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Laser Shoots Down Artillery Shell In Flight 795

Posted by michael from the hammer's-slammers dept.
An anonymous reader writes "The Mobile Tactical High Energy Laser is a joint project between the US Army and the Israeli Defense Ministry, with much of the work being done by TRW. Tuesday they had a spectacular success when they shot an artillery shell out of the air."
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Laser Shoots Down Artillery Shell In Flight More

Laser Shoots Down Artillery Shell In Flight

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  • So what happens... (Score:5, Funny)

    by Anonvmous Coward ( 589068 ) on Tuesday November 05, 2002 @07:57PM (#4603683)
    ... when they fire one of these at a disco ball? heh.
  • ...but is this thing as accurate as Luke Skywalkers light-sabre?
    If not, you'll have to use the (air)force, George...

  • More details please (Score:5, Interesting)

    by A5un ( 586681 ) on Tuesday November 05, 2002 @08:00PM (#4603711)
    Reading through the article doesn't give much info about details such as:
    How much does one unit cost?
    How long is the "reload"/"re-aiming" time?
    Will it survive real heavy artillery battle?

    • Re:More details please (Score:5, Interesting)

      by K-Man ( 4117 ) on Wednesday November 06, 2002 @12:06AM (#4605303)
      As a veteran of the last several stories on the THEL, I can say that the cost is a couple of thousand per shot; far below the cost of the Patriot.

      The system uses chemical cartridges that last a few seconds each, and tests have shown it capable of engaging at least two targets during that time (I don't remember the exact time, but the video was relatively short). The re-aiming time is also quite low, less than a second.

  • Real Genius.. (Score:5, Funny)

    by Anonymous Coward on Tuesday November 05, 2002 @08:02PM (#4603723)
    They say in the article that it was developed by the army and TRW, but we all know it was Mitch Taylor and Chris Knight.

  • How in the world... (Score:4, Funny)

    by Anonymous Coward on Tuesday November 05, 2002 @08:03PM (#4603734)
    Do you put a GPS and transmitter in an artillery shell?

  • Where does the momentum go? (Score:3, Interesting)

    by TimFreeman ( 466789 ) <tim@fungible.com> on Tuesday November 05, 2002 @08:03PM (#4603744) Homepage
    If you start with, say, 20 lbs of supersonic projectile, and then you zap it with a laser, you still have 20 lbs of something moving with about the same average velocity as before.

    Thus, if you want to protect the target, you either have to vaporise the entire projectile so the momentum is dispelled by the air, or maybe it's an explosive shell and the laser persuaded it to explode (which is another way of vaporising it, I suppose).

    Breaking it in two or poking a hole in it wouldn't be sufficient.

    Does anyone know exactly what they meant by the laser "destroying" the projectile?

    • They likely mean the laser heated a spot on the projectile sufficiently to initiate low order detonation of the explosives therein. This would likely break it into enough pieces to keep it well short of its original intended target...

    • Re:Where does the momentum go? (Score:4, Insightful)

      by TheSync ( 5291 ) on Tuesday November 05, 2002 @08:13PM (#4603864) Journal
      Shells don't kill (many) people by ballistic momentum, they kill mostly through shrapnel.

      That said, raining shrapnel from the sky could still be dangerous, but it would land short of the original target. So just overshoot?

      • Re:Where does the momentum go? (Score:4, Informative)

        by Phanatic1a ( 413374 ) on Tuesday November 05, 2002 @08:17PM (#4603900)
        Proximity fuses detonate their shells at an optimum height; the terminal velocity of an artillery fragment isn't very high, it's the fact that it's being driven into you by a bursting charge that's the dangerous part.

        If the shell detonates below this height, the resultant spread of the fragments will be limited. If it detonates above this height, then the fragments will both be spread over a wider area and lose more energy to air resistance.

        In either case, you're better off than if the shell detonates at the proper altitude.

      • Re:Where does the momentum go? (Score:5, Interesting)

        by afidel ( 530433 ) on Tuesday November 05, 2002 @08:17PM (#4603901)
        hehe, you just pointed out one of the biggest benifits of this type of antiprojectile system. If they work and are fast enough you can explode the ordinance over the enemies own lines. If the enemy is using nasty stuff like biological, chemical, or nuclear arms you've just doubled the effectiveness of your defense by making it an offense.

        • Not nuclear (Score:3, Informative)

          by Galvatron ( 115029 )
          Nuclear devices cannot be detonated by random shots. They require very precise triggers. The most you'd get would be radioactive shrapnel from the destroyed bomb.
    • I have to assume that it was some sort of explosive warhead that was detonated by the heat of the laser.

      History clearly demonstrates that all surface-to-air weapons systems demo slightly better when you pack the target to the gills with high explosives.

      But yeah, the original momentum isn't getting "blown up", so if the thing that's shooting at you is a battleship lobbing volkswagon-sized projectiles, the fact that you warmed it up a little bit before it hit you isn't going to make much difference.

      But if the enemy is going to helpfully pack all his warheads with heat sensitive HE, then this should work great!

      G.

    • Re:Where does the momentum go? (Score:5, Informative)

      by nadador ( 3747 ) on Tuesday November 05, 2002 @08:15PM (#4603889)
      A cloud of shell parts has a very different aerodynamic profile. The remnants of the shell might still be initially traveling in the same direction, but the fragments will not maintain that course. You only have to change the trajectory of the shell enough to make it fall short of its target.
    • Probably depends on the shell. If the shell has fuel, propellant, or explosives in it, then the laser might cause that substance to heat up and explode. Or, the laser might simply vaporize part of the shell, causing its shape to change enough that its wind resistance changes, and its trajectory changes (even if it still hits something, that's probably better than it hitting the original target -- and if its wind resistance increases, it may slow down enough that it is falling straight down when it hits the ground). If the laser manages to mostly vaporize the shell, then the rapidly dispersing 20 lbs of metallic dust would have a hugely greater surface area, and would slow down to nothing almost instantly.
    • or maybe it's an explosive shell
      Most shells are, in fact, expolsive. I'm guessing 'destroying' translates to 'rendering harmless to the target'

    • Re:Where does the momentum go? (Score:5, Interesting)

      by mce ( 509 ) on Tuesday November 05, 2002 @08:24PM (#4603969) Homepage Journal
      You're missing 2 points:
      • The explosive bit.
      • Even if you just succeed in breaking the shell into pieces and due to some magic it does not explode, the pieces will not end up at the original target as designed. First of all, their trajectories and speeds will diverge. Next, shells are designed to do their nasty job in very specific ways (they have care- and purposefully designed geometries, windscreens, armour piercing caps, fuze delays, ...). If these things do not arrive as intended, their effect will be greatly reduced and sometimes even nullified. Hell, even a 1 degree change in impact obliquity can make the difference between piercing an armoured plate or bouncing off (for otherwise identical and intact shells).

  • Wonder if this was a gimmee (Score:5, Interesting)

    by afidel ( 530433 ) on Tuesday November 05, 2002 @08:03PM (#4603746)
    like the ones used to pass the first generation patriot missle system. The gen 1 patriots were so bad that final analysis showed that in one test the patriot missed the mark only to have the target slam into it, thus causing both to break up. In the official scoring this was marked as a hit and win for the patriot sytem even though it was a random fluke. Unless someone not affiliated with the military or the defense contractor verifies the results I shall remain skepticle until field use proves the system.

  • Shells easier to hit than rockets (Score:4, Insightful)

    by spun ( 1352 ) <loverevolutionary@@@yahoo...com> on Tuesday November 05, 2002 @08:04PM (#4603751) Journal
    They make it sound as if an artillary shell is a HARDER taregt to hit than a rocket. Rockets accelerate, tumble, and move erratically. Artillery shells move in well understood, computable trajectories. They probably had the damn flight path of the shell computed before they fired it. It's one thing to shoot down a shell when you know it's path ahead of time, another entirely to get a fix on an unknown, erratic rocket and destroy it.
    • Shells are smaller than rockets (with some exceptions -- 14in navguns come to mind :-P).
    • Really?

      I would think that a shell starts with an initial velocity, and slows down due to air resistance and gravity as it arcs upwards.

      As it begins it's decent, itmay speed up with gravity, or slow down even more, depending on the air-resistence. If it slows down, it will slow down slower (if that makes sense).

      Second, a shell goes much faster than a rocket. If the aim is off by just a little, a rocket might not have moved that much. A shell would probably be long gone.

      Third, I believe shells are smaller than rockets. Smaller target requires more accuracy.

      Ergo, a shell *IS* harder to hit than a rocket.

      • Re:Shells easier to hit than rockets (Score:5, Informative)

        by Phanatic1a ( 413374 ) on Tuesday November 05, 2002 @08:26PM (#4603989)
        As it begins it's decent, itmay speed up with gravity, or slow down even more, depending on the air-resistence.

        It's still going to closely approximate an ideal paraboloid, except at the terminal stage of flight where it's going to travel more vertically than ideal equations predict. In addition, the shell travels way up high, easily visible to radar, where most missiles people on the surface worry about tend to lose themselves in ground clutter, SR/IR/ICBMs aside.

        Second, a shell goes much faster than a rocket.

        No, not really, especially during the terminal stage when the shell's maximum speed is limited by terminal velocity; a shell gets one big push at the start of its flight, and is purely passive afterwards (well, excepting rocket-assist and basebleed, but still). A rocket continues to accelerate as long as the motor burns, and can reach speeds far in excess of artillery shells, which can routinely be seen with the naked eye as they hurtle downrange. The trouble here is that "rocket" spans such a wide range; a rocket can be a nice slow fat subsonic target like a Silkworm, or a Mach 2.5+ evasive-action-capable SS-N-22. HARM missiles have a top speed of 2300kph, ferinstance, a good bit faster than terminal velocity of most things that only travel ballistically.

        But in either case, shooting down a shell in flight is really nothing new. The Brits had Sea Dart back in the Falklands, and that was capable of shooting down 4.7" artillery shells. Shooting down the shell is *not* new, or exciting or innovative. Doing it with a laser is.

    • They've already hit rockets, apparently.

      The BBC has more [bbc.co.uk].

      Phil, just me

    • It's one thing to shoot down a shell when you know it's path ahead of time, another entirely to get a fix on an unknown, erratic rocket and destroy it.
      Actually, that depends on how you look at it. A rocket, while certainly being much harder to target and track with the laser, is still holding volatile propellent, which the artillery shell would lack. The artillery shell would also have a thicker casing then a missile. This makes me wonder the same thing as another poster, what they mean when they say the shell was "Destroyed". Still, it is interesting to see lasers coming into use in the military, for purposes other than just targeting things.
    • You might be right, but it's a freaking hard problem in any case.

      There's a simple formula for calculating how far you will miss by if the laser is misaligned: e = d tan t where t is the angle of misalignment and d is the distance from the laser to the target. Disclaimer: this formula is only accurate for extremely small angles, but those are the kind we're dealing with here.

      Say, for example, you're shooting at a missile that's 1500 meters away, and you are misaligned by 15 arc minutes (0.25 degrees). The laser will miss the rocket by 6.5 meters, according to the formula. That's a significant error.

      Not only do you have the difficulty of tracking the rocket to within sub-meter accuracy, you also have the problem of keeping the laser in constant alignment to extremely low tolerances, for a long enough period of time to actually destroy the target.

      This accomplishment is no laughing matter!

    • "They probably had the damn flight path of the shell computed before they fired it."

      I saw a thing on the Discovery Channel once where they had a video camera that could watch for bullets. They had a computer hooked up to it that could detect the bullets, watch their movement, and show where it originated. It was even capable of predicting where the bullet'd end up before impact.

      Damn cool demo, but I cannot recall what the context of it was or what show it was. They wanted to use it to locate snipers.

    • Re:Shells easier to hit than rockets (Score:5, Insightful)

      by hondo77 ( 324058 ) on Tuesday November 05, 2002 @08:55PM (#4604202) Homepage
      That's why they're called TESTS. This is like complaining to the Wright Brothers, "That's nice but it's not as hard as carrying 50 people across the Atlantic non-stop." It's all hard, of course, so one has to expect little steps like these.

    • Re:Shells easier to hit than rockets (Score:5, Insightful)

      by f97tosc ( 578893 ) on Tuesday November 05, 2002 @09:14PM (#4604323)
      They make it sound as if an artillary shell is a HARDER taregt to hit than a rocket. Rockets accelerate, tumble, and move erratically. Artillery shells move in well understood, computable trajectories. They probably had the damn flight path of the shell computed before they fired it. It's one thing to shoot down a shell when you know it's path ahead of time, another entirely to get a fix on an unknown, erratic rocket and destroy it.

      You are right that it is easy to compute the trajectory of an artillery shell if you know the speed (and this you can measure by radar). You just solve the same equations that the artillery battery did before firing. These computations are very well understood. That being said, I disagree with the statement that (cruise) missiles are easier.

      First of all, rockets don't really "accelerate, tumble, and move erratically" that much. They can be mostly considered like an artillery shell with a constant forward force. A cruise missle may make one or two smooth turns during its flight, rocket artillery not a single one. If you are firing a laser it is a safe bet that the missile will keep on the same path for a couple of more seconds - and remeber, the laser reaches its target instantaniously so it is easy to cancel or readjust your beam.

      Now a couple of factors that makes it harder to kill the artillery shell
      -It is much faster than a (cruise) missile -It is smaller, about one third of the size -It is not particullary sensitive. The shell is basically a piece of metal shaped like a cone travelling only by momentum; the cruise missile has little wings, complex control systems and yes, it burns rocket fuel.

      I think this is quite revolutionary. I venture guess they will put these bastards on Aircraft carriers. Not a hostile shell, missile, airplane or UAV will come within miles. And there are nuclear power plants to drive them.

      Tor (served in the Swedish artillery)

  • Awesome, (Score:5, Funny)

    by tcd004 ( 134130 ) on Tuesday November 05, 2002 @08:04PM (#4603756) Homepage
    So when WWIII starts, we just pop in some Pink Floyd and watch the show!

    I wonder if they can make it look like an animated running man? Those are the best!

    Visit Richard Gere's Ass Zoo [lostbrain.com]

    tcd004

  • Good, but... (Score:4, Informative)

    by anzha ( 138288 ) on Tuesday November 05, 2002 @08:05PM (#4603766) Homepage Journal

    Guys, really, once they demonstrated shooting down Katyusha's, the artillery shells were pretty certain to be a succesful shootdown. I am glad to see that they are not just sitting on their laurels tho.

    Look here [prnewswire.com] for TRW's story and here [trw.com] for press info on the MTHEL.

    It does look like they just used the THEL tho for the test. I am more than willing to be wrong though.

  • dramatic pause to spit "tobaccy" juice on the ground...
    If I can shoot yer .38 bullet out th' air with my MTHEL then you an' yer posse need to get otta Dodge...
    pilgrim.

  • Yay! (Score:4, Funny)

    by Cervantes ( 612861 ) on Tuesday November 05, 2002 @08:06PM (#4603782) Journal
    Yipee! Won't we all be safe once the "civilized world" is protected from the barbarians? Why, the "bad people" won't even be able to shoot at usat all, let alone support the "terror-ists" with their insidious "terror-ism".

    So, lets review. 'Predator' unmanned aircraft armed with Hellfire missles for patrol and attacks, lasers to shoot down artillery (and you know bullets are coming soon), Star Wars V2 to protect us from missiles, and any country that tries to develop anything we don't like gets a "regime change".

    Yeah, I can't see why the rest of the world hates the west, can you? We turn war into a fuckin' video game, and relegate them to attacking us with swords while riding their camels.

    I know it's the natural evolution of war, but it also seems like the natural evolution of capitalism applied to the battlefield. He with the most money to make the best toys wins, and he who doesn't hopes for an aid package to be sent to his widow.

    Of course, we might get charitable in a few years and let them have some low powered lasers, but only if they attach them to the sharks... I mean, come on, is it too much to ask for some sharks with frickin lasers on their heads?

    I think it's time for some sugar... rants like this could be dangerous... nice Echelon, niiiice Echelon.

    Hm, maybe I should get a book on lasers from the librar

    NO CARRIER

    • Re:Yay! (Score:3, Interesting)

      by Frank of Earth ( 126705 )
      So, lets review. 'Predator' unmanned aircraft armed with Hellfire missles for patrol and attacks, lasers to shoot down artillery (and you know bullets are coming soon), Star Wars V2 to protect us from missiles, and any country that tries to develop anything we don't like gets a "regime change".

      Hrm.. well we [Americans] have to get something out of our tax dollars. It sure made my day when CNN reported they were able to identify the target of the hellfire by the leg fragment they found by the blast site.

  • One meeeelion dollars! (Score:4, Funny)

    by broken ( 1648 ) on Tuesday November 05, 2002 @08:12PM (#4603852)


    Who? Who is predictable?

  • Laser weapons (Score:3)

    by zephc ( 225327 ) on Tuesday November 05, 2002 @08:12PM (#4603854)
    looks like we're getting ready to fight the Goa'uld invasion forces... ;-)

  • The future is coming (Score:3, Interesting)

    by NewtonsLaw ( 409638 ) on Tuesday November 05, 2002 @08:12PM (#4603855)
    Gosh, it looks as if all those old sci-fi books really were a glimpse of the future.

    Now if this prediction made in the 1969 edition of Popular Mechanics would just come true:

    "Future watches won't just be for keeping time either. Wlatham engineers forsee this exciting possibility: Wristwatches in the year 2000 will be used for more than time measurement. They will be total communication centers, containing devices not only for accurate timing but also for voice and vision communication; and simple recording -- they'll even contain simple miniaturized computers"

    Wow -- imagine that, a miniaturized computer in your wristwatch -- nah, it could never happen!

    But a Dick-Tracy wristwatch communicator, yeah, that'll work :-)

  • Mirror coating? (Score:4, Interesting)

    by Quixote ( 154172 ) on Tuesday November 05, 2002 @08:15PM (#4603881) Homepage Journal
    What if the shell had a very glossy finish (like a mirror or something). Would the laser still have the same impact (no pun intended)? I'm just curious.

  • Throw me a frickin' bone, people (Score:5, Funny)

    by Junior J. Junior III ( 192702 ) on Tuesday November 05, 2002 @08:21PM (#4603938) Homepage
    All I asked for is that the word "la-ser" be printed with quote marks around it, is that so hard?

  • Targeting is the problem (Score:3, Insightful)

    by Brother52 ( 181351 ) on Tuesday November 05, 2002 @08:24PM (#4603971)
    ...the laser tracked, locked onto and fired...

    I wonder how the laser could do this. This is indeed the most technicaly challenging part of the task. I visit military exhibitions regularly but I never heard of a system that could work against targets of that size (projectile). Even tracking rockets is very difficult and they're way bigger and emit a lot of detectable heat.

    My guess is that in their setup the targeting system knew from where exactly the gun fired. In a real-life war this is usually not the case. So until the tracking is reliable (and not easily fooled), this sounds entirely vaporware.

    • The military has been tracking projectiles for a long time. They had mortar tracking radar during the Vietnam War that could track the shell, predict its impact point, and more importantly, back calculate the launch point.

      Tracking a shell can be very easy, depending on the circumstances. They are made out of conductive metal, so a radar can certainly track them.

      You detect the firing with a rapid scan radar, then lock onto it with a finer resolution radar. Then you use lidar (Laser radar) for final tracking and range finding.

      This really is not much of a trick.

      What is impressive is integrating all of that technology with a laser that is powerful enough to damage the projectile while at the same time being able to track it.

      Vaporware. Hardly - this system is already being used in Israel and to shoot down Katyusha rockets. In this sort of issue, the main difference between an artiller shell and a rocket is that the rocket is likely to be longer. But an artillery rocket doesn't burn for long, and then it is just another ballistic projectile.

  • Nasty chemicals (Score:4, Informative)

    by shadowj ( 534439 ) on Tuesday November 05, 2002 @08:29PM (#4604010)
    The article mentions that it's a "deuterium flouride" chemical laser. I wasn't surprised that flourine is involved, but why deuterium? Why wouldn't hydrogen do? Deuterium's chemical properties are the same as those of plain old H, I though.

    It took a little poking around, but I found an explanation [peacevision.org.uk] of how this thing works... looks like deuterium gets them a longer wavelength that travels through the atmosphere better.

    Whatever the reasons are, I wouldn't want to be anywhere near that thing while it's fueled. Raw flourine is incredibly nasty stuff, and the hydrogen flouride exhaust is really awful [ilo.org], too... it dissolves in water to form hydrofluoric acid, which is reactive enough to eat glass (you have to keep it in teflon bottles). I hope they're not discharging it into the atmosphere!

  • Don't Forget ... (Score:3)

    by Poligraf ( 146965 ) on Tuesday November 05, 2002 @08:36PM (#4604075)
    ... how the computing started.

    IIRC, one of the goals for the first computers was to calculate the trajectory of the anti-aircraft (read: anti-bomber) fire.

    Scroll 60 years ahead, and we have even more precise shooting at the air-based attack weapons.

  • artillery expert (Score:5, Informative)

    by cr@ckwhore ( 165454 ) on Tuesday November 05, 2002 @08:58PM (#4604216) Homepage
    As an ex army cannoneer, I'd like to know more about the artillery shell that was destroyed by the laser.

    Here's what I can tell you ...

    I worked on the m198 Howitzer, which can fire a 100 pound 155mm HE (high explosive) shell at a muzzle velocity of around 750m/s. With other combinations of propellants and rounds, the velocity could easily reach 1 kilometer per second or greater. Not too shabby for a 100+ pound piece of steel going down range into a target the size of a 5 gallon bucket.

    The inherent problem with an artillery shell is that its trajectory is highly predictable... its all about math. So, for the purposes of a high powered laser, as long as it can perform some really nifty calculations in a split second, and point itself right into the path of a traveling artillery shell, then the shell will actually fly into the laser if everything goes according to plan.

    Artillery shells can also be detected with radar ... we used radar at night to track where our shells were landing.

    So, whats next... assuming that the laser works by calculating the trajectory of the shell, and positions itself ahead of the shell, would the next advancement in artillery be shells that wobble to avoid running into a high powered laser?

    Besides these basic artillery shells, there are also laser guided and rocket assisted shells, whos trajectories may be a bit harder to calculate.

    Here are just some of the factors that go into calculating the trajectory of an artillery shell...

    1. The exact weight of the shell.
    2. The type, amount, and temperature of the propellent.
    3. Resistence of travel (air friction) based on weather conditions and altitude.
    4. Curvature of the earth and gravity.

    So there you have it folks... this laser is an amazing piece of technology.

  • Great! (Score:4, Interesting)

    by Rogerborg ( 306625 ) on Tuesday November 05, 2002 @09:01PM (#4604240) Homepage

    Now, all we need to do is to find an enemy to use it against.

    If we don't know where the shells are coming from, what's the chances that this system will be able to realistically identify a genuine incoming round, activate (from idle) and reliably shoot it down in time? We're not getting the first couple of rounds, and after that, our existing counterbattery systems will be silencing the enemy artillery.

    If we do know where they're coming from (and we damn well should, given what we spend on reccetech), then why aren't we pasting them with our existing overwhelming air superiority and artillery?

    So what's the theatre? Where are these systems going to be deployed?

    One in the White House, one in the Pentagon... where else? Whatever we build on the WTC site? But do we reckon that any grunts are going to get the benefit of it? Hmmm.

    It's neato technology, but it seems like a solution to a problem that the US has spent trillions to ensure that it doesn't have any more.

    • Re:Great! (Score:3, Insightful)

      by neema ( 170845 )
      Given the fact that the Israeli Defense Ministry has been aiding the US with this, I'm going to go ahead and assume that they'll definately be having systems such as this.

  • a real world application? (Score:3, Informative)

    by Sarin ( 112173 ) on Tuesday November 05, 2002 @09:02PM (#4604247) Homepage Journal
    ofcourse they knew exactly which flightpath the shell was going to follow and where it was going to be at what time beforehand. So taking it down wasn't really that hard.

    They probably shot some shells before and got the flightpath recorded into a computer. Then they shot the "test" shell during compareable weatherconditions and perhaps they even did some minor adjustments, it doesn't really matter, they knew the trajectory beforehand, so when they shot the "test" shell the laser knew exactly at which point to fire at which coordinates.

    This isn't how things go in the real world, so I wonder how much of an defense contractor technology bragging hype this is and whose interests are behind this (it's not difficult to make a guess here).
  • I'm suprised no one else caught this. The initial description of "concentrated light energy photons" made me a little wary, but then I noticed:

    "the laser tracked, locked onto and fired a burst of concentrated light energy photons at the speeding shell... Seconds later, at a point well short of its intended destination, the projectile was destroyed"

    I dunno what kind of crazy trajectory that laser had, but at 300km a second, this thing must have been pretty darn far away...

    One would think that "instantly, the projectile was destroyed" would sound even better--and more importantly, have been accurate.

  • Begging to violate the Geneva Convention (Score:4, Interesting)

    by ProfessorPuke ( 318074 ) on Tuesday November 05, 2002 @10:07PM (#4604592)
    Most nations have signed the Geneva Convention to regulate the conduct of war- amoung other things, this means that you can only attack people with weapons meant to kill them, but not infect, poison, or maim.

    (A gentleman's agreement between the respective military-industrial-complexes, really. Dead soldier -> proud military funeral -> enhanced militarism and anticipation of future retaliation. Wounded soldier -> disabled veteran begging on sidewalk -> budget pressure for providing care, and public squeamishness about enrolling in future conflicts. Too much peace hurts our economic growth!)

    This means no chemical weapons (tell that to Russia!), no hollowpoint or fragmentary bullets, few shotguns, and no lasers aimed at people. Because the easiest ways to hurt someone with a laser is to burn his eyes out, this is consistent with Geneva.

    But, today's new, powerful anti-munition lasers will be an attractive option in the anti-aircraft role as well. Military planners must be thinking of this, but they don't want to talk about it for fear of striking taboo/war-crimes territory.

    But I wonder what'll happen if a laser-defense battery suddenly finds themselves face to face with an enemy Hind who snuck up terrain-masked. Will they run for it and hope he's a slow shot, or light it up and watch the fireworks?

    And, if the the ABL gets built and we get another hijacker repurposing an airliner into a weapon, the president will be hard pressed not to order him zapped, too.

    (Of course, another reason planners might not talk much about targeting aircraft with lasers is that the US and Israel have no potential opponents whose aircraft can't be simply destroyed with Beyond-Visual-Range missiles. Won't stop me from speculating.)
    • Right before your head turns to ash.

      It seems to me that a laser that can pump enough energy into a rocket or a shell to destroy it is going to pump enough energy into your face to melt it off. I really don't think being blinded is much of a concern. That's like saying, "watch where you point that shotgun! You could put someone's eye out!" Sure, their eyes come out the back of their head. They ain't blind... they dead.

    • Define "aimed" (Score:3, Insightful)

      by Mulletproof ( 513805 )
      "...and no lasers aimed at people"

      Except that this system will be used principly for shooting down shells, not people. It'll most likely be aimed up, 24/7 to do it's job. If a Hind should wander into it's attack radius, maybe it'll lock on, maybe it won't, but I serverly doubt it will specifically target the people inside, just the big radar blob that represents the helo. Tough shit for them. If you could ban it on that point, well hell, lets ban all surface to air weapondry while we're at it.

      As far as the ABL against terrorsists, sure, why not. That's why the white house has SAM sites and marines equipped with Stingers. Again, the effect is the same.

  • what it means to destroy an incoming projectile (Score:5, Informative)

    by v1 ( 525388 ) on Tuesday November 05, 2002 @10:59PM (#4604889) Homepage Journal
    There was some confusion as to what value there was in shooting a hole in an artillery shell.

    If you hit a rocket with a laser, your best shot would disable its guidance and control systems. This would quite possibly shut down its engine, but would certainly prevent it from hitting you at all. Secondary targets on a misile include control surfaces, engine, and fuel, all of which have the potential to destroy the misile before it reaches you.

    Now if you are applying these countermeasures on a misile that is already very near you, another factor comes into play... what kind of a hit it is. If you're on an aircraft carrier and someone shoots an antiship misile at you from reasonably close range, and it's of a Russian design, it's going to fly up at 45deg, and then sharp down at 45 degrees at you, very fast. If you manage to detonate the propellant or disable the rocket, there's still a good chance it will hit you and deliver its full damage. (a "hard" hit) If you get luckier and detonate its payload, or destroy the control and detonation systems, you are still going to get hit, but this is a "soft" hit. The misile body, rocket motor, and all the other bits (in one piece or many) will still do appreciable damage, but at least it's not likely to sink the boat.

    Shells are different. Major shells are going to have armor piercing or high explosive payloads, and C4 just doesn't blow up if you vaporize it with a laser... it burns. So you are not all that likely to detonate it. Shells are fired with great precision, and if all factors are known, they will land with that same precision. Your best hit on a shell is to damage it physically, and change its aerodynamic characteristics. Take a shell and scar the nose with a pocket knife, and it's totalled... you won't hit anything with it, it's not going to fly straight anymore. The laser just has to damage the casing. It's worth noting that if you punch a hole in it fast enough and start burning up the C4 inside, you might just plain burst the shell by simple gas expansion. In any event, it's effectively dealt with. It may still land and blow up, but it's not going to hit what it was aimed at.

    Even changing the orientation of the misile/shell is very useful in countermeasures. Most of these have "shaped charges", where the explosive payload is directed in a very carefully engineered way to do maximum damage. When hitting a tank with an antitank round, having the "business end" hit the tank is the difference between destroying the tank (piercing the armor and sending chaff all around the cabin to kill the crew) or doing negligible damage by exploding harmlessly outside the tank. Misiles are essentially the same... a misile that would normally destroy a target may not even detonate if it's tumbling when it hits and contacts sideways, and if the target is even lightly armored, damage will be minimal rather than fatal.

    I expect lasers to prove very effective as a projectile countermeasure.

    I did have one curiosity about the shell test they did... does anyone know how long they "beamed" the shell before it was effectively dealt with? That's one thing that must be considered... if you have to hold the beam on the target for a considerable length of time, it may be much more difficult to get in a fatal shot. Misiles tend not to roll, so if you are shooting at it from the side, (i.e.you're not the target) you still can hit one spot continuously. Shells on the other hand, are usually designed to spin as they fly downrange, and so targetting the side is actually targetting a band around the shell.

  • Yes, the guidance systems today are _that_ good (Score:5, Informative)

    by sgtrock ( 191182 ) on Wednesday November 06, 2002 @01:10AM (#4605639)
    Anyone who has served on board ship in the US Navy since 1980 knows just how good our targeting systems can be. Ever heard of the acronym CIWS? It stands for Close In Weapons System. It was designed to take out inbound projectiles such as cruise missiles between 10 km and 1 km from the ship. It is still actively deployed on many US ships.

    The system consists of a tracking radar system with enough computing power to track up to 150 threats at once. It prioritizes the targeting system based upon inbound speed, size of the object, IFF status, and distance from the ship. Once this sucker is enabled, you'd better hope your planes have their IFF turned on, or they'll be shot down quicker than you can blink.

    The system did all this using a Vulcan cannon, which is a gatling gun design throwing depleted uranium rounds downrange. The system was designed to fire and correct inflight to hose down a target until it dropped out of the sky. The system's biggest weakness was the fact that it went through rounds so fast (up to 6,000 rpm theoretical, 2,000 rpm typical) that the magazines had to be HUGE. I once saw a picture of the USS New Jersey after its refit. The 4 magazines on board held enough rounds to fire for a grand total of 15 minutes without stopping. The smaller ships that had the system frequently were limited to less than 2 minutes. A decent laser system's power plant occupying the same space would solve this problem.

    This system was successfully demonstrated almost 25 years ago. Its first active deployment was in 1980 or 1981. And you "experts" are trying to tell me that the targeting technology hasn't improved enough since to take down an artillery shell? Oh, please. Go do some very basic research on what's in use TODAY before hollering about weapons tests for stuff that might be deployed tomorrow.

    The only question in my mind is the size of the power plant necessary to drive a powerful enough laser to be useful. Can it be mounted on anything smaller than a ship? Anyone know?

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