

[Call me snake]

Sorry, but I had to get the "sharks with frick'n laser beams on their heads" Dr. Evil reference out right now.

[Stevo Darkly]

Actually, we couldn't get sharks. We got ... sea bass.

They are mutant sea bass.

[Xenox]

It is not difficult to maintain laser fixation on the occular nerves of the pilots of your primitive aircraft. You are merely speculating within the limits of your insect intelligence.

[R C Dean]

Homeland Security transportation chief Asa Hutchinson assures us no terror is involved.

Well, that settles it, then. Move along, nothing to see here . . .

[Evan Williams]

This has to be the stupidest goddamned shit I've ever heard. It reminds me of the various posts on Dave Barry's blog, where the title is "Those Terrorist Bastards..." or "Terrorism Update", and then the body of the post is something like "Now the bastards are using exploding gravy. What's next? Someone finds a mouse on a jet, and suddenly, all the "news" outlets are breathlessly declaring that the terrorists are trying to frighten the pilots with mice and cause them to crash?

We are now, officially, unequivocally, a nation of complete fucking retards.

[Swamp Justice]

maybe it is the co-pilot who is shining the laser in the pilot's eyes?

What is the range of a laser pointer? Do we really KNOW these people are using laser pointers and not Val Kilmer using REAL GENIUS lasers?

[Thomas Paine's Goiter]

We are now, officially, unequivocally, a nation of complete fucking retards.

Fucktards, for short.

And we've been a nation of fucktards since FDR's time.

[thoreau]

Evan-

Actually, the mice are carrying the Cordilla virus.

And for anybody wanting a technical rundown on why this is implausible, check out this discussion.

One correction, though: I've looked online for used lasers, and I'm revising my cost estimate down to a little less than $100,000 for equipment, plus whatever the going salary is for skilled engineers devoted to destroying the decadent West. (I imagine they're willing to take a pay cut to participate in the Jihad, but I don't know how much of a pay cut.)

I still think, however, that if Al Qaeda has a budget of $100,000 for equipment, plus skilled engineers, there are far more effective ways to deploy those resources than a weapons system that hasn't crashed a single plane, assuming (for the sake of argument) that the stories are true.

[Jamie]

I think the idea this is terrorism is bogus too, however, green lasers are cheaper than ever, blind the human eye easier than any other color, and can be obtained or made more powerful reletively cheaply by pulsing them (as report seem to indicated). Lasers do diverge enough to make aiming them as easy as using a shotgun, depending on the setup. Since they move in perfectly straight lines, it should be reletively simple to mount one to a rifle scope for sighting. You could even use one of those telescope mounts to move it smoothly. Not hard. Whether it would crash a plane or not is something else: at least you could send a pilot to the doctors office. Thoreau: where did you research price? I looked for the same things, and my estimate was about 1/10th of yours + expertise of course...

[thoreau]

Jamie-

I assumed a power requirement of 1 watt or more. You can indeed permanently blind a person with much less power, even with only about a second's worth of exposure, but:

1) Hitting the eye is hard from the ground. The easier thing to do is to expand the beam to fill the cockpit window. Once you expand the beam, however, the energy is spread out and so less energy is hitting the eye. So you need more power to compensate.

2) Getting a few seconds of exposure is hard. People instinctively react to bright lights by closing their eyes and turning their heads. It's like the sun: Staring at it will blind you permanently, but a quick glance won't. To do real damage with a quick exposure you need a very bright light.

3) A bright light can still temporarily disorient a pilot, but my understanding is that momentary disorientation isn't enough to bring down a plane. The pilot who writes for Salon pointed out that he once flew near a light show and was momentarily disoriented but the plane never crashed. The pilots who were allegedly attacked by lasers recently were momentarily disoriented by something but they didn't crash.

Also, while green would be the best choice among the visible colors, infrared would be far better. With infrared, they wouldn't realize what's happening and avert their eyes until it's too late. Plus, an infrared beam won't stand out against the sky (unlike green laser pointer beams), so there won't be anything to tip off the authorities to where the terrorists are operating from.

My price tag: I assume an Nd-YAG with a few watts of power (operating at 1064 nm, not 532 nm). I assume the use of 2 cameras coaxial with the laser, one operating in the visible range to identify the plane and another operating in IR to see where on the plane the light is hitting. I assume a good goniometer to center the plane in the camera's sights, and finely controlled mirrors to adjust the location of the beam on the plane.

Maybe my price tag is a little high. But $50k would be a MINIMUM. And it would go up if they couldn't get a good base of operations from atop a hill or tall building near the flight path. In that case, the aiming would be more difficult.

[Richard]

Hitting a plane at high altitudes may not be easily done, but on approach, I doubt that it would be too difficult.

[thoreau]

Richard-

On approach, it all depends on where you're standing. If you're off to the side of the approach path then it will be moving at a very high speed relative to you. Tracking will be very difficult.

If you're directly in the flight path, you'll need to be at a high elevation to have a line-of-sight to the cockpit window for a good portion of the approach. Otherwise you'll illuminate the aluminum bottom of the plane.

The problem is that flight paths tend not to have too many tall buildings and hills. And you usually can't do this from opposite the flight path (i.e. if they're approaching the airport from the east, situate yourself on the west of the airport) because the opposite side of the airport is usually the takeoff path where, once again, tall buildings and hills are rare.

Oh, and my price tag also includes a large portable power supply and, for some lasers, cooling system. This isn't something that they can plug into the cigarette lighter of their van. Depending on the laser system that you buy, you might also need some good lenses with anti-reflection coatings tuned to the wavelength of the beam and capable of withstanding high powers. Those lenses can be several hundred dollars or more. Not a huge amount, but on top of everything else it all adds up.

[Mark Draughn]

thoreau, man, the government is going to be visiting you real soon now if you keep posting stuff like that.

[Lord Duppy]

I think these stories are made up. That, or the guy with the laser is on the plane itself.

Consider the math. A 747 cruises at about 30,000 feet and moves at 850 ft/sec. Not only is the angle of the laser constantly changing, but that rate of change itself is changing as the plane gets closer or farther away. And when dealing with such distances, you have to take into account the curvature of the Earth as well.

The math isn't hard if you know calculus; it took me about 15 minutes, and I'm unusually slow at it. But what I now have is an equation. I would need a machine to implement it.

And, of course, my equation only works when I am beneath the flight path of the plane, exactly.

If you can build a machine to keep a laser in the cockpit of an airborne 747, you're halfway to having your own SAM launcher.

[linguist]

Evan writes:

"We are now, officially, unequivocally, a nation of complete fucking retards."

Oh, go for it. Go ahead and just use "fucktards". It's got panache.

[thoreau]

Mark, you really don't want to know about some of the conversations I had with people in my lab during the second season of 24. Suffice it to say that we got into arguments about nuclear bomb physics, and even though none of us work on anything even remotely related to nukes, it was scary how much we were able to figure out with a little ingenuity.

Then again, there's a big difference between doing the calculation and actually putting it into practice. Thank God for that!

[elvis]

uh, weren't most these instances near airports, where planes are MUCH lower, and going much slower?

[jeff]

Well now the Patriot Act is going to be used to take one of these 'evil' laser pointing 'terrorists' down.

[Pro Libertate]

I had a weird moment this past Sunday, when my brother and I tried to look at an approaching plane through our new telescope (we succeeded, though it wasn't easy to keep it sighted). I didn't think anything of it until I stood up and looked at the 'scope: "Hmm, 8-inch Dobsonian (over five feet long--looks like a cannon) pointed at an. . .airplane. Uh, oh." For the record, we didn't point any lasers at the plane, in case anyone is wondering.

[Isaac Bartram]

New Jersey man charged under Patriot Act
Dodge City Daily Globe

"Federal authorities Tuesday used the Patriot Act to charge a man with pointing a laser beam at an airplane overhead and temporarily blinding the pilot and co-pilot. The FBI acknowledged the incident had no connection to terrorism but called David Banach's actions 'foolhardy and negligent.' Banach, 38, of Parsippany admitted to federal agents that he pointed the light beam at a jet and a helicopter over his home near Teterboro Airport last week, authorities said. Initially, he claimed his daughter aimed the device at the helicopter, they said." (01/04/05)

http://ap.dodgeglobe.com/stories/20050104/2699985.shtml

[Evan Williams]

The terrorists have won! They don't even have to actually do anything anymore!

Not even Allah himself could have predicted that, if you were to slam a few planes into buildings, then, foreverafter, any time anything out of the ordinary happened, the collective IQ of an entire nation would be cut in half.

[Warren]

Also, while green would be the best choice among the visible colors, infrared would be far better.

Are you sure? Seems to me, the windshield (or whatever it's called) would greatly attenuate the beam.

[thoreau]

Warren-

I'll have to think about that. My initial reaction is that if they used a near-IR wavelength, something close to the visible range, then it would almost definitely still work. For wavelengths further out it would depend on what type of plastic it is.

[Soda]

Maybe the pilots will start wearing reflective sunglasses now. Or would that make things worse?

[thoreau]

Soda-

It couldn't make things worse, but I wouldn't assume that it's a panacea either. Still, it would be better than nothing. If a terrorist used visible light, the initial exposure might not be as damaging, so the pilot could quickly respond by shutting his eyes and averting his gaze and escape more severe damage. If they used infrared light, I don't know how effective the glasses would be, since most sunglasses are designed with the goal of minimizing UV light transmission. That's not to say that the material is necessarily transparent to IR, but if IR isn't one of the design specs then you can't really predict the properties in the IR.

[Xenox]

You pathetic, hairless apes are so three-dimensional in your thinking..

We will blind you all with science.