4 ms·

True, but the horizon goes down as you go up ;) Besides those are just weapon delivery systems. Those same systems can be used to transport a laser weapon syst

True, but the horizon goes down as you go up ;) Besides those are just weapon delivery systems. Those same systems can be used to transport a laser weapon system to the area they want to attack (e.g. missile + laser, aircraft + laser)

Retric 11y ago
These systems are huge, so you might get them in a drone but it would be a large target as in the size of 20 seat business jet to a full 747. Line of sight is ed: Nm.
- peterderivaz 11y ago
  I think in this formula the altitude should be in feet, while the result is in miles, so 30,000 feet actually gives 213 miles.
  - deleted 11y ago
    [deleted]
- crymer11 11y ago
  "The distance to the horizon in miles from height of an observer is approximately equal to 1.23 times the square root of the height in feet." - http://www.davidsenesac.com/Information/line_of_sight.html http://www.davidsenesac.com/Information/line_of_sight.html
- trhway 11y ago
  >These systems are huge, not really - 10kw laser diode pack is something like laptop size. 35kw (as we have 30% electric to light conversion efficiency) light-duty generator with small motorbike engine - like another 70 kg. Add some other pieces - total will be under 100Kg.
  - Retric 11y ago
    In October 2012, the firm successfully used its 40-kW combined fiber-beam system. Not 10-kW and 40kw is on the low end of what you want. Worse, 100kg per 10kw seems optimistic. Anyway, as a first approximation if you’re dumping X energy on target with a 30% efficacy laser using a 30% efficient generator your net efficiency is at most 9%. So, you need to dump 11 times as much energy as you can get on the target. This is why most early designs focused on chemical lasers.
- mrec 11y ago
  Probably a silly question, but would it be even remotely feasible to bounce a ground- or ship-based laser off a drone-mounted mirror? Pretty sure the obstacles to positioning the drone/mirror precisely enough (and keeping the mirror clean enough) would be insurmountable, but couldn't help wondering.
  - Retric 11y ago
    Only in the rube Goldberg sense of a ridiculously inefficient system. Also, if you can build a mirror to bounce the laser you can use that same mirror to protect the target. But, N beams and N mirrors sidesteps this issue. PS: An amusing idea is to use a fleet of drones with mirrors to cook the target using sunlight.
    - gliese1337 11y ago
      Also, if you can build a mirror to bounce the laser you can use that same mirror to protect the target. Not necessarily. The attacker controls the focal distance of the laser. If they are using a mirror offensively, they can adjust the focal distance to ensure that flux is not destructively high at the location of the relay mirror, but is at the target. If you are trying to use the same mirror defensively, the attacker can simply consider that mirror to be a new armor target that needs to be destroyed before they can get at you, and adjust their focus to create unsurvivable flux at the mirror surface.
      - Retric 11y ago
        To be clear, I did not mean that as a total defense. Still mirrors can be useful in combination with other things. For example the target can use a high deflection angle to disperse the beam. AKA you beam's intensity is sin X and as it covers 1 / (sin X) area. So full intensity = 90 degrees, and at 10 degrees your down to 17.4% intensity. For something like a Mortar rotation can also be a significant benefit.
  - cli 11y ago
    The article states that the firm MBDA in Germany had helped to show that reflective armour, at least with mirrors, is not a good defense against lasers, as >any dust on the mirrored surface would get burned in, and lead to the destruction of the target even faster than with a non-reflective surface.

Retric 11y ago

These systems are huge, so you might get them in a drone but it would be a large target as in the size of 20 seat business jet to a full 747. Line of sight is ed: Nm.

peterderivaz 11y ago
I think in this formula the altitude should be in feet, while the result is in miles, so 30,000 feet actually gives 213 miles.
- deleted 11y ago
  [deleted]
crymer11 11y ago
"The distance to the horizon in miles from height of an observer is approximately equal to 1.23 times the square root of the height in feet." - http://www.davidsenesac.com/Information/line_of_sight.html http://www.davidsenesac.com/Information/line_of_sight.html
trhway 11y ago
>These systems are huge, not really - 10kw laser diode pack is something like laptop size. 35kw (as we have 30% electric to light conversion efficiency) light-duty generator with small motorbike engine - like another 70 kg. Add some other pieces - total will be under 100Kg.
- Retric 11y ago
  In October 2012, the firm successfully used its 40-kW combined fiber-beam system. Not 10-kW and 40kw is on the low end of what you want. Worse, 100kg per 10kw seems optimistic. Anyway, as a first approximation if you’re dumping X energy on target with a 30% efficacy laser using a 30% efficient generator your net efficiency is at most 9%. So, you need to dump 11 times as much energy as you can get on the target. This is why most early designs focused on chemical lasers.
mrec 11y ago
Probably a silly question, but would it be even remotely feasible to bounce a ground- or ship-based laser off a drone-mounted mirror? Pretty sure the obstacles to positioning the drone/mirror precisely enough (and keeping the mirror clean enough) would be insurmountable, but couldn't help wondering.
- Retric 11y ago
  Only in the rube Goldberg sense of a ridiculously inefficient system. Also, if you can build a mirror to bounce the laser you can use that same mirror to protect the target. But, N beams and N mirrors sidesteps this issue. PS: An amusing idea is to use a fleet of drones with mirrors to cook the target using sunlight.
  - gliese1337 11y ago
    Also, if you can build a mirror to bounce the laser you can use that same mirror to protect the target. Not necessarily. The attacker controls the focal distance of the laser. If they are using a mirror offensively, they can adjust the focal distance to ensure that flux is not destructively high at the location of the relay mirror, but is at the target. If you are trying to use the same mirror defensively, the attacker can simply consider that mirror to be a new armor target that needs to be destroyed before they can get at you, and adjust their focus to create unsurvivable flux at the mirror surface.
    - Retric 11y ago
      To be clear, I did not mean that as a total defense. Still mirrors can be useful in combination with other things. For example the target can use a high deflection angle to disperse the beam. AKA you beam's intensity is sin X and as it covers 1 / (sin X) area. So full intensity = 90 degrees, and at 10 degrees your down to 17.4% intensity. For something like a Mortar rotation can also be a significant benefit.
- cli 11y ago
  The article states that the firm MBDA in Germany had helped to show that reflective armour, at least with mirrors, is not a good defense against lasers, as >any dust on the mirrored surface would get burned in, and lead to the destruction of the target even faster than with a non-reflective surface.