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
- 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.
What is low earth orbit (LEO)?
- LEO is an Earth-centred orbit with an altitude of 2,000 km (1,200 mi) or less or with at least 11.25 periods per day (an orbital period of 128 minutes or less) and an eccentricity less than 0.25.
- Most of the artificial objects in outer space are in LEO
- It is relatively close to Earth’s surface.
What is space debris?
Space debris (also known as space junk, space pollution, space waste, space trash, or space garbage) is a term for defunct human-made objects in space, principally in Earth orbit which no longer serve a useful function.