LEO
Pronunciation: LEE-oh
Also written as: LEO — Low Earth Orbit
A satellite orbit typically between 200 km and 2,000 km altitude, characterised by short orbital periods, low latency, and the need for ground station tracking and handovers.
Full Definition
Low Earth Orbit is the orbital regime used by Earth observation satellites, scientific missions, and modern broadband constellations such as Starlink and OneWeb. LEO satellites travel at approximately 7.8 km/s and complete an orbit in roughly 90–120 minutes, meaning any given ground station has a limited contact window per pass (typically 5–15 minutes). This necessitates tracking ground station antennas and, for continuous coverage, networks of ground stations or inter-satellite links. Editors must distinguish LEO from GEO and MEO and be alert to marketing materials that blur these distinctions. LEO is always in full caps.
Usage
Usage note: Always full caps. The hyphenated form 'low-Earth orbit' (adjective) is acceptable before a noun (e.g., 'low-Earth-orbit constellation'). Flag when authors conflate LEO with polar orbit—they overlap but are not synonymous.
In Context
- "The LEO constellation's 48 orbital planes required a globally distributed network of ground station gateways." — Network architecture document
- "Ground station contact time for a single LEO satellite is typically less than 12 minutes per pass, which must be considered in data volume calculations." — Mission operations manual