During the first years of the space era, it wasn’t given much importance to the theme of the space junk. But since the first lunar landing, the proliferation of satellites and other spatial vehicles that turn around the Earth, in addition to their orbital remainders, has been an increasing problem.
The quantity of objects in orbit
Nowadays, in the terrestrial orbit, there are more than two thousand satellites and more than 12 000 artificial objects big enough to be located. These include propellant rockets and disused satellites, scrap metal, bags full of rubbish and broken pieces. When these objects are situated in the low orbit of the Earth, they finish by re-entering in the atmosphere, where they disintegrate. Even so, when a satellite or another spatial object impact between them, they can leave a swarm of residues that remain in orbit for much more time than the bigger object from which they come from.
Even if there are zones around the Earth relatively empty of space junk, the big concentrations of these objects are a big source of worry for the space agencies from all around the world. Apart, when a piece of space junk collides against another one, the two of them can break into smaller pieces. Scientists estimate that there are more than 21 000 fragments of space junk of more than 10 cm around the planet.
Fortunately, the density of the objects in the terrestrial orbit continues to be relatively small. In the zone which is the most densely occupied from the low terrestrial orbit, there is an approximative average of one object every 50 000 000 km2. But the true difficulty with these residues is their relative speed. The space junk, as any other object in orbit, travels at a speed of 28 000 km/h. Due to this elevated speed, even a small piece of these objects, or the micrometeorites, can cause elevated damages to anything against they impact with.
Observation of the residues
The Strategic Command of the United States and other investigation centres are trying to follow the trail to the spacial objects of more than 10 cm of diameter. Currently, more than 8 000 objects have already been located, but it is estimated that there are a lot more of them. This information can be used to get away the spacial vehicles from the biggest pieces of junk. But despite all these measures, sometimes accidents take place. In July of 1996, a small French military satellite impacted against the remainders of a rocket. The satellite was briefly destabilized, but fortunately it was maintained in orbit and under control.
Creation of more fragments
Even so, the occurrence that has generated the biggest quantity of spacial residues in orbit wasn’t produced due to an accident. In January of 2007, the meteorological Chinese satellite Fengyun-3A was deliberately destroyed, as part of the tests of an anti-satellite weapon. The produced explosion created more than 2 000 new fragments in the low terrestrial orbit, thing which augmented in about one third the quantity of spacial residues in orbit.
To not be left behind, the Americans answered to it by destroying one of their ancient satellites, to test their anti-satellite capacities. However, they aimed to a low altitude satellite to be sure that the residues field that would create entered in the atmosphere, and, for consequent, to disintegrate there.
In the future, this problem will make no more than going worse, and finally, all the countries that have a place in the spatial navigation will have to pact some type of regulation with the proposal of reducing the contamination provoked by the space junk.
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