With Mars I feel like everything is going to have to be underground and heavily protected from radiation and anyone there for extended amounts of time will have a hard time not turn out looking like a meth addict from being on the surface where the gravity is only 38% of Earth gravity. The entire time they fly to get to Mars they will have to be working out hard to slow down the muscle loss and effects. Then once they get there they will have to continue to workout hard. It is hard for me to imagine Mars every becoming a place where if life ended on Earth and we had a large Mars colony that they would ever be able to sustain themselves and live for generations and potentially get to the point of interstellar travel to leave the solar system utilizing materials mainly developed from Mars. I know that seems like a weird thing to think about but imagine we had a million people living and working on Mars and then something weird happened to Earth and everyone was vaporized. Then the Mars colony was all that was left and they had to figure out a way to progress and get off that rock. It is hard for me to imagine there would ever be enough to sustain them. I'm not going to lie Earth is pretty cool!