Space debris

Computer generated image of the distribution of the
catalogued space debris around the Earth (Credit ESA)

Updated 9.2.2014 Gravity - the movie about space debris colliding with space stations and their astronauts (check the trailer) - gives us an excellent understanding of the dangers up there. Even if it isn't quite that bad, yet.  But it could be one day, judging from the accumulation of debris in Earth's atmospheric layers. Since the start of the space age in 1957, there have been some 5000 launches that almost all leave something behind in the space, as do all the collisions between satellites and meteoroids - or between two satellites! In 2009 the much feared first accidental collision between two large spacecraft took place as the satellite Iridium 33 collided with an old, non-operational Russian satellite at 789 km above Siberia. There are currently some 20 000 pieces of space debris larger than 5 centimeters traversing around the planet.
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Earth way back when

So the space in the low Earth orbit region is becoming more and more crowded (the white area closest to Earth in the picture above). NASA scientist Donald J. Kessler proposed already in 1978 in his Kessler Effect a scenario in which the density of objects in low Earth orbit is high enough that collisions between objects could cause a cascade - each collision generating space debris which increases the likelihood of further collisions. That likelihood is increasingly alarming. Satellite communication that we so rely on in our daily lives will in fact be in real jeopardy as time goes by, and the same goes for the lives of all those brave men and women up in the space. We can only hope that future technologies are able to solve this growing problem. Meanwhile it doesn't do any harm keeping our fingers crossed.

United Nation's Committee on the Peaceful Uses of Outer Space (COPUOS) deals with issues of the international legal regime of space and the guidelines and protocols. The issue is not forgotten, it is very much on the front burner. The director of the United Nations Office for Outer Space Affairs Mazlan Othman was asked among other things in this excellent interview what UN has to say about space debris - read her answer to the question under "Given the problem of space debris, is it a positive development that more countries can send satellites into orbit?"

LEO (Low Earth Orbit) below about 2000 km - the most crowded zone
MEO (Medium Earth Orbit) between 2000 km and about 30 000 km - increasingly crowdy
GEO (Geostationary Earth Orbit) above 30 000 km

IN THE NEWS
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'Urgent need' to remove space debris (BBC 4/2013)
UFO over Arabia? It's just the flash from Chinese space junk (NBC News 1/2014)


LINKS
- IADC - NASA:EarthObservingSystem - Scholarpedia:SpaceDebris - Wiki:KesslerSyndrome - Wiki:SpaceDebris -