what does it take to get to a spaceport? None show on my possible destinations drop down list. Someone please tell me what I'm missing. Thank you.

That is because they are down towards the bottom.

First you have Trade Depots, then you have your Spaceports and Techcenters AFTER the trading depots. So try scrolling down past Zosma, then you should have Aldeberan and other Spaceports.

thanks