Martin Lee: A great idea – but really not very realistic

I THINK they have got a lot of enthusiasm and it is a very exciting idea, but very technically difficult.

Firstly, you have got to find one of these bodies, then get yourself in a situation to land on it and then extract what you want to extract. We have never managed to do that before – although the Japanese mission Hayabusa managed to collect microscopic samples of the asteroid Itokawa in 2005.

One of the more realistic things you could do is try to extract water. In theory this could be converted into fuel or used as drinking water on missions to Mars.

It is certainly true that these bodies could contain a lot of precious metals – but extracting them is something that has never been achieved.

But these are very clever people, and they have got a lot of money behind them. Whether it is realistic or not is another matter.

• Martin Lee is professor of earth and planetary science at the University of Glasgow