Our past is explosive

The millions of fragments of debris in orbit today are the direct result of 'fragmentation events' in the past. Of the 550 events known to date, those caused by propulsion have created the greatest amount of space debris.

Energy left undisposed of on-board a satellite or rocket body can lead to explosions. For this reason, the international space debris mitigation guidelines require that satellites are 'passivated' at the end of their mission - for example by emptying fuel tanks and disconnecting batteries.

Over the last two decades, the average number of fragmentation events has remained stable at roughly 12.5 per year. Depending on which type of event is counted this number can be as low as 0.3 events per year; if the lifetime of debris created is taken into account and unexplained events are excluded. The suggestion is that debris creating events not due to collisions, that have a large environmental impact, are still taking place partly due to re-use of a design with known issues.