The space age began 50 years ago with the launch of Sputnik 1 by the Soviet Union on 4 October 1957. Since that time, some 4500 additional launches have taken place. Today 850 active satellites are in orbit, supporting a wide range of civil and military uses. The US owns and operates roughly half of those satellites, as shown in figure 1.
As a result of this space activity, a tremendous amount of debris has been left orbiting in space. Orbital debris is any human-made object in orbit that no longer serves a useful purpose. It comes in the form of discarded equipment and rocket stages, defunct satellites, bolts and other hardware released during the deployment of satellites, and fragments from the breakup of satellites and rocket stages.
Space debris is a growing concern. With their high speed in orbit, even relatively small pieces of debris can damage or...
