Just to confirm my understanding: Is a spaceport basically a combination cargo shuttle station, ordinance transfer station, and refueling station? Earth has all four - is there any reason to keep the three specialized stations since I have a spaceport? And is there any reason to have more than one of any of these stations on a planet?
The spaceport costs 3000 to construct and requires 1m population to run, where the other three are 1200 each, without a population requirement. Since it looks like population limit will be a bigger factor here than in my VB game I don't see much need to construct spaceports except for RP reasons on major population centers.