For one thing, there are thousands of satellites and good-sized pieces of old satellites just hanging around in orbit.
These bits of “space junk” can be hazardous to other working satellites and other spacecraft traveling in or through Earth’s orbit.
In the early days of space exploration, we didn’t worry so much about what would happen to the stuff we launched into orbit. These days, though, there is so much junk that we are worried one tiny collision could trigger a big chain reaction. This possibility is called the “Kessler Effect.”
To prevent such a disaster, anyone launching something into orbit these days has to have a plan to either send it into a graveyard orbit, or send it back down to burn up in Earth’s atmosphere.
A computer-made image of objects in Earth orbit currently being tracked. About 95% of the objects in this illustration are orbital debris, not functional satellites. The dots represent the current location of each item, but are not scaled to Earth. The image provides a good idea of where the greatest orbital debris is.
