>Generating an atmosphere on mars is all well and good, but it will just blow away again without some protection.
NASA estimates the Martian atmosphere is ~2.5e16 kgs[0]. Current estimate[1] is that the Martian atmosphere loses 2-3 kg/s. Presently losing something on the order of 1e-9 percentage per day. I think if humans ever have the ability to thicken the Martian atmosphere, we can cover the loss.