NASA keeps track of space junk, “orbital debris” in fancy-talk, which is basically the litter that floats around the earth. The first ever bit of junk sent up there was Sputnik, which served it’s purpose the exact second it entered orbit. (mission: to scare the bejeebus out of the Americans) Other junk includes more inactive satellites, discarded fuel tanks from shuttle launches, and even a lost glove from a 1965 spacewalk. (NASA should have looked into “mitten-string technology”) It’s been adding up for half a century. They are tracking more than 19,000 objects larger than 10 cm, big enough to be seen on radar. They estimate another 500,000 smaller pieces, and another tens of millions of specs smaller than 1 cm, like chips of paint.
It doesn’t sound so bad, as we picture it gently floating around the nothingness of space… but in order to stay in orbit, these hunks of stuff are moving along at more than 25,000 kilometres per hour. (that’s 15,000 miles per hour for those of you who haven’t yet bowed down to the awesome power of ten) Getting hit by anything at that speed packs quite a punch. To wrap your head around that, consider a speeding bullet and/or Superman travels at a casual 4000 km/h.
Spacecraft are built to handle getting hit by the little stuff, leaving nice dents behind, but the reason they track the bigger stuff is so they can get the heck out of the way before it comes close. As anything else in orbit, all this junk is slowly moving closer to earth and NASA estimates that one piece enters the atmoshpere every day. So far, there have been no reports of anybody getting hurt by falling debris.
- Source: http://science.nationalgeographic.com/science/space/solar-system/orbital.html
- Source: http://orbitaldebris.jsc.nasa.gov/faqs.html
