Over what amount of time? 2 weeks wouldn't be good, but 10K years... that I could live with (I will be sincerly dead by then).
Most models I've seen have had solar wind stripping atmosphere from Mars because it doesn't have a real magnetic field like a grown up planet.
/johnny
It’s not so much that it leaks, as Earth leaks as well, but the rate of leaking. It’s unlikely that we could produce enough atmosphere to compensate to the point where we could make it viable.
Can’t we just insert perils in the center and let them spin the planet a bit faster to create a stronger magnetic files and pull?