terraforming mars is not practical. bio domes is a better solution.

it took the earth m/billions of years to create this 23% oxygen atmosphere from a highly CO2 one, even if machines can do it in a fraction of the time, thats still a long long time.

not to mention the energy cost of running such a machine....

even large scale space stations are not that feasible in the next few decades as the economic push is not there.