Eggplant @101 The surface temperature of Venus is 735.3 deg.K. … A spacecraft landing on Venus typically dies from overheating after about an hour on the surface. The fun bit is the overheating is not due to the heat from Venus soaking in but rather the heat from the spacecraft’s own electronics. In order to survive at all on Venus, a spacecraft needs to have extremely effective thermal insulation. That insulation is so effective at keeping the Venusian heat out that the option of rejecting the spacecraft’s own heat is prohibited so the spacecraft ends up dying from its own heat (the payload is refrigerated before the spacecraft enters the atmosphere).

You’re making it sound as if were physically impossible to cool a spacecraft on Venus. I don’t know if you mean that it’s physically impossible, but in case you do mean it, I don’t see that you’re right. If it’s physically impossible, then why isn’t an ordinary refrigerator physically impossible on earth? Venus just makes for a far more difficult refrigeration problem, requiring far more energy and different materials. For all I know, it’s not a problem for which engineers know a practical solution at the present time, but that’s not at all the same as saying that it’s physically impossible.

Contrary to what you say, the heat from the electronics is not the main problem; the heat of Venus is the main problem. If the electronics are cooler than Venus, Venus, in the absence of refrigeration, will heat them.