US and Russian satellites collide in space

The US satellite was part of the Iridium network

Nasa has confirmed that two satellites, one Russian and one American, have collided in space.

The US satellite was part of the Iridium network, a global telephony service set up by Motorola in the late 1990s that went bankrupt and is now owned by private investors. The US military is a major client.

The Russian satellite, Cosmos 2251, was an out-of-control communications satellite weighing almost a ton. The resultant debris cloud is being monitored to make sure that other satellites are not in danger.

"We knew this was going to happen eventually," Mark Matney, an orbital debris scientist at the Johnson Space Center in Houston, told Associated Press. "The collisions are going to become more and more important in the coming decades."

Space debris is an increasing problem as satellites break up in orbit, and is now considered by Nasa as the number one danger to Space Shuttle flights.

The Iridium network was originally conceived as a network of telephony satellites that allowed calls to be made anywhere in the world. Despite start-up costs estimated in the billions, the network was sold at auction for around $25m (£17m).