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posted by mrpg on Monday April 09 2018, @03:08PM   Printer-friendly
from the death-from-below dept.

Submitted via IRC for SoyCow8317

[...] This weapon, cobbled together from a half-dozen industrial cutting and welding lasers to produce a total power of only 30 kilowatts, was hardly the megawatt monster military scientists dreamed of decades ago to shoot down ICBMs. But it's a major milestone, advocates say, toward a future in which directed-energy weapons are deployed in real military engagements.

[...] Pentagon officials think the technology for high-energy lasers, like the one tested on the now-decommissioned Ponce, can serve a variety of roles on land and at sea: zapping the cheap rockets, artillery, drones, and small boats loaded with weapons that insurgents have deployed in places like Iraq and Afghanistan. Today, destroying an insurgent rocket costing around a thousand dollars can require a tech-laden Patriot interceptor costing $2 million to $3 million. By comparison, a laser shot from a fiber-laser weapon would cost only $1 in diesel fuel, officials claim.

[...] "The Defense Department has wanted a laser weapon system ever since the laser was invented," says Robert Afzal, senior fellow for laser and sensor systems at the defense contractor Lockheed Martin, in Bothell, Wash. "The key element has been to build this high-power electric laser small enough and powerful enough that we can put it on Army trucks, Air Force planes, and Navy ships, and not take everything [else] off" to make room for it.

Source: Fiber Lasers Mean Ray Guns Are Coming


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  • (Score: 1) by tftp on Monday April 09 2018, @09:19PM (7 children)

    by tftp (806) on Monday April 09 2018, @09:19PM (#664685) Homepage

    serve a variety of roles on land and at sea: zapping the cheap rockets, artillery, drones, and small boats loaded with weapons that insurgents have deployed in places like Iraq and Afghanistan.

    Boats? Laughable. That's what machine guns are for. Let's cut to the chase: the laser is best to shoot at humans. And it will be used for that purpose. No agreement will stand in the way. Humans are more dangerous than any boat, faster, numerous, and they have no protection.

  • (Score: 2) by takyon on Monday April 09 2018, @09:24PM (6 children)

    by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Monday April 09 2018, @09:24PM (#664687) Journal

    The lasers will have better range and accuracy.

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    [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
    • (Score: 2) by Arik on Tuesday April 10 2018, @12:39AM (5 children)

      by Arik (4543) on Tuesday April 10 2018, @12:39AM (#664754) Journal
      "The lasers will have better range"

      Not against surface targets of any kind. A lasers range, in a naval context, is limited by the curvature of the earth to around 12 miles, give or take a little depending on exactly how far each of the ships rises above the waves. The same limit applies to targets on land. Many naval guns have significantly more range than that. They don't have to have line of sight, they're quite capable of indirect fire against targets well over the horizon.

      Against aerial targets that doesn't apply, but the fundamental difficulty of trying to hit a small and very fast-moving target is only multiplied exponentially as range increases. Direct fire weapons are useful against fast military jets, let alone missiles, only at short range largely because of that factor, and going to a laser just doesn't fundamentally change that. At 12+ miles your only hope is a guided missile, or wait until the target is closer.
      --
      If laughter is the best medicine, who are the best doctors?
      • (Score: 2) by Immerman on Tuesday April 10 2018, @01:21PM (4 children)

        by Immerman (3985) on Tuesday April 10 2018, @01:21PM (#664927)

        > and going to a laser just doesn't fundamentally change that

        I think it might. As far as I can tell, there's really only three issues with trying to hit an aircraft with direct-fire weapons:
        1) Lining up the shot - tricky with a fast moving object, but well within the ability of a high-end automated turret
        2) Compensating for wind, which may be erratic especially when shooting across a significant altitude gradient
        3) Hoping the aircraft is still lined up with that shot by the time your bullet reaches them.

        Going to lasers basically eliminates 2 and 3 - you can hit it for just as long as you can draw a bead on your target.

        • (Score: 2) by Arik on Tuesday April 10 2018, @03:33PM (3 children)

          by Arik (4543) on Tuesday April 10 2018, @03:33PM (#664986) Journal
          "1) Lining up the shot - tricky with a fast moving object, but well within the ability of a high-end automated turret"

          I don't want to beat this into the ground but I do think you and other posters drastically misunderstand just how tricky this is. Even a large plane at something like 12 miles is basically invisible to the human eye, if you try to scope it it's a dot smaller than the cross-hairs you lay across it. Weapon mounts can only divide the circle into so many 'clicks' - there's a granularity, a resolution level measurable in seconds-of-angle, and targets that are effectively smaller than that resolution level are damned hard to target effectively, even when they're standing still. Just as an example, the B1 Bomber, a nice middle-sized military plane much larger than most fighters but still smaller than many bombers, runs about ~1700 inches long. That means that it will occupy approximately 1 minute-of-angle at 2.5 miles. That's doable, that's a shot a good marksman can make reliably, but it's not easy. Move out to 5 miles? A 30 second shot? You'll have to have a good computer guidance system to hit that reliably. 10 miles? We're probably getting close to the edge of the resolution on the gunmount at this point, even with every possible advantage reliable hits may be impossible. 20 miles? Forget about it. And all this is assuming that the plane is turned directly sideways to provide the best possible target, and that neither the target nor the weapon are moving at all. Figure the plane is actually supersonic, and the weaponmount is on a ship that's rocking back and forth with the waves, and this is really a nightmare problem.

          And even if I'm wrong on that, suppose somehow that's magically solved, what are the attackers going to do? It seems obvious to respond by flying extremely low, staying behind the horizon to avoid the laser until close enough to launch missiles. A plane flying low over water can reduce the effective horizon dramatically, and the world has an abundance of guided missiles with plenty of range to use for this. Then you're back to point defense against missiles. The missiles are MUCH smaller and move MUCH faster than the B-1 though. There's only the tiniest sliver of time between when they come into line of sight (can't hit them with the laser until then!) and when they actually hit your ship.

          But ok, moving on to

          "2) Compensating for wind, which may be erratic especially when shooting across a significant altitude gradient"

          Lasers have to compensate for variable atmospheric conditions, which is probably at least as complicated, and much less well understood at this point.

          "3) Hoping the aircraft is still lined up with that shot by the time your bullet reaches them."

          And there we have a real advantage, I'll grant. Lasers are faster than bullets, for sure.

          This isn't so significant at short range though, where either sort of weapon is nearly instantaneous, practically speaking. It could be very significant, in terms of long range interception, except that for the reasons stated above long range interception just doesn't seem like a realistic capability in the first place.
          --
          If laughter is the best medicine, who are the best doctors?
          • (Score: 2) by Immerman on Tuesday April 10 2018, @04:56PM (2 children)

            by Immerman (3985) on Tuesday April 10 2018, @04:56PM (#665017)

            I think you're underestimating what we have the technology to do - accurate gear reductions of millions, even trillions-to-one are trivial to produce (https://www.youtube.com/watch?v=kYmUJVE6Vo0), the only limiting factor is the play in your gears, which we also no how to virtually eliminate. Use that as the precision aiming mechanism atop a more traditional fast-targetting platform, and you can do incredible things. As for your scope, you can set the magnification to anything you like. The limiting factor is really the focal range and precision of the laser optics. At least for ground-mounted systems - I'll grant you that an air- or sea-mounted platforms turbulence is going to present additional challenges. But if your Humvee can only provide an effective missile shield when stationary, it's still pretty damned useful.

            As for your low-flying planes, etc. - yes, absolutely. If you're facing off against a fellow high-tech enemy, you'll probably see limited benefit any time soon. Where laser DO offer a massive benefit is in asymmetric warfare - which covers pretty much every war we've been involved in since WWII. It gets really expensive firing $1M interceptors against $5000 missiles. Even in a more symmetric encounter, it makes incredibly good economic sense for your opponent to fire hundreds of cheap, dumb rockets against you whenever they have the opportunity, spending millions of dollars to force you to spend billions. WWI and II were decided far more by economics than technology.

            2) There is the convenient fact that you can use targetting optics operating on or near the same frequency as your laser (i.e. an infrared scope), so that the atmospheric distortion are already taken into account - fire at where the target *appears* to be, and your shot will trace the same optical path back to where it actually is.

            3) Depends what you mean by short range - from what I can find the fastest muzzle velocity out there is an experimental military railgun firing at 8000 feet/second, or 1.5miles/second. If your target is three miles away, that gives them 2 seconds to dodge. More than enough time, especially if they're already engaging in evasive maneuvers because they expect you to try to shoot them down. There's no possible way to shoot down a modern "drunk-fire" rocket using bullets, short of than pure luck, or "wall of bullets" scenarios.

            Basically, worst-case scenario you completely miss your opponent, but force them to use extreme evasion tactics to survive, drastically reducing their own accuracy.

            • (Score: 2) by Arik on Tuesday April 10 2018, @05:55PM (1 child)

              by Arik (4543) on Tuesday April 10 2018, @05:55PM (#665037) Journal
              "The limiting factor is really the focal range and precision of the laser optics."

              There are more problems with trying to use optics with such high magnification at less than astronomical distances as well. You really have to have zero movement of the platform. When you're peering at something 10 or 20 miles away, the slightest, completely un-noticeable movement in that scope will result in you seeing nothing but a blur.

              "It gets really expensive firing $1M interceptors against $5000 missiles."

              And there's little evidence of those interceptors actually intercepting anything, they typically seem to give up and self-destruct instead, so even if the laser is not effective, it might be a less expensive way to appear to be doing something I suppose. But the thing will cost a lot more than just electricity.

              "Depends what you mean by short range - from what I can find the fastest muzzle velocity out there is an experimental military railgun firing at 8000 feet/second, or 1.5miles/second. If your target is three miles away, that gives them 2 seconds to dodge. "

              Sounds about right. And yes, a two second lead time is significant, but that's pretty easily overcome if you're able to do barrage fire. Against a surface target you can throw out a pattern of rounds in a spread with a very good chance that no matter what the target does in the intervening 2 seconds, one of them will hit; or if this is close defense against a missile, you actually get multiple mounts firing more conventional projectiles at a rate of ~6k rounds per minute so these are essentially producing streams of flying metal. Dodging one stream means moving towards another if this is done right, and AEGIS is pretty sharp.

              --
              If laughter is the best medicine, who are the best doctors?
              • (Score: 2) by Immerman on Wednesday April 11 2018, @02:05PM

                by Immerman (3985) on Wednesday April 11 2018, @02:05PM (#665363)

                A movement that's unnoticeable to you can be a huge adjustment by a computer-controlled platform - our senses are really incredibly limited, they only evolved for dealing with things within rock-throwing distance or less.

                But yes, hitting 20 miles away is likely to be a challenge - but that's even more true of projectiles. Even a barrage at that distance is going to be unlikely to hit anything - not with 20-30 seconds of dodge time.

                Last I heard the poor performance of interceptors is one of the leading motives for laser systems - at $1 per shot and instant-hit feedback you can miss a (single) missile several times and still have a decent chance to destroy it. Targetting gets easier the closer it gets, so you try at range, and keep trying until either you or it successfully hits it's target. And lets be honest, you're going to want to target the "soft" systems anyway - the glancing shot that barely scorches the paint will likely be more than enough to blind the pilot or targetting optics, which is your problem half-solved anyway.

                I'm wondering what "more than electricity" you think it will cost. There's up-front costs of course, but those are largely irrelevant in a weapon that's going to see regular use - unless the individual shots are so cheap that yo0u can use it for years and have the ammo costs still not compare. Maintenance costs should be far lower than pretty much anything else, lasers are pretty resilient devices so you'll mostly be looking at the turret mechanism and keeping the optics properly aligned.