Comment by TeMPOraL

No, but building bridges is a good example - it's also a solved problem. Show civil engineers a river, tell them how much and what type of traffic needs to allow it, and they'll tell you it obviously can be done, they'll even tell you what structural elements will be needed and roughly how expensive they are. The problem to solve here isn't whether this can be done, but which off-the-shelf parts to use to make a design that you can afford.

We're past the point of every satellite being a custom R&D job resulting in an entirely bespoke design. We're even moving past the point where you need to haggle about every gram; launch costs have dropped a lot, giving more options to trade mass against other parameters, like more effective heat rejection :).

But I think the first and most important point for this entire discussion thread is: there is a paper - an actual PDF - linked in the article, in a sidebar to the right, which seemingly nobody read. It would be useful to do that.

They literally have a solution, it's a trivial one and described in the paper. I'll try to paraphrase the whole thing, because apparently no one read it.

1. Take existing satellite designs like Starlink, which obviously manage to utilize certain amount of power successfully, meaning they solved both collection and heat rejection.

2. Pick one, swap out its payload for however many TPUs it can power instead. Since TPUs aren't an energy source, the solar/thermal calculation does not change. Let X be the compute this gives you.

3. Observe that thermal design of a satellite is independent from whether you launch 1 or 10000 of them. Per point 2, thermals for one satellite are already solved, therefore this problem is boring and not worth further mention. Instead, go find some X that's enough to give a useful unit of scaling for compute.

4. Play with some wacky ideas about formations to improve parameters like bandwidth, while considering payload-specific issues like radiation hardening, NONE OF WHICH HAVE ANY IMPACT ON THERMALS[0]. This is the interesting part. Publish it as a paper.

5. Have someone make a press release about the paper. A common mistake.

6. Watch everyone get hung up on the press release and not bother clicking through to the actual paper.

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[0] - Well, some do. Note that fact in the paper.

> Which mission of this kind exemplifies the solution? Where's the datacenter in the sky to which I can point my telescope?

Big bunch of satellites communicating with each other?

Starlink.

Specifically Bus F9-2 and Bus F9-3 have PV arrays about the size needed for the upper limit of what I read a single DC rack might use (max 25kW, someone correct me if it is ever higher than that). That's what's being proposed here, making a DC by making each rack its own satellite.

Section 2.1 is seeing what data link is needed between satellites, and what you can actually get with realistic limitations, and how close the satellites need to be to make this work.