Colony cost
This article contains information relevant to both the C# and VB6 versions of Aurora. Where differences exist, they are noted in the appropriate sections.
The Colony Cost(CC) of a body is a measure of that body's suitability for sustaining human (or alien) life. The higher the Colony Cost, the more effort it takes to build habitable cities there.
If a planet has zero colony cost, like your homeworld, the population is not restricted in any way other than the maximum growth rate, and (C# only) the maximum supportable population. Otherwise, the maximum population is limited by your infrastructure. Infrastructure installations support populations on bodies with gravity of 0.1G or higher, and Underground Infrastructure(VB6)/Low Gravity Infrastructure(C#) can support populations on any body, albeit at a significantly higher price.
The total supportable population on a body with CC>0 is equal to (Infrastructure * 10,000)/Colony Cost. For more details on colony cost, see the System View window F9, or the Environment tab of the Economy window F2. The Colony Cost of a body can be lowered by terraforming.
Note that the civilian sector produces and ships infrastructure to your colonies by itself, although perhaps not in great quantities. See Trade System for details. Note also that any population on an Orbital Habitat Module ignores colony cost, so this can be a good alternative for high-CC worlds.
Workforce Implications
[edit]A higher colony cost also increases the share of the population who is required to work on non-manufacturing tasks. The mathematics of this are somewhat complex, but in brief, the population that's available to do manufacturing work (i.e., running your installations) will start to decrease at some point. If the colony cost is below 5 then it will eventually recover to exceed its previous peak, but if the colony cost is 5+, then the available workforce will eventually hit zero as population increases, and never increase again. See this thread for details, and this spreadsheet for the numerical analysis.
| Colony Cost | 2 | 3 | 4 | 5 | 6 | 8 | 10 |
|---|---|---|---|---|---|---|---|
| Population Where Workforce Begins Dropping (million) | 215 | 169 | 131 | 99 | 74 | 38 | 17 |
| Workforce at Peak (million) | 36.2 | 26.8 | 19.4 | 13.7 | 9.5 | 4.1 | 1.5 |
| Population to Exceed Previous Peak (million) | 242 | 268 | 388 | N/A | N/A | N/A | N/A |