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, the most commonly used orbits for both manned and unmanned space vehicles are Low Earth Orbits, which cover an altitude range low enough for residual air drag to be sufficient to help keep the zone clear. Collisions that occur in this altitude range are also less of an issue, since the directions into which the fragments fly and/or their lower specific energy often result in orbits intersecting with Earth or having perigee below this altitude.
At altitudes above the levels where atmospheric drag is significant, the time required for orbital decay is much longer. Slight atmospheric drag, lunar perturbation, and solar wind drag can gradually bring debris down to lower altitudes where fragments finally reenter, but at very high altitudes this can take millennia.
Read more about this topic: Kessler Syndrome
Famous quotes containing the words generation and/or destruction:
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—C. John Sommerville (20th century)
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