geostationary orbit
A circular Earth orbit at an altitude of approximately 35,786 km above the equator in which a satellite's orbital period matches Earth's rotation, causing it to appear stationary to ground observers.
Full Definition
Geostationary orbit (GEO) is the specific circular equatorial orbit at 35,786 km altitude where the orbital period equals 24 hours, making the satellite appear fixed relative to the Earth's surface. This property simplifies ground antenna pointing and eliminates the need for tracking systems on fixed terminals, making GEO the dominant orbit for broadcast and broadband satellite services. The term 'geostationary' is preferred over 'geosynchronous' in precise editorial usage: all geostationary orbits are geosynchronous, but geosynchronous orbits include inclined or elliptical orbits that are not geostationary. The abbreviation GEO is standard in technical documents.
Usage
Usage note: Use 'geostationary' when the orbit is circular and equatorial; use 'geosynchronous' only when referring to the broader class that includes inclined or elliptical orbits with a 24-hour period. The abbreviation GEO is acceptable after first use.
In Context
- "Because the satellite was in geostationary orbit, the VSAT terminal's fixed antenna required no tracking mechanism." — System design document
- "The two-way propagation delay inherent to geostationary orbit was noted as a limiting factor for latency-sensitive applications." — Service comparison whitepaper