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The ongoing Kessler syndrome

The usual understanding of the Kessler syndrome is that colliding satellites will produce swarms of debris and a few of those debris will eventually hit other satellites or space junk and create further swarms of debris. Some of the debris can reach higher orbits. This can diverge, cause all satellites in low earth orbit to be destroyed and create a shell of killer debris around Earth that can hamper further space missions. This is currently being coped with by tracking part of the debris, have satellites dodge potential hits and enforce that every satellite that comes to the end of its life cycle reenters the atmosphere to burn up.

Yet, big satellites causing debris is not the only aspect of the problem. Another aspect is the cloud of very small debris that sustains itself, causes damages to satellites and can potentially inflate and trigger the massive destruction of satellites.

Whatever the size of a very small debris, be it a micron or a millimeter, when it hits a satellite or any piece of space junk at orbital speed, that will be in a flash of plasma; a tiny yet very powerful explosion, that will create a swarm of new tiny debris, some tinier than the initial impactor, some bigger.

The crater created at the point of impact can be minute but its volume is way bigger than that of the impacting microparticle. This will most often not hamper a working satellite yet sometimes it does. Big pieces of space junk start rotating following impacts, which will make it more difficult to capture and gather or de-orbit them in possible future attempts to clean up the mess.

Coatings for satellites are being developed to reduce the effect, to have less or no small debris being created by a micro-impact and protect the satellite against this ongoing abrasion.

In low earth orbit, little debris will more or less quickly be braked by the atmosphere and reenter. There is an equilibrium between the rate at which new micro-debris are created and the rate at which they renter the atmosphere.

The Kessler syndrome is currently happening, at the scale of those micro-debris.

Eric Brasseur  -  February 16 2019