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The Kessler syndrome, also known as the Kessler effect, collisional cascading, or ablation cascade, is a scenario proposed by NASA scientists Donald J.

It describes a situation in which the density of objects in low Earth orbit (LEO) becomes so high due to space pollution that collisions between these objects cascade, exponentially increasing the amount of space debris over time. This proliferation of debris poses significant risks to satellites, space missions, and the International Space Station, potentially rendering certain orbital regions unusable and threatening the sustainability of space activities for many generations. In 2009, Kessler wrote that modeling results indicated the debris environment had already become unstable, meaning that efforts to achieve a growth-free small debris environment by eliminating past debris sources would likely fail because fragments from future collisions would accumulate faster than atmospheric drag could remove them.

In June 1978, Kessler and Burton Cour-Palais co-authored "Collision Frequency of Artificial Satellites: The Creation of a Debris Belt", demonstrating that the process controlling asteroid evolution would cause a similar collision process in LEO in decades rather than billions of years. In an interview shortly after the publication of the 1978 Kessler paper, Gabbard coined the term Kessler syndrome to refer to the accumulation of debris; it became widely used after its appearance in a 1982 Popular Science article, which won the Aviation-Space Writers Association 1982 National Journalism Award.

This chain reaction is known as the Kessler syndrome.

A significant event related to the Kessler Syndrome occurred on August 9, 2024, when a Chinese Long March 6A rocket broke apart in low-Earth orbit, creating a cloud of hundreds of debris fragments.

The theoretical cascading Kessler syndrome becomes more likely as satellites in orbit increase in number.

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.

Any intelligent civilization which becomes spacefaring could eventually extinguish any safe orbits via Kessler syndrome, trapping itself within its home planet. Such a result could happen even with robust space pollution controls, as a lone malicious actor on a planet could cause a Kessler syndrome scenario.

SpaceX's Starlink program raises concerns about significantly worsening the possibility of Kessler syndrome due to the large number of satellites the program is placing in LEO, as the program's goal will more than double the satellites currently in LEO.

Torres calibrated an economic model to estimate an aggregate threshold value of 72,000 satellites to prevent a Kessler syndrome scenario and explore space debris' unique negative externality, noting that space debris is unique from other forms of pollution due to its direct effect on capital assets. An analysis in 2025 reported that a large solar storm could knock out the ability to issue avoidance maneuvers of satellites long enough to result in collisions, thus potentially setting into motion a Kessler syndrome, and that there would be less than about three days to take action. The Collision Realization and Significant Harm (CRASH) Clock was developed for calculations involving a solar storm since the Kessler syndrome anticipates a decades-long process.

The 2003 Manga/Anime Planetes has a terrorist organization, the Space Defense Front, try to create a Kessler syndrome catastrophe by colliding an orbital satellite with Space Station Seven, thereby cutting Earth off from the Moon and its sole source of Helium-3, which has become the primary energy source used in the setting. The 2013 film Gravity features a Kessler syndrome catastrophe as the inciting incident of the story, when Russia shoots down an old satellite. Neal Stephenson's 2015 novel Seveneves begins with the unexplained explosion of the Moon into seven large pieces, the subsequent creation of a cloud of debris by Kessler syndrome collisions, and the eventual bombardment of Earth's surface by lunar meteoroids.

Quick Facts

• It describes a situation in which the density of objects in low Earth orbit (LEO) becomes so high due to space pollution that collisions between these objects cascade, exponentially increasing the amount of space debris over time.
• This proliferation of debris poses significant risks to satellites, space missions, and the International Space Station, potentially rendering certain orbital regions unusable and threatening the sustainability of space activities for many generations.
• The theoretical cascading Kessler syndrome becomes more likely as satellites in orbit increase in number.
• A significant event related to the Kessler Syndrome occurred on August 9, 2024, when a Chinese Long March 6A rocket broke apart in low-Earth orbit, creating a cloud of hundreds of debris fragments.
• This chain reaction is known as the Kessler syndrome.

Source material: Wikipedia - "Kessler syndrome". Adapted and summarized for DiscoverScroll. Original contributors are credited through the linked Wikipedia article. Read original on Wikipedia. CC BY-SA 4.0. Changes were made from the original.