All ships and stations require a per turn upkeep cost. Ships that are placed in reserve only have 1/3 the per turn upkeep cost of Operational ships. Currently, as of version 18950b, modules do not contribute to upkeep costs. However, the addition module upkeep costs is planned.  It is also possible that older ships will eventually begin to cost more per turn in upkeep costs, but that functionality doesn't appear to be implemented in version 18950b.
The per turn upkeep cost of ships is listed below. Weapons, sections or modules do not have any effect on the upkeep cost, only the size class of the ship.
The per turn upkeep cost of Stations is listed below. Modules do not have any effect on the upkeep cost, only the size class of the Station.
|Level||Civilian Station||Diplomatic Station||Gate Station||Naval Station||Science Station|