Planetary structures have an impact on the happiness of the colonists and the natives. They also have an impact on the production and defensibility of the planet.
If there are 200 or fewer colonist clans on the planet, the maximum number of mines that can be built is equal to the number of clans.
If there are more than 200 colonist clans on the planet, the maximum number of mines that can be built is equal to:
200 + SQRT( (Colonist Clans) - 200)
If there are 100 or fewer colonist clans on the planet, the maximum number of factories that can be built is equal to the number of clans.
If there are more than 100 colonist clans on the planet, the maximum number of factories that can be built is equal to:
100 + SQRT( (Colonist Clans) - 100)
If there are 50 or fewer colonist clans on the planet, the maximum number of defense posts that can be built is equal to the number of clans.
If there are more than 50 colonist clans on the planet, the maximum number of defense posts that can be built is equal to:
50 + SQRT( (Colonist Clans) - 50)
For more details on defense posts, please look here.