if the atmosphere bleeds off to space faster that it can be made where does that leave the people who went there?
but this is all talk about terraforming a planet in this solar system. I agree that it may be attempted as an expirement to study effects. But to seriously propose that it is possible to, more or less, make a breathable atmosphere on a world with a mass like that of Mars is pretty far-fetched!
Most models show that the atmosphere would bleed off over hundreds of millions of years.
I read a really far-fetched idea last year:
Move Venus into the spot exactly opposite the sun from the Earth, so that it is never visible (always on the other side of the sun). This creates a climatic advantage as it is the exact same distance from the sun as the Earth.
Then-crash Mars into it. Most of Mars' minerals and water will evaporate into Venus, and the core will spit back out into orbit creating a moon.
The impact will increase Venus' rotational speed.