Geostationary orbit

A geostationary orbit (abbreviated GEO) is a circular orbit directly above the Earth's equator (0º latitude). Any point on the equator plane revolves about the Earth in the same direction and with the same period (speed) as the Earth's rotation. It is a special case of the geosynchronous orbit (abbreviated GSO), and the one which is of most interest to operators of artificial satellites (including communication and television satellites). Satellite locations may differ by longitude only (remember in Geostationary orbit latitude is zero).

Related Topics:
Circular orbit - Earth - Equator - Latitude - Geosynchronous orbit - Artificial satellite - Satellite location - Longitude

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The idea of a geosynchronous satellite for communication purposes was first published in 1928 by Herman Potocnik. Geosynchronous and geostationary orbits were first popularised by science fiction author Arthur C. Clarke in 1945 as useful orbits for communications satellites. As a result they are sometimes referred to as Clarke orbits. Similarly, the "Clarke Belt" is the part of space approximately 35,786 km above mean sea level in the plane of the equator where near-geostationary orbits may be achieved.

Related Topics:
Herman Potocnik - Orbit - Science fiction - Arthur C. Clarke - Mean sea level

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Geostationary orbits are useful because they cause a satellite to appear stationary with respect to a fixed point on the rotating Earth. As a result, an antenna can point in a fixed direction and maintain a link with the satellite. The satellite orbits in the direction of the Earth's rotation, at an altitude of approximately 35,786 km (22,240 statute miles) above ground. This altitude is significant because it produces an orbital period equal to the Earth's period of rotation, known as the sidereal day.

Related Topics:
Antenna - Altitude - 35,786 km (22,240 statute miles) - Orbital period - Rotation - Sidereal day

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