Geosynchronous Orbits + Geostationary OrbitsWebster"s Dictionary defines a Geostationary orbit as of, relating to, or being a satellite that travels above Earth"s equator from west to east at an altitude of approximately 35,900 kilometers 22,300 miles and at a speed matching that of Earth"s rotation, thus remaining stationary in relation to Earth. 2. Of, relating to, or being the orbit of such a satellite. In plain English, a satellite matches the earth"s rotation making it seemingly hover over one spot of the globe enabling coverage of half the earth"s surface. Three such satellites, appropriately spaced longitudinally, have worldwide coverage except...
burned through and left the first Tracking and Data Relay Satellite TDRS-1 in a useless orbit. Ground controllers were able to use the satellite"s onboard thrusters to put it in the proper Geostationary orbit over a period of weeks, but the IUS was grounded until the nozzle problem was resolved.

Because the IUS was too large and expensive for most satellites going to Geostationary orbit, McDonnell Douglas developed the payload assist module, a special cradle with a turntable to spin and then release satellites. A small rocket motor and the satellite"s own rockets then boost it into Geostationary orbit.