most of the artificial satellites are in a low earth orbit (leo) or a geostationary orbit. to stay in orbit, the satellite's sideways speed must balance the force of gravity. satellites in low orbit are often less than one thousand kilometers above the ground. close to the earth, in leo, the satellites must move faster to stay in orbit. low orbits work well for satellites that take pictures of the earth. many do jobs that call for high orbital inclination (they swing above and below the equator), so they can communicate, or look at other areas. it is easier to put a satellite in low earth orbit, but the satellite appears to move when viewed from earth. this means a satellite dish (a type of antenna) must be always moving in order to send or receive communications with that satellite.