Kessler Syndrome

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The Kessler Syndrome is a scenario, proposed by NASA scientist Donald J. Kessler in a 1978 publication, where the volume of space debris in Low Earth orbit is so high that objects in orbit are frequently struck by debris, creating even more debris and a greater risk of further impacts. The implication of this scenario is that the escalating amount of debris in orbit could eventually render space exploration, and even the use of satellites, unfeasible for many generations. [1]

[edit] Debris generation and destruction

Every satellite, space probe and manned mission has the potential to create space debris. As the number of satellites in orbit grows and old satellites become obsolete, the risk of a cascading Kessler Syndrome becomes greater.

Fortunately, at the most commonly used Low Earth Orbits residual air drag helps keep the zones clear. Collisions that occur under this altitude are also less of an issue, since the energy lost in the collision results in fragment orbits having perigee below this altitude.[citation needed]

At altitudes above the levels where atmospheric drag is significant, lifetimes before orbital decay are much greater. Slight atmospheric drag, lunar perturbations, and solar-wind drag can gradually bring debris down to lower altitudes where fragments finally re-enter, but at very high altitudes this can take millennia.

[edit] Seriousness

The Kessler Syndrome is especially insidious because of the "domino effect" and "feedback runaway". Any impact between two objects of sizable mass spalls off shrapnel debris from the force of collision. Each piece of shrapnel now has the potential to cause further damage, creating even more space debris. With a large enough collision (such as one between a space station and a defunct satellite), the amount of cascading debris could be enough to render Low Earth Orbit essentially impassable.

The Kessler Syndrome presents a unique problem to human space travel. Space debris is very difficult to deal with directly, as the small size and high velocities of most debris would make retrieval and disposal impractically difficult. Given thousands of years, most debris in Low Earth Orbit would eventually succumb to air resistance in the rarefied atmosphere and plunge to the Earth.[citation needed]

[edit] Avoidance and reduction

To minimize the chances of damage to other vehicles, designers of a new vehicle or satellite are frequently required 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[2].

One technology for the bigger fragments that can be tracked is the laser broom, a multimegawatt land-based laser that could be used to target fragments. When the laser light hits a fragment, one side of the fragment would ablate, creating a thrust that would change the eccentricity of the remains of the fragment until it would re-enter harmlessly.[3]

[edit] Kessler Syndrome in popular culture

Generation of space debris to the point where space travel is impacted has been a subject of several works of science fiction, including various movies and novels.

  • The 2007 video game Mass Effect does not reference it directly, but the in-game encyclopedia describes being in Earth orbit without protective shields as being dangerous because of debris.[citation needed]
  • In the anime series Cowboy Bebop, an accident in space has caused debris to cloud space around Earth. Entering and leaving the atmosphere is dangerous, and falling debris makes living on the Earth's surface risky.
  • Kessler Syndrome was explicitly mentioned by name in the manga/anime series Planetes, while the efforts to remediate the problem serve as a running backdrop for the series.
  • An ablation cascade that rendered space travel impossible is a plot driver in "Under the Covenant Stars," a short story by John Barnes.
  • An ablation cascade is part of the background to Ken Macleod's 1999 novel The Sky Road.
  • In the 2008 Disney movie WALL-E, Earth orbit is depicted as completely clogged with satellite debris (which EVE's home spaceship nonetheless passes through with no difficulty).
  • The late 60s sci-fi series UFO has an episode concerning clearing of space debris in earth orbit. (Ambush/renamed Conflict).
  • Bill Maher, host of "Real Time with Bill Maher", mentioned the Kessler effect on April 3, 2009 in his weekly edition of "New Rules".

[edit] See also

[edit] References

  1. ^ Donald J. Kessler and Burton G. Cour-Palais (June 1, 1978). "Collision Frequency of Artificial Satellites: The Creation of a Debris Belt". Journal of Geophysical Research 83 (A6): 2637-2646. 
  2. ^ "FCC Enters Orbital Debris Debate". 
  3. ^ SpaceDaily- NASA Hopes Laser Broom Will Help Clean Up Space Debris
  • Primack, Joel R. (2002). "Debris and Future Space Activities". Physics Department, University of California,. "With enough orbiting debris, pieces will begin to hit other pieces, setting off a chain reaction of destruction that will leave a lethal halo around the Earth"  (Gscholar indicates that paper has been presented at a 2002 Conference on Future Security in Space (more details needed))

[edit] External links

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