I was motivated to research this by discovering plans for a Venus rover: Windsurfing on a Wicked World | NASA That planet has the problem of a surface temperature of about 450 C and pressure around 92 bar. Its atmosphere is mostly CO2 with a few percent N2 and much less of various other gases. To date, the champion survivor on that planet is Venera 13 at 127 minutes. Toleration of Venus surface temperature will be necessary for doing better than that. On the mechanical side, that is not much a problem. That temperature is rather mild by some industrial standards, and I easily found several lubricants that can work in much higher temperatures. For electricity storage, sodium–sulfur batteries run at 300 - 350 C, so a 450-C battery may be feasible. Ferromagnetic materials are likely not a problem. They lose their ferromagnetism at above their Curie temperatures, but some common ferromagnetic materials have Curie temperatures well above Venus's surface temperature. The big weak spot is semiconductor components, and that's what I'm asking about. Design of high-temperature electronics is not very advanced, as far as I can tell (High-Temperature Electronics at Analog Devices, Extreme-Temperature Electronics (Tutorial - Part 1)). Some commercially-available components are rated for temperatures of 200 C or even 300 C, but they look like rather simple ones. There are various things that one can do to improve temperature tolerance, like trench isolation and silicon-on-insulator. Looking at alternative materials, silicon carbide goes up to over 600 C, though only simple components have been demonstrated with it, as far as I've been able to find out. Fun fact: a favorite way of torture-testing electronic components is to run them at high temperatures. That makes them fail much faster. Is anyone here familiar with the state of the art in such components?