Kessler syndrome
modified versions of the database in two-line element set,[6] and during the early 1980s the CelesTrak bulletin board system re-published them.
[8] Some were deliberately caused during the 1960s anti-satellite weapon (ASAT) testing, and others were the result of rocket stages blowing up in orbit as leftover propellant expanded and ruptured their tanks.
[citation needed] However, Gabbard was aware that the number and type of objects in space were under-represented in the NORAD data and was familiar with their behavior.
In an interview shortly after the publication of the 1978 paper, Gabbard coined the term Kessler syndrome to refer to the accumulation of debris;[4] it became widely used after its appearance in a 1982 Popular Science article,[10] which won the Aviation-Space Writers Association 1982 National Journalism Award.
[4] Returned spacecraft were microscopically examined for small impacts, and sections of Skylab and the Apollo Command/Service Module which were recovered were found to be pitted.
In 1979, this finding resulted in establishment of the NASA Orbital Debris Program after a briefing to NASA senior management, overturning the previously held belief that most unknown debris was from old ASAT tests, not from US upper stage rocket explosions that could seemingly be easily managed by depleting the unused fuel from the upper stage Delta rocket following the payload injection.
At higher densities, production exceeds decay, leading to a cascading chain reaction reducing the orbiting population to small objects (several centimeters in size) and increasing the hazard of space activity.
[4] In an early 2009 historical overview, Kessler summed up the situation: Aggressive space activities without adequate safeguards could significantly shorten the time between collisions and produce an intolerable hazard to future spacecraft.
The collision occurred at an altitude of 865 kilometres (537 mi), when the satellite with a mass of 750 kilograms (1,650 lb) was struck in a head-on-collision by a kinetic payload traveling with a speed of 8 km/s (18,000 mph) in the opposite direction.
[19][20][21] 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 incident highlights ongoing concerns about space debris and the increasing risk of a cascading effect as more objects are launched into orbit.
[26] 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.
The catastrophic scenarios predict an increase in the number of collisions per year, as opposed to a physically impassable barrier to space exploration that occurs in higher orbits.
[citation needed] Some astronomers have hypothesized Kessler syndrome as a possible or likely solution to the Fermi paradox, the lack of any sign of alien life in the universe.
Any intelligent civilization which becomes spacefaring could eventually extinguish any safe orbits via Kessler syndrome, trapping itself within its home planet.
[29] 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.
[32] Designers of a new vehicle or satellite are frequently required by the ITU[33] to demonstrate that it can be safely disposed of at the end of its life, for example by use of a controlled atmospheric reentry system or a boost into a graveyard orbit.
[34] US government regulations similarly require a plan to dispose of satellites after the end of their mission: atmospheric re-entry,[clarification needed] movement to a storage orbit, or direct retrieval.
[39][41] In response to these concerns, SpaceX said that a large part of Starlink satellites are launched at a lower altitude of 550 km (340 mi) to achieve lower latency (versus 1,150 km (710 mi) as originally planned), and failed satellites or debris are thus expected to deorbit within five years even without propulsion, due to atmospheric drag.
