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Like weather satellites, communication satellites (radio, telephone, and television) orbit the planet at an altitude of 22,223 miles (35,786 km) above the Earth. This orbit is referred to as geostationary or geosynchronous because at this altitude a satellite orbits the earth at the same speed as the Earth's own rotation, roughly once every 24 hours. Being synchronized, a satellite appears to be stationary above the same Earth-based location. In the article titled "How Satellites Work," the friendly experts at How Stuff Works explain that "communications satellites are essentially
radio relay stations in space," sharing a congested area directly over the equator and about one-tenth of the way to the moon with hundreds of television, weather, and communications satellites. Geosynchronous satellites must maintain speeds of approximately 7000 mph (11,300 km/per hour) in order to stay in their fixed positions overhead. The tricky part of launching and keeping a satellite in orbit is to achieve just the right orbital velocity so there is a balance between gravity's pull on the satellite (causing it to fall back towards Earth) and the inertia of a satellite in motion (causing it to keep heading out into space). The geosynchronous, or geostationary ring, is sometimes called the Clarke Orbit, after the noted
2001: A Space Odyssey author, Arthur C. Clarke, who first described the principles of geosynchronous communications satellites in the 1940s. Want to see for yourself? We found resources for observing and photographing commercial satellites in the night sky.
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