The
Kessler syndrome proposed by
NASAThe National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
scientist
Donald J. KesslerDonald J. Kessler is an American astrophysicist and former NASA scientist known for his studies regarding space debris.Kessler worked at the Johnson Space Center in Houston, Texas, as part of NASA's Environmental Effects Project Office...
in 1978, is a scenario in which the density of objects in
low Earth orbitA low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
(LEO) is high enough that collisions between objects could cause a cascade – each collision generating debris which increases the likelihood of further collisions. One implication is that the distribution of debris in orbit could render
space explorationSpace exploration is the use of space technology to explore outer space. Physical exploration of space is conducted both by human spaceflights and by robotic spacecraft....
, and even the use of
satelliteIn the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
s, unfeasible for many generations.
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 at or below this altitude are also less of an issue, since the directions into which the fragments fly and/or their lower
specific energySpecific energy is defined as the energy per unit mass. Common metric units are J/kg. It is an intensive property. Contrast this with energy, which is an extensive property. There are two main types of specific energy: potential energy and specific kinetic energy. Others are the gray and sievert,...
often result in orbits intersecting with Earth or having
perigeeAn apsis , plural apsides , is the point of greatest or least distance of a body from one of the foci of its elliptical orbit. In modern celestial mechanics this focus is also the center of attraction, which is usually the center of mass of the system...
below this altitude.
At altitudes above the levels where atmospheric drag is significant, the time required for
orbital decayOrbital decay is the process of prolonged reduction in the altitude of a satellite's orbit.This can be due to drag produced by an atmosphere due to frequent collisions between the satellite and surrounding air molecules. The drag experienced by the object is larger in the case of increased solar...
is much longer. Slight atmospheric drag, lunar perturbation, and
solar windThe solar wind is a stream of charged particles ejected from the upper atmosphere of the Sun. It mostly consists of electrons and protons with energies usually between 1.5 and 10 keV. The stream of particles varies in temperature and speed over time...
drag can gradually bring debris down to lower altitudes where fragments finally re-enter, but at very high altitudes this can take millennia.
Seriousness
The Kessler Syndrome is especially insidious because of the "
domino effectA cascading failure is a failure in a system of interconnected parts in which the failure of a part can trigger the failure of successive parts.- Cascading failure in power transmission :...
" and "feedback runaway". Any impact between two objects of sizable mass
spallSpall are flakes of a material that are broken off a larger solid body and can be produced by a variety of mechanisms, including as a result of projectile impact, corrosion, weathering, cavitation, or excessive rolling pressure...
s 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 or explosion (such as one between a space station and a defunct satellite, or the result of hostile actions in space), the amount of cascading debris could be enough to render low Earth orbit essentially impassable.
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 reentryAtmospheric entry is the movement of human-made or natural objects as they enter the atmosphere of a celestial body from outer space—in the case of Earth from an altitude above the Kármán Line,...
system or a boost into a
graveyard orbitA graveyard orbit, also called a supersynchronous orbit, junk orbit or disposal orbit, is an orbit significantly above synchronous orbit, where spacecraft are intentionally placed at the end of their operational life...
.
One technology proposed to help deal with fragments from 1 cm to 10 cm in size is the
laser broomA laser broom is a proposed ground-based laser beam-powered propulsion system whose purpose is to sweep space debris out of the path of other artificial satellites such as the International Space Station.-Technical description:...
, a proposed multimegawatt land-based laser that could be used to target fragments. When the laser light hits a fragment, one side of the fragment would
ablateAblation is removal of material from the surface of an object by vaporization, chipping, or other erosive processes. This occurs in spaceflight during ascent and atmospheric reentry, glaciology, medicine, and passive fire protection.-Spaceflight:...
, creating a thrust that would change the
eccentricityThe orbital eccentricity of an astronomical body is the amount by which its orbit deviates from a perfect circle, where 0 is perfectly circular, and 1.0 is a parabola, and no longer a closed orbit...
of the remains of the fragment until it would re-enter harmlessly.
Further reading
In 2009, Kessler wrote a page to clarify the intended meaning of "Kessler Syndrome".
An article in the July 2009 issue of
Popular MechanicsPopular Mechanics is an American magazine first published January 11, 1902 by H. H. Windsor, and has been owned since 1958 by the Hearst Corporation...
by Glenn Harlan Reynolds discusses the Kessler Syndrome in regards to the February,
2009 satellite collisionThe 2009 satellite collision was the first accidental hypervelocity collision between two intact artificial satellites in Earth orbit. The collision occurred at 16:56 UTC on February 10, 2009, at above the Taymyr Peninsula in Siberia, when Iridium 33 and Kosmos-2251 collided...
and how international law may need to address the problem to help prevent future incidents.
See also
- Space debris
Space debris, also known as orbital debris, space junk, and space waste, is the collection of objects in orbit around Earth that were created by humans but no longer serve any useful purpose. These objects consist of everything from spent rocket stages and defunct satellites to erosion, explosion...
- Laser broom
A laser broom is a proposed ground-based laser beam-powered propulsion system whose purpose is to sweep space debris out of the path of other artificial satellites such as the International Space Station.-Technical description:...
- SNAP-10A
SNAP-10A was the first and so far only known launch of a U.S. nuclear reactor into space . The Systems Nuclear Auxiliary Power Program reactor was developed under the SNAPSHOT program overseen by the U.S...
, reactor sat parked in mid-60s; 1979 'anomaly'
- P78-1
P78-1 or Solwind was a United States satellite launched aboard an Atlas F rocket from Vandenberg Air Force Base in California on February 24, 1979. The satellite operated until September 13, 1985, when it was shot down in orbit by an F-15 Eagle fighter aircraft during an US Air Force ASM-135 ASAT...
, a US satellite destroyed Sep. 13, 1985 by an ASM-135 ASATThe ASM-135 ASAT is an air-launched anti-satellite multi stage missile that was developed by Ling-Temco-Vought'sLTV Aerospace division. The ASM-135 was carried exclusively by the United States Air Force 's F-15 Eagle fighter aircraft.-Development:...
test.
- 2007 Chinese anti-satellite missile test
The 2007 Chinese anti-satellite missile test was conducted by China on January 11, 2007. A Chinese weather satellite—the FY-1C polar orbit satellite of the Fengyun series, at an altitude of , with a mass of 750 kg—was destroyed by a kinetic kill vehicle traveling with a speed of 8 km/s in...
- 2009 satellite collision
The 2009 satellite collision was the first accidental hypervelocity collision between two intact artificial satellites in Earth orbit. The collision occurred at 16:56 UTC on February 10, 2009, at above the Taymyr Peninsula in Siberia, when Iridium 33 and Kosmos-2251 collided...
- Graveyard orbit
A graveyard orbit, also called a supersynchronous orbit, junk orbit or disposal orbit, is an orbit significantly above synchronous orbit, where spacecraft are intentionally placed at the end of their operational life...
- Space Liability Convention
- Planetes (anime)
is a Japanese hard science fiction manga by Makoto Yukimura. It was adapted as a 26-episode television anime by Sunrise, which was broadcast on NHK from October 2003 through April 2004...
External links