A spacecraft capable of saving the world from a catastrophic asteroid collision has been designed by British space scientists.
Their invention, called a "gravity tractor", would be deployed when an orbiting rock is detected on a collision course with Earth.
The spacecraft would intercept the asteroid and position itself to fly alongside it, just 160ft from its surface.
From this position, the 10 tonne craft is able to exert a small gravitational force on the rock, pulling the asteroid towards it.
It estimates there are more than 100,000 asteroids orbiting near the Earth that are large enough to destroy a city. So far the agency has only been able to identify and track 6,363 of them.
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