US and Russian communications satellites have collided in space in what is thought to be the biggest incident of its kind to date.
The US commercial Iridium spacecraft hit a defunct Russian satellite at an altitude of about 800km (500 miles) over Siberia on Tuesday, Nasa said.
The risk to the International Space Station and a shuttle launch planned for later this month is said to be low.
The impact produced a cloud of debris, which will be tracked into the future.
Russian and US satellites collide
