To boldly go: Nasa's mission orders come in... put astronauts on an asteroid within 15 years

With the space shuttle now history, Nasa's next great mission is so audacious, the agency's best minds are wrestling with how to pull it off.

They have presidential orders to to send astronauts to an asteroid in less than 15 years.

The challenges are innumerable, but many Nasa brains are thrilled to have such an improbable assignment - and believe civilisation may even depend on it.

The asteroid Vesta, as photographed by the orbiting Dawn spacecraft on July 17. Nasa now aims to place astronauts on an asteroid within 15 years

An asteroid is a giant space rock that orbits the sun, like Earth. And someday one might threaten the planet.

But sending people to one won't be easy. You can't land on an asteroid because you'd bounce off - it has virtually no gravity. Astronauts couldn't even walk on it because they'd float away.

Reaching it might require a Nasa spacecraft to harpoon it.

Read more: http://www.dailymail.co.uk/sciencetech/article-2018477/Nasa-ordered-astronauts-asteroid-15-years.html#ixzz1T7bXFRko