communications satellite

The satellite's solar panels are arrays of solar cells that provide the electrical energy needed for its functions, the power being stored in batteries. Its antennas may be 8 ft (2.5 m) in diameter and may transmit wide-area-of-coverage beams or narrowly focused “spot” beams.

communications satellite, 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.

This article was most recently revised and updated by William L. Hosch.