Until now we've filed the idea of mining asteroids into the same 'nice idea, let's wait 100 years' box as Elon Musk's Hyperloop and the release of Half-Life 3.
In theory, it's a great idea. If asteroids contain either rare metals or - even better - water, they might be a fantastic stepping stone to true exploration of the Solar System. Currently companies like Planetary Resources are scooping out possible plans.
But it's not just madcap investors and bright-eyed billionaires involved. Nasa is into the idea too, and its mission roadmap includes several steps towards eventually landing on, and possibly retrieving, a giant rock in space.
And now researchers have announced that there are at least 12 asteroids close enough to Earth, with the right kinds of flight path, to blast into a safe orbit where we can go and get them.
The team from the University of Strathclyde look at the official list of more than 9,000 currently known-about near-Earth asteroids to find those which could be sent into an accessible orbit by changing their velocity by just 500 metres per second.
The orbit in question would be a point where the gravity of the Earth and the Sun are in balance, about a million kilometres from our planet.
One of the asteroids - 2006 RH120 - is just 7 metres in diameter and could be sent into a useful orbit by changing its velocity by just 58 metres per second. The researchers say this could feasibly be done by 2021.
So while nobody is quite ready to get out their drills and start looking for space gold quite yet, we at least have a better idea of the sorts of rocks we might end up targeting.Suggest a correction