What is Geostationary orbit?
[[File:Geostationary227x221simple3Dtopview.gif|thumb|Geostationary orbit.To someone on Earth, each satellite appears to stay in one place in the sky. Looking down at the North Pole|alt=]] [[File:Geostationaryjava3D.gif|thumb|right|Geostationary orbit.To an observer on the rotating Earth (green dot on the blue sphere), the purple and red satellites appears to stay in one place in the sky.]] [[File:Geostationaryjava3Dsideview.gif|thumb|Side view of 2 satellites of Earth]] [[File:Geosats compilation.jpg|thumb|right|A 5 x 6 degrees view of a part of the geostationary belt, showing several geostationary satellites. Those above the equator form a diagonal belt across the image: a few objects with small inclinations to the equator are visible above this line. Note how the satellites are pinpoint, while stars have created small trails due to the Earth's rotation.]] A '''geostationary orbit''' (or '''Geostationary Earth Orbit''' - '''GEO''') is a type of [[geosynchronous orbit]] directly above the Earth's [[equator]] (0° [[latitude]]). Like all geosynchronous orbits, it has a period (time for one orbit) that is 24 hours. This means it goes around the Earth as fast as the Earth spins, and so it appears to stay above the same spot all the time. A person watching from Earth sees a satellite in a geostationary orbit as not moving, at a steady place in the sky. ==Satellites in geostationary orbit== [[Communications satellite]]s and [[weather satellite]]s often use these orbits, so that the [[satellite antenna]]s that communicate with them do not have to move to track them. The ground atennas can be pointed permanently at a fixed position in the sky. This is cheaper and easier than having a satellite dish that is always moving to track a satellite. Each one stays above the equator at a set [[longitude]] (distance east or west). The idea of a geosynchronous satellite for communication was first published in 1928 (but not widely so) by [[Herman Potočnik]].<ref name='NASA SP-4026'>{{cite book |last= Noordung |first= Hermann