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This seems misleading: > Both costs pennies on the dollar compared with missiles and smart bombs A laser weapon is not an over-the-horizon weapon, so its spea

This seems misleading: > Both costs pennies on the dollar compared with missiles and smart bombs A laser weapon is not an over-the-horizon weapon, so its spear of effect is quite a bit smaller than a "missile and smart bomb." It might be able to displace a Mark 45 gun or the Phalanx CIWS point defence system, but neither of which are missiles or smart bombs, and both fire relatively inexpensive (but heavy) ammunition. It could not replace weapon systems like the Harpoon, Tomahawk, or Trident. You could, in theory, get rid of SAMs and replace them with this laser system. But you better be damn confident in the laser system's ability to automatically target and destroy incoming projectiles as the laser has to wait a lot longer to fire than a SAM system does just due to line of sight (which is damn scary if the attackers are in supersonic aircraft, as it is reasonable to expect them to be). Now you might say: "It is computer controlled! It will be like Robocop!" But if you look at the Phalanx CIWS which is also computer controlled, it is damn terrible at targeting pretty much anything unless it is someone approaching in a trawler going 8 knots (and maybe even then you might miss a few times).

Havoc 13y ago
>A laser weapon is not an over-the-horizon weapon I'd imagine the long term plan is to roll both lasers and rail guns. The combo seems ideal. Cheat laser shots to swat missiles and drones out of the surroundings whilst bombarding everything further away with the railgun. I bet with a bit of clever tech you can pull off some insane over-the-horizon railgun shots. >Phalanx CIWS which is also computer controlled, it is damn terrible at targeting pretty much anything Laser having +- zero flight time should solve most of that.
- UnoriginalGuy 13y ago
  > I bet with a bit of clever tech you can pull off some insane over-the-horizon railgun shots. The projectiles would only have the force of gravity/terminal velocity behind them unless they have been able to create an explosive railgun projectile (that doesn't explode on the launchpad due to the extremely high temperatures and other shock railguns apply to their projectiles). > Laser having +- zero flight time should solve most of that. I think "most of that" is a little overly optimistic. Target tracking is a complex problem, particularly in a war-like scenario where the target might very well be supersonic and in less than ideal weather conditions. Anti-ship missiles can and are designed to travel below radar range, so trying to get a good sense of depth against a blue sea and white/blue horizon is far from trivial even for a computer. The laser still might be the "least bad" defensive weapon against anti-ship missiles, but the whole thing is far from full-proof. We haven't really seen a full on naval conflict between two modern navies, so we kind of forget just how amazing most of the weapons are these days.
  - njharman 13y ago
    > The projectiles would only have the force of gravity/terminal velocity Horizontal velocity will, presumably, be reduced by drag. But it won't be zero for a long, long ways over the horizon.
    - UnoriginalGuy 13y ago
      Not sure I follow. You point the projectile too low and it just hits the ocean (due to the curvature of the earth), you point it higher than the horizon then the projectile will continue to travel upwards indefinitely until it runs out of energy and then will fall back to earth with the force of gravity. The only way what you're saying works is on a flat planet or against a target within your horizon.
      - Filligree 13y ago
        It will still be travelling sideways when it hits the target, and unless your target is a long, long way off it'll be travelling sideways with significant speed. Railgun projectiles, like cannon shells, travel on a parabolic curve - not a half-circle.
        UnoriginalGuy 13y ago
        Cannon shells cannot be fired over the horizon either. Firing over the horizon will convert the projectile's forward momentum into height, it will reach whatever its apex is, run out of momentum and then fall due to gravity. The angle is just too steep. The only way to make this an effective weapon is to fill it with explosives (since then you've just created a mortar). But firing explosives from a railgun has its own issues. Most weapons which depend on a steep parabolic curve to hit their targets also have explosives in them, like artillery, mortars, ICBMs, etc. You can use a less steep curve to deliver blunt force to a target (catapult, cannon, gun, etc) but these weapons have a finite range as the earth is curved, therefore you'd have to tilt them too far back to overcome that, which will cause all that lovely forward force you're depending on to do damage going up into the sky as it flies higher and higher.
- wavefunction 13y ago
  I assume rather than rail-guns, we will simply park laser batteries in NEO calibrated or perhaps just powerful enough to punch through the intervening atmosphere and water vapor to strike their targets. Of course I am just a sci-fi enthusiast in this regard, so take this comment for what it's worth... (I am not at all excited about the weaponization of space, but unfortunately feel it is inevitable given "politicians")
  - dublinben 13y ago
    That would probably violate the Outer Space Treaty.
  - waiquoo 13y ago
    https://en.wikipedia.org/wiki/Project_Thor#Project_Thor https://en.wikipedia.org/wiki/Project_Thor#Project_Thor
TeMPOraL 13y ago
Could it be possible to reflect the laser with a mirror? If so, maybe the navy could use UAVs with mirrors to guide the laser for over-the-horizon shots.
- UnoriginalGuy 13y ago
  That is such a crazy concept it just might work. The logistics of it are mind boggling, but other than mirror-heat I cannot see too many huge issues with it right off the bat (aside from logistics).
  - TeMPOraL 13y ago
    > The logistics of it are mind boggling Could you elaborate? I don't think it would be just as simple as putting a big mirror on a Predator drone, but then I can't see it being that much more complicated.
- jloughry 13y ago
  When a high power (megawatts) laser hits a surface, even a mirrored surface, the effect is more like a hammer than a reflection. This was studied extensively during the SDI program. Chrome plating missiles is, in the long term, ineffective; the beam transfers energy kinetically like a bullet, not through heating effects. That said, it might work for now against kilowatt lasers. Edit: an interesting and non-theoretical example of catastrophic optical damage is the "fiber fuse" effect: a spot of light burns its way along the length of a strand at about 1m/sec (destroying it as it goes). See this video (the narration is in Japanese): http://www.youtube.com/watch?v=BVmIgaafERk http://www.youtube.com/watch?v=BVmIgaafERk
jandrewrogers 13y ago
Yes, this is strictly a point-defense augmentation. The challenge of Phalanx CIWS is not targeting, it is that you have to (1) predict bullet trajectory in a complex environment that continuously deviates from the "in a vacuum" trajectory and (2) predict the trajectory of the target while the bullet is on its way to the target. In the case of the original Phalanx gun, they compensated for the intrinsic difficulty of this with a high rate of fire. However, today the CIWS guns are being replaced with small missiles, which solves the problem of hitting the target. Terminal guidance against hypersonic targets was a solved problem twenty years ago; a computer can react much quicker than materials science allows a real object to alter its trajectory in a material way. The obvious problem with using small missiles for CIWS is that they are relatively expensive and more difficult to store and handle. This is where a laser CIWS system becomes a nice augmentation to both gun and missile CIWS. Tracking targets in real-time with high-precision is a problem solved many years ago so the real challenge is getting sufficient power on target in a practical laser package, which they apparently have figured out.

Havoc 13y ago

>A laser weapon is not an over-the-horizon weapon I'd imagine the long term plan is to roll both lasers and rail guns. The combo seems ideal. Cheat laser shots to swat missiles and drones out of the surroundings whilst bombarding everything further away with the railgun. I bet with a bit of clever tech you can pull off some insane over-the-horizon railgun shots. >Phalanx CIWS which is also computer controlled, it is damn terrible at targeting pretty much anything Laser having +- zero flight time should solve most of that.

UnoriginalGuy 13y ago
> I bet with a bit of clever tech you can pull off some insane over-the-horizon railgun shots. The projectiles would only have the force of gravity/terminal velocity behind them unless they have been able to create an explosive railgun projectile (that doesn't explode on the launchpad due to the extremely high temperatures and other shock railguns apply to their projectiles). > Laser having +- zero flight time should solve most of that. I think "most of that" is a little overly optimistic. Target tracking is a complex problem, particularly in a war-like scenario where the target might very well be supersonic and in less than ideal weather conditions. Anti-ship missiles can and are designed to travel below radar range, so trying to get a good sense of depth against a blue sea and white/blue horizon is far from trivial even for a computer. The laser still might be the "least bad" defensive weapon against anti-ship missiles, but the whole thing is far from full-proof. We haven't really seen a full on naval conflict between two modern navies, so we kind of forget just how amazing most of the weapons are these days.
- njharman 13y ago
  > The projectiles would only have the force of gravity/terminal velocity Horizontal velocity will, presumably, be reduced by drag. But it won't be zero for a long, long ways over the horizon.
  - UnoriginalGuy 13y ago
    Not sure I follow. You point the projectile too low and it just hits the ocean (due to the curvature of the earth), you point it higher than the horizon then the projectile will continue to travel upwards indefinitely until it runs out of energy and then will fall back to earth with the force of gravity. The only way what you're saying works is on a flat planet or against a target within your horizon.
    - Filligree 13y ago
      It will still be travelling sideways when it hits the target, and unless your target is a long, long way off it'll be travelling sideways with significant speed. Railgun projectiles, like cannon shells, travel on a parabolic curve - not a half-circle.
      - UnoriginalGuy 13y ago
        Cannon shells cannot be fired over the horizon either. Firing over the horizon will convert the projectile's forward momentum into height, it will reach whatever its apex is, run out of momentum and then fall due to gravity. The angle is just too steep. The only way to make this an effective weapon is to fill it with explosives (since then you've just created a mortar). But firing explosives from a railgun has its own issues. Most weapons which depend on a steep parabolic curve to hit their targets also have explosives in them, like artillery, mortars, ICBMs, etc. You can use a less steep curve to deliver blunt force to a target (catapult, cannon, gun, etc) but these weapons have a finite range as the earth is curved, therefore you'd have to tilt them too far back to overcome that, which will cause all that lovely forward force you're depending on to do damage going up into the sky as it flies higher and higher.
wavefunction 13y ago
I assume rather than rail-guns, we will simply park laser batteries in NEO calibrated or perhaps just powerful enough to punch through the intervening atmosphere and water vapor to strike their targets. Of course I am just a sci-fi enthusiast in this regard, so take this comment for what it's worth... (I am not at all excited about the weaponization of space, but unfortunately feel it is inevitable given "politicians")
- dublinben 13y ago
  That would probably violate the Outer Space Treaty.
- waiquoo 13y ago
  https://en.wikipedia.org/wiki/Project_Thor#Project_Thor https://en.wikipedia.org/wiki/Project_Thor#Project_Thor

TeMPOraL 13y ago

Could it be possible to reflect the laser with a mirror? If so, maybe the navy could use UAVs with mirrors to guide the laser for over-the-horizon shots.

UnoriginalGuy 13y ago
That is such a crazy concept it just might work. The logistics of it are mind boggling, but other than mirror-heat I cannot see too many huge issues with it right off the bat (aside from logistics).
- TeMPOraL 13y ago
  > The logistics of it are mind boggling Could you elaborate? I don't think it would be just as simple as putting a big mirror on a Predator drone, but then I can't see it being that much more complicated.
jloughry 13y ago
When a high power (megawatts) laser hits a surface, even a mirrored surface, the effect is more like a hammer than a reflection. This was studied extensively during the SDI program. Chrome plating missiles is, in the long term, ineffective; the beam transfers energy kinetically like a bullet, not through heating effects. That said, it might work for now against kilowatt lasers. Edit: an interesting and non-theoretical example of catastrophic optical damage is the "fiber fuse" effect: a spot of light burns its way along the length of a strand at about 1m/sec (destroying it as it goes). See this video (the narration is in Japanese): http://www.youtube.com/watch?v=BVmIgaafERk http://www.youtube.com/watch?v=BVmIgaafERk

jandrewrogers 13y ago

Yes, this is strictly a point-defense augmentation. The challenge of Phalanx CIWS is not targeting, it is that you have to (1) predict bullet trajectory in a complex environment that continuously deviates from the "in a vacuum" trajectory and (2) predict the trajectory of the target while the bullet is on its way to the target. In the case of the original Phalanx gun, they compensated for the intrinsic difficulty of this with a high rate of fire. However, today the CIWS guns are being replaced with small missiles, which solves the problem of hitting the target. Terminal guidance against hypersonic targets was a solved problem twenty years ago; a computer can react much quicker than materials science allows a real object to alter its trajectory in a material way. The obvious problem with using small missiles for CIWS is that they are relatively expensive and more difficult to store and handle. This is where a laser CIWS system becomes a nice augmentation to both gun and missile CIWS. Tracking targets in real-time with high-precision is a problem solved many years ago so the real challenge is getting sufficient power on target in a practical laser package, which they apparently have figured out.