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.
In Dec 2004 there were 1124 known objects in the vicinity of the geostationary ring. 31% are controlled satellites. 37% are drifting around the Earth and 13% are librating around one of the stable points. There are 153 (14%) uncontrolled objects with no orbital information available and 60 (5%) unidentified objects.
