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Solid Wastes/Sewage

Space junk

One solid waste problem requiring increased efforts at minimization is space junk, the increasing amount of debris from old rockets and satellites orbiting the earth. A collision with even a small fragment can damage a satellite, shuttle or space station. Debris have dented shuttle windows on several occasions and in August 1996, the French military satellite Cerise became the first casualty of space junk (Ward, 1996). The risks to the international space station, with a surface area of some 11 000 square meters when completed, are alarmingly high (Kiernan, 1997a). Chances of penetration by orbiting space junk and meteors were calculated in 1996 to be 1% per year (David, 1996).

Failure to take preventive measures could severely limit future uses of space (National Research Council, 1995). Indeed, NASA has calculated that if the amount of debris exceeds 150 000 fragments 1 centimeter or larger, space flight could become impossible (Ward, 1997). Major efforts are already required to map such materials and to try to avoid dangerous orbits (Iannotta, 1995).

Every time a satellite is put in space, second- and third-stage rockets used to get into orbit are discarded. And our use of space is increasing. International telecommunication companies are currently putting up three times as many satellites in orbit as were launched in the past forty years, with a predicted total in excess of 1000 satellites in space (Ward, 1997). And new technologies involving microscopic rocket thrusters will allow swarms of small satellites of a few kilograms to be built, with telecommunications, military, and astronomical applications, and a dramatic increase in space junk (Iannotta, 1999).

Possible solutions range from better designs to bringing down satellites at the end of their lifetime. However, this just slows down the rate of increase, and more long-term solutions must be devised. Using satellites specifically to sweep up debris (http://rsd.gsfc.nasa.gov/goes/text/pacman.html) seems, although plausible, to have been a scheme proposed on April the first.

Further information can be obtained from the ESA website on debris: http://www.esoc.esa.de/external/mso/debris.html
A collection of articles on space junk can be found at http://see.msfc.nasa.gov/see/sparkman/Section_Docs/article_1.htm

References

David, Leonard.1996. "Junk that goes bump". New Scientist,11 May 1996, p. 25.

Iannotta, Ben. 1995. "Spinning images from mercury mirrors." New Scientist, 15 July 1995, p. 38-41.

Iannotta Ben. 1999. "Pocket rocket". New Scientist, April 10 1999, p. 38.

Kiernan, Vincent. 1997a. "Orbital junk threatens space station". New Scientist, 18 January 1997, p. 7.

National Research Council (US). 1995. Orbital Debris: A Technical Assessment. National Academy of Sciences, Washington, D.C. Cited in Kiernan, Vincent. "Please dispose of your spacecraft carefully." New Scientist, 24 June 1995, p. 9.

Ward, Mark. 1996. "Satellite injured in space wreck". New Scientist, 24 August 1996, p. 5.

Ward, Mark. 1997. "Did Sally die in vain?". New Scientist, 11 May 1997, p. 49.

 

 

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