I have no experience with this stuff, but: instead of a plastic case, could you carve out 2 blocks of polystyrene foam to exactly contain the equipment, with mo

I have no experience with this stuff, but: instead of a plastic case, could you carve out 2 blocks of polystyrene foam to exactly contain the equipment, with more temperature-sensitive stuff nearer the middle? It's a good thermal insulator and extremely light. Or will polystyrene burst/disintegrate at such low pressures? In any case, this sounds like a fantastic project, best of luck!