Popular orbits are crowded

Some orbits around Earth are more popular than others. Most satellites orbit less than 1,000 km above Earth – that is true for Earth observation satellites, whose instruments must preferably be close to the surface. Orbits above the poles are particularly popular, as the satellite will pass all regions of Earth, as it orbits, and the planet rotates below it. The geostationary orbit 35,786 km above the Equator is also popular, as the satellite is always above the same point, which is obvious for communication satellites.