Communications satellite. Artist's representation of a communications satellite in space orbiting the Earth. The Earth with brown land masses and white clouds is seen on a starfield. 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. Communications 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.