@Uwe's comment below Parachute material used for the Venera probes to survive 500 °C raises an interesting issue. Venus is really hot, and pyrotechnic actuators (e.g. explosive bolts, frangible nuts etc.) are a staple of spaceflight.
We have many questions here about how various electrical and mechanical cables and even tubes and hoses were cut by pyrotechnic actuators after the Insight landing, the top of the spacecraft is littered with the cut ends of various things.
Temperatures of the atmosphere near the surface of Venus are high. At 50 km where the pressure is already 1 atmosphere the temperature is around 75 °C and by the time it gets to the surface it's 460+ °C. With such a dense, supercritical fluid atmosphere near the surface heat transfer will be rapid and anything on the outside of the spacecraft will be just as hot as the atmosphere itself.
Implicit in my question is the premise that a Venus lander will have at least a parachute or other decelerator that needs to be reliably actuated and later detached, and perhaps several for different pressures regimes, and that pyrotechnic devices will be used to do this as they have in other lander missions on atmospheric worlds.
If my implicit premise is incorrect, then a well-sourced answer explaining why and how it will be avoided will constitute a good answer.
Question: How can/will premature detonation of pyrotechnic devices such as explosive bolts, frangible nuts or explosive cable-cutters on a lander be prevented from exploding prematurely in the hot atmosphere of Venus?
Related; Venus landings or background on the various pyrotechnic devices and their long history of use in spaceflight:
- How did the Venera Probes manage to safely descend to the surface of Venus?
- What are the benefits of using pyrotechnics on spacecraft?
- Reliability of explosive bolts and redundant initiators
- Would a "pyrotechnics" tag be useful? (in meta; apparently so!)
- How does a landing spacecraft control main parachute inflation?
- Why is the Hayabusa2 capsule collection team in protective gear
- Which explode in spaceflight more often, nuts or bolts?
- First instance of a frangible nut in space? Which space-nut was first successfully "franged"?
- How does a simple construction keep a firing rocket on the ground?
These examples are on Mars, not Venus. Click for larger
left: From How were Perseverance's cables "cut" after touching down? in Space Exploration SE right from this answer to How were Perseverance's cables “cut” after touching down?. source: NASA/JPL-Caltech and source: NASA/JPL-Caltech
