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LEO (Low Earth Orbit)

Also known as: Low Earth Orbit

📘 Definition
Low Earth Orbit (LEO) is defined as an orbit with an altitude between approximately 200 km and 2,000 km above Earth's surface. Orbital periods range from about 90 to 127 minutes. LEO is the most populated orbital regime, home to the ISS (420 km), Starlink (480–550 km), and most Earth observation satellites. The proximity to Earth provides low communication latency and high imaging resolution, but satellites experience atmospheric drag requiring periodic orbit maintenance. Satellites below about 600 km will naturally deorbit within 25 years due to drag.
200–2,000 km
Altitude Range
90–127 min
Orbital Period
15,645
Objects Tracked
5–40 ms
Signal Latency
EARTH LEO 200–2,000 km MEO 2,000–35,786 km GEO 35,786 km

Understanding LEO

Why LEO Dominates

LEO is the cheapest orbit to reach — requiring approximately 9.4 km/s of delta-v from Earth's surface — and provides the best balance of coverage, latency, and imaging resolution. This is why mega-constellations like Starlink and Amazon Leo operate here.

Atmospheric Drag

Below about 600 km, residual atmospheric particles create drag that gradually lowers a satellite's orbit. Without periodic reboosts, a satellite at 400 km altitude will re-enter within roughly 1–2 years. This natural decay is actually beneficial for space debris mitigation — debris in low LEO cleans itself up.

LEO at a Glance

ConstellationAltitudeSatellitesPurpose
ISS420 km1Crewed research station
Starlink480–550 km7,000+Broadband internet
OneWeb1,200 km648Broadband internet
Landsat705 km2 activeEarth observation
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Frequently Asked Questions

The vast majority of active satellites — over 12,000 — operate in LEO, with Starlink alone accounting for roughly 7,000. In total, including debris, over 28,000 tracked objects are in LEO.
Earth's atmosphere doesn't end abruptly — traces of gas extend hundreds of kilometres into space. This residual atmosphere creates drag on LEO satellites, gradually lowering their orbits. Without periodic thruster firings to reboost altitude, satellites would eventually re-enter and burn up.
Below about 180 km, atmospheric drag is too strong for any satellite to maintain orbit even with continuous thrusting. Practically, the lowest useful orbits are around 200 km, though most satellites operate above 300 km for reasonable orbital lifetimes.