Just because iron might be abundant in asteroids that doesn't mean it is a good idea to harvest and process it in space. It would make more sense to build the infrastructure to harvest the lighter metals such as aluminum and magnesium. Those can then be used to build not just space stations but also the spacecrafts capable of landing on and taking off from Mars.

This isn't such a bad idea. Think about how much suffering and bloodshed could have been prevented in Iran if the hard line clerics had been able to use an emergency kill switch for the internet during their last election.