object placed into orbit around the Earth and designed to transmit communication signals
an artificial satellite that relays signals back to earth; moves in a geostationary orbit
a satellite that is used to send radio, television, and telephone signals around the world. Earth-orbiting system capable of receiving a signal (e.g., data, voice, TV) and relaying it back to the ground. Communications satellites have been a significant part of domestic and global communications since the 1970s. Typically they move in geosynchronous orbits about 22,300 mi (35,900 km) above the earth and operate at frequencies near 4 gigahertz (GHz) for downlinking and 6 GHz for uplinking