Comment by cogman10
1 day ago
It's quiet the power requirement. I wonder how long it has to focus on a drone to eliminate it. Like how long is this thing consuming 100kW?
1 day ago
It's quiet the power requirement. I wonder how long it has to focus on a drone to eliminate it. Like how long is this thing consuming 100kW?
Good question, probably depends a lot on how much energy actually makes it to the target some distance away. And then how much is actually absorbed. Probably depends more on the power density then, rather than total power?
Can't imagine they get a very small spot at multiple km unless they use gigantic lenses or multiple independent laser focused on the same spot
I also wonder the extent to which the effectiveness is reduced by painting the projectile white or wrapping it in aluminum foil. Maybe 100kw is so large that it simply does not matter at that power level.
I imagine that it depends greatly on the laser’s spectrum. Aluminium is a good reflector of infrared but not ultraviolet, for example.
Maybe it involves multiple converging beams to reduce transmission losses?
yes it does
Even small divergence angles add up if they’re trying to intercept at visual ranges outside of traditional munitions.
That being said, probably ~10kW/m^2 is enough to overheat or disable a UAV
It'll get a lot of time to react at that energy as it's not going to "instantly" fry anything*. That's probably less energy/m2 than consumer heat guns, especially if consider that these drones are likely going to get sprayed in reflective paint. Easy defense for the drone would be just: get into a spin to get roasted evenly -> shut off -> fall for a few hundred meters, cooling using air that rushes by to counteract the laser further -> catch itself once it lost the laser.
That would force these laser systems to point each drone until it either visibly goes up in flames or impacts the ground (which means you also need to be able to track them all the way down), otherwise you can't be sure it won't just snap back to life once you started engaging the next drone.
I don't feel like 10kw/m2 would be anywhere near useful. It's gotta be more than that.
* Stadium floodlights aren't going to instantly grill any bird that flies in front of them either, and they reach that ballpark.
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Is that output power of the laser? If it's input power, it doesn't really seem that high. Some US homes could draw 100kW if charging multiple EVs etc.
> Some US homes could draw 100kW if charging multiple EVs
No. Most US homes are on 200 or 100A service. 200A tops out at 48kW
You won't find many home chargers that are more than 60A.
As the sibling comment notes, these days 400a residential service is available as an option in many places.
One home actually consuming close to 400a is pretty rare, but it's possible mainly in gas-free builds, if using things like electric tankless water heaters (a bit niche) in addition to multiple EV chargers, a range, dryer, etc.
Maybe a better way to convey that 100kW is “small” is to point out that industrial sites all around us, such as smaller datacenters, are well into the MW range.
There is 400 amp residential service you can get 80 amp 19.2 kw level 2 chargers.
You would need 5 80 amp charger to approach 100kw but with other loads in a large house, I have seen large HVAC systems and elaborate pools with lazy rivers etc that can add up very quickly which is why they had 400 amp service.
100kw isn't really that much, a modern EV can put out 3 times that from its battery pack into the motor for short bursts and easily sustain 100kw until drained.
480v 200 amp 3 phase commercial supply can provide 100kw continuous and would be some thing used in a medium sized office building.
I guess they are using it in pulsed mode, continuous mode would be a little bit much power
Huh, to what degree is this technology gatekept by battery advances?
A few decades ago lasers were dismissed because they involved chemical reagents for high power and explosive capacitors for even low-power applications.
> Huh, to what degree is this technology gatekept by battery advances?
Not too much. The power delivery was doable even 15 years ago. It would have just been more expensive and heavier.
The bigger issue I believe would have been the lens and tracking capabilities. For the tracking to work you need some pretty good cameras, pretty fast computers, and pretty good object recognition. We are talking about using high speed cameras and doing object detection each frame
> The power delivery was doable even 15 years ago.
Not really. It took a long time for solid state lasers to make it to 100KW. That's the power level military people have wanted for two decades.
Megawatt chemical lasers are possible, and have been built. But the ground based one was three semitrailers, and the airborne one needed a 747. Plus you ran out of chemicals fairly fast.
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Wouldn’t they be able to just use radars?
Hm, you think longer than the laser is firing? Could there be windup?
I imagine there's some sort of storage system, like a huge bank of ultra-capacitors, that are constantly kept charged.
The wind up would be if that bank is depleted and they need to recharge. Delivering 100kW for a short period of time is definitely a feat.
If these things are even 50% efficient, then power delivery is really not a problem these days. Most EVs have no problem delivering 200kW for quite a few seconds at a time, limited mostly by components getting warm. Higher-end EVs are generally rated for 300-500kW.
It would by amusing to see one of these lasers mounted on an EV, possibly with a small range extender to recharge it on the go.
Ah, good point, that seems likely.
Depends on how tightly they can focus the beam.
http://panoptesv.com/SciFi/LaserDeathRay/DamageFromLaser.php
few seconds. it (lower power version) was deployed during war with hezbollah and intercepted 40 drones (big one, not fpv).
there is footage of intercepts out there. was released about half an year ago