Sci-Fi Weapons to Join US Arsenal?

marct22 writes to tell us CNet is reporting that the next weapons coming out of the US arsenal could be stepping right off the pages of science fiction to be there. From the article: "By the end of this year, the Air Force plans to conduct a first, fully loaded test flight of its Airborne Laser, a jumbo jet packed with gear designed to shoot down enemy missiles half a world away, at the speed of light. The ABL also packs a megawatt-class punch--it's not exactly your garden-variety laser pointer."

Re:Half a world away?

[Anonymous Coward]

Wouldn't be too hard

God, how I hate that statement! Yes, it would be hard. In addition to atmospheric attenuation and disturbance in the beam, you have beam divergence spreading the beam out, and diffraction off of the mirror edges throwing it everywhere. By the time you get to the other side of the world, maybe you can use it as a night light.

Re:Mega Watts are easy, and misleading.

[drinkypoo]

From the article:

Now, this thing is also going to take a lot of juice, right? Everything you need to power the lasers is going to be able to fit in the 747?
Beason: Absolutely, and that's why you need a 747 to carry all the chemicals necessary to generate the laser light. Basically, the laser is generated by the transition of an excited iodine atom going from its excited state to a nonexcited state, but in order to get that iodine to the excited state, there is a chemical reaction that has to occur that transfers energy from oxygen to the iodine.

This is not an ordinary laser, it's a chemical laser, that means that it consists of compounds that when mixed, lase. The reactions happen quite rapidly.

Lasers are always rated in watts or fractions thereof. Saying it's a multiple megawatt laser is meaningful, although I couldn't find any information on precisely what the watt ratings for lasers mean.

Re:fantastic new weapons

[skam240]

Hitler lost the war because he was out produced, not because of his faith in technology. The Russians and the Americans could just produce one hell of allot more "stuff" than the Germans. Granted this stuff was often inferior to the German's stuff (the Sherman's cannon couldn't even penetrate the front or side armor of a German Tiger) which resulted in far higher loss rates but even then the Germans didn't have the resources or the production capacity to keep replenishing their forces.

So basically you're wrong :)

Re:Half a world away?

[Bad D.N.A.]

Wouldn't be too hard to coordinate with a satellite to bounce off of them. I'd just be concerned about the laser transmission loss going through the atmosphere for that long of a distance.

To coordinate with a satellite... easy. To worry about the transmission loss... irrelevant. To achieve the pointing requirements, both from the plane and the spacecraft, to hit the target (priceless... literally...). What happens when a little gust of wind hits the plane (they do bounce around a bit). Your beam will miss the target by many kilometers (and that's if you were lucky enough to hit your mirror-in-space?). GPS or something along those capabilities would not even come close to the resolution required for this type of thing, to say nothing of a moving target, a moving source, and a moving relay.

Re:Garden Variety laser?

[spagetti_code]

I'm sorry, thats been patented [freepatentsonline.com].
You need to pay a licensing fee or purchase
an official Cat Chaser(tm) if you want to play
with your cat.

Re:Overcoming countermeasures?

[BJZQ8]

All of this research was done a long time ago. The laser delivers its power in such a burst that no amount of mirroring or spinning will make a difference. As to the atmospheric attenuation, that's what the laser's adaptive optics are for. It's kind of like a telescope in reverse. In any case, this sort of thing was tried for short-range defense in the 70's, and even a small laser was capable of shooting down Sidewinders (mounted on a KC-135.) We're talking about serious firepower here...this thing was tested at a low-altitude range of 50km, and worked fine...up in the high atmosphere where they hope to catch boost-phase weapons, it should be much easier. It's not like the things can evade or maneuver, after all, they're called ballistic missiles for a reason.

http://www.nae.edu/nae/bridgecom.nsf/weblinks/MKEZ -4ZPQHJ?OpenDocument [nae.edu]

Re:Half a world away?

[DoctorStarks]

[...] designed to shoot down enemy missiles half a world away, at the speed of light

That's a pretty impressive feat. Does it shoot the laser straight through the Earth's core? Or have they managed to get the jumbo to fly at the speed of light?

You got modded funny, as you intended to be, I'm sure. But it seems to have launched a series of replies trying to theorize about how the laser is going to propagate halfway around the world. So let me rain on the parade.

The Airborne Laser [missilethreat.com] is an in-theater weapon, designed to intercept ballistic missiles during the boost phase. It flies up at around 40,000 feet and can engage targets within range that appear above its horizon.

It doesn't bounce lasers off satellites or propagate a laser beam "halfway around the world", as TFA says. The author was being a bit grandiose but caused some confusion in the process. It is half-way around the world, if that is where the missiles are coming from. The plane is there with the missiles, though. So are the radars that help it target.

There has been a lot of research put into making this weapon functional (directed energy, targeting, adaptive optics), and the early results are promising. The upcoming tests should be very interesting indeed.

OK. Resume speculating.

Re:Oh my gosh

[hibiki_r]

It's pretty well known that US troops used depleted uranium weapons in Yugoslavia, just like they did in the gulf war. I'm not aware of the specific incident the grandparent is talking about though.

Re:Half a world away?

[Bad D.N.A.]

Although there are numerous other practical problems as others have pointed out

If you want to talk about practical problems let's get the obvious out.

Where I work we build spacecraft. Could we build this spacecraft to the "required" specs? YES I have great 'faith' in myself, my colleagues, and our system. We have been very successful in building spacecraft over the years that do the job.

this one doesn't seem unsolvable.

Your right, it's not. Now let's talk about the cost, you know, the practical part of it. If I were the project manager of this system I would take a typical s/c cost and start adding zeros to the end of the cost (one if not two).

Tracking the source is easy. Tracking the target has been "Star Wars" from the beginning, right? The part that gets me is the relay. We would have to develop a gimbaled relay that responds in real time to both the target and the source. The velocity vector of both the source and the target would have to be tracked with enormous accuracy. I do not think this could be done with one spacecraft. We would need multiple spacecraft that could transmit tracking information in real time to adjust the pointing of the beam-relay. Nothing like this has ever been done before (to my knowledge). The costs to develop such a system would be enormous. I think it would be far cheaper to launch the source and remove the entire relay system (but I guess this thing is exactly what has been under study for all these years).

Honestly, if lasers from planes to spacecraft to target is our best defense option I would strongly support prayer as an alternative (it's much cheaper and equally effective)... and yes, I'm an atheist.

Re:Oh my gosh

[dbIII]

Depleted uranium should be no more radioactive than background

It is a lot more radioactive than background but a lot less radioactive than the other isotopes that have been removed. All Uranium is radioactive. Small amounts at a distance would be ignorable, as would exposure for a small amount of time. Small amounts of Uranium used as a ceramic glaze on some old bowls produces enough radiation that daily use would be stupid. Look up a Material Safety Datasheet for details - there's been copies online even on gopher before www was thought of.

Re:Oh my gosh

[LittleLebowskiUrbanA]

The depleted uranium munitions you speak of were not "dropped", they were fired out of a barreled weapon.