To Keith1 Attacks directed to me do not change astronomical facts* I cited, so there is no need to reply more to you until you answer my now four times asked question: What do you think one can bring back from an asteroid to even just a near Earth orbit that is not now available on Earth for less than 1% of the cost?** ----- * Nothing man can do will ever change these facts but you are welcome to ignore them and dream instead. (More details in last paragraph.) ** Or less as advance in technology do reduce the cost of production on Earth. As an interesting example of this, is the top of the Washington Monument in DC. It is a tiny pyramid of not very pure aluminium, chemically produced before the Hall processed was invented. - It was the most precious metal then, far more valuable than gold, but now that metal is thrown in trash cans when you finish drinking your soft drink. However no future technology advances will cause the Earth and moon to not move around the sun at ~107,000 km/h or asteroids to cease their very different directions and speeds in orbit about the sun. Landing on one requires huge energy to change from Earth's velocity (speed and direction) to their's and then after taking on the cargo, huge energy is required to again re-match the Earth's velocity, just to co-orbit with it around the sun in near Earth orbit. Technology will not change the kinetic energy changes required. Going to the moon and back was very easy by comparison as both go around the sun with the same speed and direction.