How to Read the Chart
- Across: height above Earth, from 200 to 2,000 km. That is all of low Earth orbit.
- Up: how many objects are inside each one-kilometre slice of height at any moment.
- Colours: Starlink on top, then other satellites, rocket bodies and debris at the bottom.
- Tall, thin spikes: constellation shells, each only a few kilometres thick.
- Low, wide humps: debris clouds, spread over hundreds of kilometres.
What Changed Since 2014
In January 2014 the busiest kilometre of height was at 776 km, with about 51 objects in it, most of them debris. Today it is at 462 km, with about 1,474. Outside Starlink, the busiest height is now 629 km, with about 307 objects.
Frequently Asked Questions
It is how many objects are inside that one-kilometre band of height at any moment, on average. A satellite in a round orbit stays in one band. An object in an oval orbit passes through many bands, so it counts in each of them for the share of time it spends there. Add up every band and you get the number of objects in low orbit at any moment.
Large constellations put their satellites at set heights, each a shell only a few kilometres thick. Keeping each shell at its own height keeps the satellites in it from crossing paths with the next one, which is why the chart shows tall, narrow spikes rather than a smooth spread.
Air drag is stronger lower down. A satellite that fails at about 480 km falls back and burns up sooner than one at 550 km, so lowering the shells means dead satellites clear out faster. Our data shows the move through 2026: the band from 520 to 600 km has emptied as the band below 520 km has filled.
Two events: China's 2007 missile test on the Fengyun-1C weather satellite at about 865 km, and the 2009 collision between Iridium 33 and Cosmos 2251 at about 790 km. The air is so thin at those heights that their pieces take decades to fall. Pick "All of low orbit" or "700 to 1,500 km" to see them.
From Orbital Radar's own archive of orbital elements for every tracked object. Each snapshot uses each object's latest elements from the 10 days before it, leaves out objects that have re-entered, and is rebuilt every day. Snapshots are monthly from January 2014, plus today. Heights are measured above Earth's equatorial radius.