A laser beam striking a mirror will leave a part of its energy with the mirror. Gamma radiation can interact with the atomic structure of a material to cause internal heating. A satellite, orbiting the earth, is exposed to three major types of environmental heating. A heat pipe is a self contained heat pump that has the capability of transporting heat at a high rate over fairly substantial distances with no external pumping power. A porous capillary wick covers the inside surface and extends over the length of the pipe.
Heat is applied at the evaporator end and is removed at the condenser end.
At the evaporator end, heat applied by the external source vaporizes that portion of the working fluid located at the evaporator. This creates a difference in pressure between the evaporator and the condenser ends which drives the vaporized fluid through the adiabatic section. At the condenser end the heat is removed by condensation. A thermostatic heater is turned full on or off as a function of the temperature of a control sensor. It is the form of radiation used for making non-contact temperature measurements.