Geostationary Orbit (GEO)

Geostationary Orbit is the unique altitude where a satellite's orbital period exactly matches Earth's rotation, so it appears stationary in the sky. This is real estate for weather satellites, fixed-pointing communications relays, and direct-broadcast TV. Slots in the GEO belt are coordinated internationally by the ITU because they're a finite resource.

Common uses: weather monitoring, fixed communications, broadcast TV, missile early-warning