It’s not inconceivable that in the far future mankind will discover a planet that is suitable for colonization. A planet won’t feel much like home if you’re forced to wear a spacesuit twenty-four-seven. If our chosen planet is too chilly to retain liquid water then heating the place up a little will be the second task on our list. If we’re eventually going to sew Martian crops, ruin Martian barbecues and shoot the ending to Martian romantic comedies, we’ll have to figure out a way to make the sky cry soggy tears from the heavens above.Oxygen is a pretty fundamental requirement for life on Mars to persist outside of an airlocked dome.