Starbases are permanent constructed installations in orbit of a planet that can significantly increase that planet's defenses. They usually have the capability to build and maintain starships. Starbases can also instantly build torpedoes (for use on starships) and fighters (either for their own defense or to use on starships).
In addition to the checkbox controls standard to the other interface screens, starbases have these:
On the Starmap , a planet with a starbase is represented by a square, while a planet without a starbase is represented by a circle.
Starbases are expensive to build, both in terms of minerals and funds, but they have the potential to offer huge benefits, both defensively and offensively. To build a new Starbase, select the Build Starbase button on the Planetary Interface Pane.
Normal
StarbaseShielded
Starbase 1Mining
Station 2Duranium (KT) 120 145 70 Tritanium (KT) 402 582 242 Molybdenum (KT) 340 380 160 MegaCredits 900 1100 480 Maximum Defense 3 200 250 50 Maximum Fighters 60 80 20 Bonus Combat Mass 4 0 200 0 Image 
Starbases are powered by fusion generators. Because they're in orbit and don't move at warp speed, they have no need to be powered by Neutronium fuel.
Note 1: A Shielded starbase may only be built in the Radiation Halo of a Star Cluster , and except for the Robots (due to their Star Cluster Radiation Immunity ) are the only type of starbase that can be built there.
Note 2: A Mining station may only be built inside of a Debris Disk , and is the only type of starbase that can be built there. A mining station doesn't have a contingent of the Ship Builder's Guild, and is therefore incapable of building starships.
Note 3: Each Defense Post built on a starbase adds 1 KT to the Combat Mass. This Combat Mass increase might allow more defensive beams to be built, but will not effect the beam tech level or the number of ground-based fighters.
Note 4: This Combat Mass is due to the defensive shielding of the starbase. It increases the combat mass similarly to adding 200 Defense Posts. Because of this, it will usually allow more defensive beams to be built, but will not effect the beam tech level or the number of ground-based fighters.