Humans are a step closer to mining valuable minerals from space. But just how would you get hold of an asteroid?

Europe's Rosetta space probe has finally reached its destination, and come into the orbit of a comet five hundred and fifty million kilometers from Earth - somewhere between Jupiter and Mars.

Rosetta is mankind's first attempt to land a space craft on the surface of a comet, and its mission is to help scientists learn about the origins of comets, stars and planets.

Later this year the probe will land on the comet's surface and eventually use its technology to mine for water.

We talk to Matt Taylor, a scientist with the Rosetta project, and ask Professor Monica Grady from the UK's Open University - who helped build some of the instruments on board the Rosetta probe - about whether today's breakthrough opens the door to one day mining asteroids for minerals we're running out of here on Earth.