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Amphibious Warship USS Portland Shot Down a Drone with Its New High-Power Laser (thedrive.com)
40 points by smacktoward 5 days ago | hide | past | web | favorite | 36 comments

all sorts of Project Crossbow news these last couple of months. after what happened with Hathaway at Pac Tech back in the 80s I thought it'd never come around

Is that a Real Genius (movie) reference?

[0] https://en.wikipedia.org/wiki/Real_Genius

Always, er never, forget to check your references.

The military meaning of amphibious warship is a bit disappointing.

It deploys a battalion of marines in an amphibious landing, it does not itself move on land.

Last time Star Wars was a lie, so I'd like to know exactly what has happened this time around, is it in even close to a usable weapon in the field.


I'd imagine "40 years of laser research" is exactly what has happened this time around.

You can already buy lasers off Amazon or Aliexpress that can set things on fire. I'm giving it 10 years tops before we have lethal man-portable laser rifles.

You can measure width of a hair using laser pointer: https://youtu.be/kpsN78mQ6YY

Wouldn't that require about a hundred times better batteries than we have today?

It always amazes me that the upper limit on these things is to avoid killing satellites.

Getting pretty close to the end of this tech tree. :)

What happens if the beam his a person (for example on a boat)? I hope it's not a very painful death.

According to a professor at University of Texas, "It would take about a 1kW laser to boil through someone’s eye to their brain in a reasonable amount of time." This laser is 150-kilowatts.

src: https://gizmodo.com/how-many-laser-pointers-would-it-take-to...

So it would be not good for a person to be hit by this laser. Got it.

I wonder how long it takes between rounds to recharge the system?

I wonder if the ship is nuclear powered and if that has any bearing on whether it can support a laser or not.

The only surface ships the US has that are nuclear powered are the supercarriers. Nuclear ships are expensive.

Ah, that's what I was thinking of. Makes sense. That and some submarines right?

All of the submarines to my knowledge, yes.

We need to start replacing our nuclear attack subs with AIP subs like Swedens. Way cheaper, and stealthier.

The ship is powered by diesel engines, not nuclear. New surface ship classes being designed now will have increased electrical generation capacity to support lasers and railguns.

Next: drones that can detect a laser source and point a mirror back to it.

Mirrors are not an effective defense.

I wonder about smoke, then )

Seems doubtful. Unless the drone is stationary, it would fly right out of it's own smoke cloud.

Even with smoke, it's a pretty good bet that the total thickness of smoke particles in the path of the beam is less than that of a coat of paint. No problem for a 150 kW laser to cut through.

Water vapor might work. It takes ~3MJ to boil a liter of water from room temperature, so if the drone can put water into the laser path somehow, it may slow down the process significantly. Also depends on how long the laser can keep up the firing.

What about smoke and mirrors?

Why not?

Here's a video of a 500 W laser cutting a set of mirrors: https://www.youtube.com/watch?v=p-VlVmBZGI4

From a few inches away from the focusing lens, yeah.

If the ship-mounted laser is powerful enough to take down a drone, it's already delivering way, way more power at a distance than the cutter shown in the video does at a few inches.

Mostly because mirrors aren't perfect.

Let's say if a mirror can reflect 99% of the light that hits it, and we shot it with 1kw laser. That means 100w is still heating the mirror and it might melt or shatter it.

No. It’s 10W. Not 100W.

Ofc, it's just an example. I realized later I made mistake, till then edit window was gone.

Still, that would require a laser blast 100x as powerful to take down the drone. Also: what would that do to the effective range of the weapon?

Plus, depending on how much control the attacking drone has, that's also 99% of the beam being deflected back at the ship with the laser.

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