I've lost count of the number of times I've posted the following to /., well anyway another try with my idea, a further thought, if we can control robots 70 odd million miles away on Mars, why can't we control mining robots an average of 238,857 miles away on the moon, some estimates have put the amount of oxygen in moon rock at 40%, there is also aluminium in moon rock. As well as being able to create rocket fuel from water, you can also create rocket fuel from oxygen + aluminium.
The high cost to the human race's colonisation of space is caused by the complexity and danger of reaching and leaving escape velocity within the earth's atmosphere.
The Space Shuttle turned out to be an expensive and dangerous white elephant, the reason the Shuttle was so expensive is, because of its complexity with millions of different manufactured parts, and the need to cover it with the equivalent of bathroom tiles.
There is another route, we can reach the edge of space no problem Burt Rutan proved this with Space Ship one, when he won the 'X' prize by reaching over 100 km twice in one week.
Yes the Shuttle was 'reusable' but in name only. They could not have turned that around in a week.
What NASA should be doing is creating rocket fuel on the moon, there is lots of water on the moon, use solar energy to split water into hydrogen and oxygen, which when combined make very good rocket fuel, because of Newton's third law.
Use the rocket fuel to fuel a space tug, use the space tug to accelerate and decelerate Space Ship one, to and from escape velocity in the safe vacuum of space, no atmosphere = no friction = no heat = no bathroom tiles and no foam shielding on the external fuel tank.
Less bathroom tiles + insulation foam = less rocket fuel = less pollution in the Mexican Gulf.
Once we can accelerate and decelerate space craft with rocket fuel that is obtained from outside of the earth's gravity well, space travel becomes cheaper by many orders of magnitude, ok the capital cost would be very high, but once the systems are in place, the number of human beings, living in space increases exponentially.
A good example for the way very high capital cost projects work, is the Panama canal.