The first ever collision between two giant satellites in orbit has created vast clouds of debris, adding to the deadly perils facing future space explorers.

A defunct Russian satellite weighing nearly a ton crashed into a half-ton communications satellite around 500 miles over Siberia on Tuesday.

NASA stressed that there was no immediate danger to astronauts on board the International Space Station because it is flying in a much lower orbit. But the debris could threaten the Hubble space telescope and other satellites in higher paths.

And the fragments, speeding faster than a bullet, will spread out to threaten the lives of astronauts in the decades to come.

It will take experts weeks to discover the extent of the wreckage. But it adds to the millions of fragments already circling the earth that have turned our patch of space into a cosmic junkyard.

The drama happened when an out-of-control Russian satellite, Cosmos 2251, launched back in 1993, ran straight into a working communications satellite that is part of a constellation of dozens of spacecraft called Iridium.

Travelling at many thousands of miles an hour, it smashed the comms satellite to smithereens as it broke up itself into thousands of pieces. Space scientists believe there will be dozens of large chunks, hundreds of smaller fragments and many thousands the size of grains of sand.

Fragments travelling in lower orbits will eventually burn up as they descend then burn up in the earth’s atmosphere. But in high orbits they can remain a real danger for hundreds of years.

NASA is already monitoring 13,000 man-made objects more than four inches wide that are circling the earth. There are more than 110,000 bigger than a centimeter. And the millions of smaller pieces can be just as deadly.

A tiny metal chip is like a rifle bullet which can rip a hole in a spaceship. A chunk the size of a tennis ball, speeding at 20,000 mph, packs the lethal power of 25 sticks of dynamite.

In September 2006, the shuttle Atlantis landed with a hole in its cargo doors blasted by a meteor or fragment of space junk. Other shuttles have had to have their windows replaced after they were damaged by speeding flakes of paint.

A TV and comms satellite, Express-AM11, was sent spinning out of control by a chunk of cosmic crud in March 2006 in a special orbit that is becoming the Piccadilly Circus of the space lanes.

That is because its height of 22,240 miles means satellites will remain above a fixed point on the ground, allowing our TV dishes to stay pointed at them. The satellites that bring us satellite TV all orbit at the same altitude making it a relatively crowded patch of space.

In January 2007, China used a ballistic missile to destroy one of its own satellites in an orbit about 550 miles high. That “Star Wars” test, condemned by the West, created a cloud of countless pieces of debris.

A Russian booster rocket exploded over Australia in March 2007 adding around 1,100 chunks of rubbish. And around 300,000 fragments were left when the upper stage of a US Pegasus rocket blew up in 1996.

Other odd bits of space jetsam include nuts, bolts, an astronaut’s glove and a £70,000 toolbag lost by NASA’s Heidemarie Stefanyshyn-Piper as she was working outside the shuttle Endeavour in November last year.

In August last year, Europe’s Jules Verne craft, while attached to the International Space Station, fired its rockets to steer the orbiting outpost clear of the path of some Russian space junk.

Picture: A NASA computer plot of the debris in low-Earth orbit (NASA).

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