>>If we can get to the point where we have the technology to colonize Mars, which will hopefully happen this century, then I would imagine it probably won't be

>>If we can get to the point where we have the technology to colonize Mars, which will hopefully happen this century, then I would imagine it probably won't be long after that until we manage to have permanent space habitats that harvest materials from asteroids. We are already capable of that now. The issues are politics and economics and not science/engineering. If I'm not wrong the USA spent like $1T on building a fighter plane, and something like double digits trillion dollars and ongoing on wars since the past 20 years alone. You can mine asteroids for a part of that kind of budget already. Going down gravity wells of planets makes no sense, space colonies are the way forward, and there is no shortage of resources in space for that.