Space debris: Trackable objects in orbit around Earth

Between the launch of Sputnik on 4 October 1957 and 1 January 2008, approximately 4600 launches have placed some 6000 satellites into orbit, of which about 400 are travelling beyond geostationary orbit or on interplanetary trajectories.

Today, it is estimated that only 800 satellites are operational - roughly 45 percent of these are both in LEO and GEO. 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. About 50 percent of all trackable objects are due to in-orbit explosion events (about 200) or collision events (less than 10).

The launch of the first artificial satellite by the Soviet Union in 1957 marked the beginning of the utilization of space for science and commercial activity. During the Cold War, space was a prime area of competition between the USSR and USA, reaching its climax with the race to the Moon in the 1960s. In 1964 the first TV satellite was launched into a geostationary orbit in order to transmit the Olympic games from Tokyo. Later, Russian launch activities declined while other nations set up their own space programs. Thus, the number of objects in Earth orbit has increased steadily - by two hundred per year on average.

Note: The debris objects shown in the image are an artist's impression based on actual density data. However, the debris objects are shown at an eggagerated size to make them visible at the scale shown.

Source: ESA (Europeon Space Agency)