That’s correct, but it will definitely require more time, which practically speaking, you won’t have, after all the mirror is made of thin sheet of metal, which requires an extremely high temperature to melt. I think beryllium -which is used already in military- make a good choice, plus the spinning drone as mentioned above would disperse the energy, making it harder to take down.
> which requires an extremely high temperature to melt
What do you think 4kW in a square centimeter generate? Spring air?
Also, beryllium would be an odd choice because all you get is energy soaked up by ablation. No reflection whatsoever. How thick would you like to make that beryllium coating?
If you assume one millimeter (which is a pretty chunky coating), you'd need about 1/10th of a second to ablate it.
As for spinning... you do spin around an axis. And that axis is likely aligned with the direction of travel, otherwise you have interesting dynamic properties.
Which means if you aim at the nose, you can spin all you want. It's not moving. If you miss the nose a bit, oh well, it'll take maybe 2 or 3 tenths of a second. Even if you're well into hypersonic speed range, that's not enough to get the missile on target.
And drones... well, drones just limber along at speeds that make any rotations just a waste of engineering resources. You have time to heat up the whole thing. And fry an egg on it.
Look, there are issues with DE weapons. But 50 years of research mean you're not discovering them from first principles while typing a HN comment.
That’s all nice and sounds good in theory, but practically speaking, drones are always ahead. Assuming the laser is indeed effective, the drone was detected too, and the accuracy is spot on, good luck taking down a swarm that’s piloted by AI, all at the fraction of the cost compared to that defense system in place.
That's a heckin' assumption you're injecting there.
For a drone to fly a system of motors, batteries, sensors and microprocessors has to engage in a complex real-time process to maintain stability, navigate and acquire targets.
Disrupt any of that, the drone falls out of the sky. Or goes off course. Or explodes.
Punching through steel is useful when you're trying to shootdown dumb-fire artillery rounds which have to survive being fired under a 310MPa pressure and need to trigger an internal detonation.
A drone with a camera will be blinded if it catches even a glancing reflection of a 50kW laser. And every bit of defense you add to that system is now increasing cost, weight and power requirements. How quickly can the laser track and engage a drone? It's light, so the time is limited solely by optics tracking speed - for all purposes impact is instantaneous.
And the idea of "stealth" runs in direct opposition to all ideas of reflective coatings - since that does the exact opposite of what stealth materials do to defeat RADAR and LIDAR.
You're arguing from the wrong position. The cost of a defense system competes against the cost of other defense systems, and only very indirectly against the cost of the attack.
If you haven't read the article: The final paragraph addresses most costs. Prototyping the laser - which is always a bit more expensive than a productionized version - was $73 million. A single missile shot is $4 million.
That's 20 missiles shot at drones. That's it. Which means, on a pure cost basis, this thing getting off 20 shots at drones means it's paid for itself. Given it's capable of firing 6 shots per minutes, you need 4 minutes to make it worth the investment. Which, given drone speeds, probably means you fire for 2 minutes and start moving - another advantage it has over a more stationary missile systems.
Cost isn't the issue here.
As the fine article points out, the problems are of an operational nature.
Polished metal will not work at these power levels. It would need to be a dielectric mirror, which can only be tuned to be extremely reflective for a narrow range of wavelengths. The mirrors would cost more than the drone in many cases. Furthermore, the US has developed "white" lasers that don't have a specific wavelength to optimize for, they emit photons with a wide range of wavelengths specifically to defeat dielectric mirrors.
That’s correct, but it will definitely require more time, which practically speaking, you won’t have, after all the mirror is made of thin sheet of metal, which requires an extremely high temperature to melt. I think beryllium -which is used already in military- make a good choice, plus the spinning drone as mentioned above would disperse the energy, making it harder to take down.