This whole "let's go to Mars" business is over-rated. Way over-rated. Why would we want to escape one gravity well to go focus on another one??
What is more important in my view is building an industrial and manufacturing business in some place well beyond High Earth Orbit. There are already a couple of companies out there actively designing equipment to harness and collect asteroids and mine them for their contents for manufacturing and cheap rocket fuel, all using unlimited solar energy far from the Earth/moon shadow in space.
Chew on this for a moment....NASA recently decided to send a probe out to an immense metal asteroid named Psyche. They think it is the stripped Iron/Nickle core of an ancient planet.
On earth, the Platinum group of metals occurs naturally in Iron/Nickel deposits, roughly .001 Grams or so of all per ton of Iron/nickel ore. If Psyche is a 300 mile diameter ball of nearly pure iron/nickle, how many thousand tons of Platinum group metals would be buried within it??
See the Commercial exploitation possibilities??
All of this talk of 3-D printing....show me a 3-D printer that can make structural components out of carbon in a weightless environment.
We're only a little over a century since the first manned flight.....
