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What is Low Earth Orbit?
Quick answer
The region of space roughly 160 to 2,000 km above Earth, home to the International Space Station and many communication satellites.
Low Earth Orbit, explained
Satellites in low Earth orbit (LEO) travel fast, circling the planet in roughly 90 to 130 minutes. Because they are close to the surface, signals have a short distance to travel, which means lower latency than satellites in much higher geostationary orbit. LEO is also cheaper to reach with rockets.
These advantages have fueled large satellite constellations for broadband internet, as well as Earth observation satellites that photograph the ground in detail. The trade-off is that each satellite only sees a small area at a time and passes overhead quickly, so many are needed for continuous coverage. The growing number of objects in LEO raises concerns about space debris, collision risk, and interference with astronomical observations.
Related terms
Earth Observation
Gathering information about the Earth's surface, oceans, and atmosphere using satellites, aircraft, and drones, often as imagery and sensor data.
Geostationary OrbitA circular orbit about 35,786 km above the equator where a satellite circles at the same rate Earth rotates, so it appears fixed in the sky.
LatencyThe time delay between a request being sent and a response beginning to arrive, usually measured in milliseconds.
Satellite ConstellationA group of satellites working together as a system to provide coverage, such as global internet, navigation, or Earth imaging.
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