III.

Geostationary (or Geosynchronous) Orbit

A satellite in a geosynchronous orbit follows a circular orbit over the equator at an altitude of 35,800 km (22,300 mi), completing one orbit every 24 hours—the time that it takes the Earth to rotate once. Moving in the same direction as the Earth’s rotation, the satellite remains in a fixed position over a point on the equator, thereby providing uninterrupted contact between ground stations in its line of sight. The first communications satellite to be placed in this type of orbit was Syncom 2, launched by NASA in 1963. Most of those that followed were also placed in geosynchronous orbit.