https://spectrum.ieee.org/orbital-data-centers-heat#liquid-d...
https://en.wikipedia.org/wiki/Liquid_droplet_radiator
( Myself from 4 months ago: https://news.ycombinator.com/item?id=46895344 (giggle)
https://spectrum.ieee.org/microfluidics-cooling-ai-chips-cor... )
I do think this is a pretty generous estimate he ends up at. I don't think emissivity is perfectly well dealt with. I don't know if his earth reflection emissivity includes the high energy thermal transfer from particles that do exist on the near vacuum (exosphere be hit, ya'll) or if that matters. But his figures seem ballpark correct & my concerns are at best marginal.
I don’t know if the “chips can be run hot” assumption is a fair one. It results in significant degradation of the chips life.
At minimum it needs a redesign of the current set of leading chips which are designed for a specific temperature range. Redesigning at a different operational temperature is not a walk in the park.