Just as human operators must be protected from extreme environments, so must the electronics that operate and control a functional system. When the environment proves too warm, the electronics must be insulated, refrigerated, or simply moved to cooler locations. This last option is sometimes very difficult, or impossible, and the perceived fragility of electronics must then be reconsidered. Vacuum-tube technology provides a historical example of this process. Although vacuum tubes may be considered mechanically fragile, tube-based radio proximity fuses were nevertheless incorporated into artillery shells over 50 years ago!.
