The Kessler syndrome (also called the Kessler effect,[1][2] collisional cascading, or ablation cascade), proposed by NASA scientists Donald J. Kessler and Burton G. Cour-Palais in 1978, is a scenario in which the density of objects in low Earth orbit (LEO) due to space pollution is numerous enough that collisions between objects could cause a cascade in which each collision generates space debris that increases the likelihood of further collisions.[3] In 2009, Kessler wrote that modeling results had concluded that the debris environment was already unstable, "such that any attempt to achieve a growth-free small debris environment by eliminating sources of past debris will likely fail because fragments from future collisions will be generated faster than atmospheric drag will remove them".[4] One implication is that the distribution of debris in orbit could render space activities and the use of satellites in specific orbital ranges difficult for many generations.[3]
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