this post was submitted on 15 Feb 2024
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[–] [email protected] 12 points 1 year ago

Euclid C Finder go brrrrrr 💥

[–] [email protected] 12 points 1 year ago* (last edited 1 year ago) (3 children)

Satellite is surrounded by vacuum. Thus insulated from getting rid of heat that way. So just pump heat into it and watch the temperature rise.

And you don't need to melt it. Just cook it till its electronics overheat.

[–] [email protected] 9 points 1 year ago

Well all things (human) in space have special paint in order to modify their blackbody radiation and maintain a trade off between disipation heat by EM radiation and keeping a temperature that allows semiconductors to work.

The point is that satellites do disipate heat. Convection disipation is the worst disipation of heat. The best disipation of energy (heat) is by radiation. Thats why the thermal blankets look shinny weird, just like the satellites. You would need a realiable source of heat in order to overcome the satellite disipation and saturate the satellite.

[–] [email protected] 3 points 1 year ago (2 children)

i've never thought about that before.

isnt that untrue though given that objects freeze instantly in space? Also that would mean you would only need to heat the ISS (rip) once, during its conception.

[–] [email protected] 8 points 1 year ago

What mariusafa said is correct, but I wanted to point out that objects in space do not freeze immediately. Dissipation via blackbody radiation is much slower than convection and it can take a long time for something to cool down without the latter. In other words, a vaccuum does function as a very effective insulator, which can sometimes make it more challenging to get rid of heat in space than it is to keep something warm. The ISS, for example, needs to use radiators to keep cool. The same goes for many (most? all?) satellites that are at least as close to the sun as the earth.

[–] [email protected] 3 points 1 year ago

It's just not true. Disipation by convection effect is one of the ways of disipating energy. Dissipation by blackbody radiation is where most of the energy goes.

For example infrared heaters transmits most of it's heat by radiation. Efficient heaters do not use convection mechanisms, well or not only.

[–] [email protected] 12 points 1 year ago

I disagree, you need to melt it, because space is more interesting when its full of lances of molten metal whipping about at orbital speeds

[–] [email protected] 25 points 1 year ago (6 children)

Isn’t there some inverse square math rule about radiation like this? The further away you are the radiation reaching you is far less than it would seem? Not good at remembering this math so maybe someone can correct me.

Even if you could get the mirrors all focused accurately and tracking the object at speed it seems like it wouldn’t be any more of a concern than a really bright searchlight or something.

[–] [email protected] 13 points 1 year ago (4 children)

The power density square law is for an emitting light source that emits in all directions. Since the incoming light is basically parallel that doesn't really apply. If you were able to accurately track a satellite (a feat I'm sure is pretty hard) you would definitely vaporize it pretty quickly I'm talking under a minute since space is a good insulator.

[–] [email protected] 4 points 1 year ago (5 children)

It holds if the light spreads wider than the target. So also for directed light sources at large enough distances. Even a perfect mirror must spread the light in the same angle as it is incomming. Hence the beam would at least 3 km wide at the satellite. Therefore the satellite can only recieve a Illumination of ~65W/m^2 which is a few percent of the normal sun brightness of 1300 W/m^2.

Another way to look at it, the mirrors cant make the sun seem brighter only larger. From the tower you see a large solid angle around you the mirror, therefore, it can seem like you are at the surface of the sun. However, fro. the position of a satellite, the power plant only takes a small solid angle, so it seems like a "smaller" sun. Assuming 400 MW and 1 kW/m^2 (at surface) solar power, it has an area of 400000 m^2, so a solid angle of 4.5e-6 sr from 300km while the sun has 70e-6 sr. So ten times smaller, therefore weaker. Note however here i did not account for attenuation in the atmosphere

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[–] [email protected] 15 points 1 year ago (4 children)

Keep in mind that atmospheric interference would likely scatter the light enough to be ineffective

[–] [email protected] 3 points 1 year ago (1 children)

But the photons made it through the atmosphere in the first place to be collected by the reflectors. Is there just not enough energy left to make it back out before cooling off?

[–] [email protected] 4 points 1 year ago (1 children)

That's the assumption, yes. But if the beams are coherent (like a laser) atmospheric interference would be a lot smaller.

The real question is whether the light would be coherent, which I lean towards no on.

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[–] [email protected] 21 points 1 year ago (3 children)

They would have to adjust really quickly to track

[–] [email protected] 2 points 1 year ago (1 children)

If the beam is powerful enough, you'd just aim beforehand and let the satellite slide into it. Not like the fucker can dodge.

Honestly the control electronics are not why this super doesn't work.

[–] [email protected] 4 points 1 year ago (1 children)

Yeah, you just need a bunch of geared stepper motors and a big computer. The atmosphere is the reason it almost certainly won't work

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[–] [email protected] 5 points 1 year ago (1 children)

But really tiny adjustments, because it's far away.

Also there's a spread in the beam, so that's nice.

Also, as I pointed out elsewhere here, there's a vacuum-bottle effect. You can just pump heat into it. And also you don't need to melt it, just overheat the electronics.

[–] [email protected] 2 points 1 year ago* (last edited 1 year ago) (1 children)

You need to move the point from one horizon to the other. Like the sun, satellites "rise" on one side and set on the other. All of that in less than 15min(in LEO).

You can watch the dishes turn.

[–] [email protected] 4 points 1 year ago

That depends on its orbit. If you're pumping enough heat into the satellite, you can just aim it at a point in its path. Because space is a good insulator, it wouldn't lose that much heat each orbit.

[–] [email protected] 4 points 1 year ago

The movement would need to be incredibly precise.

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