Just some other ideas about what else could be built in orbit:

1) It would also be great to add some sort of privateer orbital structure which creates ships around your planet that assist in planetary defense, maybe a couple of different types of privateer ships would be good (a couple of frigates and maybe a small cruiser of sorts). Once you start expanding your empire, its really hard to defend all of your planets…the citizens of each planet should take up arms (frigates) to defend themselves!

2) Maybe some other types of orbital gun emplacements (maybe laser or missile ones as well? Or maybe even orbital targeting assistance platforms… This has been floated around the general forum recently. I think an orbital emplacement that is only effective again CapShips would give raiding commanders a run for their money - we wouldn't want to overpower these types of emplacement of course (I know some people are against additional emplacements).

3) An orbital structure that slows down approaching enemy fleets in phase space (to buy you some time to ready your defenses and call in reinforcements from adjacent planets). Not to slow an incoming enemy to a crawl, just down a little to give a well defended planet time to get ready for a massive attack

4) The trade ships that are auto-built and set up trade routes really added a really cool level to the game – protecting them and their routes really felt like you were protecting your expansive empire, other than just static planets. Any other types or empire ships that would go about their business and would periodically require your fleet’s protection would add even more. Maybe something like large leisure vessels (tourism could be a great addition for credit increases at specific destination planets), passenger vessels, maintenance crew ships, etc... Adding specific orbital structures to create ships similar to the function of trade ships would be cool and would add even more empire traffic - I for one like the economic aspect of these types of games as well as then tactical combat (I know some will disagree, some of you want to just blow stuff up - and thats also totally cool). Who knows, maybe another empire's ship could be disguised to infiltrate a commonly used trade route to gather intel on planets, maybe another type of orbital structure could be a phase jump checkpoint prior to allowing civilian and other non-military ships to enter or leave gravity wells...

Just some ideas to float around.