And to get this back on topic, I'm worried about LEO and MEO debris for a large rotating station. According to Google, the ISS only has to maneuver once a year on average. So my fears are probably unjustified. That said, moving around a rotating large object is probably a bit trickier than a non-rotating object. I expect the maneuvering would need to happen at the hub.
I don't think it would be all that tricky. However, the larger the mass of the station, the more energy is needed to maneuver it. And the larger the cross section, the greater the chances of being hit by space debris. The latest episode of Astronomy Cast mentioned that there are now a bunch of 4-inch satellites that are not being tracked because basically, they've lost track of them. I'm thinking here of LEO. It will be many hundreds of years before we'd be able to send a ship to Mars that's large enough to have artificial gravity, as accelerating that much mass will be prohibitively energy-expensive.
AFAIK there's been zero research into things like the ability of animals, never mind humans, to conceive, bear and raise young (children) at anything other than 1.0 G. All the research into micro gravity has shown serious short term (<2 year) consequences. Not only has there been no research into this, I'm unaware of any plans to do such research.
Anyone, and their spouses, ready to experiment on their children to be?
And there's the rub: You cannot ethically perform that experiment. Would-be colonists, in addition to the cruelty of raising kids on Mars, would be experimenting on them to see if they can even survive gestation.
Astronomy Cast also touched on the economics of being a Mars colonist. Nobody ever asks about that. Immigrants to America often came as indentured servants. It's likely that Mars colonists would have to pay for their trip with indentured servitude, working for the company that sent them and established the colony. Company mining towns in America often charged miners so much for food and supplies that they just went deeper into debt every year. (Recall the line from the Tennessee Ernie Ford song:
"Ya load sixteen tons, and what do ya get?
Another day older and deeper in debt!
Saint Peter, dontcha call me 'cause I can't go:
I owe my soul to the company store." )
But on Mars there will be no government but the company, no legal recourse, and no way to leave. Even communication with Earth will be controlled by the company. Colonists will become debt slaves, never able to pay off their transportation. In America, kids don't inherit their parents' debts, but on Mars, who's to stop the company from demanding that kids take on their parents' debts? After all, they'll have nowhere to go: They can't leave; they can't walk away, they can't return to Earth. Who on Earth is going to pay to rescue them?
That's assuming they can survive there at all, which I highly doubt. NASA or the Chinese may send a couple of people there just to say we/they did it. But a colony won't be able to support itself. Colonies are financed in the hope of profit, and there's no profit to be had from Mars. Political bragging rights and maybe research. Not a self-sustaining colony.
