Terraforming
Terraforming or terraformation (literally, "Earth-shaping") of a planet, moon, or other body is the hypothetical process of deliberately modifying its atmosphere, temperature, surface topography or ecology to be similar to the environment of Earth to make it habitable by Earth-like life.[1]
Mars edit
Mars lacks a magnetic field, hence its upper atmosphere has no protection from the solar wind. Hydrogen molecules get blown away easily, when solar activity is at a maximum. Ideally, for Mars to be terraformed, the lack of its magnetic field must be addressed.