Low Earth orbit (LEO)
지구 저궤도
The region of space close to Earth, from the ground up to a height of 2,000 km.
Overview
The International Space Station circles at a height of about 400 km, and most observation satellites and groups of communication satellites are in this zone. It is close to Earth, so it is easy to reach and signals travel quickly.
The trade-off is that a satellite cannot stay over one spot. It goes around Earth once every 90 minutes to 2 hours. So to offer a service that never drops out, you need a very large number of satellites.
An everyday example
If a geostationary satellite at about 36,000 km is a broadcast tower on a high mountaintop, a low-orbit satellite is like a low base station set up in every neighborhood.
Why it matters
Satellite internet, Earth observation and space stations all happen here. As the number of satellites grows, worries about space debris and collisions are growing too.
Also calledLEO