Low Earth orbit
LEO is the busiest neighbourhood in space — everything from the ISS at ~420 km to mega-constellations like Starlink lives in the band between roughly 160 and 2,000 km. It is where launches happen, where the fastest orbits live, and where most of the world's satellite traffic now flies.
What is low Earth orbit?
// the factsLEO is the orbital band from roughly 160 km to 2,000 km altitude. It is low enough that launch costs are comparatively modest, and close enough for short communication round-trips — which is why internet constellations, Earth-imaging fleets and crewed spacecraft all operate here.
It is the fastest-moving traffic in space. A satellite at 400 km completes an orbit in about 90 minutes, which is why the ISS sees sixteen sunrises a day. The trade-off is drag: LEO is high enough to orbit, but not empty — spacecraft must boost regularly or they slowly decay.
LEO is the frontier of the new space economy. The vast majority of the thousands of satellites launched in the last few years are LEO spacecraft, and the catalogue below is dominated by them. Every object is tracked and its orbit published as TLE data.