>>3826542The Venera probes overheated and suffered electronics failures.
The surface of Venus is about 450°C and the atmospheric pressure is about 95 Bar (for reference, earth atmospheric pressure at sea level is about 1.1 Bar).
The Soviets were aware of Venus' hostile environment, so they basically built a small submarine that wouldn't melt in the sulphuric acid clouds, and basically designed the probes to do as much science as possible in the 20 or so minutes that they expected the things to last.
One Venera probe did last over 40 minutes before the orbital relay went below the horizon. We don't know how long the probe lasted beyond that, but it's expected it probably lasted about an hour before the electronics failed.
We're not aware of the probes melting, or combusting, but a lack of oxygen in the atmosphere would make the later hard to happen.
Any future probe that hopes to survive longer would likely need to use very simple electronics. Fortunately, radiation hardened IC chips now exist, so we could theoretically send smaller, more thermally resistant probes in future. But a rover seems out of the question.
A blimp, however, might be possible, as the upper atmosphere of Venus is nowhere near as hot or as crushing as on the surface. France managed to get some weather balloons on a Venera probe, where they managed to find out that there are some very fast winds in the upper atmosphere.
