I just skimmed that linked paper. Only mention I found of cooling is:

> Cooling would be achieved through a thermal sys- tem of heat pipes and radiators while operating at nominal temperatures.

Isn't that drastically underselling potentially one of the harder parts of this whole endeavor?

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ben_w 2 hours ago | parent | next [-]

> Isn't that drastically underselling potentially one of the harder parts of this whole endeavor?

Everything in space is hard; but these are Alphabet researchers not NASA researchers, and honestly even the NASA papers I've been skimming through have a lot of simplifying assumptions in them, so that's not something to hold against them here.

They are just saying when they think it's worth considering, after all, not giving a detailed all-aspect proposal for how to make one.

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piva00 5 hours ago | parent | prev | next [-]

Very drastically, the ISS solar panels can generate up to 120kW of power, look at the size of its radiators needed to cool it down.

Scaling that to the hundreds of GW range is quite laughable.

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trothamel 4 hours ago | parent [-]

https://x.com/SawyerMerritt/status/2064108916611420273?lang=...

While I'd suspect the design is still in flux, the current design is for a 120kw satellite with 110 square meters of radiators. Scaling to hundreds of gigawatts is intended to be by repeatedly launching smaller designs.

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piva00 2 hours ago | parent [-]

300GW / 120kW = 2.5 million satellites, I don't think SpaceX can launch 2.5 million satellites. Even less keep replenishing all the ones needing decommissioning after 3-5 years, no maintenance can be made, so on and so forth.

It's ridiculous anyway you cut it, it's a pipe dream.

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ben_w 2 hours ago | parent [-]

Indeed; though one thing I've found researching this is that the exact numbers are all over the place, so for some it's "let's make a single giant DC" and others are "let's make one million small ones", with mass estimates for each bird in the bigger constellations varying from 1200 kg (at 120 kW, which is an absurd ratio) to about 8000 kg.

Like I said higher up, at this scale, if you want to make your own fantasy plan you can draw a contiguous ring filling a single orbit.

	▲	Ekaros an hour ago \| parent [-]
		Pretty much. There isn't really question could you build satellite with GPUs at certain scale and launch it to space. It is certainly already doable. No special unsolved engineering challenges when you have say dozen or hundred... Now if we are talking about thousands or millions you have some real questions. Well cost was question to start with. But at millions satellites yeah there is clear issues. Simple rule for numbers 1 gigawatt is 1 000 megawatts or 1 000 000 kilowatts... So math is pretty simple there in estimations.

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antonvs 4 hours ago | parent | prev [-]

I view articles like that as a kind of roleplaying, essentially. The authors are pretending to be space hardware engineers, but the results are not remotely realistic.