Geosynchronous Equatorial Orbit
(from geo = Earth + synchronous = moving at the same rate)
A satellite in geosychonous equatorial orbit (GEO) is located directly above the equator, exactly 22,300 miles out in space. At that distance, it takes the satellite a full 24 hours to circle the planet. Since it takes Earth 24 hours to spin on in its axis, the satellite and Earth move together. So, a satellite in GEO always stays directly over the same spot on Earth. (A geosynchronous orbit can also be called a GeoSTATIONARY Orbit.)
Because they're so far away, GEO satellites have a very broad view of Earth. For instance, the footprint of one EchoStar broadcast satellite covers almost all of North America.
And, since they stay over the same spot on Earth, we always know where GEO satellites are. If our antenna points in the right direction, we'll always have direct contact with the satellite.
Many communications satellites travel in geosynchronous orbits, including those that relay TV signals into our homes.
A satellite is a complex machine. All satellites are made up of several sub-systems that work together as one large system to help the satellite achieve its mission. This simplified illustration shows the key parts of a remote sensing satellite.
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