What Is Low Earth Orbit, and What Goes There?

More objects are being launched into space than ever, and most are headed for low Earth orbit. This region of space has become increasingly crowded with launches from SpaceX and others that have doubled the number of Earth satellites in just a few years. We talk about rockets and low Earth orbit (LEO) a lot, but we rarely explain where it is and why it's essential. Here, we'll address both—and more.

How High Is Low Earth Orbit?

According to NASA, a low Earth orbit (singular) is any orbital trajectory that stays within 1,200 miles (2,000 kilometers) of Earth's surface. There's also a practical inner boundary to LEO space below which spacecraft can't orbit, imposed by atmospheric drag. In another sense, the term "LEO" is also frequently used as a collective noun denoting the region of space within which low Earth orbits take ...