Truck-Mounted Laser Guns

bl8n8r writes "Boeing has announced a contract with the US Army to develop laser cannons that are to be mounted atop 20-ton trucks for the purpose of shooting down incoming artillery, rockets, mortars, or bombs. The High Energy Laser Technology Demonstrator project actually shoots stuff instead of just painting a mark on a target for other armament to hit."

No, not really

[everphilski]

The range to shoot down a RAM (rocket-artillery-mortar) threat is on the range of a few kilometers. Laser attenuation ovr that short a distance is pretty minimal. My master's thesis was on this concept, but swapping out the laser for a gun-launched projectile... you actually don't need that much focused energy to destroy a RAM threat mid-flight.

Re:They're getting smaller every day.

[zamboni1138]

They're still working on the 747-mounted laser [wikipedia.org].

Re:How do clouds and smoke change this?

[everphilski]

I don't have numbers to throw at the question ... yes, of course, there is attenuation. My point is, and what I do know from experience, the range to downing a RAM threat is not that far, and secondly the amount of energy you need to impart to down a RAM is not as much as you might imagine (tens of kJ).

MTHEL?

[Lazarian]

Why don't they just work with the already tested MTHEL [wikipedia.org] system?

Re:No, not really

[everphilski]

The event horizon for a RAM threat is incredibly short. Seconds. Depending on the scenario, if you do not get your shot off within a few seconds of detection, you are dead in the water. Secondly, the amount of energy necessary to take out a RAM is pretty low... on the order of tens of kilojoules. These facts I know from my research.

(Up until a few months ago, I worked 2 rooms over from some of the guys doing the modeling and simulation for this particular system ... this is a test bed, not the finished product)

MTHEL already tested against multiple mortars

[vg30e]

The Laser in the article is a development of the MTHEL project. The purpose of MTHEL is to defend positions against incoming rockets and mortars. One of the test videos actually shows the MTHEL hitting 3 different mortar rounds launched from 3 different positions all traveling through the air at the same time.

Re:So will this be the demise of their ...

[coredog64]

Rail guns are absolutely not a replacement for cruise missiles. A rail gun projectile in ballistic in nature -- if the wind is blowing the wrong way at the target you're SOL. Yes, you can use lasers for terminal guidance but that requires something to paint the target (hard to do when the target is in hostile territory. Being ballistic, it's also vulnerable to the laser defense systems being discussed here. The launch profile for a rail gun also limits the guidance package you can fit. A cruise missile has a very gentle launch profile -- a rail gun that has to accelerate to maximum velocity in under 50 ft. is much more difficult to deal with.

Re:I'm so proud

[Eternauta3k]

Most materials aren't reflective enough, the people who make laser etching machines can tell you how even the best mirrors (gold, polished to under a 1/4 wavelength) are only 80% reflective. That means 20% is being absorbed as heat. With enough power, you could burn through anything.

Re:Dude...

[VagaStorm]

Because the Geneva Convention states that any country who has signed it is bound by it even if fighting others that have not:
From http://www.icrc.org/ihl.nsf/FULL/365?OpenDocument [icrc.org]

"Although one of the Powers in conflict may not be a party to the present Convention, the Powers who are parties thereto shall remain bound by it in their mutual relations."

Re:They're getting smaller every day.

[Nefarious Wheel]

Truck-mounted Phalanx? You're joking. Way too much metal to carry around to feed it. Even used intermittently it takes a ship to carry the necessary ordinance, and mortars can happen to you all day. Photons weigh a lot less.

The truck they are using

[Widowwolf]

For all of you who dont know the HEMTT http://en.wikipedia.org/wiki/Heavy_Expanded_Mobili ty_Tactical_Truck/ [wikipedia.org] are 20 ton trucks useful for providing transport capabilities for re-supply of combat vehicles and weapons systems..The HEMTT trucks exist in several configurations: M977 and M985 cargo trucks carry all types of equipment, especially ammunition. A crane is mounted at the rear of the vehicle. M978 tanker refuels tactical vehicles and helicopters in forward locations. M983 tractor tows the trailer-mounted MIM-104 Patriot missile systems. M983 with 30 KW generator and a crane mounted behind the cab towed the MGM-31 Pershing Erector Laucher in CONUS (a MAN tractor was used in West Germany). M984 recovery vehicle uses a lift-and-tow system to recover disabled vehicles in two-to-three minutes. It mounts a recovery winch, a crane and a large storage box. These things have great manuevering capabilities and can knock down several feet thick trees (We used to do it to make shaded parking spots when out on bivouacs.(That and you can make ranger brownies in the Exhaust pipe)

Re:So will this be the demise of their ...

[ztynzo]

Rail guns are what the navy is going to use to replace cruise missiles

Realistically, the Navy uses cruise missiles to hit long range targets that are beyond line of sight (usually ~10mi due to curvature of the Earth). While scientists may be able to come up with targeting systems that make extremely high velocity projectiles accurate beyond line of sight, it is highly unlikely that the Navy would retire such a versatile offensive weapon for one that seems very limited in capabilities... (A cruise missile can hit a target on the other side of a mountain, let's see you figure out how to do that with a weapon designed to be fired in a straight line..)

More likely to replace the 5" .54cal Mk45 [wikipedia.org] and its successors.

Re:Not to be a party-pooper...

[BoothbyTCD]

If you know of a 99% reflective material, patent it now and make lots of money. In the real world however, even precision mirrors top out at 80% or so. That means the other 20% of incoming energy is heating the incoming shell (assuming every shell is polished in a lab before being fired out of perfectly smooth barrels).

Re:So will this be the demise of their ...

[Whomp-Ass]

All projectiles (including missiles) are ballistic in nature. There is a reason they're called "Ballistic Missles".

A railgun projectile, acting as a cruise missile would, would simply be the same cruise missile without the propulsion system. The guidance system would be the same, the warhead would be the same, only the manner of providing the impulse would change.