Satellites orbit Earth at altitudes ranging from about 160 km (100 miles) to more than 36,000 km (22,000 miles), depending on their purpose. Most cluster in one of three main zones: low Earth orbit, medium Earth orbit, or geostationary orbit. Each altitude offers distinct advantages for different jobs, from streaming internet to guiding your phone’s GPS.
Low Earth Orbit: The Busiest Zone
Low Earth orbit, or LEO, covers everything from roughly 160 km up to 2,000 km (1,200 miles) above the surface. This is where the vast majority of satellites operate today, and it’s getting more crowded every year. The International Space Station circles at an average altitude of 400 km (248 miles), traveling at about 28,165 km/h, fast enough to complete one full orbit every 90 minutes.
LEO is popular because it’s the cheapest destination to reach and the closest to Earth’s surface, which means lower signal delay and better image resolution for cameras. SpaceX’s Starlink constellation, the largest satellite network ever built, currently operates at around 550 km. The company announced plans to lower its entire fleet to 480 km over the course of 2026, partly because the space below 500 km has fewer debris objects and other planned constellations, reducing collision risk.
Physically, satellites in the lower part of LEO fly through the thermosphere, the same atmospheric layer the ISS passes through. Higher LEO satellites reach the exosphere, the outermost layer of atmosphere where most Earth satellites spend their operational lives. Even at these altitudes, trace amounts of atmosphere create drag that slowly pulls satellites downward, which is why the ISS needs periodic boosts to maintain its orbit.
Sun-Synchronous and Polar Orbits
Not all LEO satellites travel along the equator. Earth-observation satellites often use sun-synchronous orbits, typically between 550 and 850 km altitude, passing over both poles as the planet rotates beneath them. This geometry keeps the satellite crossing any given latitude at the same local solar time each day, so the lighting conditions in its photographs stay consistent from pass to pass.
Some sun-synchronous satellites follow what’s called a “dawn-to-dusk” orbit, tracing the boundary between Earth’s sunlit side and its shadow. Canada’s Radarsat, for example, orbits at 798 km with an inclination of 98.6 degrees relative to the equator. Because it never dips into Earth’s shadow, its solar panels stay in constant sunlight, eliminating the need to rely on battery power. This combination of consistent lighting, pole-to-pole coverage, and reliable power makes sun-synchronous orbits the standard choice for weather monitoring, environmental mapping, and agricultural surveillance.
Medium Earth Orbit: The Navigation Belt
Medium Earth orbit sits between LEO and geostationary orbit, generally starting above the Van Allen radiation belts (around 2,000 km) and extending up to about 35,000 km. GPS satellites are the most familiar residents, circling at an altitude of 20,200 km with an orbital period of exactly 12 hours. That 12-hour cycle means each GPS satellite passes over roughly the same ground locations twice a day, giving the constellation predictable, repeating coverage patterns.
Europe’s Galileo navigation system also operates in MEO, providing positioning data for everything from commercial aviation to the turn-by-turn directions on your smartphone. Navigation satellites need to be high enough that each one can “see” a large swath of Earth at once, but not so high that signal travel time becomes a problem. MEO hits that balance: a constellation of a few dozen satellites can blanket the entire planet, while signals still arrive quickly enough for precise location fixes.
Geostationary Orbit: The Fixed Position
At exactly 36,000 km above the equator, a satellite’s orbital speed matches Earth’s rotation. The result is a spacecraft that appears to hover over a single point on the surface, never drifting east or west. This is geostationary orbit, or GEO, and it’s the backbone of satellite television, long-range communications, and broad weather monitoring.
The “fixed” position is what makes GEO so valuable. A TV dish on your roof can point at one spot in the sky and maintain a constant link without tracking a moving target. Weather satellites like those in the GOES series use geostationary positions to watch the same hemisphere continuously, capturing imagery of developing storms in real time. The tradeoff is distance: signals take roughly a quarter of a second for the round trip, which is why GEO isn’t ideal for applications like video calls or online gaming where latency matters.
Because geostationary orbit is a thin ring directly above the equator, real estate there is limited. Satellites must be spaced carefully to avoid radio interference with their neighbors, and international agreements govern who gets which orbital “slot.”
What Happens When Satellites Retire
Satellites don’t last forever, and where they go at end of life depends on where they started. LEO satellites can be nudged into a lower orbit where atmospheric drag pulls them back to Earth within a few years, burning up on reentry. This is one reason SpaceX is moving Starlink to lower altitudes: a satellite that loses power at 480 km will deorbit on its own much faster than one stranded at 550 km.
GEO satellites can’t practically be brought back to Earth from 36,000 km. Instead, operators use their last remaining fuel to push them about 300 km higher into what’s known as a graveyard orbit. That buffer is considered a safe distance to prevent retired spacecraft from drifting back down and interfering with active geostationary satellites. Hundreds of dead satellites and spent rocket stages now circle in this disposal zone, quietly drifting above the operational belt.
Why Altitude Matters for Everyday Life
The altitude a satellite occupies directly shapes the service you experience on the ground. Starlink delivers low-latency internet because its satellites are only 480 to 550 km overhead, keeping the round-trip signal time under 40 milliseconds. GPS works because its satellites at 20,200 km are high enough that just 24 to 32 of them can cover the whole planet simultaneously. Your satellite TV stays locked to a dish because its source is parked in geostationary orbit, motionless relative to your house.
Each orbit is a compromise between coverage area, signal delay, launch cost, and how many satellites you need. Lower means faster signals and cheaper launches but smaller coverage footprints, requiring larger constellations. Higher means fewer satellites can do the job, but signals travel farther and launches cost more. The explosive growth of LEO mega-constellations in recent years reflects a bet that launching thousands of cheap, close satellites is now more practical than relying on a handful of expensive ones far away.