Posted on 09/28/2004 8:12:49 PM PDT by ableChair
Greta Van Susteren reported that a Delta pilot enroute to Salt Lake City was lazed in the cockpit this last Wednesday. Only country I know that has that hardware (for lazing bomber pilots) was the Soviet Union. Pilot reportedly required medical treatment and this was not a minor injury (weak laser) wound. More will come out to tomorrow as this story hits the print press.
Do you know about ABL?
Talbott was State point man on this, and (page 20) "the State Department had notified the Russian embassy in Washington that a search party would be boarding the ship. The tip-off gave the Russians time to notify their vessel of the planned inspection so that any lasers on board could be disposed of or hidden. The National Security Agency later confirmed exactly that though an intercept--officials at the Russian embassy in Washington had directed an official at the Russian consulate in Seattle to have the Kapitan Man's captain get rid of the laser rangefinder on board."
Talbott was then ranking State official on the secure videoteleconference 12:15am April 8 which let Kapitan Man leave after the single limited search. (Gertz, 21)
OK - I have to weigh in here, and please understand, I mean no offense to ANYONE here (and yes, I know people say that right before they offend, but I'm really going to make an effort here). I work with lasers, I've read the literature, I've written some of the literature - I don't know if I am an expert, but I have been hired as one, and my clients (including several military customers) have been happy with my performance. That's as close as you get to my credentials in this public forum. That said, here are my thoughts, and although some of this repeats information already here, I'll try to be complete:
IF such a device as a laser was going to be used to blind pilots in an aircraft, either permanently or temporarily, it would have to be:
A) Visible (not because the pilots have to see it, but because it has to get through the glass of the cockpit, which filters out both UV and IR)
B) "High power" - not high continuous power, but high pulsed power, and not high compared to those used for boost phase intercept, but high compared to that used for eye surgery or laser pointers. The power would be "high" because the natural reflex of the target would be to close their eyes immediately, so damage would have to be inflicted as rapidly as possible. At sufficiently high levels of power the atmosphere will ionize (this is the kind of power required to perform boost phase intercept on ballistic missiles, for example), but MUCH lower power levels are required to blind humans, and the losses through the atmosphere are much lower at these "lower" power levels. (Was all of that confusing enough??) These lasers are available commercially, and are not cheap, but are certainly within reach of a terrorist organization, or an upper-middle class whacko.
3) Low diffraction, or "spreading" - luckily for the designer of pilot-blinding lasers, this goes with making the beam just a little bit bigger than your standard eye-surgery/laser pointer beam - that is to say, spreading the beam out larger at the point of transmission (together with other appropriate optics choices) helps to reduce the spread of the beam over distance - there's no point in making the beam narrower than you can point it, or than you can hold it on the target during the time of the "attack".
4) Pointed accurately during the "attack" - this can now be accomplished with available optical processors and optics with a minimum amount of programming, together with a beam director appropriate to the laser being used - these are now available for a variety of applications, especially for such a slow-moving and high-stability target as a commercial aircraft - these kind of targets used to be hard to hit, and are still nearly impossible to hit with a "hand-held" device like a laser pointer, no matter what kind of aids might be provided, but current technology provides easily purchased solutions for our pilot-hating whackos.
OK - I've probably missed 40 posts by now, so I'll go ahead and submit this, and stand by for flames. Please also understand that if this is being done in the US, this is a serious and credible threat, and it needs to be taken seriously. These components are available, and can be integrated by an average engineer - many of whom are available for the right price. Scary.
They needn't last long to cause dielectric breakdown.
A simple $150 Nd:YAG surplus tank designator, for sale on ebay, can give you, oh, 50 mJ in, 10 nanoseconds on 1 square centimeter.
Thats a peak intensity of 5 million watts per square centimeter.
Golly, I bet that will get some electrons moving. Add the natural lens of your eye, and now we have nasty plasma forming on your retina . Bummer.
Yeh, but that space heater is emitting a broad spectrum of light, most of it in the infrared. A laser emits a single frequency (well technically a very narrow range of frequencies), IOW it's all one color of light. It's also coherent, which means that it remains in a small cross sectional area for much longer distances that non coherent and multi frequency light. 50 Watts is a lot of laser power. Nothing compared to the sort of laser used to shoot down missiles, but plenty to damage your eyes. Not much of the energy would go to heating the air, if the frequency was properly selected.
If you have time during your current discussion for a question from a technodolt, has the diffraction problem been solved? Seems like you'd have to defeat chaos to beat it.
Telling them beforehand defeated the idea of searching the ship...standard Clinton crap.
Interesting article and information.
It's been ages since I've looked at the stuff, and I didn't fully understand it then, but my understanding is that beyond a certain point, air becomes increasingly opaque as more and more energy is pumped through it. A low power beam may be able to pass a certain distance through the air while being attenuated 10%, while a much higher power beam travelling the same distance might be attenuated 90% or even 99%. Because the power level required to blind someone is much smaller than the power level required to destroy metal, I don't think atmospheric attenuation would be anywhere near as major a factor as it would be with SDI.
Its not a hobby.
Okay, if it's so easy to do TODAY, then why doesn't GWB run down to radio shack and buy all the lasers he needs, throw 'em into orbit on a Delta rocket and scrap the missile to missile interceptor he's building now? Common sense would tell you that the atmosphere plays a HUGE role in dissipating laser energy. It's not hard to see or understand.
Because an antimissle system needs to delivery energy to the target, not just high peak intensity as is the case for a blinding weapon.
This probly wont help but it looks complicated.
Knowing the size of the focused spot is helpful in calculating energy density at the work surface.
For a fundamental mode (TEM00) beam:
S = ( 4l / p ) × ( F / D)
where:
In performing a laser weld, optics to focus the laser beam to the desired size are necessary.
S = Focused Spot Diameter
l = Laser Wavelength
F = Focal Length of Objective Lens
D = Diameter of Laser Beam
For a multimode beam:
S = F × f
where:
F = Focal Length of Objective Lens
M = Laser Beam Divergence
If one assumes the part to be welded as a semi-infinite solid, with a constant incident heat flux, then the temperature distribution as a function of depth into the material is given by:6
T(x,t) = (2E/K) × [(kt/p)½× exp(-x2/4kt) - (x/2)erfc(x/2(kt)½)]
where:
T(x,t)=Temperature at a distance x below the work surface, at a time t after start of constant heat input
E = constant heat flux input
K = thermal conductivity
k = thermal diffusivity
x = depth below surface
t = time after start of heat flux input
erfc = complimentary error function
and at the surface (x=0), the temperature rise will be:
T(x,t)x=0 = (2E/K) × (kt/p)½
....sorry......
The laser was fired from a ship, not a plane.
"No 'hobbyist' is ever going to be able to easily generate the TOTAL amount of energy needed to penetrate miles of atmosphere. The Joules needed would be enormous."
I'm sorry but that is just plain wrong.
Low power laser communications systems easily extend miles over line of sight. Obviously atmospheric conditions are highly variable and effect the reliability of such systems but they are used nontheless.
Hobbyist have successfully bounced laser light off the moon and back to earth. They did it some time ago.
I think some later posts answered it. My point with the space heater was simply that I couldn't imagine a laser traveling through 5 miles of air without releasing as much HEAT energy as the heater. But, apparently, the atmosphere responds differently (by becoming more opaque with increasing energy) depending on how much power is put into it.
You are confusing multiple types of laser systems.
Unlike chemical laser info, I imagine most of the hard core x-ray laser info is still classified.
Still, just pondering the problem for a second or two, any decent physicist could tell you it probably wouldnt work. Or would only work under lab conditions, not in space,etc.
(hint: thats why the current system isnt a nuke driven x-ray laser)
OK, as this is obviously a serious threat, is there a defense available? Glasses or a window shield which would prevent this spectrum of light from passing through?
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