> aka fancy air conditioning pumps

Yeah, pumps, tubes, and fluids are some of the worst things to add to a satellite. It's probably cheaper to use more radiators.

Maybe it's possible to make something economical with Peltier elements. But it's still not even a budget problem yet, it's not plainly not viable.

> getting quite good here with nanotechnology

Small features and fractal surfaces are useless here.

Peltiers and heat pipes don't remove heat, they just move it. You still need the radiator.

My dude, heat pipes were invented for satellites and there’s people walking around with piezo pumps in their phones these days. We’re getting close.

Peltiers generate a lot of heat to get the job done so even though electricity is pretty much free, probably not a sure bet.