Geosynchronous orbit

A geosynchronous orbit is an orbit around a planet with an orbital period matching the planet's sidereal rotation period. The term geosynchronous can be used to describe any orbital pattern with a period equal to that of its orbiting body, and in the same direction as the parent's rotation, but is specifically used for orbits with no inclination and a semimajor axis of equal length to the minor axis (i.e. circular). Satellites in geosynchronous orbits appear to maintain their longitude, while their latitude oscillates in a 24-hour period. The geosynchronous orbit over the equator is called the geostationary orbit. Satellites in the geostationary orbit appear stationary relative to the planet's surface.

Uses
Orbital defense platforms in particular make use of geosynchronous orbits to protect the planet they orbit from attack. The terminus stations of space elevators are also anchored to a geosynchronous, near-geostationary orbit.

List of appearances

 * Halo 2
 * Halo: Contact Harvest
 * Halo: Ghosts of Onyx