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Iranian fliers pose a deadly indirect threat to U.S. warships in the Persian Gulf

Conventional ballistic projectile weapons are cheap and good at taking out larger targets. However, they rely on line of sight, run the risk of friendly fire, and have difficulty hitting smaller, fast-moving targets like unmanned aerial vehicles (UAVs).  Guided missiles are good for attacking targets outside the line of site; but while they certainly could be effective against small targets, the cost of doing so is awfully wasteful (you're spending anywhere from hundreds of thousands to millions of dollars to eliminate a target worth a thousand dollars or less).

Lasers, while suffering the same line of sight limitations as projectiles, eliminate the friendly fire risk and are faster, travelling at the speed of light in the medium.  That speed in theory should allow them to successfully (and affordably) shoot down enemy UAVs.

I. Meet the Navy's New Laser Weapon, LaWS

After successful demonstrations of UAV shootdowns by the U.S. Air Force and U.S. Navy, the Navy looks to put laser systems to the test in the real worldinstalling a laser defense system on the U.S.S. Ponce.  The U.S.S. Ponce is an amphibious transport dock class vessel used in joint land-sea operations with the U.S. Marines.  The vessel was originally commissioned in 1971, built by Lockheed's Lockheed Shipbuilding unit (which closed prior to Lockheed's merger to become Lockheed Martin Corp. (LMT)).

The selected laser weapon will be the Laser Weapon System (LaWS), a laser autoturret made by Raytheon Comp. (RTN).  LaWS is essentially a drop-in upgrade/replacement to the projectile based MK 15 Close In Weapon System (CIWS), a.k.a. the Phalanx gun, a radar-guided autocannon.


The LaWS system will be fully operation by Summer 2014, and will be tasked with protecting U.S. ships in the 5th fleet region (which includes the Persian Gulf). 

The high-power infrared laser onboard the most recent model operates at 33 kilowatts and consists of 6 separate solid-state lasers focused on the target.  A Navy official tells Fox News, "It operates much like a blowtorch ... with an unlimited magazine."

LaWS (1 of 2)
The LaWS system is seen here during a temporary installation on the U.S.S. San Diego missile destroyer. [Image Source: Navy/John Williams]

While the initial investment costs have been relatively high, LaWS could save the Navy a lot of money in the long run.  The system cost around $32M USD to make, and will reportedly have initial per-unit costs of around $17M USD, according to Ronald O'Rourke's Congressional Research Service report [PDF].

LaWS (2 of 2)
[Image Source: Navy/John Williams]

However, the cost to fire the laser is only around $1 per shot.  Chief of Naval Research Rear Adm. Matthew Klunder comments, "Compare that to the hundreds of thousands of dollars it costs to fire a missile, and you can begin to see the merits of this capability."

II. Iran Has Been Spying on U.S. Warship With UAVs for Nearly a Decade

The unofficial goal of the LaWS deployment, ostensibly will be to shoot down pesky fliers from Iran which have been videotaping U.S. ships in the Persian Gulf and Strait of Hormuz in recent years.

While Iran is developing larger weaponized UAV warplanes/bombers, a more immediate concern for the U.S. Navy is small, cheap UAVs which Iran may be using to target American warships.

The first reported UAV flyover occurred in early 2006, and was conducted by an Iranian Ghods Ababil ("swallow") UAV flying over the U.S.S. Ronald Reagan aircraft carrier.  Since the 2006 flyover, multiple UAV flyovers have been detected.  Iran has even released a propaganda video containing UAV footage it filmed over a U.S. carrier:


The Ababil flyer is a propeller-driven design similar to the U.S.'s RQ-7 Shadow (AAI Corp.) or ScanEagle (The Boeing Comp. (BA)).  Like the RQ-7 and ScanEagle, the Ababil launches via a pneumatic catapult, typically mounted in a truck bed.

Ghods Ababil
The Ghods Ababil ("swallow") UAV [Image Source: FARS]

Intelligence indicates that dependent on communications capabilities, the Ababil has a range of 150 km (93 mi) (or 240 km (150 mi) in newer models) and a maximum ceiling of 14,000 ft (4,268 m).  About 2.9 m (9.5 feet) long (shorter than a Volkswagen Beetle) and weighing 83 kg (182 lb.), it can carry a payload of approximately 45 kg (88 lb.) -- enough to haul the camera equipment necessary to spy on U.S. warships.

III. Iranian UAV Feeds Could Help Target U.S. Warships With Missile Strikes

The Iran Project organization suggests that the true goal of these missions is not mere surveillance.  It says that by imaging heat signatures and visual images from certain angles, the UAV could provide targeting information for Iran's anti-ship units in a war scenario.  Those units would use the information to target U.S. warships.

Currently Iran's anti-ship units use Khalij-e Fars (Persian Gulf) ballistic missiles, a derivative of the Fateh 110 missiles equipped with a thermal imaging guidance system.  Developed in 2011 these solid-fuel single-stage supersonic missiles travel at a cruising speed of Mach 3 and have a range of 300 km (186.4 mi).  Once in the generally vicinity of hot targets (e.g. warships), these missiles can home in on them and take them out, employing a 650 kg (0.72 ton) payload.

FARS
Iranian UAVs could provide targeting info to Iran's Khalij-e Fars anti-ship ballistic missiles
[Image Source: FARS]

The problem is that the U.S. knows about this capability and may deploy hot decoys during an actual conflict.  Additionally, certain U.S. warships possess air defense capabilities, which could be used to take down incoming ballistic missiles.

Using a database provided by floating UAVs, the Iran Project suggests that Iranian forces could avoid decoys and selectively target air defense vessels, overwhelming them at the start of a conflict.  Additional missiles could then be sent to take out the remaining non-decoy U.S. warships.

However, if you take out UAVs, you remove the ability to differentiate between ships and decoys, or between various kinds of ships.

IV. UAV Terminator

So far the U.S. laser system has been 12 for 12 in UAV shootdown tests, including sea-based tests, according to Raytheon and Navy's Office of Naval Research (ONR).  Those shootdowns include five UAVs destroyed in a May 2009 desert-setting test at the Naval Air Warfare Center in China Lake, California and four UAVs destroyed in a May 2010 test off the coast of San Nicholas Island in southern California.

LaWS shootdown
So far LaWS has killed a perfect 12 for 12 in UAV target tests. [Image Source: Raytheon]

Peter A. Morrision, program officer for ONR's Solid-State Laser Technology Maturation Program, is bullish on the prospect to use the technology to target real-life hostile fliers.  He remarks, "The future is here.  The solid-state laser is a big step forward to revolutionizing modern warfare with directed energy, just as gunpowder did in the era of knives and swords."

LaWS in action
LaWS in a 2010 live test shot down four UAVs at sea. [Image Source: Navy]

If all goes well, those real world shoot-downs could occur as early as in the middle of next year.

Sources: NPR, Congressional Research Service



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What about a mirror ?
By max_payne on 4/9/2013 8:22:08 PM , Rating: 2
Advise to Iranians ; build your UAVs with highly reflective materials, mirrors wrapped to deflect the beam. Better yet, use tracking mirrors to send back the laser to it's source.




RE: What about a mirror ?
By Wiggy Mcshades on 4/9/2013 8:51:27 PM , Rating: 2
This is actually the coolest part about this technology. The laser is so powerful that even if it hits a mirror that reflects 98% of the beam (no mirrors are 100% reflective), the 2% that doesn't get reflected will heat the mirror until it deforms and stops being reflective. The mirror is destroyed in a fraction of a second. The only defense that works is to use a material that is able to absorb massive amounts of heat, which generally are very heavy and expensive (so not really a good match for a uav).


RE: What about a mirror ?
By Solandri on 4/10/2013 3:21:35 AM , Rating: 2
Water absorbs a huge amount of energy as it evaporates. 2.26 megajoules per kg. So designing your UAV with a double hull with a layer of water in between, with a 1 liter reservoir would be enough to delay any damage from a 33 kW laser for over 1 minute.

And a return mirror is simply 3 facets at 90 degrees from each other (the inside of the corner of a cube). Many naturally-occurring crystals have this property. They're what makes reflective paint reflect your headlights back at you.


RE: What about a mirror ?
By Flunk on 4/10/2013 1:04:39 PM , Rating: 2
How will you get it to fly with all that extra weight? That is presuming all your other numbers are right.


RE: What about a mirror ?
By Motoman on 4/10/2013 6:05:51 PM , Rating: 4
Doesn't matter, the idea is pants.

1. Putting a liter of water in a jacket around your UAV probably means the depth of the water at any point is like a quarter inch.

2. Lasers are rather confined to a very tight area.

3. The laser will boil the 1/4" of water beneath the outer fuselage instantly, then melt the fuselage, then take down the UAV.

Even if somehow you managed not to do that, at the very least the pressure within the water jacket would skyrocket like crazy - in short order either blowing out of the outer fuselage, or blowing into the guts of the UAV - either way accomplishing the goal of destorying it.

Dumb idea all around.


RE: What about a mirror ?
By ShieTar on 4/10/2013 3:36:26 AM , Rating: 2
Really? 2% of 33 kW, so 660W, will destroy a metal mirror in seconds? At that point, we are talking about 5 times the power of direct sunlight. That will not melt any kind of metal within seconds.


RE: What about a mirror ?
By polarity on 4/10/2013 8:39:03 AM , Rating: 2
If 660W isn't enough to melt metal, then I guess my 12W soldering iron must be working by magic.


RE: What about a mirror ?
By WinstonSmith on 4/10/2013 9:33:39 AM , Rating: 2
If drones were made of 60% tin and 40% lead that would be a valid point. But they be a bit too heavy to fly.


RE: What about a mirror ?
By half_duplex on 4/10/13, Rating: -1
RE: What about a mirror ?
By tomx78 on 4/10/2013 10:25:53 AM , Rating: 5
Amazing, kids these days don’t even know that solder is a metal. Facepalm.


RE: What about a mirror ?
By 3DoubleD on 4/10/2013 11:15:00 AM , Rating: 5
660W is more than enough to melt the highest melting point metal, I can say that with 100% certainty.

What the previous poster failed to consider is the energy per unit area. If I focus 660W on a mm^2 area, then that is actually 660MW/m^2, which is about 660,000x stronger than the intensity of the sun.

Moreover, it is not very simple to build a 99.99% mirror (even a >98% mirror). Firstly, such mirrors are designed to work with a specific angle of incidence. Grossly deviating from this geometry will result in a very significant amount of absorption. Additionally, these mirrors are engineered PERFECTLY flat. I'm talking about 0.2-0.1 nm roughness. I don't think you can expect that kind of engineering on a cheap UAV, there will be seams and edges, scratches and dents.

Secondly, mirrors with such a high reflectivity are tuned to a wavelength window. The ship would merely need to have a second wavelength available outside this window. For example, if the red laser doesn't work, use the blue laser. Now it would double the cost of the laser, but since it is such an easy way to defeat an engineered reflective coating, it would probably deter the use of reflective coatings.

Thirdly, such laser mirrors are used in CLEAN environments. Dust on a mirror or lens under a 33kW laser can be catastrophic. Dust or dirt will absorb the laser light, burn, create a black mark on the mirror, and then the mirror will absorb and melt. The surface of the UAV would need to be pristine. Along the same lines, if the landing gear is visible, they could melt the tires - the resulting fire would coat the UAV in soot which would make even the most reflective surface vulnerable to the laser.

Finally, the UAV's camera is always vulnerable. Any filter that you place in front of the camera lens to block the laser would also block the video footage. Since you need far less power to damage a camera sensor compared with melting metal, you can employ a whole rainbow of cheap lasers for this task - so filtering the laser would be impossible.

So it would be very hard to defend against a high powered laser. If they can hold the laser on you, then you are probably toast. Your best shot is to overwhelm the targeting system, keeping the laser from being stationary on any one point of the drone. I think the strategy would be to build many small, cheap drones. When the drones locate a ship, they would need to be programmed to as fly chaotically as possible until they they have achieved their ship locating goal. Not an easy task, but flying straight and relying on reflectivity alone won't work. The video above shows the laser taking a few seconds to do its damage, so if the drones can spin, dive, barrel roll around for an extended amount of time, it might achieve it's goal. Of course the navy could always keep upgrading the power of the laser or add additional lasers...


RE: What about a mirror ?
By topkill on 4/10/2013 11:23:30 AM , Rating: 1
Yes, and I found (and cited) some experimental results in a post down below. The energy from this laser is MORE than enough to damage the UAV.

Also, judging by the fact that they are actually shooting them down in tests would indicate that all the arm chair quarterbacks are "kind of wong" when they say it can't be done. LOL


RE: What about a mirror ?
By BRB29 on 4/10/2013 11:36:24 AM , Rating: 2
Next, lasers to shoot down high speed jets. All they need is moar powah!!! and a better tracking system.


RE: What about a mirror ?
By 91TTZ on 4/10/2013 1:29:20 PM , Rating: 2
That would be against the Geneva convention.


RE: What about a mirror ?
By topkill on 4/10/2013 2:38:14 PM , Rating: 2
So is water boarding...what's your point?


RE: What about a mirror ?
By 91TTZ on 4/10/2013 3:47:59 PM , Rating: 2
Are you actually advocating that we break international laws that we've agreed to?

You might be able to pull that off against some nationless rebels, but if you pull that against a large country they could use that as an excuse to break the convention as well.


RE: What about a mirror ?
By BRB29 on 4/11/2013 9:19:36 AM , Rating: 2
Considering that the US funds about 95% of the UN and most of the coalition forces are US forces. I feel that all the other countries does is whine whine whine. We're actually being quite generous. So far, the only country that actually followed the the Geneva Convention is the US. Granted, there were a few bad eggs.


RE: What about a mirror ?
By Totally on 4/10/2013 11:37:33 PM , Rating: 2
Nope, I could see what you are getting at but laser don't have infinite range in an atmosphere, lasers don't break convention any more than a piece of artillery.
FYI, Genevea convention bars the use of 'technology whose scope of destruction cannot be limited."


RE: What about a mirror ?
By Adonlude on 4/11/2013 12:00:17 PM , Rating: 2
Actually, the convention only prohibits lasers whose primary purpose is to blind. Clearly this is not the case with this tech.


RE: What about a mirror ?
By 91TTZ on 4/10/2013 1:23:47 PM , Rating: 2
quote:
Yes, and I found (and cited) some experimental results in a post down below. The energy from this laser is MORE than enough to damage the UAV. Also, judging by the fact that they are actually shooting them down in tests would indicate that all the arm chair quarterbacks are "kind of wong" when they say it can't be done. LOL


This test was very favorable for the laser. It was a clear day, the drone was painted in a dark color, the lens on the laser wasn't coated with salt (pretty hard to maintain on a ship that's in the ocean), etc.

You'll never make the drone invulnerable but you can do a lot of really cheap things to make it more survivable.


RE: What about a mirror ?
By topkill on 4/10/13, Rating: 0
RE: What about a mirror ?
By 91TTZ on 4/10/2013 4:06:32 PM , Rating: 1
quote:
LMAO!!! Dude, you didn't even read the post! You're just saying things you think sound "sciency" or something.


You're getting emotional about a scientific argument and trying to sound like you're knowledgeable, but you clearly lack knowledge. Once in a while you're going to have to deal with people that are far more intelligent than you. This is one of those times.

I was respectful to you even though you simply didn't understand the math or the paper that you read, and I tried to point that out nicely.

quote:
was talking about a lab experiment and the actual, measured energy to melt polished aluminum (another person claimed polished aluminum would shield the UAV). And even assuming only 5% of the laser's energy was delivered to the target, it was still 2,500 times MORE energy than was needed.


No you did not. You tried to but you didn't understand what you were reading. You didn't understand the test they were performing and you didn't understand the results. I pointed it out to you but you ignored my post.

They were using a laser that was far more intense than the one in this Navy system. Instead of a 33 Kilowatt solid state laser your paper was showing the effects of a short pulse from a 200+ Megawatt Nd:YAG laser.

You're trying to sound intelligent, and while it may work for other people it won't work on me. Please continue replying so I can continue dismantling your intellect.


RE: What about a mirror ?
By topkill on 4/10/2013 10:35:22 PM , Rating: 1
Nice try jerk off, but here are your actual words:

quote:
This test was very favorable for the laser. It was a clear day, the drone was painted in a dark color, the lens on the laser wasn't coated with salt (pretty hard to maintain on a ship that's in the ocean), etc.


You were talking about a missile test and not a laboratory test. So now we know you're a LIAR.

Second: As for your "facts", you can't even read the damn paper correctly. The diameter of the laser was 240 micrometers, that was NOT the power of the laser. Geez, the paper is riddled to references of the melting point and the boiling point of various samples in ranges of between .5-15 J/CM^2 and you think they're using a 200MegaWatt laser? To do what? Shoot down a ballistic missile?

Here is a quote from a military paper about their early power targets on the laser used for shooting down ICBMs:

quote:
With the BIL operating the COIL laser is engaged and a multi-MegaWatt beam of 1.315 micron infrared radiation is put on to the target. In a viable engagement scenario, this would lead, within seconds, to the breakup of the target missile.
http://www.ausairpower.net/APA-DEW-HEL-Analysis.ht...

And yet you want to claim they're using a "200MW laser" to melt microscopic, SINGLE CRYSTAL, samples in a lab??? Are you even smart enough to be embarrassed by the shit you say??? It would vaporize that sample you ASSCLOWN.

You really are an assclown. Hell, I was halfway kidding before, but you really are an assclown.


RE: What about a mirror ?
By topkill on 4/11/2013 8:49:09 AM , Rating: 2
Ok, I see your other post down below where you did respond to the lab part. But you're mixing threads here and above in this thread you did refer to the drone shoot down.

But we're clearly miscommunicating on which thread we're debating. However, that was just a mix up so I do apologize for calling you a liar.

However, I still disagree with you on the results of the experiment. And I'll answer your post below regarding the J vs kW. I know the difference between energy vs power...note I said J/s and was "skipping ahead" mentally to figure out the total amount of heat energy put into the target for a few seconds while they had the laser on it.

Overall, I don't understand why you insist this can't be done. As you said, this is not your direct field and the guys who are doing it for a living did all the calculations and they've done sea trials, as well as desert trials and it has been working. If they didn't think 33kW was enough energy, it's not like they couldn't have made it 500kW or something. There is plenty of power available a large ship to do that, so clearly they have actual, real world data and tests saying that 33kW is the right size. Should it be 50kW or even 100kW to deal with rain, etc? Maybe. That's why they run the tests to find out.
But you keep making assertions like they're off by orders of magnitude or that they can't make it work as sea because of salt spray. It would seem that their test results so far don't support your assertion.


RE: What about a mirror ?
By 91TTZ on 4/11/2013 11:45:58 AM , Rating: 2
quote:
But we're clearly miscommunicating on which thread we're debating. However, that was just a mix up so I do apologize for calling you a liar.


I replied to your above post before reading this one. I don't like to argue on the internet but I do like to get my point across. I don't think I'm unrealistic.

quote:
And I'll answer your post below regarding the J vs kW. I know the difference between energy vs power...note I said J/s and was "skipping ahead" mentally to figure out the total amount of heat energy put into the target for a few seconds while they had the laser on it.


Sure, if you could have a pulsed laser work continuously at those power levels you'd vaporize the target. But pulsed lasers can't be run continuously, and even if they could they'd probably melt because the output is too high.

quote:
Overall, I don't understand why you insist this can't be done. As you said, this is not your direct field and the guys who are doing it for a living did all the calculations and they've done sea trials, as well as desert trials and it has been working. If they didn't think 33kW was enough energy, it's not like they couldn't have made it 500kW or something.


I'm not saying that it can't be done, I'm saying that there are countermeasures to mitigate it. The fact that a defense contractor is trying to deploy it shouldn't be taken as proof of practicality, though. They'll do anything for money, even push unpractical weapons.


RE: What about a mirror ?
By 91TTZ on 4/11/2013 11:23:58 AM , Rating: 1
quote:
Geez, the paper is riddled to references of the melting point and the boiling point of various samples in ranges of between .5-15 J/CM^2 and you think they're using a 200MegaWatt laser?


Yes, I think they're using a 200 Megawatt laser. I know you think that's ridiculous (since the laser on the ship is only 30KW) but that's because you don't understand the math or science here.

quote:
And yet you want to claim they're using a "200MW laser" to melt microscopic, SINGLE CRYSTAL, samples in a lab??? Are you even smart enough to be embarrassed by the shit you say??? It would vaporize that sample you ASSCLOWN.


You think I'm an assclown because I'm very technical and I understand the science here.

The material isn't a single crystal. But it is a 200MW laser. I know you think that's unrealistic because these weapons systems are a tiny fraction of that. But let me explain:

1. I showed you that Joules are a measure of work and not intensity
2. Joules divided by time would give you intensity
3. The paper you linked to gave us the Joules (2.3J in one test) and the time (10 nanoseconds)
4. 2.3 Joules in 10 ns would give you a power of 230 Megawatts.

Is my math wrong? Let's look at the laser they used and see what we can find. The paper says that they used a Q-switched Nd:YAG laser. A quick search on Wikipedia yields this:

In this Q-switched mode, output powers of 250 megawatts and pulse durations of 10 to 25 nanoseconds have been achieved

http://en.wikipedia.org/wiki/Nd:YAG_laser

Suddenly my claims seem to make sense, don't they?


RE: What about a mirror ?
By BRB29 on 4/10/2013 11:32:59 AM , Rating: 2
thanks for the thorough explanation.

The problem with flying a uav chaotically is overcoming inertia. Even then, I don't think you can avoid the laser. It looks like their targeting system can compensate the rough seas easily. With today's computing power and the laser's instant and direct impact, there's nothing you can do to avoid being shot.

I think the only real way to overcome these lasers is sending a ton of uavs. Most of them being decoys. These lasers takes a few seconds to burn one uav so it will take a few mins to get them all. By then, the uavs would already collect the information they need.


RE: What about a mirror ?
By 91TTZ on 4/10/2013 1:20:38 PM , Rating: 2
quote:
>660W is more than enough to melt the highest melting point metal, I can say that with 100% certainty.


That's a really bold claim, especially when you don't know how much heat the airframe is sinking away.

quote:
For example, if the red laser doesn't work, use the blue laser. Now it would double the cost of the laser, but since it is such an easy way to defeat an engineered reflective coating, it would probably deter the use of reflective coatings.


Only the big laser is used to shoot down the target. The other ones are used for optics correction.

quote:
Thirdly, such laser mirrors are used in CLEAN environments. Dust on a mirror or lens under a 33kW laser can be catastrophic.


Or dried up salt on the lens. That ship is going to be constantly going through seawater, with salt spray all over the place. It's easier to keep a drone skin clean than a an object constantly getting caked with salt.

quote:
The video above shows the laser taking a few seconds to do its damage, so if the drones can spin, dive, barrel roll around for an extended amount of time, it might achieve it's goal.


It looks like it took around 3 seconds to shoot down a dark gray drone that didn't attempt to maneuver. Apply a coating that's reflective in the IR spectrum and try it again. It would probably take 20x as long.


RE: What about a mirror ?
By 3DoubleD on 4/10/2013 3:40:48 PM , Rating: 2
I can say that 660W is enough because the power density (and time interval) wasn't defined. Lasers are great at placing an enormous amount of power in a small area (as well as enormous amounts of energy is a short time interval). So long as I can focus the spot size small enough, 660W projected on a small enough area is more than enough to melt any solid material that I could imagine. That 660W could also be delivered as 660 MJ (Mega Joules) in 1 microsecond on a small target area. That would certainly ablate the material of any target. In this way, by delivering extremely short bursts of intense energy, you could overwhelm any heat sinking technology.

Now we can debate whether 660W in absorption is enough to down a drone in real world conditions all day - I honestly don't know the answer (I certainly wouldn't stand in front of that beam though). The beam spot size has a lower limit when you are projecting it so far away. If the object is too reflective and you can't focus the spot size any smaller at that distance you can 1) increase the power or 2) choose a wavelength that is absorbed more strongly... or 3) both. You could also moved to a pulsed design and ablate the target with a rapid succession of high energy pulses. But most certainly, downing drones with a laser is very feasible - as they have demonstrated. If you make the conditions less favorable does it make it 10x harder? 100x harder? I think these barriers can be overcome.

quote:
Only the big laser is used to shoot down the target. The other ones are used for optics correction.

I was aware that the colored lasers in the video were for other uses, I was pointing out the fact that they could build another high powered laser with a different wavelength.

quote:
Or dried up salt on the lens.

Yes, you are correct, this is obviously a problem. They do have a special dome for the laser though, so I imagine they've thought about it. They could also employ technology like air knives (like the Dyson hand drier) to protect the lens from dust and small droplets while the dome is open. I also hope they keep a couple extra outer lenses on hand in case something goes wrong and it melts.

quote:
It looks like it took around 3 seconds to shoot down a dark gray drone that didn't attempt to maneuver. Apply a coating that's reflective in the IR spectrum and try it again. It would probably take 20x as long.

I agree. Adding some sort of reflective surface is a good start. Making it difficult to keep the beam spot stationary on your drone is the other necessary component though. That means flying the drone somewhat chaotically like I suggested earlier. I don't doubt that the targeting system can hit the drone (several meters wide) with fairly high accuracy, but I doubt it can continuously hit the same spot (several cm wide) on the drone unless it is flying very predictably. Targeting such a small area several km away would require the strictest angular resolution in your targeting system and optics. The system would also have a very low response time. It would be incredibly hard (expensive) to design a system like that. Still, I think in the end the drone would always lose to a well designed, powerful laser system.


RE: What about a mirror ?
By 91TTZ on 4/10/2013 5:14:14 PM , Rating: 2
You bring up good points. Thanks for at responding rationally instead of calling me an assclown like the other guy.


RE: What about a mirror ?
By BillyBatson on 4/10/2013 9:42:57 PM , Rating: 2
Agreed. Seeing as my 1W laser can burn many things including my skin, a 660W laser would still cause lots of damage including to metal.


RE: What about a mirror ?
By 91TTZ on 4/10/2013 11:25:41 AM , Rating: 2
Your soldering iron melts lead, not aluminum. If they built aircraft out of lead the aircraft would have more serious problems, such as not being able to fly because they're so heavy.


RE: What about a mirror ?
By Wiggy Mcshades on 4/10/2013 12:04:40 PM , Rating: 2
The number I gave was the best case scenario for using a mirror as a defense and even in that case it's not a viable option. You don't need to melt any metal, all you need to do is deform the surface of this reflective material a small amount. Once it's deformed then it will stop reflecting a significant amount of the beam and then comes the melting and fire.


RE: What about a mirror ?
By BillyBatson on 4/10/2013 9:49:04 PM , Rating: 2
Your math is wrong all over th place...
The incident solar radiation at the highest point in our atmosphere is about 1400W per square meter, by the time you reach ground level it is approximately 1000W/m^2 HOWEVER this value is VERY rough. It varies drastically as a function of zenith angle, latitude, time of year, etc, etc. so where did you get "5 times the power of direct sunlight" unless you did the math to figure out Sun watts at a single point like a laser.
Again my handheld laser pointer at just 1W can burn and though it can't melt metal 660W sure could...


RE: What about a mirror ?
By Strunf on 4/10/13, Rating: 0
RE: What about a mirror ?
By BRB29 on 4/10/2013 9:07:55 AM , Rating: 3
Lasers are normally very efficient. A 33KW output laser will only need a little more than that to operate.

You watch too much superhero cartoons man. UAV pack a lot of equipment to do their job. If they pack a mirror, motor and whatever guidance system to reflect the laser directly back then it would be too heavy and doesn't even sound like it's stable enough to fly. The point of this is to save money, they can easily shoot down a UAV with their other weapons. They can also send a jet to shoot it down. But any of that cost a ton of money.

The best and cheapest way they can do is add reflective coating on their UAV on the underside. At which point, I hope we still keep some of our CIWs to shoot it.


RE: What about a mirror ?
By Strunf on 4/10/13, Rating: -1
RE: What about a mirror ?
By BRB29 on 4/10/2013 11:24:38 AM , Rating: 1
So what you're telling me is that the UAV will open a bay and deploy a mirror via a robotic arm ran by a motor. Let's just say somehow it only weighs 2 lbs through magic. You still can't have the undeniable facts that your aerodynamics is fubar so your flight is unstable. But let's say somehow it is stable. Now you face the problem that your stupid arm and mirror will create so much drag that it will just plummet into the water. Not to mention with anything flat surface sticking out like that, any gust of even the smallest turbulence will send it plummeting.

I get it now. Your laser defense system is to hide it under the ocean water.

Yes a laser is very efficient but it's not perfect. It loses some of its energy going through the air because the air has plenty of particles in it. The gun itself is not 100% efficient either but it's pretty damn close. The fact is that most of the energy used on the gun will end up on the target. There's no other weapon sytems that can do that. Projectiles are horribly inefficient. Missiles needs lots of fuel.


RE: What about a mirror ?
By JPForums on 4/10/2013 9:25:27 AM , Rating: 3
Good reflectivity, AFAIK, requires heavier material. It's probably not impossible to do, but would reduce the payload significantly. Also, even a simple passive system would raise the cost. When you are talking $1000, this kind of extra expense is not insignificant. These issues are magnified when you start talking about an actively adjustable system. Weight goes up significantly and cost goes through the roof for all the components with which you adjust the array. Further, you have to have a 360 degree sensor array in there to detect which direction to adjust the mirrors to fire back. More weight, more expense, and potential lack of technical know how. I'm not sure you could even fit this capability in their UAVs given the load limitations. Even if you could, you certainly wouldn't be carrying cameras. Further, I don't know of any current sensors that can sense a laser while being shielded from the laser it is trying to sense. It probably wouldn't work out.

It may become possible with development for IRAN to develop a cost effective means to protect their UAVs against lasers to some extent and maintain the ability to carry a camera system, but I don't see the active system as a viable option. Even if the UAV survived, I have no doubt that an exposed camera system would not.


RE: What about a mirror ?
By Strunf on 4/10/2013 11:08:51 AM , Rating: 1
IT doesn't necessarily needs a camera, let's say the said UAV has some good but not 100% reflective coating, when it gets hit the temperature will build up, with thermal sensors on its fuselage and by moving around it would be able to detect the trajectory of the beam and since beams go straight it is possible to detect it's point of origin.

Sure a active mirror would be quite unlikely on a UAV but the fuselage of the UAV doesn't need to be 100% reflective all over it either, with thermal sensors it could adjust its position in a away that it never gets to hot on one spot, if the UAV could also fly upside down then it could spin or lower its altitude away from the line of sight.


RE: What about a mirror ?
By max_payne on 4/10/13, Rating: 0
RE: What about a mirror ?
By topkill on 4/10/2013 10:24:35 AM , Rating: 2
You can't really defeat a laser by reflecting it. It sounds good, but reflective surfaces only work on specific ranges of wavelengths. Most weapons grade lasers have the ability to use multiple wavelengths so they can easily knock out a slow moving target like a UAV which is hovering around. Plenty of time to adjust and try different wavelengths.

You're thinking of visible light, low power lasers for fun, or even simple tools like pointing devices where the laser is visible light and hitting a mirror. Even then, it's not reflecting all the energy.

Try it some time with a powerful laser, even in the visible spectrum. Your mirror will heat up nicely unless it's tuned exactly for the laser it's working with.


RE: What about a mirror ?
By BRB29 on 4/10/2013 10:34:31 AM , Rating: 2
The UAV doesn't have to have perfect defense against lasers. It only has to survive ~1 min over it's objective. Its main function is scan, capture image, send. They are relatively cheap to make compared the any weapon systems we have. I'm pretty confident it's probably much cheaper than the missiles we are using to shoot it down with right now.


RE: What about a mirror ?
By ShieTar on 4/10/2013 10:53:01 AM , Rating: 2
Actually, polished aluminum will deflect about 95% over a very broad range, as will most other metals. And solid state lasers may be capable of changing their wavelength by a few%, but not over a relevant range.

Sure you can put enough energy into a laser that even the remaining 5% will destroy the UAV, but then you also run into trouble keeping the laser itself intact. As any decent broadband mirror has a damage-threshold around 500 kW/cm², and you need at least a 2cm beam waist (~12cm² area) in order to have a range of about 1 Km, this means you have to go and build a 6MW laser. That is a whole different tool than the 33kW toy they are playing around with right now.

Of course, you can probably destroy the camera of the UAV with a cheap 1W visible laser.


RE: What about a mirror ?
By topkill on 4/10/2013 11:17:53 AM , Rating: 2
Interesting. I did a search for some experimental data on lasers melting polished aluminum. I found one reference with an experimental result showing 0.6J/cm^2 to melt electropolished aluminum. Considering you would get about 1,000 J/s with a 1kW laser, then even if you're only getting 5% of a 33kW laser on the target then you're talking about 33*.05*1,000= 1,650 J/sec on the polished aluminum target.

Unless I'm missing something in my calculations and interpretation of the work, that is 2,500 times the energy needed to melt the targets skin.

That would seem to indicate it would work and the fact they have successful test tells me they're either totally full of shit and lying through their teeth to get funding or we're all very wrong in our arm chair quarterbacking.

I'm just saying :-)

Link with data is as follow, and look at the bottom of page 580:

http://books.google.com/books?id=4KgN89rw7ykC&pg=P...


RE: What about a mirror ?
By ChronoReverse on 4/10/2013 12:56:22 PM , Rating: 2
The idea of a mirror to defend against laser weaponry has never been taken seriously.

At the power levels weapons-grade lasers operate at, even a spec of dust on even the most perfect mirror would instantly "explode" as it's vaporized by the laser and render the mirror decidedly not mirror-like at the point of impact.

You'd need better than stealth fighter coating inspection to keep such a mirrored surface clean and it'd mostly be a wasted effort the moment such a drone is taken outside.


RE: What about a mirror ?
By 91TTZ on 4/10/2013 5:06:16 PM , Rating: 2
If a speck of dust can destroy the surface of the target, what about salt on the lens of the laser itself? This thing will be operating on a boat in salt water, after all.


RE: What about a mirror ?
By ChronoReverse on 4/10/2013 5:10:11 PM , Rating: 2
Interestingly enough, the emitter itself isn't as bad since it's not the focal point of the laser(s). I put possible plural because a multiple laser approach is more efficient and means individual lasers are even lower power.

They'll still have to keep it clean to maximize output of course but it's not as exacting.


RE: What about a mirror ?
By Gondor on 4/10/2013 1:46:00 PM , Rating: 2
Right, so 5% of absorbed power destroys the mirror eventually and the drone with it). What happens with the 95% of light reflected back at the shooter ? Or more specifically, what happens to the targeting system's optics, the laser mount and anybody unfortunate to be in the vicinity of the beam when the mirror starts deforming and beam shifts away from the point where it was initially being reflected ?

(this is assuming they used 95%-efficient corner retroreflector that somebody mentioned above)


RE: What about a mirror ?
By ChronoReverse on 4/10/2013 1:57:31 PM , Rating: 2
It ceases to be a reflector really quickly. Plus the light it reflects back isn't going be nicely lined up and focused to a point.

See, the 5% absorbed bit isn't going to be sustained for any meaningful period of time. It basically is a positive feedback loop.

The 5% absorption warms up, deforms and discolours any reflector which makes the absorption grow beyond 5% which leads to even quicker heat up, deformation and discolouration.

There is the issue where the scattered reflected light, despite not being enough to burn the emitter or anyone else, is still enough to blind everyone for a large radius. Goggles will be needed for these (and I wonder if Geneva will frown upon even accidental blinding).


RE: What about a mirror ?
By 91TTZ on 4/10/2013 2:32:41 PM , Rating: 2
If I'm not mistaken (and correct me if I'm wrong here because I don't work with this stuff) a Joule is a unit of work, not a measure of intensity. If you were to shine a 1 Joule burst from a laser for 1 second, you'd have a 1 watt laser. If you were to shine a 1 Joule burst in a half second you'd have a 2 watt laser. In the test you linked to, they were able to melt aluminum with a 2.99J/cm^2 Joule burst in 10 nanoseconds. That's a very high intensity.

1 watt = 1 Joule for 1 second
a 1KW laser would transfer 1,000 Joules for 1 second.
2.99J in 10 ns would be a 299 MW laser, wouldn't it?

It looks like your link says it takes 2.99J/cm^2 to melt the aluminum. The .06 figure was for the creation of slip lines. It also doesn't look like that test was trying to measure how much power it took to burn through an aluminum sheet, it was seeing what the surface effect of a laser burst was at a certain intensity. Their burst was only 10 nanoseconds and they used a microscope to see what happened at the microscopic scale. They're able to determine by looking at the crystal structure whether the aluminum was unharmed, melted, or boiled.

Also, in such a short burst you don't really have conduction working against you. On a longer burst you have to deal with the fact that the metal sinks heat away from the area. While 2.99 2.99J/cm^2 in 10 nanoseconds is certainly enough to melt the aluminum, if you spread that out over 1 second the sheet might sink that power away.


RE: What about a mirror ?
By ChronoReverse on 4/10/2013 2:44:13 PM , Rating: 2
I wouldn't be too concerned because they've thought through these things for a long time already:

http://singularityhub.com/2013/01/07/german-milita...

quote:
In fact, weather at the Ochsenboden Proving Ground in Switzerland where the demonstration was carried out included ice, rain, snow, and extremely bright sunlight – far from ideal.

quote:
The laser modules are 30 kW and 20 kW, but a Beam Superimposing Technology (BST) combines two lasers to focus in a “superimposed, cumulative manner” that wreaks havoc on its targets. First, the system sliced through a 15mm- (~0.6 inches) thick steel girder from a kilometer away.

quote:
the laser’s ability to track a very small ballistic target was demonstrated. It honed in on and destroyed a steel ball 82mm in diameter traveling at 50 meters per second.


RE: What about a mirror ?
By ChronoReverse on 4/10/2013 2:46:04 PM , Rating: 2
I know this is an entirely different system but my point is that the obvious "problems" people are bringing up are really not problems with some engineering work.

Nobody is being clever by saying "I'll just mirror my drone".


RE: What about a mirror ?
By 91TTZ on 4/10/2013 3:45:37 PM , Rating: 1
I don't think it's practical to use a mirror to reflect the laser back to the ship, but from a simple mathematical point of view if you can reduce the amount of energy absorbed you can lengthen the time required to shoot it down.

Painting it with a special paint that reflects infrared radiation could make the drone absorb a tiny fraction of the light. It could increase the shootdown time from seconds to minutes.


RE: What about a mirror ?
By ChronoReverse on 4/10/2013 4:02:36 PM , Rating: 2
I was trying to bring across that no such paint could last more than a very short period before its reflective properties would be completely lost. It's a positive feedback loop so it goes from worse to complete failure in very short order.

Plus dust/grime that pervades all real-life applications would render it moot.


RE: What about a mirror ?
By 91TTZ on 4/10/2013 5:11:27 PM , Rating: 2
That's why in my previous point I said that it's important for the ash to be a certain color. The paint is going to turn to ash either way, but that ash should be a color that reflects light, not absorbs it.

I'm also curious to see what would happen to the laser housing itself when it gets covered in sea spray and there's salt crust on it.


RE: What about a mirror ?
By ChronoReverse on 4/10/2013 5:18:27 PM , Rating: 2
They'll have to keep it clean (and covered when not in use, the dome it's in is likely for that purpose) but unlike at the target point, grime on the emitter end isn't catastrophic.


RE: What about a mirror ?
By ShieTar on 4/11/2013 5:37:19 AM , Rating: 2
This book is talking about pulsed lasers. So a usual 20ns-pulsed laser with 0.6J per pulse has a power level of 0.6J/20ns = 30MW. That is way above the damage threshold of course.

But as I understand it, nobody is building ns-pulsed weapon lasers, but rather continous wave lasers operating for up to 20s before having to recharge.


RE: What about a mirror ?
By 91TTZ on 4/11/2013 11:12:03 AM , Rating: 2
In that paper that was linked, .6J per pulse gave the aluminum sheet stress lines but didn't melt it. The pulse that melted it was of a higher power.

But I agree with the rest of what you said.


RE: What about a mirror ?
By 91TTZ on 4/10/2013 11:23:28 AM , Rating: 2
Why would you use a mirror instead of painting it white? White can actually reflect more light, it just scatters it.


RE: What about a mirror ?
By FaaR on 4/10/2013 1:34:08 PM , Rating: 2
Paint would heat up, blacken, catch fire and not be white anymore. Laser punches straight through, destroying the target.

You can't defeat a laser with as simple a method as this. Even a laser diode out of a blu-ray drive (a few hundred mW at most) can set fire to wood at a distance of 1-2m, maybe more.

This kind of laser the article's talking about isn't in the same league, it's a whole different ballgame. 33kW focused down to a decently small spot, even with most of the incoming radiation scattered would still heat the surface to hundreds, then thousands of degrees in seconds. No manmade material (suitable for UAV use) stands up to that kind of abuse, it'll deform, melt, burn.


RE: What about a mirror ?
By 91TTZ on 4/10/2013 5:16:34 PM , Rating: 2
quote:
Paint would heat up, blacken, catch fire and not be white anymore. Laser punches straight through, destroying the target.


Not all materials turn black when they burn. Some turn white and some other ones turn other colors depending on what's in the ash. I think the color of the ash is more important than the color of the paint.


RE: What about a mirror ?
By ChronoReverse on 4/10/2013 5:24:03 PM , Rating: 2
Yes but even white ash isn't going to be nearly as good as a 95% reflector. I think good white paint might put you at 90%? That's not nearly good enough to handle it ASSUMING you find a white paint that reflective which burns into white ash equally reflective.

Incidentally, 99+% reflectors are usually thin films of some sort and are even more quickly destroyed by focused heat build up =(


RE: What about a mirror ?
By Yeah on 4/10/2013 5:07:08 PM , Rating: 3
Can you Drive a 6" Spike throught a board with your Pen¥s?


Tested in the desert
By mcnabney on 4/9/13, Rating: 0
RE: Tested in the desert
By JasonMick (blog) on 4/9/2013 7:22:20 PM , Rating: 5
quote:
All the test were in the desert under good conditions. They need to try it out in the rain.
I think you missed the part about it being tested at sea since 2010...

The desert tests were only in the preliminary stages in 2009.

Testing in rain doesn't make a lot of sense as I see it, as hostile forces are unlikely to launch small fragile UAVs with sensitive imaging equipment onboard during a storm.


RE: Tested in the desert
By Phoque on 4/9/2013 8:55:09 PM , Rating: 2
He didn't say 'during a storm', he said 'in the rain'. I think he has a good point.

And I'm sure Iran could make their UAV rain proof if it's not already the case.


RE: Tested in the desert
By topkill on 4/10/2013 10:17:00 AM , Rating: 5
I'm not sure rainy conditions are such a big issue in the Persian Gulf region :-)


RE: Tested in the desert
By BRB29 on 4/11/2013 1:04:55 PM , Rating: 2
No but jelly fish is a big problem. It was beautiful and I tried to peacefully swim with them. Then it started hurting.


RE: Tested in the desert
By M'n'M on 4/9/2013 10:09:40 PM , Rating: 2
quote:
Testing in rain doesn't make a lot of sense as I see it, as hostile forces are unlikely to launch small fragile UAVs with sensitive imaging equipment onboard during a storm.

Why ? If I'm a small-fry looking to take on the Big Dog, I'm going to do it when he has the least chance of defending against me. If it costs me a few drones to get the info I need for an attack, well it's a good thing they're cheap $$s.

And who knows how much better they'll get in a few years.

The laser is a good adjunct weapon to have despite it's limitations. It's not a replacement for existing systems.


RE: Tested in the desert
By JPForums on 4/10/2013 9:47:51 AM , Rating: 2
This.

Initial testing, as normal, took place in optimal settings. You could consider it a proof of concept to the U.S. military. However, we are well beyond that now. Dedicating naval assets for real world testing is expensive, and not something any military takes lightly. You can be sure that the laser's rainy day performance is a know quantity if the U.S. military is willing to spare such resources.


RE: Tested in the desert
By bug77 on 4/10/2013 5:02:06 AM , Rating: 4
If the drone can have a direct line of sight to take photos of the ship, it's reasonable to assume the ship's laser will have a direct line of sight to "photograph" the drone.


Lasers vs Conventional Munitions
By Wulf145 on 4/10/2013 4:41:06 AM , Rating: 2
As cool as lasers are, I would have thought that conventional Munitions would be a much cheaper (and less influenced by weather) to solve the problem of shooting down a drone.

Why go for such an expensive solution?




RE: Lasers vs Conventional Munitions
By Amiga500 on 4/10/2013 6:24:22 AM , Rating: 2
quote:
Why go for such an expensive solution?


This is only the beginning. SM2s are a finite resource on-board a ship. To a lesser extent, so are cannon rounds.

The resources of the laser are as finite as the oil in the
ships bunker (or in the case of a select few - the uranium in their reactors).

Don't be under any illusions - this is the beginning of a paradigm shift in warfare similar to the Dreadnought and the rifled barrel.


RE: Lasers vs Conventional Munitions
By M'n'M on 4/11/2013 5:58:40 PM , Rating: 2
And conventional munitions can have the nasty side-effect of blowing up the ship if hit by enemy fire.


RE: Lasers vs Conventional Munitions
By ShieTar on 4/10/2013 6:56:05 AM , Rating: 2
First, the military has a fixed budget for developments. They don't restrict themselves to financing good ideas, the just finance the best ideas currently around until the budget runs out.

Second, the minor point that lasers have is their large velocity, so you basically cannot maneuver to avoid them. Basically a laser beam hits you in exactly the same moment you first see it. I don't think any currently existing drone actually has the capability of detecting high-velocity projectiles in advance and react to it, but that could probably be achieved within the next decade, so they are developing the laser in advance.

Third, the probability of friendly fire / collateral damage is a bit lower with lasers. Munitions are affected by gravity, and have the tendency of falling to the ground a few Km after they missed a target. If you are shooting drones in international waters, you can easily kill innocent people at random places at the coast, or end up sinking some Oil Tanker worth 100M$. When a laser fired from the ground into the air misses a target, it never comes back down. Population of the Air-Space is much less dense than on ground, so the chances to hit something else behind the primary target are reduced. Of course, blinding the pilots of a commercial air-craft would be a very likely event once you start using lasers on a regular basis, and a lot of satellite-based cameras with their large magnifications might also get destroyed by stray high-energy laser pulses.


RE: Lasers vs Conventional Munitions
By JPForums on 4/10/2013 9:02:25 AM , Rating: 2
quote:
Of course, blinding the pilots of a commercial air-craft would be a very likely event once you start using lasers on a regular basis, and a lot of satellite-based cameras with their large magnifications might also get destroyed by stray high-energy laser pulses.
Perhaps not.
quote:
The high-power infrared laser onboard the most recent model operates at 33 kilowatts and consists of 6 separate solid-state lasers focused on the target.
Now I may be missing something here, but infrared is outside of the visible spectrum. Unless the laser is somehow shifted to a higher frequency, humans would never see it. I suppose satellites that pick up infrared would be effected, but for those that capture the visible spectrum, the same thing applies.


RE: Lasers vs Conventional Munitions
By BRB29 on 4/10/2013 9:15:06 AM , Rating: 2
you will would not see it even if it's in the visible spectrum...unless it's shot through smoke or steam or directly at your eyes.


RE: Lasers vs Conventional Munitions
By 3DoubleD on 4/10/2013 10:24:31 AM , Rating: 2
That isn't quiet correct.

Firstly, wavelengths outside the "visible" spectrum can most certainly blind you. In fact, infrared and UV lasers are the most dangerous types of lasers with regards to blinding because we don't have a blink reflex and thus are more prone to being blinded by them. Now IR and UV wavelengths are poorly focused in our eyes, but even still, even weakly powered lasers and their reflections can blind you. I wouldn't be surprised if the sailors on deck of these ships would need to wear protective goggles when this laser is operating, regardless of the laser wavelength.

Secondly, you can most certainly see high powered laser beams in the atmosphere. It may be difficult during the day when there is plenty of ambient light, but at night, even a mediocre 50mW laser can be visible. Look up astronomy lasers.

A 33kW laser in the visible wavelength regime could possibly be visible during the day, depending on the wavelength. Lasers can be visible in air due to Rayleigh scattering in addition to scattering off of larger dust particles and certain gases. Rayleigh scattering is strongest at shorter wavelengths (towards the blue end of the spectrum), but the human eye is most sensitive to green wavelengths. I imagine the optimal wavelength for visible laser beams in the atmosphere lies around the short end of the green spectrum ~500nm. The popular astronomy laser is 532nm - the wavelength is a result of the relatively inexpensive DPSS laser technology.


RE: Lasers vs Conventional Munitions
By BRB29 on 4/10/2013 10:46:46 AM , Rating: 2
So simply put, lasers are not visible to you unless it is directly beamed at your eyes or reflected off of something in the air or object. The atmosphere has plenty of things in it to scatter some of that beam and thus enabling you to see it. If you shoot a laser weapon, it will be mostly invisible and don't expect it to be like star wars.

The point i was trying to make is that it's not like the movies that everyone thinks of when they think lasers.


RE: Lasers vs Conventional Munitions
By FaaR on 4/10/2013 1:42:46 PM , Rating: 2
Not so simply put, actually... Lasers don't need particles scattering the beam to become visible. A sufficiently high-powered laser will excite air molecules and cause them to glow. Kind of like the aurora borealis, apart from that the mechanism that drives the phenomenon isn't charged particles... :)


By 3DoubleD on 4/10/2013 3:57:37 PM , Rating: 2
Yes, as I said. Look up Rayleigh scattering. It is the reason the sky is blue, why sunsets are red, and the reason the moon can sometimes look yellow/red. You don't need any dust particles to see a visible laser beam or achieve any of these other effects.

If the laser is in the IR or UV spectrum, you won't see Rayleigh scattering because you can't see those wavelength anyway.

If the laser is in red, Rayleigh scattering is weak and your eyes don't see red well anyway, so you would need a relatively powerful laser. It is possible see the red laser beam though.

If the laser is green, Rayleigh scattering is much less weak and you can easily see even a low powered laser beam in the dark.

If the laser is blue, Rayleigh scattering is very strong in the atmosphere (blue sky, red sunsets, ect.) and if the beam is powerful enough to make up that we don't see blue very well, you could see the blue laser beam too.


Good idea....not
By Ammohunt on 4/9/2013 7:19:55 PM , Rating: 4
So shooting down a UAV is not an act of war? half measures will not solve the Iran issue.




RE: Good idea....not
By JasonMick (blog) on 4/9/2013 7:28:19 PM , Rating: 2
Well to be fair Iran has regularly fired on our UAVs... Granted they were over Iranian airspace but still... ;)

http://articles.washingtonpost.com/2012-11-08/worl...


RE: Good idea....not
By Solandri on 4/10/2013 3:12:10 AM , Rating: 2
Nearly all of this stuff is happening in international waters. There's a 200 mile economic exclusion zone, but that only affects resource harvesting. Customs/immigration and pollution controls can extend out to 24 miles. But a country can only limit what goes on out to 12 miles from their borders.

Further than that and it's a no-man's land (well, water) - anything goes. If you want to shoot at someone you can. Likewise, if you don't like that someone is shooting at you, pretty much the only thing you can do about it is shoot back. Furthermore, ships are generally considered to be under the law of the country whose flag they're flying. So if an uninvited UAV is buzzing a ship, the ship is within its right to treat it as if it were intruding on its sovereign territory (unless the buzzing is being done for enforcement of activities under the 24 and 200 mile limits).

There's certainly a grey area about how close the UAV can be before it's too close, but there are no formal rules establishing that something constitutes an "act of war" on the high seas. If Iran wants to call a UAV shootdown an act of war, it can. If the U.S. wants to call it self-defense, it can. There is no law or judge with the authority to decide which country is right. The two countries either beat each other up until one concedes the other was right, or resolve it diplomatically, or agree to disagree.


RE: Good idea....not
By toyotabedzrock on 4/10/2013 3:21:27 AM , Rating: 4
So if China used a destroyer launched missile in international waters to sink a use navy ship it would be ok?


RE: Good idea....not
By Solandri on 4/10/2013 3:23:19 AM , Rating: 1
There's no law saying it would or wouldn't be ok. All that matters is what China and the U.S. decide to do about it.


RE: Good idea....not
By Just Tom on 4/10/2013 11:34:55 AM , Rating: 2
Well, actually there is. There is a UN Resolution defining "An attack by the armed forces of a State on the land, sea or air forces, or marine and air fleets of another State;" as an act of war. And 18 USC § 2331 defines an act of war as "(A) declared war; (B) armed conflict, whether or not war has been declared, between two or more nations; or (C) armed conflict between military forces of any origin;"

I am pretty sure lobbing shells at a naval ship would constitute an act of war under either definition.


What are they thinking?
By BRB29 on 4/10/2013 8:14:04 AM , Rating: 2
Iran can easily put a reflective coating and the UAV will at least last long enough to do its job before going down.
It's really not that hard to deflect most of the energy from an infared beam




RE: What are they thinking?
By bug77 on 4/10/2013 9:09:15 AM , Rating: 3
By using a reflective coating, you're forfeiting radar-absorbent coatings. So you're still vulnerable.


RE: What are they thinking?
By ShieTar on 4/10/2013 10:10:21 AM , Rating: 2
Not necessarily, Radar and Laser work on very different wavelengths. You can put an optically reflective but radar-transmitting dielectric coating on top of the radar-absorbent coating, or probably develop a combination coating that does both jobs at the same time.

But really, defense and stealth are generally exclusive options anyways. If you send a stealth drone the plan is to not be shot at, not to survive it. On the other hand, a non-stealth UAV that can send a video-stream can probably be built for about 1k$, so you don't care all that much about loosing them. And if loose a drone, it is pretty much proven that the attacking ship was not a decoy.


RE: What are they thinking?
By 91TTZ on 4/10/2013 1:28:41 PM , Rating: 2
quote:
On the other hand, a non-stealth UAV that can send a video-stream can probably be built for about 1k$, so you don't care all that much about loosing them. And if loose a drone, it is pretty much proven that the attacking ship was not a decoy.


Yeah, and if the Iranians really wanted to avoid the laser they could just fly the thing at low altitude. The Navy isn't going to risk frying another ship in an attempt to shoot down a glorified RC airplane.


RE: What are they thinking?
By BRB29 on 4/10/2013 10:26:45 AM , Rating: 2
These UAVs can't fly very high. It is meant to identify ships and its capabilities. They don't care about radar coatings as it can easily be seen with your eyes and maybe binos.

Trying to shoot a small UAV is hard and expensive. Even a guided missile doesn't have 100% chance of intercept. That's why a constant beam of laser is better and cheaper. UAVs also have very low heat signatures so thermal guided missiles won't work good either. It's like trying to swat a fly in the air. It's going to take a few swings but each swing cost you money.


The day has arrived
By ChronoReverse on 4/9/2013 5:51:52 PM , Rating: 2
I felt like they've talked about weaponized lasers for the longest time but it sounds like they've finally gotten something practical on the field?




RE: The day has arrived
By bigboxes on 4/9/2013 9:36:46 PM , Rating: 4
OK, no problem. Here’s my plan. Back in the ’60s, I had a weather-changing machine that was, in essence, a sophisticated heat beam which we called a “laser.” Using these “lasers,” we punch a hole in the protective layer around the Earth which we scientists call the “Ozone Layer.” Slowly but surely, ultraviolet rays would pour in, increasing the risk of skin cancer. That is unless the world pays us a hefty ransom.


RE: The day has arrived
By Dorkyman on 4/10/2013 1:53:53 AM , Rating: 2
"A ransom of.......ONE MILLION DOLLARS!!!

No--wait--

A ransom of.......ONE HUNDRED BILLION DOLLARS!!!!"


Electronics
By toyotabedzrock on 4/10/2013 3:17:47 AM , Rating: 2
So Iran can control our UAVs but we can only shoot them down?

And the laser will have limited power on a non nuclear powered ship.

And removing a proven weapon like ciws is a bad idea.




RE: Electronics
By Solandri on 4/10/2013 3:40:56 AM , Rating: 2
quote:
And the laser will have limited power on a non nuclear powered ship.

33 kW is less than 50 horsepower. You could power it with a generator smaller than your car engine.


RE: Electronics
By inperfectdarkness on 4/10/2013 7:54:56 AM , Rating: 1
This. It's a much shorter-range weapon than a rail-gun, which WILL require a nuclear reactor for power.


RE: Electronics
By BRB29 on 4/10/2013 8:22:44 AM , Rating: 2
the military tests its weapons very thoroughly before fielding and standardizing them.
For example, the XM8 is supposed to replace the M16 as the new standard. It's still undergoing testing and approval. It's been nearly a decade and still in the process.

This laser has a much easier testing process since it's a limited application. I just hope they didn't forget to account for the fact that lasers can easily be countered by a good reflective coating for that frequency range.


More American paranoia
By mike66 on 4/10/2013 9:04:26 AM , Rating: 1
So America puts a warship off the coast of Iran and they don't expect the Iranians to spy on it, what do you think if Iran put a warship off the coast of America. God save us all from the paranoid American zealots.




RE: More American paranoia
By bug77 on 4/10/2013 9:10:37 AM , Rating: 2
It's not that they don't expect Iranians to spy on them, it's just that they need something to interfere with the spying.


RE: More American paranoia
By BRB29 on 4/10/2013 9:18:36 AM , Rating: 2
We are expecting them to spy on us. That's why we have the system duh!!
If you've read the whole article, you'll notice that this is to save money and shoot down UAV to prevent missile strikes against our ships. They can still see our ships by radar but they don't know which ship to aim for if we have decoys.


RE: More American paranoia
By ironargonaut on 4/16/2013 4:42:49 PM , Rating: 2
Not even remotely close to what the article was talking about.

Iran sending one UAV to shadow the fleet is expected. One reason most countries don't get too carried away with stopping spies is they let the other country know you are not massing troops to attack and thus diffuse tensions. Iran sending 1000, of which 100 are spotters for land based missiles and 900 carry explosive/missiles to either be fired crashed into American ships, that is another matter all together.

I can think of a defense, but it won't prevent loss of optics/sensors, of course if a course has already been established to target may not need them.


now...
By The Imir of Groofunkistan on 4/9/2013 10:08:11 PM , Rating: 4
now...all we have to do is attach them to sharks!




RE: now...
By BRB29 on 4/10/2013 9:20:03 AM , Rating: 2
Aquaman! where are you!!


capability to shoot down uavs
By Rasputin814 on 4/15/2013 2:54:54 PM , Rating: 2
We had the capability to shoot down UAVs for decades. It's called a surface to air missile.




By ironargonaut on 4/16/2013 4:53:21 PM , Rating: 2
I'll take your surface to air missile and raise you 10,000 drones at $1000 a piece. How many surface to air missiles do you have in your fleet? Can you make supply and fire them faster then I can make, supply and launch a drone from my own shores, when your factory is on the other side of the world? Once, you run out of surface to air missiles, I will launch my ground to ship missiles and my fighter aircraft.

The world is changing as are the tactics, your decades old tactics just cost your country 20k men and a fleet.


By 91TTZ on 4/10/2013 1:09:15 PM , Rating: 1
While these tests are impressive, they're always stacked in the laser's favor. For instance, once thing I always notice is how the targets are always dark in color. This is very convenient for a laser since the dark color absorbs light and heats up faster.

However, these effects are easily mitigated. Different colors have a different albedo (reflectiveness). For sunlight, white paint can reflect up to 95% of the light that strikes it. A black aircraft might absorb almost 1000 watts of energy from sunlight per square meter on its skin while a white aircraft would absorb only around 50 watts. A dark drone might absorb almost 20 times the amount of visible light.

Obviously any paint is going to eventually burn, but this also can be designed in your favor. If any of you burned things with magnifying glasses when you were a kid you'd know that some materials like wood turned black when they started burning, which made it absorb even more light and get even hotter, while other things would get ashy and turn white, which stopped them from burning and you had to move on to a new spot.

Now this laser operates in the infrared spectrum so your reflective colors will be different. Colors that don't look that reflective to your eyes might be very reflective in the infrared spectrum. If you ever wondered why plants always seem cool even though they're dark green take a look at this comparison between visible and near infrared light: http://www.torontoist.com/attachments/toronto_marc...

Long story short, while nothing is invulnerable from a laser you can substantially reduce its effectiveness. You'd have to design a paint that reflects infrared and whose ash reflects infrared. While the dark gray test target might have absorbed 20,000 watts of the 30KW laser, a drone painted with a specially formulated 98% reflective paint might only absorb 600 watts. The highly conductive aluminum frame of an aircraft might be able to sink that kind of power. Even if it couldn't, a dark drone that took 3 seconds to burn through might now take a minute or more- plenty of time to escape.




By CubicleDilbert on 4/11/2013 1:58:44 PM , Rating: 2
Exactly.
Every weapon on earth met its match in an anti-weapon. Has been so for thousands of years. Not much different with lasers.

Use a highly reflective paint. Use highly thermal conductive aluminum as main material coupled with an ablation melting ceramic (think re-entry space capsule), coupled with a water filled spongy insulator. This will defend even a high powered laser for a few hundred milliseconds or seconds.

Put infrared sensor on board the drone and if a search and focus beam is detected start erratic manouvers to disable tracking.
Further start your flight in misty/cloudy/humid/dusty weather, which drastically reduces the laser power.

An if nothing works, use styrofoam, wood and plastics as main material which can not be detected by radar. Reduce the size of the drone to mini drone.

It's only a few miles across the gulf, so even a small styrofoam RC model with a strong wireless connection is sufficient.

There are always ways to circumvent American military power.


wait
By lagomorpha on 4/10/2013 7:40:30 AM , Rating: 2
quote:
If all goes well, those real world shoot-downs could occur as early as in the middle of next year.


Shouldn't this read, "If all goes well, the US will stop getting itself involved in expensive wars on the other side of the world?"




1 ga buck shot
By half_duplex on 4/10/2013 9:47:38 AM , Rating: 2
Could we just use a massive form of a shotgun instead?

Who am I kidding... Iranian UAVs are just a reason to spend billions on the beginnings of what will eventually be strapped to a satellite.




DREDD RULES!
By Motoman on 4/10/2013 6:10:14 PM , Rating: 2
I don't even want to hear about this unless every time you fire the weapon, Sylvester Stallone pops out and yells "I AM THE LAWS!"




Drone, shmone...
By delphinus100 on 4/11/2013 9:37:40 PM , Rating: 2
'Drone.' 'Unmanned aerial Vehicles' that may pose a threat to ships...

Yes, ships need good terminal defense, but didn't we used to call these non-ballistic things cruise missiles?

Anyone remember Iran's Chinese-made 'Silkworms,' that we feared they'd use to choke off the Straits of Hormuz? The threat is absolutely real, but with 'drones' on everyone's mind, you'd think the threat was new. (There was a time when the Navy had to contend with what one might call a manned cruise missile [Kamikaze aircraft, some rocket powered], and the Vincennes once took down an airliner, thinking it to be a similar kind of attack enroute.)

Again, serious, but invoking the 'd' word doesn't make it new.




YAAWWN...
By Ramstark on 4/12/2013 8:16:51 PM , Rating: 2
Wake me up when they attach it to a flying shark with a scuba monkey riding it armed with a EMP mine...




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