Magellan was subjected to sunlight approximately twice as intense as Earth, potentially for several years. On the other hand, shaded exterior spacecraft temperatures could plunge to -204 degrees centigrade. Thus, special efforts were required in thermal control to keep electronics from overheating and moving parts from freezing, while minimizing weight and the need for electrical-heater power.
Electronics housings were wrapped in multi layered thermal blankets that insulated and reflected light. The outer layer of all external blankets was a material called astroquartz. It was similar to glass-fiber cloth, but was better able to withstand intense solar radiation.