Kessler Syndrome

What is Kessler Syndrome?

The Kessler syndrome, also called the Kessler effect, collisional cascading or ablation cascade, is a scenario in which the density of objects in Low Earth Orbit (LEO) is high enough that collisions between objects could cause a cascade where each collision generates space debris that increases the likelihood of further collisions.

Who proposed it?

• It is a theory proposed by NASA scientist Donald J. Kessler in 1978, used to describe a self-sustaining cascading collision of space debris in LEO.
• In an article published on June 1, 1978 in the American Journal of Geophysical Research,  the authors Donald J. Kessler and Burton G. Cour-Palais, two NASA experts, identified the risk of an exponential increase in the number of space debris or orbital debris under the effect of mutual collisions. 
• The two authors believed that a belt formed by these objects or fragments of objects around the Earth would soon form. 
• Eventually threatening space activities, this phenomenon will be popularized a few years later under the name of Kessler syndrome

Implications 

• One implication is that the distribution of debris in orbit could render space activities and the use of satellites in specific orbital ranges impractical for many generations. 
• The Kessler syndrome is troublesome because of the domino effect and feedback runaway wherein impacts between objects of sizable mass spall off debris from the force of the collision
• Every satellite, space probe, and manned mission has the potential to produce space debris.
• A cascading Kessler syndrome becomes more likely as satellites in orbit increase in number. 
• The most commonly used orbits for both manned and unmanned space vehicles are LEO. 
• The number of space debris that naturally falls back into the atmosphere is less than the number of those generated by the collision of existing space debris. 
• According to the authors the debris population would continue to increase exponentially, leading to a situation in which some orbits would become impassable in the long run.