Satellite Orbits Compared: LEO, MEO and GEO Explained

Every satellite picks an altitude, and that choice shapes almost everything about the mission. A low satellite sees a small patch of ground but responds quickly. A high satellite sees a huge area but takes longer to answer and needs more power to reach. Engineers group orbits into three broad bands: low Earth orbit (LEO), medium Earth orbit (MEO) and geostationary orbit (GEO).

The three bands

The bands are defined by altitude above the surface, though the boundaries are conventions rather than physical walls. LEO runs from about 160 km up to roughly 2,000 km. MEO covers the wide range above that, up to just below GEO, and is home to navigation constellations. GEO sits at about 35,786 km above the equator, a single height with special properties.

Each band has a signature trade. LEO gives short signal paths and fast response. MEO balances coverage and latency. GEO gives a fixed view of one hemisphere but a long round trip for every signal. Mission designers choose the band first, then size the rest of the spacecraft around it.

Low Earth orbit: close and fast

LEO satellites circle in roughly 90 to 130 minutes. The International Space Station flies near 400 km, the Hubble Space Telescope near 540 km, and many communications constellations operate between about 500 and 1,200 km. Iridium used orbits near 780 km for its voice network.

Closeness is the main advantage. A signal that travels 550 km up and back down has far less distance to cover than one that travels to GEO, so latency for a low-orbit link can be a few tens of milliseconds end to end. That speed suits broadband, imaging and anything that needs fast reactions.

The drawback is coverage. One LEO satellite can see only a small circle of ground at any moment, perhaps a few thousand kilometers across, and it moves away from a user within minutes. Continuous service therefore needs many satellites in several planes, and ground stations must hand off between them. Atmospheric drag also limits lifetime, as described in the companion article on staying in orbit.

Earth observation satellites often use sun-synchronous LEO, typically near 600 to 800 km. Their tilt lets them pass over each area at the same local time, so shadows and lighting stay consistent from image to image.

Medium Earth orbit: the navigation band

MEO sits between the dense LEO belt and the high GEO belt. The best known examples are the global navigation systems. GPS satellites fly at about 20,200 km, Galileo at about 23,200 km, GLONASS near 19,100 km, and BeiDou's medium orbit satellites near 21,500 km. Their orbital periods run from about 11 to 14 hours, close to half a sidereal day.

MEO gives wide coverage with a moderate number of satellites. A navigation receiver needs signals from at least four satellites to fix its position and clock, and a MEO constellation of about two dozen spacecraft can supply that from almost anywhere on Earth. The orbits are high enough that each satellite is visible from a large portion of the planet at once, yet not so high that the signal delay becomes a problem for timing.

MEO also crosses the edges of the Van Allen radiation belts. Mission designers protect the electronics with shielding and radiation-tolerant parts, and they plan for gradual degradation of components over the satellite's design life.

Geostationary orbit: fixed in the sky

Arthur C. Clarke described the idea of geostationary relays in a 1945 article. A satellite placed at 35,786 km above the equator, traveling eastward in the same direction as Earth rotates, completes one lap in one sidereal day of about 23 hours 56 minutes. From the ground it appears to hang motionless over one longitude. Ground antennas can therefore point at a fixed spot and stay pointed.

That fixed view has large benefits. Television distribution, weather monitoring and many communications services use GEO because receivers never need to track a moving target. Weather satellites such as the GOES and Meteosat series watch the same disk of Earth continuously, producing a new image every few minutes.

A single GEO satellite sees about a third of the planet, roughly everything within a wide cone centered on the equator. Three evenly spaced satellites cover almost the whole globe except the polar regions. The cost is delay. A signal going up to the satellite and back down to another ground station travels about 72,000 km, which takes roughly a quarter of a second. Voice calls and interactive applications feel that lag immediately.

GEO also has a crowded-slot problem. The arc of usable slots above the equator is limited, and satellites must hold position with station-keeping burns, typically around 50 m/s of velocity change per year. At end of life, operators raise the satellite into a disposal orbit roughly 300 km higher to free the slot for others.

Comparing the three bands

The table gives representative figures. Values are rounded and assume circular orbits.

Band	Altitude (km)	Period	Satellites for global cover	One-way delay to overhead
LEO	400 to 1,200	93 to 110 min	hundreds to thousands	1 to 4 ms
MEO	about 20,000	about 12 h	about 24 to 30	about 67 ms
GEO	35,786	23 h 56 min	3	about 119 ms

The delay column is ground to satellite straight overhead, with light taking roughly 3.3 microseconds per kilometer. Real links add processing and ground-to-satellite slant distances, so end-to-end figures are larger.

How to choose

The right band depends on the job. Imaging and low-latency broadband favor LEO because the signal path is short and the sensor sits close to the ground. Navigation favors MEO because global coverage with a moderate fleet matters more than instant response. Broadcast, weather and fixed links favor GEO because a stationary dish and continuous view outweigh the delay.

Cost matters as well. Lower orbits need less energy to reach, so a LEO satellite can be launched on a smaller rocket or share a ride with many others. GEO satellites must climb to 35,786 km, which requires a larger launch and a propulsion stage that circularizes the orbit. Higher orbits also spend more time in harsh radiation, so designers must budget shielding and component life accordingly. Those trade-offs often decide the band before any question of coverage is asked.

Many modern systems mix bands. A network may use LEO for latency-sensitive traffic, GEO for broadcast, and ground infrastructure to tie them together. Understanding the trade in each band explains why no single orbit serves every purpose.

Key takeaways

LEO is close and fast, which suits imaging and low-latency links, but it needs large constellations to keep coverage continuous.

MEO hosts the navigation systems, combining global coverage with a moderate number of satellites and a period near half a day.

GEO hangs over one spot because its period matches Earth's rotation. It gives a fixed view and simple ground antennas, at the price of a quarter-second round trip.