Nasa has drawn up plans for a huge nuclear spacecraft capable of shunting or blowing up an asteroid if it was on course to wipe out life on Earth.

The US space agency published details of its Hammer (Hypervelocity Asteroid Mitigation Mission for Emergency Response) deterrent, an eight tonne spaceship which could deflect a giant space rock.

Nasa has said previously that Earth is overdue a huge asteroid strike and programmes are in places across the globe to map dangerous rocks as they move through the Solar System.

Last year an 100 foot asteroid named 2012TC4 passed within 27,000 miles of Antarctica, a distance that astronomers described as 'damn close.'

In detailed plans published in the journal Acta Astronautica, Nasa and the National Nuclear Security Administration, calculated the time and payload it would take to move or destroy the 1,600-foot-wide asteroid Bennu.