Communications satellite. Artist's representation of a communications satellite in space orbiting the Earth. It is passing over an arid region of the Earth, with white clouds seen. The satellite has two long solar cell arrays (blue) to produce power, and a number of round dish antennae to receive and transmit communication signals. These satellites act as relay vehicles for radio signals. Communication satellites usually have a high geostationary orbit and hover at the same point above the Earth. They may be used to relay telephone and fax messages, computer data, and to broadcast television signals.