[laughing_man]

When people attack satellites with lasers, what they're trying to do is blind surveillance sats. To actually physically damage a satellite would take enormous amounts of power and accurate tracking tied into powerful radars. That's something a state might do, but too many resources are involved for terrorists.

[impossiblefork]

I don't think that's necessarily true. I think with modern lasers the power to get permanent damage is there.

I don't think powerful radars are required either. The satellites will probably reflect the laser. At 4000 km this is 26 ms, so you would probably be able to use the laser itself for the adjustments.

[ben_w]

Previously, perhaps.

I'm saying the only limit to damaging them now is the optics.

Radar is pointless here. Both for crude and precise positioning. For crude, we already know roughly where the satellites themselves are because those are well-advertised.

For precise, you still wouldn't use radar, physics prevents high enough resolution ever. Even for tracking, angular resolution is k(λ/D), i.e. you care about aperture size in wavelengths, and radar uses wavelengths much much larger than visible or IR laser light. But even with arbitrarily large equipment, you get a spot size ~= wavelength, which wastes a lot of power as the wavelength is much larger than the necessary spot size for a critical component on a satellite.

So you'd use optical targeting and tracking, i.e. you'd look through the exact same system that the laser also fires through, with the exact same adaptive optics, and say "this specific point on this satellite".

The hard part is focussing a spot size order of cm scale (it can't be the same size as you find in a welding system for same reason radar is useless, k(λ/D) gets you ≥300m telescope and that's obviously a no). This requires adaptive optics (and also a wide telescope). Adaptive optics is the really hard part here.

Getting a 12 kW industrial laser is relatively easy, and putting that power into a spot on the joint between the PV and the main body, that has a decent chance[0] of weakening or severing it while also causing catastrophic loss of control, even with just a few minutes over the horizon. Weakening is still important, see all 9/11 memes about steel beams and why they miss the point. Severing is plausible but only because of space design constraints, see [0] again.

As I understand it, PV cells themselves have a much lower threshold for catastrophic damage, a 12 kW system is basically guaranteed to cause irreparable damage to that even in a few minutes even though the spot size here is much much larger than you'd find in a welding system.

The prices I see for 12 kW industrial lasers are significantly lower than the estimated cost per missile for most of what the Houthis used to attack shipping last year, and they fired quite a lot of those missiles.

[0] can't say for sure without detailed plans that it would be genuinely insane[1] for me to have access to; but do consider that everything in orbit is mass constrained, even with SpaceX pricing, and designed without expectations of e.g. wind or needing to support its own weight, so the thickness of structural elements is likely much lower than you'd expect from anything you see on the ground

[1] the world is currently going insane, so if it turns out they are available, either deliberately or via a leak, this is just more evidence of insanity rather than a contradiction