Science: Modeling Space Debris

Modeling Space Debris:

Orbital debris, or “space junk,” is any man-made object in orbit around the Earth that no longer serves a useful purpose. Space junk can be bad news for an orbiting satellite.
To minimize the risk of collision between spacecraft and space junk, the U.S. Space Surveillance Network tracks all debris larger than 10 centimeters. These images represent all man-made objects, both functioning and useful objects and debris, currently being tracked. The images were made from models used to track debris in Earth orbit. Of the approximately 19,000 manmade objects larger than 10 centimeters in Earth orbit as of July 2009, most orbit close to the Earth, bottom image. The top image shows all items in orbit, both close to and far from the Earth.

Source: NASA Earth Observatory