Two old satellites have collided over Siberia creating a cloud of pieces that may damage other satellites, the International Space Station, or future manned flights. Space monitoring has to track about 17,000 objects above 10cm in size that orbit Earth.

Richard Crowther, an expert on space debris and near-Earth objects, told BBC News: "It is unfortunate but inevitable, first that we would see such a collision in Low Earth orbit, and secondly - given the number of Iridium satellites in its constellation - more likely that the Iridium system would be affected rather than single satellite systems."

The commercial Iridium satellites comprised a network of 66 spacecraft up until the accident. According to Dr Crowther, from the UK's Science and Technology Facilities Council (STFC), the group also occupies "a very crowded altitude of low- Earth orbit".