source:Al Jazeera English - Americas - US and Russian satellites collide A privately-owned US telecommunications satellite has collided with a defunct Russian satellite in what US military officials say is the first such orbital collision ever recorded. The crash occurred on Tuesday at an altitude of about 780km, destroying both satellites and creating a cloud of debris that officials say could threaten other satellites including the International Space Station. The satellites hit each other at a combined velocity of about 11km-a-second, or 10 times faster than a rifle bullet. The US satellite was operated by Iridium, a satellite telephone provider, which operates a global network of 66 communication satellites. The Maryland-based company said the collision was not a result of any error on its part and said it would be deploying a spare satellite already in orbit to replace the one destroyed. The collision took place in an area of space known as low-earth orbit which is used by hundreds of communications and weather-monitoring satellites "We believe it's the first time that two satellites have collided in orbit," he told the Reuters news agency, adding that the area where the collision took place was "very important for a lot of satellites". He said the Command's Joint Space Operations Centre was tracking 500 to 600 new bits of debris, some as small as 10cm across. Nasa, the US space agency, said it was assessing the risk posed to the international space station and its crew of three, but said it believed any danger was "very small".