When we imagine catastrophes, we think of disasters involving mass destruction such as volcanic eruptions, tsunamis and nuclear war. But there are so many creative ways the future of humanity can go awry. For example, there exists a possibility of humanity losing the ability to launch anything into space for the foreseeable future.
This interesting hypothetical scenario was described by astrophysicist Donald J. Kessler in 1987. Earth is currently surrounded by many layers of orbiting satellites. Unfortunately, satellites eventually break down and its components can end up as space debris. Since there is nothing in the vacuum of space that will degrade them, space debris stay in an endless orbit around the Earth unless they fly low enough that they get caught by air resistance and burn up in the atmosphere.
Kessler proposed the following problem: what happens when debris collide and set off a chain reaction? Although we think of orbital objects as slow moving or even geostationary, orbital objects are travelling at extreme speeds – at least 8km/s (or 28,800km/hr). When two objects collide at such incredible speeds, there is a huge amount of energy released in the form of shrapnel.
If the orbit is dense enough with debris, it is theoretically possible that these shrapnel will hit another piece of debris and set off another reaction. If the chain reaction can sustain itself long enough, soon the entire orbit will be littered with high-speed shrapnel, obliterating any object trying to cross the orbital layer.
The implication of the Kessler syndrome is that it would essentially make it impossible for us to launch any new satellites or rockets into space. This would stop us from exploring the depths of space and dash any hopes of interstellar travel and space colonisation. Scientists are already working on policies to reduce further space debris and experiments on how to clear up debris. But without awareness of the issue, no change would happen.
With climate change becoming an increasingly pressing issue, it is ironic that our littering of space could potentially ruin our chances of escaping and finding a new home if the need should arise.