Any of you guys ever heard of heat pumps or peltier coolers? heat dissipation scaling to T^4 is insane. If you double the temp your radiator is at your heat dissipation increases 16x, ie 16x reduction in radiator mass. So its all an optimization of the power needed to run the cooling loop, the mass of the solar panels to generate said power, and the mass of the cooling system. A relatively simple system would be to use a peltier heat pump stack to move the heat away from the compute into the cooling loop, stepping up the temp of the loop and decoupling it from the temp of the compute.