Now, you may have heard of the problem of orbital debris before, and you may be thinking, ‘Okay, we've got some space junk floating around up there. We'll get to it eventually.' But here's the problem, well, the first part of the problem: it's not floating, it's rocketing. Every piece of orbital debris is traveling at about 17,000 miles per hour. Here's another part of the problem: things in orbit collide, the way two satellites did in 2009. These were both big, heavy objects. The derelict soviet Strela military communications satellite weighed 2,094 pounds, and the Iridium 33, part of a cell phone network of satellites, weighed 1,235 pounds. Oh, and since both objects were traveling at hyper velocities, along different orbits, their combined collision speed was around 44,000 miles per hour.
So, as you might imagine, when two big, heavy satellites hit one another going at these massive velocities, they're going to create a lot of debris. NASA estimates that as a result of just this one collision, approximately 1,000 pieces of debris larger than 10 centimeters were created. But there are also likely hundreds, possibly thousands of pieces of smaller debris. NASA doesn't know. It can't track debris that's this small.
But wait, it gets worse: debris clouds don't stay in one place. They keep orbiting at these faster-than-a-speeding-bullet speeds, and since they're all different sizes they don't all go at the same speed, or stay at the same altitude. And while all of this is happening the debris cloud is spreading out, a lot, eventually over hundreds, and then thousands of miles. Oh, and, by the way, this is all just from one collision. So far there have been eight ... that NASA knows of. Then, of course there's the 2007 Chinese anti-satellite missile test when they intentionally blew up one of their own satellites.
‘Okay,' you may be thinking, ‘so we got some little space pebbles floating around up there. What harm could they do?' Well, researchers have determined that a one inch piece of debris traveling at roughly 17,000 miles an hour, would have about the same effect as a browning 50 caliber round fired here on Earth. But here's the real kicker: collisions, or explosions, make debris. Each of the hundreds or thousands of pieces of debris can cause another collision, creating more hundreds or thousands of pieces of debris, which can cause more collisions, and so on, and so on, and so on. Starting to see the problem? The scenario used in the 2013 movie Gravity, where a debris cloud hits the International Space Station and destroys it? that's not just possible. It's likely, and, given enough time, inevitable. Also, keep in mind, GPS? cell phones? TV? shipping the food you eat? pretty much every aspect of our lives involves the use of satellites, and unless we do something to start cleaning up these bullets in space, they'll all be in the crosshairs.
(Source: Wikipedia)