You need to make a mod. To do this you need the reference files converted from BIN to TXT
7-zip.org required German
The allowed starbases and tactical modules are set in the GameInfo/PlanetXXX.entity
GameInfo/PlanetTerran.entity
path:TacticalModules
stageCount 4
is near the middle. Each stage is an upgrade to the planet with allowed tactical slots and upgrade cost
maxStarBaseCountPerPlayer 1
is near the bottom
each planet type and asteroid needs to be set
[Tutorials] Modding, Modeling, Texturing & Converting