Terraforming

Terraforming is the process of transforming the characteristics of a planet or asteroid to make it habitable, including atmospheric composition, soil, weather, and flora/fauna. It is usually preceded by some form of base or habitation on the planet. It is also a long-term process that can take millennia or tens of millennia. If the object is too far away from its home star, a stellification engine may be required.

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Artificial planet construction