|Civilian Station -- Diplomatic Station --|
|Gate Station -- Hiver Imperium only|
|Tribute Station -- Breeding Station -- Suul'ka Horde only|
There are four basic types of Stations for the majority of Factions: Civilian Stations, Diplomatic Stations, Naval Stations, and Science Stations. Hivers have an additional Station type, the Gate Station, and the Suul'ka Horde Faction, which has no use for either "Civilian Stations" or "Diplomatic Stations", build Breeding Stations and Tribute Stations instead. Additionally, a Mining Station is a special type of station that can either be built by the state or by it's citizens.
Whether acting as the Base for major fleet operations, the hub of both local and inter-faction trade, the center for a particular study of scientific research or as the primary locale for inter-Faction negotiation for either diplomacy or tribute.
Only one of each type of station is allowed in any single system, except for mining stations which can have more per system. Additionally, stations are now limited by population - one station per 750M population (Imperial + Civilian).
All stations begin their lives with the smallest possible investment of resources, and then evolve over time based on your choice to upgrade them. Each phase of development increases the service capacity of the station, but also the expenses associated with its upkeep.
You start the process by designating a fleet with a construction ship to the mission of building a station in the selected system. The initial outlay is immediately deducted and the fleet begins to travel to the system selected. Upon arrival, the fleet will begin construction of the station. Actual time spent on construction varies depending on station type and the amount of industrial output the fleet containing the construction ship is capable of. Additional construction ships in a fleet will contribute additional industrial output capability towards constructing stations.
While most stations have to be constructed by the state, Mining Stations on the other hand are small and simple enough that common citizens can bang one together, and may do so if they see a profit opportunity. Like most civilian opportunities, you can specifically order civilian enterprise to not develop a location by "closing" the system.
Stations can be customized by the addition of modules which have various functions. Each such modular upgrade expands on the capability of the station in its intended role.
In order to upgrade a station to the next size of development you will have to add modules which meet the minimum requirements for the upgrade. Which modules are required depends on the type of station.
Gate Stations are a little bit different initially in that the base of such a station is the gate ship which was initially deployed is then upgraded to become the next level of Gate Station.
As with the initial build, a fleet with one or more construction ships is required for assignment to the process via an upgrade mission.
Stations have the ability to place excess ships into reserve status. 
The cost of planetary development is linked to proximity of a "supply base" in SotS 2.