The Kessler Syndrome is a name given to the idea that enough space debris will start to cause a cascade and exponential growth of secondary debris such that spaceflight and operations in low earth orbit become more difficult, leading to nigh on impossible.
As this article describes the original idea came from Donald Kessler in 1978 when working for NASA. It was coined “Kessler Syndrome” some time later.
In a completely different vein, the director Wim Wenders produced two movies in the late 80s and early 90s about angels in Berlin, listening in on people’s lives. In the first film “Wings of Desire” one of the angels, Damiel, falls in love with a trapeze artist and becomes human. In the second film “Faraway, So Close” his old friend, Cassiel, also becomes human but by accident and the movie deals with how he copes and ultimately returns to being an angel.
The reason I linked these two ideas, and apart from that fact that Wings of Desire is one of my favourite movies, is that the listening angels in Berlin are analogous to the silent growing cloud of debris that the Kessler Syndrome predicts: an almost etherial organism that will slowly influence and even deter spaceflight in low orbit. Unlike the passive observing angels though, the Kessler Syndrome may well become a serious issue with direct influence on life. Or as that article, written in 2022 states, it may already be happening.
The angels may already be amongst us causing havoc.
But then again it may take decades to get to that state, even with the increasing population of satellites in low earth orbit. Mostly made up of constellations or fleets of cubesats.
Which is what this article proposes. It’s a Schroedinger’s catastrophe.
Kessler problems
As the last linked article suggests, there are a few features of the Kessler idea that maintain our foggy understanding, clouded in uncertainty rather than bits of satellites.
Measurement
Measurement of Kessler Syndrome evolution is currently still very hard. There are gaps in radar coverage and there is no way to know objectively if satellites are encountering clouds of debris. However theoretical extrapolations from what we do know and have measured suggests that there HAS to be a growing cloud of debris as observations of paint flecks and little bits of satellites has already been made. But is it serious?
Timescale
A serious build-up is not going to happen overnight, or maybe within the time that spacecraft have become able to mitigate impacts to a high degree. The population growth process of bits and chunks and flecks is predicted to take decades. That is unless there are deliberate and dedicated campaigns to shoot stuff out of the sky. Then the growth and coverage of debris clouds can be in the order of months. But the likelihood of this is more about politics than science.
In the end…an inevitable bang?
When Cassiel and Damiel fell to Earth their armour falls as well. And it falls with a bang, a metaphor representing a sudden change of situation. If there is a Kessler incident it may very well be a blunt and brutal event where a satellite or satellites break apart followed by secondary effects. The hope is that with enough surveillance, tracking and predictions these events can be forseen or at least bounded with realistic uncertainty ranges.
However in doing so, just like the angels, the world of orbital debris and the world below will collide. The reality of what has been there, silently evolving, will be apparent.
This scenario is likely far-fetched but the will to try and do something with objects in orbit is not a stretch of the imagination. Companies such as AstroScale and programs like Clear Space in ESA (European Space Agency) aim to show that objects can be caught and ferried around giving some valuable data as to the logistics of how this can be implemented in low earth orbit.
The question remains though: is it worth the money worrying about it and trying to do something about it?
Is it a “low probability, high impact” event (like a Black Swan) or an extreme extrapolation?
The Overhead app data shows predicted conjunctions, some very close, but there aren’t large scale panics every time this happens. There are systems and services in place aiding companies to deal with these events. Yet we also see passive satellites with no active propulsion coming into range of active satellites, which have to take the burden of manoeurvres.
Either that system is robust enough still or there are going to be close moments. And then a Kessler seed may begin. Maybe it’s complacency in current operations that will cause the issue rather than a natural growth of a background cloud of debris.
Do we call on the angels to save us then?