Kessler Syndrome:

What Happens When Satellites Collide

Short Documentary

In 2009, the American and Russian satellites Iridium-33 and Cosmos 2251 collided 800km over Siberia.

The collision resulted in two massive debris clouds encircling the globe, critically endangering other satellites in Lower Earth Orbit—an already dangerously overcrowded place. The collision shone a light on the growing problem of space debris. It wasn’t the first collision in orbit, and it won’t be the last, as the problem is self-perpetuating. It’s become known as Kessler Syndrome.

Of all the man-made satellites in Low Earth Orbit, 95% are junk known as space debris. Rocket thrusters, derelict satellites, and most of all, fragments of debris from collisions and explosions. Earth’s orbits are facing an environmental crisis that’s almost completely invisible to us, but which may carry dire consequences for our infrastructure and the future of spaceflight if left unchecked.

The worst case scenario is that you end up creating enough debris that it’s not cost-effective to depend on space. Now, that may take a long time, but because it’s a non-reversible process, once you’ve reached a certain threshold where you’re generating debris from these collisions faster than it can be cleaned out, it’ll just continually get worse unless you can do something drastic.

—Donald Kessler, Astrophysicist and former Head of the Orbital Debris Program Office at NASA

If we continue operating the way we do today, we will have a disaster in 50 years, in 100 years. It compares quite nicely to the CO2 issue, and the climate on ground, so it’s not our generation suffering from all the CO2 released into the atmosphere, it is future generations, but it is our generation that has to take the action. And the space debris problem is quite similar.

—Holger Krag, Head of the Space Debris Office at the European Space Agency

Written, Animated, Edited, and Narrated by

Asher Isbrucker

Special thanks to

Donald Kessler & Holger Krag

Executive Producer

Willem Isbrucker


Charlie Mitchell
Caitlin Docking
Josh Ennis
Simon Bullock
Mom & Dad


Silver Maple
Johannes Bornlöf
Jonatan Järpehag
Blue Dot Sessions

Footage, Images, and Assets

European Space Agency
University of Surrey (RemoveDebris demonstration)
AGI (Iridium–Cosmos collision model)
tashtego (ENVISAT 3D model)
unaipl2003 (Dawn satellite model)