Mankind has been putting things into space since 1942 with the German V2 Rocket and 1957 with the first orbiting satellite Sputnik. Since that time we have put a lot of useful things into orbit. But we have also left behind a bunch of space junk that is still up there.
What is space junk?
This junk can be any kind of object from abandoned satellites, parts from launch vehicles, discarded parts left over from separation, debris from collisions, and even random rocks floating around up there naturally. These objects can be anywhere from less than a centimeter in size to the size of a car. Over time all this debris has built up and it is starting to cause issues.
How much space junk is there?
The United States Department of Defense is currently tracking 20,000 objects in orbit. But there is over 500,000 objects that are less than 10 centimeters in size that are very hard to track or impossible to track. There may even be Millions of objects that are less than 1 centimeter in size.
Why is space junk a problem?
A size of 1 centimeter may not sound like a big deal but you have to take into account that they could be flying around Earth at over 1,700 mph. A bullet from a firearm can travel between 1,000 mph and 2,800 mph depending on the gun it was fired from. So that means we have over half a million bullets flying around in earth’s orbit. With speeds like that you can start to see the problem. Even a small object can cause fatal damage to a satellite or a spacecraft. A larger object will outright destroy whatever it comes into contact with.
The Kessler Syndrome
When there are collisions in orbit they generate tons more debris and we get a compounding problem. It is also not helpful when China blows up its own satellite in orbit creating even more debris. All this new debris can go on to destroy other objects. That makes even more debris until low earth orbit is unusable. This scenario is called the Kessler Syndrome and it is something the spaceflight industry worries about.
Space Debris Cleanup and Removal
SpaceX is working with a project to clean up low earth orbit by using a kind of net to scoop up all the space trash.
Space Debris Tracking
If your interested in looking at a 3D visualization of space debris then check out http://stuffin.space/. It is updated daily with new position data and gives a nice look at what everyone is dealing with.