Spaceport Usage

By lostcymbrogi, in Merchant of Venus

Just got my copy and have a question regarding the green spaceports. When you are first discovering races are these in use with the same trade restrictions as planets or are they not in use until a player buys/builds them.

It's my understanding that the "green dot" orbit markers are places that space ports CAN go, but are not able to be used until they are built.

(At least for the Standard game rules)