In almost 50 years of space activities, more than 4800 launches have placed some 6000 satellites into orbit, of which only a minor fraction - about 800 - are still operational today. Only 6 percent of the catalogued orbit population are operational spacecraft, while 38 percent can be attributed to decommissioned satellites, spent upper stages and mission-related objects (launch adaptors, lens covers, etc.).
The remaining 56 percent originates from more than 200 in-orbit fragmentations which have been recorded since 1961. Except for a few collisions (less than 10 accidental and intentional events), the majority of the 200 break-ups were explosions of spacecraft and upper stages.
Note: Images in this gallery are artist's impressions; size of debris objects are exaggerated as compared to the Earth.
What happens after an explosion in space? A geostationary satellite has a velocity of about 3 kms/second (11,000 kms/hour). The fragments are ejected with a much lower velocity and thus stay close to the initial orbit. However, some will travel a bit faster and others a bit slower. Within a few days the debris cloud will form a diffuse ring at 36,000 km altitude around the Earth.
