Geosynchronous / Geostationary
A geosynchronous orbit (sometimes abbreviated GSO) is an Earth-centered orbit with an orbital period that matches Earth's rotation on its axis, 23 hours, 56 minutes, and 4 seconds (one sidereal day). The synchronization of rotation and orbital period means that, for an observer on Earth's surface, an object in geosynchronous orbit returns to exactly the same position in the sky after a period of one sidereal day. Located at 22,236 miles (35,786 kilometers) above Earth's equator, this position is a valuable spot for monitoring weather, communications and surveillance.
A geostationary orbit, also referred to as a geosynchronous equatorial orbit[a] (GEO), is a circular geosynchronous orbit 35,786 kilometres (22,236 miles) above Earth's equator and following the direction of Earth's rotation. An object in such an orbit has an orbital period equal to the Earth's rotational period, one sidereal day, and so to ground observers it appears motionless, in a fixed position in the sky.
While about 55 percent of all operational satellites are in LEO, another 35 percent are in GEO, making it the second most popular orbital regime.