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
Eric Brasseur - February 16 2019