Homing In On Laser Weapons

Bloodmoon1 writes "I just came across this article at GlobalSecurity.org that gives a very good summary of the current status of solid-state lasers as weapons. It gives you a good idea of where the JSF Laser system is at and just how much time, effort, and money has went into this project. Also has some basic, but very sufficent, explanations of some of the science behind the technology."

Comments

Missile

[e8johan]

I still prefer a good old missile! It feels more destructive to fire a rocket at your enemies instead of just flashing (a really *big*) light at 'em. :-)

We`ll have to

[MrFredBloggs]

keep quiet about the whole light and mirrors thing, I guess...

Re:We`ll have to

[caveat]

if you hit a mirror with a powerful enough beam of laser light, the small fraction of light that's absorbed (no such thing as an ideal reflector) will rapidly ablate the mirror coat, and then you're screwed. we have problems with this with our pulsed IR laser at work - we need solid polished aluminum mirrors with heatsinks on the back, ad that's for a 500mJ, 500ns pulse; they don't last that long, either. a 100KW IR laser will vaporize pretty much anything that's not *perfectly* reflective, i.e. anything we can build with current technology.

Re:We`ll have to

[MrFredBloggs]

"a 100KW IR laser will vaporize pretty much anything that's not *perfectly* reflective, i.e. anything we can build with current technology."

yeah, but if you need to prevent this sort of thing from happening to keep your planes/boats/trucks up and running, then its worth looking into solutions. Who knows what`ll be effective? Perhaps some sort of sand/concrete which will degrade pleasantly? Layers of shiny foil which peels off revealing more foil below. Also, non/slow moving lasers will be the perfect target for counter-weapons to lock onto if they`re active for a few seconds at a time - usually you`d just get a flash as the weapon was fired - now you`ll have `I am here!` flashing lights (& heat).

Re:We`ll have to

[!splut]

Perhaps some sort of sand/concrete which will degrade pleasantly?

Perhaps by playing a Bach concerto and releasing a soothing lavendar fragrance as it melts to form a replica of Rodin's The Thinker.

Mirrors

[Anonymous Coward]

Wouldn't a couple of mirrors ruin the whole thing? I mean seriously. Cover a missile in chrome and the laser would just bounce off harmlessly, wouldn't it? Wasn't that one of the main stumbling blocks to SDI?

Re:Mirrors

[briggsb]

"We have a visual on the missile...er...wait...we're being attacked by a flaming disco ball!"

Re:Mirrors

[Zathrus]

Not really.

Most mirrors are only about 95% reflective. The other 5% is transmitted through the mirror and absorbed (either by the mirror itself or the backing). Really good mirrors are about 99% reflective.

Now, let's assume that somehow you manage to "chrome" a missile such that it's 99% reflective (not bloody likely in real life, but we're talking theory here). Someone targets a 100 kW laser at you. The mirror reflects/scatters 99 kW of the energy, while 1 kW is absorbed by the missile itself.

It takes 216 kWs to heat 11 kg of steel by 10 deg C. Certainly you're not going to be able to keep the laser on the mirror for 216 seconds. But, that's ok, that's not the point. All you have to do is melt the mirror at contact point, degrading its reflectance so you can effect the missile itself. So how long does it take to boil the mirror into vapor? Probably a couple seconds. After which you have no effective defense and the 100 kW beam will boil off enough of the missile to render it ineffective. After all, you don't have to destroy it -- just alter the aerodynamics enough so it's incapable of targeting correctly.

You could spin the missile to reduce spot heating, but that's going to complicate guidance considerably. And, frankly, I doubt that you'll get more than 80% reflectance on this sucker, which changes the equation drastically. And, of course, your maintainance crew didn't leave any oil, grease, or fingerprints on the missile casing right? Uh huh.

The main stumbling block to SDI was tracking, targeting, and blasting a laser through several miles of atmosphere - all in about 10 seconds after launch. That or you wait until the ICBM is in space, in which case you now have to destroy (not merely damage) a dozen warheads and a couple dozen dummys. Which means you now have 20-30 targets to destroy in 30 seconds instead of 1 target in 10 seconds. Fun!

Re:Mirrors

[Idarubicin]

Wouldn't a couple of mirrors ruin the whole thing?

In principle, yes. In practice, no. If you were to put a very high quality coating of silver (for visible wavelength lasers) or gold (for IR lasers) on your missile, in principle you could reflect 95 to 98% of incident light. Special optical coatings can result in >99% reflectance, but only over narrow wavelength ranges.

In other words, if the enemy knows the wavelength at which your laser operates, he can reduce the effectiveness of your laser weapons. For ground based installations, this still isn't a big problem--you just need a laser that's an order of magnitude more powerful, and you can cook even the reflective coatings on the other guy's missiles. I've done research work involving lasers in both physical chemistry and medicine, and I've seen a number of purportedly highly-reflective optical elements get toasted by a powerful enough beam. Also, high-quality optical coatings usually aren't meant to handle the stresses (physical and thermal) experienced by your typical missile (ballistic or tactical).

Re:Mirrors

[mikerich]

Smudges, scratches, contaminants would be unavoidable since we're talking about weapons that are meant for remote deployment to harsh environments.

Remember this is military spending here, normal sensible economics no longer apply. Remember the special air-conditioned hangers for Stealth aircraft?

A lot of incidental damage could be prevented by shipping any weapons in a protective sheath that could be removed when the weapon is either ready to fire or installed on the plane. Doesn't the cruise missile already come in a sealed cannister?

But if anyone is interested I'm planning on putting a bid in to develop nanotechnology mirrors. I've no idea how they would work, or if they're even possible, but they sound really cool. Going on yesterday's story about nanotechnology, I have about as much of a clue as real military researchers.

I think I'm up to squandering a couple of billion USD before unveiling a can of silver spray paint.

Best wishes,
Mike.

Get out the Popcorn

[Ececheira]

Anyone ready to blow up a house from too much popcorn? :)

Is it just me...

[danro]

Defense Secretary Donald Rumsfeld "is hot on ... the notion of zapping people,"

Is it just me, or does this make someone else worried.
That man is kind of scary...

Re:Is it just me...

[BabyDave]

I was scared from the moment I read

Donald Rumsfeld "is hot"

Re:Is it just me...

[Znork]

He's also a complete moron. The next sentance:

"Lasers are in line with Rumsfeld's idea of transforming the military, which is to come up with wonder-weapons that other countries can't emulate."

Uh, yeah. Guerillas, the Taliban, etc all have these huge stinger factories and AK factories, because they're really actually making them themselves.

Riiiight.

Just like everything else it'll take a year or two and then it's out on the weapons market and in five years more people like Saddam and the Taliban have laser batteries slicing and dicing US bombers into teeny weeny metal squares.

Other countries dont emulate weapons. They buy them, steal them, smuggle them or are given them. One thinks that a defense secretary would know this, but apparently learning requires actually having a brain. Maybe he can buy one on the black market.

Re:Is it just me...

[T5]

First off, understand that we're reading quotes from John Pike. A little Googling will clearly reveal his politics to be somewhat at odds with the current administration. However, for Pike to admit that these solid-state lasers are moving
into the "engineering" phase (second phase of weapons development - research, engineering, and production) is quite revealing. For him to acknowledge publically any high-tech weaponry as making significant advances is, to me, quite shocking.

Also understand that the arms race, which has existed throughout human history, is exactly that: a contest to see who can come up with the most effective weaponry the quickest. In this era of asymmetric warfare, nukes are useless. We've got a rapidly growing asymmetrical threat against which our current best practices and tools are less than ideal. New weapons and tactics are needed to counter such a threat.

As to the open market availability of weapons for terrorists, sure, there's scuds (pun intended) available. As long as there are countries such as Russia and China producing cheap, reliable low-tech weapons, and other countries willing to act as brokers for these groups, there will be a channel. This, however, is a poor argument against transformation of our armed forces to respond to such threats, including development of new weapons that give our military another advantage. And, given the technical sophistication of the level of some of these new weapons systems being developed, it'll be years before opposing forces can produce clones in sufficient quantity to be worrisome. Case in point: look how long it's taken many countries to become nuclear capable. That technology is nearly 60 years old! Lasers have been around since 1954 (microwave, 1960 for an optical laser) and we still haven't been able to weaponize them to any significant degree. And much of laser theory and practice is in the open press, unlike many aspects of the nuclear weapons programs.

Re:Is it just me...

[BurritoWarrior]

Don't forget how much damage the Taliban did with their M1-A1 tanks, Stealth Fighters, Cruise Missiles, smart bombs and Aegis cruisers.

Yep, technological superiority on the battlefield is moot.

Re:Is it just me...

[n-baxley]

Sooooo... You're basing your assumption of Rumsfeld's inteligence as a military planner not on something he himself said, but on a qoute from some guy who obviously doesn't like Rumsfeld?

Riiiight.

Sheesh

E = mc?

[Cutie Pi]

"The technology turns atomic particles into light with enough radiation to damage an object it encounters."

Umm... anyone know how that is supposed to happen?

But seriously, I'm sick and tired of science related articles being written by journalists with no clue about the science they're writing about. These articles should be checked for accuracy by the people the story is about.

I can imagine.....

[Chardish]

The warning labels on the outsides of laser weapons:

CAUTION: DO NOT STARE DIRECTLY INTO LENS

-Evan

targeting system?

[sczimme]

A Navy ship could use the laser, with its beam traveling at the speed of light, to fend off even the fastest missiles. And ground troops could use a Humvee-mounted version of the weapon to instantly knock out incoming enemy artillery and mortar shells.

I would like to know how such a weapon will acquire/track/target an incoming projectile. (That was not sarcasm; I really would like to know.) Mortar rounds generally travel in a high parabolic path - think of the St. Louis arch. Larger artillery shells - such as those fired from a battleship - follow a flatter trajectory. The targeting system would have to acquire a small incoming object, predict the path it will follow, and fire within a few seconds. That looks like a daunting task.

Re:targeting system?

[FeloniousPunk]

The answer to your question is called AN/TPQ-36 and AN/TPQ-37 "Firefinder" target acquisition radars. We've had them for 20 years - the -36 is designed to track mortar shells and the -37 other types of artillery (though IIRC, the -37 has all the functionality of the -36).
They are very effective. They calculate the location of the firing tubes, and that information is passed to artillery units tasked to provide counterbattery fire (usually MLRS rocket artillery). This all happens very quickly - 30 seconds to a few minutes' time.

Re:targeting system?

[Unipuma]

The advantage of a laser system is that you do not need to calculate the trajectory. Since you are firing at the object with the speed of light, the object will be (almost) in the same location from the moment you fire till the moment the beam hits.

Re:targeting system?

[mikewas]

A daunting task, but one that has been solved by systems such as Aegis. Presently, systems must track an incoming threat which may either be an umguided weapon traveling in an arc such as a mortar round, a guided but unpowered weapon such as a bomb that uses fins to alter it's ground course as it drops, or a powerred guided weapon such as a missile which can turn in any direction at any time.

Present systems not only have to aquire the target, catagorize the target, determine the best weapon to use in response. Then there's the same problem with the weapon you use to retaliate -- it also doesn't travel in a straight line so you must compensate not only for the threat's non-straight-line behaviour but also your own countering weapon's non-straight-line behaviour.

Is you use the LASER, the second half of the problem goes away!

BTW: Aegis solves the problem in a manner that is elegent or brute force, depending on your point of view. It uses an electronically steered RADAR to track incoming targets, shoot a gattling gun in the direction of the target, then tracks both the incoming target & the outgoing rounds, uses this data to modify the direction the guns are pointed. Elegent in the simplicity of its concept, brute force due to the fact it applies massive processing power to allow it to track an enormous number of targets.

Re:targeting system?

[sql*kitten]

I would like to know how such a weapon will acquire/track/target an incoming projectile. (That was not sarcasm; I really would like to know.) Mortar rounds generally travel in a high parabolic path - think of the St. Louis arch. Larger artillery shells - such as those fired from a battleship - follow a flatter trajectory. The targeting system would have to acquire a small incoming object, predict the path it will follow, and fire within a few seconds. That looks like a daunting task.

It's a solved problem. The Sea Wolf point defence system can shoot down 4.5-inch shells as well as supersonic missiles. Sea Wolf was first deployed in combat in 1982. Of course, you are likely to run out of missiles before they run out of cannon ammo, but maybe you can buy enough time to hit them with an Exocet.

Warships are expensive, so a lot of money has been spent on ways to protect them!

Re:targeting system?

[bheilig]

You're right. I used to work on the AEGIS weapon system's SPY radar. Once a projectile is completely ballistic it's trajectory is easily predictable. It's more difficult to determine the trajectory of a missile that is still burning fuel. In this case the radar must determine the type of missile.

In AEGIS we would fire an interceptor missile at a threat. The interceptor has mid-course guidance capability with a window of opportunity, so you can't fire the thing in the wrong direction and expect it to still hit the target. Therefore, your predictions must be highly accurate, accounting for wind, earth coriolis (the earth is moving underneath the projectiles), non-constant heterogenous gravity (weaker as the projectiles move further away from the earth, not in a straight line, and different for different parts of the earth).

The equation for filtering in this case is quite a mess. I'd imagine predicting for a laser is much easier because your interceptor is much faster, more stearable, etc.

If you're really interested in how it works, get a book on the Kalman filter. By the way, this technique is also useful in enemy AI development for games!

Re:targeting system?

[quick_dry_3]

as a few others have posted in regards to the shipboard Aegis systems currently in use - basically a fast tracker and a gatling gun - here is the method used by the ABL.

Sensors detect a target (e.g. infra-red senssors pick up exhaust plumes or radar picks up missile)

Kilowatt class Active Ranger System laser acquires and tracks target.
Tracking data goes to the Tracker Illuminator Laser, which locks onto the missiles body and determines the best position to hit the missile.

A third laser the Beacon illuminator bounces light of the laser to determine atmospheric interference.

Interference data allows the optics to be altered to 'correct' the COIL's beam so it is properly focused when it arrives on target.

Then the COIL (Chemical Oxygen Iodine Laser) fires, and hopefully burns a hole in the target. Destroying it ouright, disabling it, or blowing its fuel tanks.

Re:targeting system?

[Jester99]

The US Navy already has something like this in the form of giant guns mounted on some of its ships called "Phalanx" units. The thing fires thousands of bullets per minute, and it's all computer controlled. The purpose of this weapon is to track essentially anything that gets too close to the ship, and blow it to kingdom come. Missiles, planes, etc, are all valid targets. And it works, too.

More info is available. If you poke around online, you can also see some sweet movies of the thing. It just turns, tracks for a second, unleashes a wall of lead, then returns to the 'ready' position like it wasn't a big deal.

War is a daunting task. Fortunately, we've got some relatively clever folks thinking things like this up! :)

Re:targeting system?

[glesga_kiss]

They are extremely cool to see in action, of course.

Provided you aren't relying on them to down a real inbound threat!

Wavelength?

[Cutie Pi]

Does anyone know what wavelength these lasers are operating at? The article mentions that the lasers have a hard time piercing through clouds. It seems to me that an infrared laser would be more effective at piercing clouds than a visible one. Infrared solid-state laser technology definitely exists (the laser used in green laser pointers is in fact a 1064nm IR laser diode that is frequency doubled to 532nm).

Soon (wrings hands)

[velcrokitty]

I'll be able to walk into a store and ask for: "Phased plasma rifle in 40-watt range. "

Excellent... Oh wait. 40-watts isn't very much. Is that what the Terminator really asked for? 40 watts? Sheesh. I could just hook up a light bulb and start shining bright lights in people's eyes. Perhaps the idea is to convince them to stare into the bulb for hours on end (like several of my classes that I attended) and eventually go blind-ish...

I will be back...

Re:Soon (wrings hands)

[JKR]

A 40W laser could weld steel plate - it all depends on the beam spot size. Think about it - a 10 mW laser pointer isn't eye safe; a 40 W laser focused to a 2 mm spot would burn a hole straight through the eyeball and out the other side.

Jon.

Re:Tactically Flawed

[FeloniousPunk]

Military lasers do not lase in the visible spectrum; you're not going to see the beam. And they would fire a pulse of energy lasting only a fraction of a second.
If the target had a laser sensor, it could figure out where the fire is coming from, but I suspect the target is going to be having other concerns once it receives the laser pulse.

I'm torn...

[SquierStrat]

As someone who might one day fly the JSF (I'm trying to become a Marine Aviator...I have one of my first interviews next week *crosses fingers*) I'm kind of torn on this whole idea of a laser. The geek in me says that's too kewl! It's like Star Wars or something!

But then there is that overly logical Marine in me that says sounds unreliably. Much rather have a tried and true missile. This is is going to be very interesting to see when it actually goes into service how well it performs and is used. I could see this project either changing the way the military develops and uses weapons, or eliminating the whole idea for at least 50 years.

Re:I'm torn...

[sql*kitten]

But then there is that overly logical Marine in me that says sounds unreliably. Much rather have a tried and true missile.

I've no doubt that the first laser weapons will be pretty poor. But back in the 50s there were probably overly logical Marines just like you saying they'd rather have a tried-and-true machine gun fitted to their planes. Once a concept has been proved to work, the military have a history of being quickly able to turn it into something practical.

Re:Ob Austin Powers

[quick_dry_3]

The October edition of Aerospace International journal touches on this problem.

Yes, Geneva Convention bans blinding weapons (what party poopers), but accepts that combatants may be blinded as a side-effect of the use of a normal weapon.

So, while you can blind someone with it (e.g. a pilot) at a much longer range than the range you could destroy missiles/planes/etc, once you are within that lethal range blindeness created by the weapon would be a side-effect, not the main effect.

Bit of a grey area.

The problem with mirrors...

[caldaan]

Would be finding one that woulnd't be instantly vaporized when touched by a laser of that magnitude. Certainly paint isn't going to work as it would instantly oxidize and loose all reflective properties. Polished metals might help but they too would loose structural integrity. The mirror would have to be close to if not 100 percent reflecive of all the radiation being pointed at it and remain so for the duration of the attack. As far as using smoke cloud around missles as protection, they too need to see for guidance purposes, plus it would be almost impossibly to keep a leading smoke edge on something moving that quickly as the drag on the particles would loose the impulse of the rocket engine as soon as they were ejected, leaving the rocket exposed.

Re:Tactically Flawed

[quick_dry_3]

From October edition of Aerospace Internation journal (strange this gets posted just after i'd finished reading this article)

"beam is expected to take anywhere from five to ten seconds to burn through the casing"

That was from an article about the ABL mounted on a 747.

But as you said, if you're getting hit with a megawatt laser beam, you've got bigger problems than finding out where it came from.

And when that something firing is the size of a 747, finding it probably isn't such a huge problem.

Power source Re:Not a feasible weapon

[YrWrstNtmr]

Well, gee...I guess if you can power a laser pointer strong enough to blind you with a couple of AAA batteries, a 747 or Navy destroyer can supply enough power to run a laser strong enough to affect an incoming missile.

Re:Not a feasible weapon

[Phosphor3k]

A 15 watt Argon Ion laser will punch holes in aluminum cans. It will also cause severe burns to peolple and go through clothes like mad.

Re:Interesting, but is it legal?

[jandrese]

I certainly hope not. Almost all of our smart bombs these days are laser guided. That provision wouldn't make sense anyway. Laser guided weapons tend to be much more accurate than their dumb counterparts (you can't radar or IR guide a bomb on cold ground building), so they tend to reduce civilian casualties by letting the military only blow up military targets. The system isn't perfect (especially when armies hide behind their civilians), but it's certainly a lot better than carpet bombing.

Re:Unlimited use in battle!

[sql*kitten]

This would be the first weapon mounted on aircraft/heavy machinery that the pilot/operator wouldn't have to worry about running out of ammo in combat! That's a pretty serious advantage, no matter what other shortcomings the weapon may have.

Assuming he has an infinite energy source on board too, of course. Otherwise firing the weapon will decrease range/endurance by increasing fuel consumption. Currently the opposite it true, because it reduces weight.

Re:Asteroids

[jandrese]

Ah, yes, I can see it now. A large (Texas sized) asteroid is headed for Earth. Our satellite laser system springs into action, burning small holes and heating up the asteroid a fraction of a degree before it slams into Earth. Lasers work on missiles because they have gobs of explosive and fiddly electronics packed in a small space, whereas an asteroid is a big dumb rock that doesn't care if it's 1% less massive when it hits the Earth.

Re:Not a feasible weapon

[Idarubicin]

Lasers work by creating an inversion of atoms into an excited state and then releasing that exciting energy in a burst. But exciting the atoms obviously takes energy and, by E=mc^2, it takes a LOT. Industrial and scientific lasers can manage this by being plugged in to a dedicated power supply capable of delivering the gigawattage required for even small lasers, but a soldier in the field clearly doesn't have the luxury of an outlet needed to power his weapon.

Okay, I'll bite. Where does E=mc^2 come into this? I've worked with lasers for a number of years, and I have yet to see any of my lasing medium converted directly to energy. Lasers operate by kicking atoms into an excited state (usually an excited electronic state) and then emitting light when excited atoms relax back to ground state.

For the record, small lasers don't require "gigawattage" to operate. I have a laser pointer that runs on one AA battery--I'll be giving a talk using it in a couple of hours. A laser designed for a weapons application would be larger. Still, I could assemble a carbon dioxide laser that could start fires from several hundred feet away and still be light enough to carry--and operate for a while on a moderately hefty battery back.

Granted, I couldn't destroy missiles with it, but the article discussses lasers that are mounted on aircraft or vehicles, or are part of fixed installations. You don't need a large power supply for even an extremely powerful laser if it only fires the very short pulses (microseconds or nanoseconds) that would be most useful for military purposes.

Not Just Lasers

[dscottj]

What is not reported here, but has been mentioned in Aviation Week and Space Technology, is Israel seems to have already fielded a chem-based laser missle defense system, apparently deployed on the Syrian border (at least that's where it was last reported anyway).

Another thing not widely covered in the normal monkey media: Gulf War II will almost certainly premiere our new "directed energy" weapon systems which have quietly been brought out of the labs over the past year or so. From the (admittedly basic) descriptions given to the non-monkey press by those in the know, the systems work with microwaves to zap electronic gear. They're mounted on precision guided bodies (not bombs per-se, but probably shaped a lot like them) and are one-shot items.

The idea is superpowerful microwave radiation can fry anything with transistors in it, even stuff buried deep underground. These things deliver a burst of microwaves that fry things within a (classified) limited range. It's not clear if they can be directed or if it goes off in a sphere like a ghostly bomb.

The reason they aren't already mounting these things on F-16s and just pressing buttons is a) the range is really short right now and b) they aren't directional enough yet and would end up frying the electronics of the shooter, which would be annoying to the pilot.

Re:Tactically Flawed

[sql*kitten]

The big disadvantage to large laser weapons is that they give away their precise position since laser beams travel in perfectly straight lines.

You might think so, but tracer ammo has been around since WW2 and it's still in use today. That suggests that being able to locate a weapon that is firing at you while it is firing isn't as big a tactical advantage as it might first appear.

Re:Just for your information

[KFury]

"A kilowatt is 3,600,000 joules, 10 kilowatts in respect is 36,000,000."

What are you talking about? A kilowatt is a measure of power, and a joule is a measure of energy. The two are not directly comparable without a time factor thrown in. Do you mean a kilowatt hour is 3,600,000 joules?

By your calculation, lightning is 280-2,800 kilowatts (0.3-2.8 megawatts). As we all know, lighting is more in the range of 1.21 gigawatts (humor intended, but general priniciple remains the same). It's not like lightning strikes last for an hour.

------
"To put this in prespective, the adverage person uses 64,800,000 joules a month, or 18 kilowatts... So for every time they fire this baby, they are blowing 50-100 bucks....

They essentially are what cause the blackouts in California."

What the fuck are you talking about? This causes the blackouts in California, not some sergeant flipping the switch on $100 of electricity.

Civilians lose

[G. W. Bush Junior]

the article states:
With such lasers, a fighter jet could destroy ground targets with pinpoint accuracy, significantly reducing the chance of injuring civilians.

uhmmm... no!
The problem with lasers is, that once they hit something the beam will reflected beam/beam fragments will be able to blind people in a LARGE area (as in a radius of several miles) around the target...
Soldiers will be able to wear protective gear...
Civilians probably won't...
Civilians lose...

If anyone has ever worked with really powerful laser you'll will know how strict the safety regulations are... and you'll know how difficult it is to find all the reflections from an experimental setup.

Re:Interesting, but is it legal?

[cduffy]

Anti-personnel lasers are illegal -- not laser-guided weapons or weapons meant to be deployed against shells, missiles, aircraft or what-have-you.

Forget Stealth technology then...

[glesga_kiss]

If you build your aircraft/missle out of reflective materials to counteract lasers, your going to make it a large target for radar.

Stealth material generally works by absorbing the energy. The two defences won't be able to co-exist.

Re:Forget Stealth technology then...

[Helter]

They won't have to... Think about how a stealth aircrafts defenses work. They don't defeat a missiles blast, they defeat the tracking mechanism that controls the missile.

A laser weapon would STILL have to be targetted somehow. If the radar array can't see the aircraft the laser can't track/destroy it.

Re:Forget Stealth technology then...

[xtheunknown]

Actually, you're both right. The F-117 works both ways. It both reflects radar at odd angles and attenuates the signal by absorbing (hence a weaker return signal) radar.

F-117's are not invisible to radar, they just appear very small, approximately the size of a sparrow, and are usually over-looked by the radar technician as being natural phenomenom.

Also, they have IR emission reducing capabilities too.

The first comment was right. Defeating laser and radar are contradictory goals.

-- Admit nothing, deny everything, and make counter-accusations.
Naval Intelligence Motto

Geneva convention

[kin_korn_karn]

Wonder what the Geneva Convention will be modified to say about this.

Spinning

[ek_adam]

You could spin the missile to reduce spot heating, but that's going to complicate guidance considerably.

Some missiles spin anyway. The Sidewinder missile was intentionally slightly unstable and spun so that it flew in a spiral. Its seeker had one degree of control, up-down relative to the center of the spiral. When the heat source it was looking at was near the center of the spiral, the spiral would narrow down towards the target. When the heat source was not near the center of the spiral, the spiral would broaden out in a cone until it reacquired the heat source. Fairly early in its development a filter was added so that it would ignore anything with the precise infrared signature of the sun.

Next Gen & Counter

[limekiller4]

From the article:
"A Navy ship could use the laser, with its beam traveling at the speed of light, to fend off even the fastest missiles. And ground troops could use a Humvee-mounted version of the weapon to instantly knock out incoming enemy artillery and mortar shells. "

This is, of course, an arms race. So what happens when they're not firing missles anymore, but lasers?

I'm not suggesting it's a bad idea. I'd just love to see what protection they'll propose when our opponents get up-to-speed. I also have to wonder if there is a low-tech way of defeating it (remember when we spent millions coming up with a pen that would write in zero-G and the Russians just used pencils?)...

Re:Next Gen & Counter

[Guppy]

(remember when we spent millions coming up with a pen that would write in zero-G and the Russians just used pencils?)...

There's a page for this on the Urban Legends Reference Page.

Apparently, there are a number of problems with pencils, including the flammability of wood/graphite in the pure oxygen atmospheres that were used at that time, and that conductive graphite dust could drift into electronics and cause a short.

Re:Next Gen & Counter

[Stonehand]

(*) Do you really think they'll stop firing missiles? Most countries likely to antagonize somebody with effective, field-capable lasers (large powers) are probably bothering somebody likely to remain without them (especially in the case of the US, whose forces are often deployed into an existing conflict)... so missiles won't be obsolete.

(*) There are conflicts today where old weapons -- even as old as spears and machetes -- are side-by-side with moderately old weapons (AK-47s, for instance... and the explosive grenade goes back at least to the late 1700's, as primitive explosive-charges were thrown to detonate the powder magazines in ships... and the general concept of the gunpowder firearm goes back to the late Middle Ages; RPG-7s) and where more modern weapon systems (vehicles with reactive armor, laser-guided missiles, Phalanx CIWS) are practically non-existent.

Hell, have you ever seen a Palestinian fire an automatic rifle -- perhaps a Kalashnikov or a captured Galil or M16 -- at an Israeli Merkava, when the latter is buttoned up? It's futile, as the bullets have neglible chance of finding a spot penetrable by the small rounds (/maybe/ the vision block), but that doesn't mean that they've ditched their rifles and are now swimming in RPGs.

Weapons cost time (training), money (lots), contacts (need to find somebody who'll sell... for an example of a client with problems, I doubt that the radical Islamists can readily buy modern weapon systems from the US, Russia, China, or Israeli as they are all involved in ongoing conflicts with their brethren... well, maybe they can go to France. *shrug*)

The last major weapon system concept to be completely obsoleted was probably the battleship, which yielded to the aircraft carrier battlegroup, and even now there are still gun-armed ships meant for surface engagements, I'm sure.

(*) Remember when Snopes debunked the "NASA Space Pen" nonsense"?

And inclement weather...

[gillbates]

Lasers do have one big drawback. The beam is not very effective in inclement weather and requires greater levels of energy to pierce thick clouds.

I am not a physicist, but I believe that even the infrared laser beams would be scattered by rain or fog droplets, making a laser practically useless under such situations. Since the power of lasers as weapons is dependent on all of the light waves traveling in phase and in the same direction, something as simple as a drop of water could scatter laser light in all different directions, disrupting the beam and rendering it tactically useless.

Simple fix

[FreeUser]

if you hit a mirror with a powerful enough beam of laser light, the small fraction of light that's absorbed (no such thing as an ideal reflector) will rapidly ablate the mirror coat, and then you're screwed. [...] a 100KW IR laser will vaporize pretty much anything that's not *perfectly* reflective, i.e. anything we can build with current technology.

So you make your mirror subsystem disposable, and eject the spent mirrors like shells. Assuming you can get the desired result before or during the ablative process, you've got one shot, one mirror. We're used to such constraints with bullets and shell casings, and some disposable, portable ground-to-air missile systems, why not with mirrors?

Re:gimme war

[Stonehand]

The simplest way to invite war is to not be prepared for it -- either in terms of actual power, or psychological capability.

One of the reasons why the Great Powers were able to roundly abuse other nations is that they /had/ the power. Militarily weak nations have, historically, been treated as such...

And when nations, in the name of international law and peace, turn the other cheek to an aggressor when those same laws are abused, the results are generally obvious -- the aggression continues. Condemnations have never practically stopped a massacre, nor have battalions been routed by a tongue-lashing, while negotiations fail when there is genuinely nothing to discuss because there is nothing of perceived satisfactory mutual benefit regarding an issue.

Mildly Shocked no one has put these up

[anzha]

A bit of Karma whoring here, wish I'd gotten online sooner so that people would see this much earlier:

TheHigh Energy Laser Systems Test Facility (so-called HELSTF). Let's see if Tom's webserver can survive this...This is the laser test facility for the army and navy at White Sands Missile Range. They've got the world's most powerful laser (MIRACL: Mid Infrared Advanced Chemical Laser) there.

Being developed for them, by Livermore by the same guys that are doing the National Ignition Facility is a solid state laser. It works.

Also at HELSTF, and the first functional laser weapon, is Tactical High Energy Laser (aka THEL, and I hate that URL, btw...)

Search TRW for more stuff on lasers as well as Lockmart and Boeing, of course.

Re:giggles (from the article) and a question

[Dyolf Knip]

Silver-coated mirrors are able to to reflect 99.92% of the light

Outside of space telescopes and cleanroom labs, have you ever seen a 99.92% reflective mirror _stay_ that way? A smudge of oil on the surface would vaporize instantly, heating the mirror up and deforming it slightly. This causes the mirror to not be quite so reflective, so it absorbs even more heat, etc, etc.

Fortunately for the US military, the only practical defense to a laser would be something that could instantly conduct the heat the laser generates around the rest of the vehicle; the parts not being fired at become a giant heatsink. I don't know if electrical superconductors are also heat superconductors, but either way, such a material is much further away on the horizon than high-power solid state lasers.

Re:gimme war

[circletimessquare]

you demonstrate disdain for an aspect of human nature. unfortunately, no matter how disgusting this aspect of human nature that is war, it does not make that danger go away. discussing war is not supporting war, it is merely recognizing that war can and might happen. are there assholes out there who enjoy war? certainly. but the vast majority of people recognize war as an unfortunate aspect of human nature, and prepare for it, even though they don't like it. why are you criticizing them? if you meet a real asshole who loves waging war for the sadistic love of anarchy, verbally bitch slap the sadistic grin off his face. in the meantime, learn a little more about human nature before you start heaping your disdain upon slashdot.

the do-nothing attitude about war that you demonstrate leads to disgraceful events in history like hitler's gambit for the sudetenland before world war ii. if you don't know what i am talking about, do some googling and learn what an avoidance of war really means: just creating the conditions for an even greater, deadlier war at a later time. you can't push war away and hope it will go away. if you push war away, it simply festers and the conditions for it grow worse until it finally does punch through and there is no avoiding it at all. you have to face war when you recognize it, deal with it, and move on. you can't avoid it. nobody likes this, but you can't hold it against them for recognizing reality for what it is. don't shoot the messenger just because you don't like the message.

if some person or country aggressively approaches you with war on their mind, you cannot save yourself by capitulating to their every demand. nor is a "let's hold hands and sing campfire songs" attitude going to change the attitude of some very evil people in this world. you have to defend yourself from them or you actually encourage them to be more aggressive if they get the idea you will not oppose them with force, if necessary. do i like this? no. but not liking it doesn't make this obvious truth go away. that's just reality. face it.

there is nothing wrong making jokes about war either. humans make jokes about all sorts of bad things, like priests abusing boys, that are just plain evil, but serve to psychologically relieve our nervousness. more basic psychological human nature for you to try and understand.

by the way, your obvious arrogance is perhaps a more dangerous aspect of human nature than any discussion of war on slashdot could ever be. more evil flows from human arrogance, that you seem to have gallons of, than perhaps any other human failing. there are wonderful, accurate, logical, straightforward arguments against war to be had out there, but your arrogance demonstrates none of that, and your mean-spirited words only serve to reduce the power of those who argue rationally against war.

your meanness is just mental masturbation, making you feel better about yourself at the expense of other people's respect for you. by talking about "the average cow grazing in Wal-mart" you reveal a hatred for the common person on the street. i have 1,000 pounds more faith in those "cows grazing at walmart" to make the right decisions about life and liberty than i do in an obviously mean-spirited, common-person hating, arrogant and smug person such as yourself. think about that before criticizing what you see as "warmongers."

look at your own evil before criticizing the perceived evil in others. arrogance such as yours has spawned more useless horrible wars than anything else has. you have blind self-love that leads you to treat others arrogantly. news flash: sunlight does not shine out of your butt. you are only human too. your arrogance puts you far closer to the human evil that spawns war than a thousand austin power jokes and bin laden ass-kicking tirades ever could.

that's my rant for the day. ;-P

Why no laser sniper rifles?

[Galvatron]

Okay, question: why don't SWAT teams and the like have laser sniper rifles? Sure, they'd be bulky, and require external power supplies. Sure, you'd have to make sure they fire OUTSIDE the visual spectrum to prevent blindness. But, for a hostage standoff sitation, where you've got hours to get your people into place, wouldn't having a weapon that would be 100% accurate by virtue of traveling at the speed of light, unaffected by gravity or air currents, be really useful?

Re:What good would Anti_Missle system

[Stonehand]

Retalliation and deterrence theory

(1) Only works when everybody with sufficient access in the entire WMD system is rational. This is increasingly questionable; for an example, consider North Korea, which appears to prefer being able to hit the continental United States with a nuclear weapon (they have missiles with sufficient range, although accuracy has been questioned) to, say, being able to feed their people.

(2) Ignores the possibilities of accidental launches and launch systems which would have unclear authorship. For instance, it may be unclear who just launched an ICBM if it came from the middle of an ocean...

America is screwing up

[Mittermeyer]

We need to let this tech linger in the background for a good long while. Rumsfeld is wrong, other countries will steal this tech and duplicate it within a few short years (see Russia and A-/H-bombs). Then we will not be able to do airpower projection, and our ICBM nuclear threat may soon ring hollow because if you can mount it on a plane you can mount it on an AA vehicle and put more juice on the ground vehicle then the airplane.

Like Britain creating HMS Dreadnaught, this technology will be the seeds of our strategic decline.