Heat problems in space are so weird when you're used to thinking about an atmosphere.
Convection, conduction, radiation, man. Convection goes to zero because you have no fluid to interact with. Conduction stays exactly where it is. Radiation hits the roof because there is absolutely no dissipation between "hot thing" and "you."
What's funny is the equations are actually hella simpler because "convection" is an empirical pain in the ass to calculate. parallel plate sinks get used most often not only because they're easy to extrude but because they have some of the least heinous math.