It was not enough for us to leave our mark on the Blue Planet. We are eager to conquer space, to explore as much as we can of the Universe’s infinite expanses and to know more. For these reasons, we have sent out into our Solar System many satellites, rockets and space telescopes. The desire to find out more drives everyone, and I cannot say that I am not excited to see pictures of distant galaxies or to learn about the latest Martian discoveries made by the Curiosity rover.
But, as it is the case with so many other human endeavors (including here our own ability to reason) this space adventure generates waste and debris, which is now scattered around the outer space. What is space debris – how and when did it appear up there?
All the objects and man-made materials carried into space by man that have no use up there fall into the category of space debris. Those that form the subject of this article are currently floating in the Earth’s orbit, up to an altitude of 2000 kilometers, with the highest concentration encountered between 750 and 800 kilometers. Beginning in the 1950s, during the dawn of space flight, and until 2007, abandoned satellites and spacecraft parts that fall off during launch have formed the vast majority of space junk.
After 2007, things have changed, first with the intentional destruction of the Fengyun-1C Chinese weather satellite, followed in 2009 by the accidental collision of two communication satellites, one American and the other Russian. From the destruction of the Chinese satellite alone, 150.000 pieces of debris were released into space.
Early in 2012, NASA estimated that above the Earth’s atmosphere there were more than 21.000 objects larger than a basketball, around 500.000 objects the size of hailstones and more than 100.000.000 particles with a diameters of less than 1 centimeter. Space debris has grown so much because all these pieces constantly collide with each other and thus their number increases with every passing day.
If you though about the distances that space junk has to cross in order to rotate around our planet, it is worth knowing that this cloud of debris travels very fast, at around 7 to 8 kilometers per second, and the average velocity during collisions between space junk is around 10 kilometers per second (360.000 kilometers/hour), thus generating a substantial amount of energy.
Their numbers and speed make space debris an imminent threat. It is no wonder that NASA monitors every object larger than 10 centimeters in diameter that flies freely into space. At such speeds, even a small chip of paint can leave a crater in a weather, communications or military satellite. And in our modern world, we are dependant on the information offered by these machines for our broadcasting needs, our data transmission services and, of course, our GPS.
Neither the International Space Station is safe, as it has been forced to change its orbit several times so far, consuming precious fuel resources in order to avoid a collision with space junk. As time passes, the ever growing amount of debris will make it even harder for spacecraft to take off and reach orbit. Therefore, any attempt to leave our planet will be blocked, and we will be isolated on Earth.
According to Nicholas Johnson, the director of NASA’s Space Debris Program, we can wait no more than 10 to 15 years before we are forced to take action. Thus, the Americans are hard at work on a laser that could hit space junk and knock it out of the skies, not by destroying it, but by slowing it down just enough to remove it from orbit and force those bits and pieces to crash back into the atmosphere, where they will be vaporized before reaching the Earth’s surface.
The Swiss have also thought about a solution for the issue of space debris, and their proposal is called ClearSpace One, a satellite that will hunt down useless space junk and throw it back into the atmosphere.
Whatever method we will choose in order to clean up the Cosmos, it is essential that we preserve our ability to travel into the outer space and dream among the stars.
Web sources:
http://www.huffingtonpost.com/2012/01/22/space-debris_n_1222385.html
http://orbitaldebris.jsc.nasa.gov/faqs.html#3
http://www.zmescience.com/space/space-janitor-clean-space-junk-321334/
http://actu.epfl.ch/news/cleaning-up-earth-s-orbit-a-swiss-satellite-tack-2/
Photo sources:
http://www.universetoday.com/13587/space-debris-illustrated-the-problem-in-pictures/
http://www.star.le.ac.uk/edu/ISS.shtml
http://gamma.msnbc.msn.com/id/34826762/ns/technology_and_science-space_debris?q=Space%20debris
Article written by Alexandra Petre and translated by Mihail Andreas Mitoșeriu.
