Sublimation and Vaporization

In a vacuum, metals and semiconductors tend to sublimate; that is solids convert into a vapor, causing the loss of structural material from the satellite and its components. Additionally, fluids tend to vaporise so normal lubricants cannot be used. Satellite materials must therefore be chosen carefully to avoid those that are prone to sublimation and vaporization. Additionally, since the rate of both processes increase with temperature, spacecraft temperatures must be controlled carefully.