I think stopping the heat conductivity is a solved problem - space telescopes manage to do this. But all in all, cooling in space remains a very big challenge.
No, it isn’t solved. The James Webb telescope was shipped with cryogenic coolant, and put in an orbit in the shadow of the moon far from the radiating earth. Once it runs out in a few years, it’s done.
James Webb, being an infrared telescope, has to be extremely cold: It's Mid-Infrared Instrument is actively cooled to 7°K (-266°C).
Most other instruments (NIRCam, NIRSpec, FGS/NIRISS) operate at about 40 Kelvin (-233°C) using only passive cooling (i.e. the sunshield).
Clearly this would be cold enough for a data center. Clearly the sunshield can be very well thermally insulated from the rest of the telescopy. The sun-facing side is up to 300°C hot. The cold side is -233°C.
I'm not saying radiating the heat from the GPUs is a solved problem. Just the thermal insulation between the solar panels and the rest of the spacecraft.
There's very little on JWST that makes it hot. Furthermore, the spacecraft bus where the non-scientific instruments exist) is on the other side of the sunshade so that the waste heat from the RAD750 (a single processor clocked at 118 MHz - PowerPC 750 architecture (Macintosh computers in '97) that uses 5 watts of power designed to operate -55°C to 125°C) doesn't interfere with the scientific instruments.
Putting an AI rack there is a completely different scale of power and cooling than what JWST uses.
Yes. Radiating heat away is a big problem - I totally agree! But stopping heat conduction is a solved problem! Consider the temperature of your pot handles. That‘s all I was saying.
