Satellite cooling is long figured out, the problem is that it requires a ton of expensive mass.

Radiation hardening is not a huge issue in LEO either. It is an issue, not the issue.

Overall, it's like choosing international flights as your choice of a restaurant. It's...fundamentally...doable...? But nobody knows why you would want that, unless flying GPUs is the point rather than to offer a competitive service using the server sats.

I think the cooling mass is so expensive and fragile that it’s basically an unsolved problem.