There is a chain of about 8 or so here:

http://www.theforce.net/swtc/Pix/dvd/zs/anh/dsbeam4.jpg

Make lots of tea/coffee: The laser can heat a litre of freezing water to boiling point every second.

How much hot water does a washing machine use? How about a built in hot tub and steam room with your frikking laser?

If you want a shark-mounted laser, you will need one of the bigger sharks to pull the power supply at a reasonable pace.

Lewis, you say it will require "electrical power input of half a megawatt", but that's only whilst it's firing. I wouldn't expect it would need to be firing continuously so they may (for portable applications) get away with some kind of electrical power buffer like a capacitor bank that can be charged between firing by a lower capacity power unit. It would need to be sufficient to power the beam for the duration of the required pulse (possibly multiple shots) and also need to charge relatively quickly in between bursts.

What is the time of each "shot"? If it's relatively short (e.g. 0.1 sec) then you can get away with with a 50kw power supply and still fire at one shot per second (subject to losses in the buffer mechanism).

If it needs to fire for sustained periods then you're back to needing continous power (or a really big capacitor bank like this one http://www.rheinmetall.de/index.php?fid=1805&lang=3).

I didn't see anything in the article to say how many shots this thingy is capable of firing in a given time (presuming, of course that it's not continuous).

If one of the deployment possibilities is against mortars, it would be a real shame if it could successfully take out the first one - but have to ask the emeny if they wouldn't mind waiting several minutes before lobbing off their next $20 shell, 'cos our $10+++million laser isn't ready yet.

Will it frikkin fit on top of my frikkin Shark??

...we all start getting along together instead?

No?

Pass the stub then, Shaggy.

The laser burst duration and duty cycle are clearly important factors driving the size of the overall installation; to such an extent that I am not sure that integrating to a warship anything less than summink nuclear powered would be viable. Fixed, ground installations, then. Not sure you need a PC to control the power supplly or the laser elements of the system...

"it's more than half the engine power of a 60-ton Challenger II ", So over 600HP?

Or probably close to about half the engine power maybe of an M1 Abrams? 750HP

So assuming they can shoehorn the thing into a modified turret, would this mean they have to stop to shoot due to lack of sufficient power to drive the tracks?

Maybe Northrop should divert some of the DoD research budget into a nice small clean fusion power pack; they might have a useable system then and a hugely profitable sideline as well.

Black helicopter - that would be the Havoc-N driver laughing at the stationary target for his AT-9's

"Quantity over quality".

The Soviet counter to technologically superior American defences was always "throw so much at them that something HAS to get through." Thus, their missile-launching ships were capable of launching practically all their cruise missiles in a single salvo.

Currently Afghan and Iraqi fighters launch a couple of mortar shells at a time and skedaddle. But it's not inconceivable that they, or some other, future opponent (Iran, anyone?) would try launching dozens of shells at once.

Also, South African conscripts used to have unauthorised competitions to see how many shells from a single mortar they could have in the air at once. (What a great way to spend MY tax-money. Serves 'em right when they mis-timed it and lost a hand.)

My point is that these lasers will have to be able to fire multiple pulses for a sustained period (and come with an awesome fire-control system) to really be effective as a base defence. So for base or ship defense you would need a power source with an average output close to that of the laser's peak output.

Then again, base or ship defence is exactly the case where you do have the space for a massive generator. So smaller, faster vehicles may well be able to use smaller generators coupled with capacitors, as suggested. It's much harder to rain dozens of rounds on a moving target, after all. A couple of pulses a minute may be all you need to defend, say, a tank.

Still a long way from an offensive weapon, though. It's going to be a while still before that tank dispenses with its main gun in favour of a laser.

NorGrumm have produced a little marketing brochure here:

http://www.st.northropgrumman.com/media/SiteFiles/mediagallery/

factsheet/JHPSSL.pdf

that includes a picture of a C-130 Hercules and picture of a humungous cuboid that looks like about 10 standard IT equipment racks in volume, which I take to be the PSU. Don't doubt that the kit will fit in a Fat Albert, but I do wonder about pulse length / duty cycle as previously...

Somebody (probably NorGrumm) has slipped a viral video here:

http://www.youtube.com/watch?v=s9JZSjsgWm0

(unable to preview it, YT site is blocked from where I am sitting)

I don't think the cycle time of their current rig is meaningful yet. This is still a research device, not even a prototype. And I doubt that there's meaningful way to extrapolate final cycle-time from the current value.

So we'll have to wait and see what they can achieve once they have a production-ready model. Like you say, it had better be quite high if it's going to be any use.

Does anyone have any specs on the effective range these lasers?

Isn't taking out an incoming cruise missile at less than 100 metres is cutting it a bit fine?

Certainly store lots of power, but precession would be a bummer, especially in a 747...

it misses it's target......when does the beam stop? At least with a rifle or mortor round they will eventually stop but this has the capability to go on for quite a while. Imagine.........

Sir this is Commander Ivan Tobeoutahere at the International Space Staion, I think we have a situation. One of the solar panels has just been shot off by a frikken laser which appears to have originated from the Iraqi frikken border. Please advise........

Mines the coat with the mirrow in the inside pocket to deflect the ray....

It should be able to keep the riff-raff off my driveway or the neighbor's cat out of my garden.

This really is an amazing feat of engineering if it does what it says on the tin.

A few points of interest though are;

Ballistic projectiles tend to be spinning at several thousand RPM whilst travelling. So an impacting beam would be heating a band around the object as holding a spot is not an option.

A projectile doing mach 2 will have a sonic shockwave and this will cause light to refract through it. I wonder what the result of this would be.

Until I can get my own frikkin' Spartan Laser I'm not impressed.

Goggles?

Because its sensible, Why else?

Pulsed power is typically preferred. Consider the difference between having a litre of water poured over your hand every second to having a 1kg weight dropped onto it each second (from the same height). Now imagine that it is poured/dropped onto a nail sitting on your hand. The water might not do too much damage, the weight would but they require the same energy input to maintain as a continuous system.

However the power of the dropped weight is much larger as the time to absorb the energy is much lower.

It's really not hard arranging for half a megawatt of power for a short amount of time. Even a humble car battery can deliver 1000A (i.e. 12kW) for a good few seconds, so forty of them (or a smaller number of truck batteries) would do the job.

NiMH would be better. The battery pack in a Prius probably delivers 60kW when you floor it.

Capacitors can deliver much higher amounts of power per unit weight, but for shorter amounts of time. Either way the real question is how much energy is needed during a period of hostile incoming (minutes? hours?). It's that which will dictate the size of the generator, etc., not the peak power drain.

If I fit my mortar shells with shinny tinfoil hats will they get though?

Are you blind, man? A "chain" would be a number of lasers in series, and those beams are quite clearly in a parallel configuration. So I don't think you can call this prior art.

Actually, I think you will find that Average Power is preferred. These are solid state lasers, so for this kind of application the slight advantage in Peak power obtained by over-driving is offset by the need for continuous operation - no point pulsing it when it is the total energy delivered that matters, not the instantaneous intensity.

I haven't done any math on this or anything (Just half way through my first cup of coffee, what do you expect?) but I imagine that a cap bank to supply 500kW for any meaningful amount of time would be pretty damned large (Capacitors have about an order of magnitude lower power density than batteries.) Plus the laser (And any decent generator) runs AC, so you'd have to convert to DC and back to store it in the capacitors, and at 500kW that piece of hardware wouldn't be small either.

One of the attractions to lasers is that they /don't/ just fall out of the sky, as with normal automated projectile weapons currently used for perimeter defense. A laser will scatter as it travels through the atmosphere and probably be rather harmless by the time it gets to much else, assuming that there are no unexpected aircraft flying over combat zones. Those gating guns spew some large damned rounds, which have to come down somewhere, and hospitals, churches, schools, and mime troupes all have to be somewhere. And people would probably get angry if depleted uranium rounds drop on 3 of those.

Yes that may be the biggest but this is the prettiest:

http://en.wikipedia.org/wiki/Z_machine

That's the problem that gets swept under the carpet every time these defensive lasers are mentioned. But if you bring it up, some smart-ass will smugly point out that the laser will still get through a mirrored surface, because it will be so bright, and no mirror is perfect.

Which is true, but misses the point: As mentioned, the projectile will be spinning, so the laser is spread across a larger surface area. And if that surface area is even slightly shiny, some of that laser beam will be reflected. So now your laser has to be so much more powerful to compensate for these losses. Or it has to focus on its target for longer. And of course, there is a finite time for it to do so (i.e. the time between target acquisition and the moment where the ruddy thing takes out your troops!) Now throw in multiple incoming shells and...

Now our hypothetical smug friend will say that a more powerful laser is all you need, as nothing will make an incoming shell/missile invulnerable. But just how powerful can you make a laser? It may well be that the laser will have to be strong enough to count as an offensive weapon before it can stop a shiny, spinning projectile. And as I mentioned earlier, we're a hell of a long way away from that.

The only reason that defensive lasers are even remotely feasible right now is that the targets they're aimed at are obligingly filled with either high explosives or rocket fuel.

Brilliant, I'm going to get radiated in my own work place here in Fareham, England.

Northrop Grumman is just up the road from me!

I for one am looking forward to the possibility of laser hunting guns... though may be trouble for police ballistics in the future.

The Earth is flat and the center of the Universe, man will be unable to get enough air to breath above 25mph unless he carries it with him and the idea that anyone could actually *fly* to America from Europe is quite clearly preposterous...

Thus far, scientific "proof" that something is impossible does not exactly have a good record of success, does it really? Just because it has not been done YET does not mean it cannot be done at all.

Spot the difference between things like Newton's Laws of Motion or the Combined Gas Laws (all "proven" by repeated experimentation with consistent results) and the claims that there will NEVER be man-portable laser weaponry powerful enough to vaporize like in the movies and the ones in my first paragraph... (but at least young Al Einstein realised he didn't have all the facts, hence he called it his THEORY of Special Relativity)

You dumb asses will still be busy arguing over the reasons these things will not work when our Alien Overlords descend from their mighty starships and take over the planet.

Bags I "Quisling Traitor in charge of Northern Europe" come the Day of Visitation.

Good luck getting one of these suckers into Australia...

When ships were made of wood (and men of iron), cannon shot were often heated red hot before firing at the French ^H^H^H^H^H^H enemy, in the hope that they would ignite the target. BTW, this is the source of "hot shot".

If the laser heated but didn't destroy the incoming shell, the result might be similar.

- the powerplant of an abrams tank is a pretty compact unit and cranks out plenty of power,

- they no longer need room for ammunition,

- no longer need to carry the barrel around,

- can get rid of one guy in the tank,

- all the above reduces weight substantially.

This should be a piece of cake. Just fit a larger powerplant in the tank. and you'll have one hell of a machine .... if this thing can fire one shot a second ... you are so dead when one comes your way....

problem is : how to dissipate the excess heat.. 20% efficiency.. that;'s gonna be one hell of a heatsink...

With respect to the laser the difference may not be great. However the impact on the target is different. If the energy is delivered in a short pulse then the energy is concentrated in a smaller area (as there is no time for it to be conducted elsewhere in the target) and hence the damage is greater at that target point. If a single pulse is incapable of doing any damage then yes it makes no difference but you might hope to ablate some surface away or damage a sensor with less average power using a pulsed laser.

Folk have commented on the likely issues faced with hitting (small) projectiles but I suspect this sort of tech will be deployed against decent sized non spinning objects, such as planes and cruise missiles.

I believe the Patriot missile system was originally intended as an anti aircraft platform which was why it's F&C systems had problems against the /ballistic/ SCUD missiles.

Trying to accurately target a very small and rapid object is probably just a big a challenge.

"Hokey religions and ancient weapons are no match for a good blaster at your side, kid. "

though will they look like a dressed up British submachine gun when they go into production?:)

"(but at least young Al Einstein realised he didn't have all the facts, hence he called it his THEORY of Special Relativity)"

Might be a good idea for you to go look up the definition of scientific theory.

will be a scaled-up version for the ISS, called the "Death Star superlaser, version 0.25".

I hereby patent a mechanism of placing bicycle reflectors on ammunition. You know, the kind of reflector that sends all the light back in the direction it came.

You know like the ones Cheney seems to have cloaked .. er that is both horns.

Anyways I'd like to start the bidding .. I can name the first problem in 2 words "Friendly Fire" .. ooohh that's gonna sting.

RE: Range? .. well lets just say there are gonna be some ET's that were having a picnic on Gliese 587c and they are *really* ticked now!!

RE: and a playing card in the spokes .. you do know that devices that reflect nearly 100% of the light striking them back in the same direction they came from are called phase conjugate mirrors, and they are quite build able.

At 100% efficiency there are 683lumen per Watt

Ordinary light bulbs get 10lumen per Watt

High efficiency fluorescent get 90lumen per Watt

Sodium street lights get 135lumen per Watt

Your Northrop laser is doing 136lumen per Watt

That is about as good as it gets. What do you want, blood?

So how would this laser weapon work? I really don't understand the type of damage they would do, would they burn, slice, incinerate, or even be possible of delivering some form of explosive charge?

The rail gun I can understand they shoot a projectile but laser weapons just baffle me as I can't see them doing any real damage.

The laser will be truck mounted or stationary as the beam control system is another laser and it's all quite large. Power generation isn't an issue. Small turbines as in the A1A would work fine. Heat sink isn't all that big a problem although it would be a large IR source. The initial targeting would be a rather large radar on another unit. The laser puts out IR itself and that's often difficult to reflect in battlefield conditions. Motor shells are smoke covered after launching, etc. The aim point will be on the nose of the incoming round as they will be falling when engaged. Spinning isn't a big issue as the beam would be rather large compared to the target.

Let's all of us try and remember that several thousand bright engineers have been working on these systems since the early 70's and the chances of any reader here picking up that wasn't thought of is well..........nil actually.