russ_watters
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People looking at the target wouldn't be affected unless the target is a perfect mirror focused on them. And the laser wouldn't ever be aimed down so it wouldn't hit anyone on the ground. Even if it were, it would move too fast to damage anything on the ground.Originally posted by wimms
I wonder, what is a result of missing a target and hitting ground, say city, downtown of NY?
What is consequence of people on the ground looking at the target at instant it is hit by laser? ie - How many blind people does it take to find this weapon makes unjustified collateral damage?
Hummm, how well can we rely upon that? (just curious)Originally posted by russ_watters
(SNIP) There are also political implications: since this is strictly defensive, collateral damage is the fault/responsibility of the country that launched the missile, not the country that shoots it down. (SNoP)
By its very nature it is not well suited to attacking ground targets.Originally posted by Mr. Robin Parsons
Hummm, how well can we rely upon that? (just curious)
Here I'm afraid you are quite wrong. Its a megawatt class laser onboard, and any, even faintly reflecting surface (which laser resistent missiles will obviously be), scatters laser in random directions. Even if you receive 1 millionth of the laser power, it would be 1Watt laser into your eye. Thats fatal to your eyes. And it takes less than a blink to become blind. And your eyes might not even detect it to blink because its out of visible frequency range.Originally posted by russ_watters
People looking at the target wouldn't be affected unless the target is a perfect mirror focused on them. And the laser wouldn't ever be aimed down so it wouldn't hit anyone on the ground. Even if it were, it would move too fast to damage anything on the ground.
Well, planting h-bomb to offensive country can also be called strictly defensive, but collateral damage of this is unjustified, and now agreed to be against conventions. You have to combat weapons with similar weapons. I can't imgine how do you imagine justifying ten blind kids who have nothing to do with what their government does, to shoot down a (eg. conventional) missile.There are also political implications: since this is strictly defensive, collateral damage is the fault/responsibility of the country that launched the missile, not the country that shoots it down.
Interesting money dumpOriginally posted by russ_watters
www.airbornelaser.com
Maybe, but when I dealt with 5W argon lasers in the lab years ago, was strictly instructed to never fool with beam path optics without protective glasses, as single random reflection from any surface not limited to mirrors is sufficient to make permanent damage. That was 1mm beam.Originally posted by russ_watters
Wimms, I think you overestimate the risks from the laser.
Interesting. How do you know what I realise?There is more scattering than you realize (from both the atmosphere and the object being hit) and less of a chance that someone would be randomly looking in the right direction to see the hit.
Not quite sure what you mean here. The very beam is meant to vaporise metal spot of missile in few seconds. The energy density needed is immense. The output beam diam is about 1.5m it seems, and is focused to be much tighter at target, and all the way towards it beam diameter reduces.Also, the beam is pretty wide - something like 1-2m in diameter (about a million times the size of your iris). So you actually would get only about a millionth of the power into your eye if they aimed the beam at you.
This absorption is dependant on energy density of laser, iirc. Its a main problem to deliver 100% of energy to target as energy density is high. Reflections are subject to way lower absorption and scattering from air.And with random scattering, the amount of time the energy hits you would be pretty low. Then there's the atmosphere - it absorbs more than you might think. At the operating altitude of the plane, it'll be above something like 75% (maybe more?) of the atmosphere. Atmospheric absorption and scattering is one of the biggest engineering problems in this project.
Yes, I suppose that the 1MW is realised in pulses on example 10GW/0.1ms every second. However you require average (it doesn't matter if pulse or continual) damage power in megawats if you want to destroy rotating ballistic missile with >1 inch thick steel jacket in a few seconds.Originally posted by Tyro
Kerimek, your calculation is correct if you assume the process is a continuous one. Most lasers, despite having large wattages, only operate for a split second. As such, even a low-yield power source which charges capacitors, etc. over time would suffice. This does not affect the efficiencies, only the feasibility of various power sources.
I'm not sure it makes sense to think about efficiency of energy conversion here. Although I don't quite get how it works, laser mentioned seems to be not so dependant on electricity:Originally posted by kerimek
Interesting money dumpTake an efficiency of electricity production in engines about 30% (maximally!), efficiency of electricity to beam energy conversion 10% (maximally) and finally plane to target energy transfer efficiency 20%. Then you have total efficiency about 0.6%. So for 1MW of continual thermal damage you require minimally 130MW energy source (without laser cooling consumption and normal engines consuption). Have you any dilithium, captain Kirk?