What is low Earth orbit?
Low Earth orbit is the crowded band of space a few hundred kilometres above your head. This page covers how it works, what it is good and bad at, and how to spot a satellite tonight.
Low Earth orbit means the band of space from about 160 to 2,000 kilometres above the Earth. A satellite there circles the planet in roughly 90 minutes, moving about 7.8 kilometres every second. Being close makes signals fast and cameras sharp, but each satellite sees only a small patch of ground, so services fly many of them together.
Go outside about an hour after sunset. Look up and wait. Soon you may see a bright dot cross the sky. It does not blink like a plane. It slides along in a straight line, and after a few minutes it is gone.
That dot is a satellite. It is only a few hundred kilometres above your head. It moves so fast that it crosses your whole sky before your tea goes cold.
The band of space it sits in has a name. People call it low Earth orbit, or LEO. It is the busiest ring of space around our planet, and almost every satellite you rely on is inside it.
What counts as low Earth orbit
Low Earth orbit starts about 160 kilometres up. It ends about 2,000 kilometres up. Anything that circles the Earth inside that band is in low Earth orbit.
Those heights sound huge. In space terms they are small. The drive from Nairobi to Mombasa is longer than the floor of low Earth orbit is high.
The space station flies at about 400 kilometres. Most internet satellites fly a little higher, near 500 or 600 kilometres. Below about 160 kilometres there is still too much air, so a satellite slows down and burns up within days.
Why a satellite up there does not fall
It does fall. That is the odd part. Gravity pulls on a satellite just as it pulls on you.
Think about throwing a stone. Throw it gently and it lands close by. Throw it harder and it lands further off. Now throw it so hard that the ground curves away below it as fast as the stone drops. The stone keeps falling and never lands.
That is an orbit. AN ORBIT IS A FALL THAT KEEPS MISSING THE GROUND. To keep missing at this height, a satellite must travel about 7.8 kilometres every second. One full lap then takes about 90 minutes.
What low Earth orbit is good at
Being close brings three rewards.
The first is a fast reply. A radio signal takes time to travel. The shorter the trip, the sooner the answer comes back. A link through low Earth orbit usually replies in well under 50 milliseconds. That is quick enough for a video call.
The second is a clear view. A camera 500 kilometres up can pick out small things on the ground. Lift the same camera ten times higher and it sees far less.
The third is cost. A rocket burns less fuel to reach a low orbit than a high one. Cheaper rides mean smaller satellites, and many more of them.
What low Earth orbit is bad at
Being close has a price. A satellite this low sees only a small patch of the planet at a time.
Hold a torch close to a wall. The circle of light is bright but tiny. Pull the torch back and the circle grows. Therefore one low satellite cannot cover a country all day. It races past in minutes.
The fix is to fly many satellites in a chain. As one drops below the horizon, the next one rises. Your dish or your phone hands the call across without you noticing.
There is also air. It is very thin at 400 kilometres, yet it is not nothing. It drags on a satellite year after year. Without a push from a small engine the satellite sinks and burns up. That is useful, because it slowly clears away space debris.
How it differs from geostationary orbit
The other famous orbit sits much higher. It is called geostationary orbit. A satellite there takes one full day to go round, and the Earth turns underneath at the same rate. So the satellite seems to hang over one spot. A dish can point at it once and never move again.
| Question | Low Earth orbit | Geostationary orbit |
|---|---|---|
| Height | About 160 to 2,000 kilometres. | About 35,786 kilometres. |
| One lap | About 90 minutes. | One day. |
| Signal delay | Usually under 50 milliseconds. | About half a second. |
| View of the ground | A small patch at a time. | Most of one face of the Earth. |
| How many are needed | Many, often hundreds. | Three cover most inhabited land. |
| The dish on your roof | Must follow the satellite. | Stays still. |
Where you already meet it
Low Earth orbit shows up in daily life more than most people notice.
- Weather pictures of cloud and rain come from satellites in this band.
- Maps of farms, floods and forests use photos taken a few hundred kilometres up.
- New internet services beam broadband from low orbit to a small dish on a roof.
- Distress beacons on boats and small planes are heard by low satellites.
- The space station and its crew live inside this band.
Notice what is missing from that list. The location on your phone does not come from low Earth orbit. Navigation satellites such as GPS fly much higher, at about 20,000 kilometres.
The crowding problem
Low Earth orbit is wide, yet it is not empty. Thousands of working satellites share it. So do dead satellites, spent rocket stages and loose bolts. All of it moves at several kilometres a second.
At that speed a chip of paint hits like a bullet. Teams on the ground track the traffic and steer satellites out of the way. Our explainer on how space debris forms covers that risk in full.
Height decides how long the mess lasts. A dead satellite at 300 kilometres comes down within a few years. One at 1,000 kilometres can stay up for centuries. This is why many operators now choose to fly low on purpose.
How to see it for yourself
You do not need a telescope. Pick a clear evening. Go out 30 to 90 minutes after sunset. The sky is dark by then, and a satellite overhead still catches the sun.
Look for a steady point of light moving in a straight line. No flashing. No sound. That is low Earth orbit passing over your roof.
Free websites and apps list the times the space station crosses your town. Look up tonight’s time for your city, then go outside two minutes early.
Just Out Tech explains new research in plain language. This article was drafted with AI assistance and checked by a human against the original source.
- Low Earth orbit runs from about 160 to 2,000 kilometres up, and a satellite there completes one lap in roughly 90 minutes.
- Satellites in low Earth orbit give fast signals and sharp pictures, but each one covers only a small patch of ground at a time, so a service needs many of them.
- Thin air drags low satellites down over time, so a dead satellite at 300 kilometres clears itself within a few years while one at 1,000 kilometres can stay up for centuries.
Questions people ask
How high is low Earth orbit?
Low Earth orbit runs from about 160 kilometres above the surface up to about 2,000 kilometres. The space station sits near 400 kilometres. Most internet satellites sit near 500 or 600 kilometres. Below 160 kilometres the air is thick enough to drag a satellite down within days.
How fast do satellites in low Earth orbit travel?
About 7.8 kilometres every second. At that speed one lap of the Earth takes roughly 90 minutes. The speed is set by the height, so every satellite at the same height travels at almost the same speed.
Can you see satellites in low Earth orbit without a telescope?
Yes. Go outside 30 to 90 minutes after sunset on a clear night. Look for a steady dot of light crossing the sky in a straight line, with no flashing and no sound. The space station is the brightest and easiest one to catch.
Why do satellite internet companies use low Earth orbit?
Because the signal has a much shorter distance to travel, so the reply comes back in well under 50 milliseconds instead of about half a second from geostationary orbit. That delay is small enough for video calls and online games. The cost is that each satellite covers only a small area, so the company must launch and manage hundreds or thousands of them.
Mark Alex
Mark Alex is the founder and Managing Director of Real Biz Digital, a technology company operating out of Nairobi since 2018. He works in agentic AI and the Model Context Protocol, AI governance, enterprise software architecture and cybersecurity. He holds an MSc in Mechatronical Engineering from Obuda University in Budapest and a BSc in IT, Forensic Technology and Cybercrime, from USIU-Africa in Nairobi, and has published IEEE conference research on an AI-powered digital twin for greenhouse systems. He is the author of seven books. Between 2020 and 2024 he mentored more than 200 university students and interns in Nairobi. He writes every Just Out Tech article from the original research paper.