Since the launch of Sputnik on 4 October 1957, more than 4,200 launches have placed some 5500 satellites into orbit. Currently about 700 satellites are used operationally for science and other applications. Space debris comprise the ever-increasing amount of inactive space hardware in orbit around the Earth as well as fragments of spacecraft that have broken up, exploded or otherwise become abandoned.
What happens after an explosion in space? A geostationary satellite has a velocity of about 3 kilometer per second or 10.000 kilometers per hour. The fragments are ejected with much lower velocity and thus stay close to the initial orbit. However, some will become a bit faster and others a bit slower. Within a few days the debris cloud will form a ring at 36000 km altitude around the Earth.
