Apparently the space telescopes have liquid helium cooling, and there are .1 Kelvin pools in space for astronomical detectors. I guess you can use pools of onb

Apparently the space telescopes have liquid helium cooling, and there are .1 Kelvin pools in space for astronomical detectors. I guess you can use pools of onboard liquid as heat sinks if the radiative surface is insufficient at peak, and then radiate the rest from the heat sink pool when it is, say, behind the earth or not working as hard.