Scientists design spacecraft to save Earth

Heroic missions to stop life on Earth from being wiped out by an asteroid have become a favourite theme for Hollywood disaster films.

Now, a team of British engineers have designed a real-life spacecraft to save the world from destruction.

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.