I was in the Soviet Union for a couple of weeks at the end of the 60's. Our Intourist guide took us to see an exhibition having to do with the Soviet space effort. One of the exhibits was a spherical module which, given the date, I imagine was part of a Soyuz-A. The thing that struck me, and that I would be interested in having confirmed (or not) by someone knowledgeable, was that part of the thing (a porthole surround?) was made of/trimmed with wood. Could this be the case or is my memory playing tricks on me?
Wood actually has great properties re fire and heat. It doesn't conduct heat very well. In a fire, the outer surfaces turn to ash, allowing the structure to survive for a time at temperatures that would melt steal instantly.
Not a spacecraft, but the Germans in WW2 developed an air-to-air missile [0] that had wooden fins. It wasn't going fast enough to create significant atmospheric heating and wood wasn't a strategically limited resource. I've seen one at a museum in the US, and the wood looks really incongruous.