What starbases are good for?

Starbases (SB) are similar to bases but in orbit. You can build it the same way as bases, thru a Colony Ship.
Move it into an astro of your desire, and click the Build link in the Fleet Overview page.

You can have 1 starbase per base. The cost of your first starbase is 5,000$, to the next one it will increase by 50%, and so one to the 3rd, 4th, etc.

Over the starbases you cannot build these type of structures:

Urban Structures
Gas Plants
Hidro Plants
Metal Refineries
Crystal Mines
Command Centers
Terraform
Arcology
Biosphere Modification
Tele-Transport Pod
Capital

What starbases can build:

Automated Factories
Solar Plants
Fusion Plants
Antimatter Plants
Solar Satellite
Economic Centers
Nanite Factories
Orbital Base
Orbital Shipyards
Research Labs
Robotic Factories
Shipyards
Spaceports
Spacegate
Starbase

What starbases are good for:

Can be built over asteroid belts, bases cannot
Can be built on astros where there is already a base or other starbases
It generates 10~25 debris every full hour [beta universe only]
It generates debris at asteroid belts hourly by 25 per SB level
Good for producing ships near your enemies region or galaxy; restock FTs, HBs
Good for increasing your economy
Good for increasing your scanners capabilities
Good for increasing your research
Good for reinforcing your defenses
Can be moved