Laser Gunship?

Last weekend I heard reports that the AC-130 gunships were active over Fallujah.

Hallelujah!

The AC-130 gunship is a cargo plane that has been jammed full of advanced targeting optics and reconfigured to carry nothing but piles of ammunition to feed its hungry side-mounted guns.

The armament consists of a high-speed 25mm gatling gun, firing 1,800 rounds per minute; a 40mm Bofors cannon that can pepper an area with 100 grenade-like exploding projectiles per minute; and even a freakin' 105mm howitzer that can put a 4-inch wide high-explosive round through your window up to 10 times a minute.

This is a view of the AC-130 head-on, with the guns visible protruding from the side.

This is a view of the 105mm howitzer inside.

Here is the howitzer firing.

This is a time-lapse photo of an AC-130 saturating a ground target in Afghanistan, showing how it just flies in lazy banking circles as the advanced targeting systems keep the guns trained on a single point.

Note that only every 5th round is a tracer, so the actual volume of fire is much higher than you can see.

According to FAS,

The AC-130U is the most complex aircraft weapon system in the world today. It has more than 609,000 lines of software code in its mission computers and avionics systems. The newest addition to the command fleet, this heavily armed aircraft incorporates side-firing weapons integrated with sophisticated sensor, navigation and fire control systems to provide surgical firepower or area saturation during extended loiter periods, at night and in adverse weather. The sensor suite consists of an All Light Level Television system and an infrared detection set. A multi-mode strike radar provides extreme long-range target detection and identification. It is able to track 40mm and 105mm projectiles and return pinpoint impact locations to the crew for subsequent adjustment to the target.

And you thought those new fighter planes were fancy! We've only got about a dozen of the "Spookys" in the inventory.

At $190 million. Each!

Wouldn't it be cool to put an infrared laser heat ray on this beast?

You bet!

(BTW, John Pike doesn't really know what he's talking about. Tracking a moving target is easy. It's especially suited to laser weapons. Given the speed of the photons, and the lack of inertia in the beam, and advances in CCD camera technology, tracking fast moving targets, even missiles, is a laser weapon's raisson d'etre!)

The concept is called the "Advanced Tactical Laser", or ATL, and according to World Tech Tribune (Who are they? I don't know. It's tough to find relatively up-to-date, open-source information on this topic that isn't completely whacky),

The US Military has been working on getting lasers in their arsenal for about fifteen years, but there’s always been the problem of size. Unlike the handheld phaser guns seen in Star Trek, a laser gun in the real world is about the size of a dump truck. Unless you’re a very big boy, most men on the front lines would be unable to hoist a laser gun that size around the battlefield.

Until laser guns can be miniaturized down to handheld size, they are mounted as cannons on warships or large planes. The Boeing Advanced Tactical Laser (ATL) cannon has been in testing at Kirtland Air Force Base in New Mexico for the past year. The ATL would be used for both lethal and non-lethal missions. Just as low flying AC-130 gunships ripped Taliban soldiers and military installations to shreds over the past four months with machine guns, a laser-enabled AC-130 would be able to fry human enemies and liquefy metal targets like communications antennae with pinpoint accuracy from nearly ten miles away. The Bush Administration’s proposed defense budget increases funding for the ATL by four times and hopes to have a laser-enabled AC-130, called the AC-X or “Son of Spectre” in the skies by 2004.

Lasers require a lot of energy to be effective, so many might ask: “Is the ATL nuclear powered?” Any chance the leftist watermelons (you know the type: Green on the outside and Red on the inside) have of demonizing the ATL as ecologically dangerous are slim. The ATL is fueled by common household chemicals like hydrogen peroxide, iodine and water.

The chemicals were always the dicey part. And you're stuck with the wavelength that the chemical reaction produces, even if it's not the optimal wavelength you'd want to have to avoid the detrimental effects of diffraction, turbulence, and absorption -- especially if you're attacking a target in the atmospheric "soup" near the ground, which is what the ATL is supposed to do, unlike, say, its bigger brother the ABL (Airborne Laser), which is a modified 747 that does nothing but carry a humongous COIL laser that's an order of magnitude more powerful than the one envisioned for the ATL and is meant for high-altitude engagements against boosting ballistic missiles.

So there's a competing effort to develop electric-powered, solid-state semiconductor lasers, instead of the chemical lasers, at power levels that are sufficiently interesting. Now the big problem is cooling it.

Here's a cool promo shot of what a laser lab looks like. This is supposed to be a scaled-down version of the actual engagement, in which everything (including the physical effects of the atmosphere) was made smaller in the right proportion so the physics stays the same, which saves you from having to do unrepeatable field experiments with 5-foot wide beams and hundred+ mile ranges.

I think that's the Lockheed lab. Technically it was a disaster and got shut down. But don't worry, MIT's version of that lab worked just fine.

Here's the ABL "artist's concept" drawing that we all overuse in our powerpoint presentations. You can see why.

They're having trouble fitting the big laser into the 747. It's not clear the plane will be able to get off the ground. The plumbing for all those nasty chemicals is complex. Here for example is part of a COIL module. They claimed if given enough money, they could shrink it down and put several of them on the plane. Good luck with that. Probably they'll make do with fewer modules, and live with lower power levels (and shorter ranges) than advertised.

Anyway, it's a start.

Ground-based lasers like the THEL (Tactical High Energy Laser) have already shown they can track and shootdown Katyusha rockets and even mortar shells. The MIRACL (mid infrared chemical laser) beam it projects, however, also requires nasty chemicals like deuterium fluoride. The goal is to make THEL mobile: the MTHEL. All that requires is putting a 3-story building full of PhDs on wheels.

The artist concept looks neat anyway.

But electric-powered solid-state lasers may save the day. The boys in engineering have some interesting concepts involving coherent laser fibers and small laser diodes. They just have to get 10,000 of them all aligned and working in concert.

Mid-power lasers with power supplies carried on a small truck like a Humvee might be a few scant years away. And John Pike doesn't even say something obviously wrong:

Yet John Pike, director of GlobalSecurity.org, a defense research firm that often criticizes weapons programs as impractical, said solid-state laser weapons technology finally appears to be moving from "pure physics to engineering."

"They're starting to talk about specific platforms and specific missions for the lasers," Pike said. "They are getting close enough that they can actually ask for money with some confidence that they can deliver on what they promised."

Although the Pentagon has emphasized development of chemical lasers, the focus in the last year has begun to shift to solid-state variants, which would be easier to package and transport. Low-power solid-state lasers are used in a variety of commercial applications, from compact disc players to grocery store scanners.

The Holy Grail

Research in solid-state lasers received a major boost last month when the Pentagon quietly launched a $50-million initiative to develop a 25-kilowatt laser by the end of 2004, with the goal of deploying by the end of the decade a 100-kilowatt laser that could be installed on warplanes, tanks and ships.

The most powerful laser currently is a 10-kilowatt model that is being tested by the Army.

Information about the damage such lasers could inflict is classified. But in general, experts say, a 25-kilowatt laser could blind an enemy sensor several hundred miles away. It also could put a hole through a sheet of metal from a distance of several miles.

Correspondingly, a 100-kilowatt solid-state laser -- the Holy Grail for weapons developers -- could deliver a destructive beam to a target dozens of miles away, making it an effective tactical weapon.

A laser's beam would not by itself cause a target to explode. But it could slice through the outer casing of a missile, disabling the guidance system or causing the missile's propellant to explode...

Meanwhile, scientists working on solid-state lasers have made major strides in boosting the power output and the quality of the beam, two key factors for determining a laser's lethality and accuracy.

"Over time, solid-state lasers will become more powerful and more compact, which will make them more useful on the battlefield and perhaps revolutionize the conduct of war," said Loren B. Thompson, chief operations officer for Lexington Institute, a defense think tank.

"I have no doubt that by the end of the decade, we will have a laser weapon installed on a Joint Strike Fighter jet or an AC-130 gunship."

I don't doubt it either.