http://www.cnn.com/2004/TECH/space/05/07/laser.gun.ap/

WHITE SANDS MISSILE RANGE, New Mexico (AP) -- A high-intensity laser designed to shield Israel from missile attacks downed its largest rocket to date during a test over the New Mexico desert.
Pics, videos, and general info (http://www.st.northropgrumman.com/media/PressKit.cfm?PressKitID=23). You can also read more about the THEL on page three of this pdf (http://www.st.northropgrumman.com/media/SiteFiles/mediagallery/factsheet/SPIE_Manuscript_Tactical_high-energy_laser.pdf). It's an IR output that's about twice the longest wavelength visible to the human eye. But it actually ends up being visible because it heats airborne particulate detritus to incandescence, making the beam look like a three-foot shaft of glowing milky fog. It's really cool looking. I saw the MIRACL fire at the HELSTF in New Mexico in 1998. Of all the technologies covered by the BMDO optical intercept is probably the coolest. The Nautilus's kissing cousin, the Airborne Laser, has already taken to the sky (in 2003) and will perform its first scheduled intercept of an ICBM this fall.

The particular niche this system will fill is artillery mitigation, both due to its short range (limited to about 2km because of atmospheric refraction of a high-power density) and the near-zero flight time of a beam of light. The engagement envelope time is so short that just one Nautilus point-defense laser could completely negate an entire 24-gun battery of tube artillery. Indirect fire may very well become a thing of the past shortly. For us, at least. :cool:

That is sweet. Wonder if it could take out ICBMS coming in from orbit

Interesting. I saw a program on an airborn laser system designed for shooting down missiles but the tests were dissapointing. This was perhaps years ago and seems the technology is getting better. Now, will there be efforts to change the conditions of people's lives so that they no longer seek recourse to firing missiles or is this just palliative and not addressing the nature of the problem?

That is sweet. Wonder if it could take out ICBMS coming in from orbit
The Nautilus isn't designed to engage ICBMs; only short-ranged missiles and artillery projectiles. Israel has a hard-on for it because they've been scrambling for something like this since they went at it with Lebanon, because the Lebanese fired a bunch of Kyatushas at them, among other things. The US likes the idea because a few of them (mounted on humvees, as they will be eventually) will all but entirely negate North Korea's artillery preponderance at the DMZ.

The Airborne Laser, which is the big ass chemical laser that's directed in a 270-degree sphere from the nose of a 747, is the one that'll hit ballistic missiles during their boost phase. It's a 747-400 freighter aircraft with a Chemical Oxygen-Iodine combustion laser in its cargo bay and enough fuel for about 200 lases at 5-6 seconds each. This huge ammunition capacity is made possible by carrying fuel in precursor ingredients as hydrogen peroxide and potassium hydroxide (also known as hair bleach and Drano). These chemicals are combined with Chlorine gas and water in the lasing cavity, which resembles a jet engine more than it does an optical instrument. The only difference is that there are mirrors forming a resonant cavity at each side of the combustion chamber. When the mix is burned, the flame produces a strong line around 1,315 nanometers (about twice the wavelength of deep red) in the mid-IR spectrum. The beam then emerges from a ball turret in the nose of the 747, which is the beam director itself. It looks a lot like a large carbon arc searchlight since it's a cassegrain fed telescope in reverse, with a conscan subreflector. The telescope's main reflector is actually a composite array of some 341 parasitic mirrors with piezoelectric backings. This means that each mirror can flex and turn independently at a frequency of 1,000 Hz, driven by a pretty capable computer, to compensate for atmospheric refraction over the 200+ nm from output aperture to target. Even at 40,000 feet there is still enough air kicking around to cause blooming and lensing over the distances this thing is going to operate at. (90% of the earth's atmosphere is below 10,000 feet, so flying as high as possible is best)

Prior to actually firing the main laser, the ABL uses a set of solid state lasers of a lower power ("lower" is relative here, because the illuminating laser is still on the order of a few hundred kilowatts) to illuminate the enemy missile and compute a firing solution the same way police use lasers for speed detection. Because the acquisition and tracking laser is directed coaxially with the main beam, through the same director, when a reflection is received it is guaranteed that the main beam will score a hit.

For some cool pics and info, check out Boeing's ABL page (http://www.boeing.com/defense-space/military/abl/flash.html), for starters. Popular Science also did a piece on it (http://www.popsci.com/popsci/aviation/article/0,12543,424266,00.html), although this is over a year old now, and I don't know how accurate it is since I haven't read it. Should be some good background though.
Interesting. I saw a program on an airborn laser system designed for shooting down missiles but the tests were dissapointing.
I have a hard time believing that tests of the ABL were disappointing, primarily because it has yet to be tested.

Apparently it wasn't an ABL and apparently, according to this site, it worked (against cruise missile drones)! http://www.de.afrl.af.mil/Factsheets/ABLHistory.html This looks like what I saw on some documentary but sounds like it was quite a success rather than how I remembered it.

Oh, excuse me, I was thinking Anti-Balilistic Laser, ABL, (as in anti ICBM laser which really doesn't make sense either) rather than Airborne Laser which I believe is how you meant ABL. According to that web site and the show I saw an airborne laser has been tested though not exactly the model you are talking about. No biggy. Interesting stuff, look out Buck Rogers !