geostationary

The geostationary orbit is located at an altitude of 35,786 km above the terrestrial equator, in the plane of the equator and has an eccentricity of zero (it is circular). A body which is in this orbit has thus an orbital period equivalent to the rotation of Earth around itself, 24 hours (or more precisely, 23 hours, 56 minutes, 4 seconds). It thus appears immobile in relation to the Earth. This characteristic makes this orbit a much sought after one for positioning communication satellites: a fixed antenna aimed at the satellite is enough to capture the signals.