For those who are interesting finding out more I would recommend: Mining the Sky by John S. Lewis. It's an excellent book that discusses in length the composition of NEO, possible retrieval methods and economics of such an endeavour.

http://www.amazon.fr/Mining-The-Sky-Asteroids-Planets/dp/020...

Great response. Googling around led me to order this book on the matter: "Mining The Sky: Untold Riches From The Asteroids, Comets, And Planets"

It's a bit old but looks interesting...sadly not available on Kindle.

http://www.amazon.com/Mining-Sky-Untold-Asteroids-Planets/dp...

If this is interesting to folks, I highly recommend "Mining the Sky": http://www.amazon.com/Mining-Sky-Untold-Asteroids-Planets/dp....

Why?

Or, perhapse "Why is that obvious / why is it a necessity?"

If humanity expands into space, there is absolutely no reason for the population to ever stop growing. Space contains more energy, more living space, and more resources than we could possibly use.(1)

In fact, give the release of resource constraints, there are good arguments to keep growing--"given enough eyes, all bugs are shallow" applies to more than just software. More people is a good thing.

(1) For a really good treatment on this, read Professor John S. Lewis's _Mining the Sky_ http://www.amazon.com/Mining-Sky-Untold-Asteroids-Planets/dp...

Yes! Mining the Sky was an amazing book. http://www.amazon.com/Mining-Sky-Untold-Asteroids-Planets/dp...