Most planets will have a number of tiles initially unusable to the inhabitants but may be upgraded to make them usable. Upgrading tile first involves obtaining a specific technology. The following are the technologies needed to make the tiles usable:
- Yellow:Soil Enhancement
- Orange:Habitat Improvement
- Red:Terraforming
Upon researching the technology, the associated improvement must be built on the tile. Upon completion, this will permanently turn the tile green, allowing it to be used for other improvements and raising the Planet quality by one.
Alternatively, by choosing the Neutral alignment or building the Orbital Terraformer, all such tiles on all planets will be made green without any further research or construction.