NASA
Low Earth orbit
Everything from about 160 to 2,000 km up, where almost all spacecraft and all people are.
Low orbit is where the physics is cheapest: less delta-v to reach, a short signal round trip, and enough residual atmosphere that debris eventually falls out on its own. It is also crowded. The station orbits at about 420 km and has to be reboosted regularly because the air up there, thin as it is, still drags. Below roughly 300 km a satellite has months; at 800 km it has centuries, which is why the constellations are deliberately flown low.
Where it has come up lately
Spaceflight Now
Phys.org
NASA Science
Phys.org
Universe Today
Related terms
Sun-synchronous orbit
A near-polar orbit that crosses the equator at the same local time every day.
Geostationary orbit
The one orbit where a satellite appears to hang motionless over a fixed point.
Kessler syndrome
The runaway scenario where collisions in orbit generate debris that causes more collisions.
Orbital inclination
The angle between an orbit and the equator, which decides what ground the satellite ever sees.
Questions
What is Low Earth orbit?
Everything from about 160 to 2,000 km up, where almost all spacecraft and all people are.
Why does it matter?
The station orbits at about 420 km and has to be reboosted regularly because the air up there, thin as it is, still drags. Below roughly 300 km a satellite has months; at 800 km it has centuries, which is why the constellations are deliberately flown low.