Sure. Now do cooling. That this isn't in the "key challenges" section makes this pretty non-serious.
A surprising amount of the ISS is dedicated to this, and they aren't running a GPU farm. https://en.wikipedia.org/wiki/External_Active_Thermal_Contro...
More seriously though, the paper itself touches on cooling and radiators. Not much, but that's reasonable - cooling isn't rocket science :), it's a solved problem. Talking about it here makes as much sense as taking about basic attitude control. Cooling the satellite and pointing it in the right direction are solved problems. They're important to detail in full system design, but not interesting enough for a paper that's about "data centers, but in space!".
It's solved on Earth because we have relatively easy (and relatively scalable) ways of getting rid of it - ventilation and water.
Which mission of this kind exemplifies the solution? Where's the datacenter in the sky to which I can point my telescope?
> Whether they can make it work within the power and budget constraints is the actual challenge, but that's economics.
It's a weird world, where economics isn't a fundamental part of engineering, any engineering proposal's got to include it, much more one that has never been done beopre.
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.