Starbases are the most advanced fortification and were added in Entrenchment. The base cost of a starbase is comparable to that of a Capital Ship, and the cost of a starbase fully outfitted with additional modules is several times higher.
A Starbase Construction Cruiser is needed to build a starbase, with the exception of the Vasari who use their Colony Frigate, the Jarun Migrator, instead. In both cases, the ship is lost when the starbase construction is initiated. Any Gravity Well except a Magnetic Cloud can house a single starbase, and a star can support up to four. Unlike ships, a starbase does not require Fleet Supply. Therefore, the construction ship's supply is reclaimed upon activation.
Starbases have 8 module slots, which can be filled in whatever way the user sees fit. Each module has a resource cost and many have some research that has to be done first before you can build them.
Like Capital Ships, Starbases have a name that can be changed. Starbases do not gain experience levels, but they do have some researched abilities which require antimatter and can be used much like capital ship abilities, either manually targeted or on autocast. An example of this is the dreaded Meteor Storm of the Advent's Transcencia Starbase.
While a player is free to use a starbase in any way they see fit, much like any other unit in the game, there are several archetypal uses:
The most common use, and the one for which starbases are primarily intended. You build a starbase in one of your gravity wells -- presumably a frontier planet which you consider exposed to risk of enemy attack. Rear-area defense generally does not merit the expense and player attention required by the construction of a well-outfitted starbase, and can be more economically served for example by hangar defenses. A fully-upgraded starbase is essentially impervious to anything other than a full fleet attack -- a light or medium task force usually used to take lightly-protected systems just won't cut it against a starbase, and marauding frigate squadrons won't even make a dent. A fully (intelligently) upgraded starbase can also stop virtually any grade of pirate raid.
A daring tactic that can really throw an enemy off-balance is to bring a starbase constructor along with your fleet when attacking a gravity well. Assuming the fleet can hold its own long enough for the starbase to construct, you can instantly deploy a roughly capital ship's worth of extra support, without actually diverting your count-limited capital ships from elsewhere. Furthermore, unless you are severely outclassed and as long as you have the resources, the starbase will probably survive long enough for resilience and offensive power upgrades to construct, which can easily turn the tide of battle. If the starbase survives the engagement and you take the gravity well, you also already have full-size fortifications in place for your newest acquisition. The only downsides are the considerable costs (particularly if you would not otherwise build a starbase in the given well if it were captured through traditional means) and the additional management the combat deployment of a starbase requires.
A starbase can be used to fortify uncolonizable gravity wells and, depending on your race, supplant some of the logistics structures that you otherwise cannot build in these wells. All races have a researchable trade port upgrade for their starbases, which can make the placement of a starbase in an otherwise useless gravity well key to your empire's economy, by allowing you to continue your principal trade route (which determines the income of all your trade ports) through that well. In some situations, there may be no other feasible routing available to connect a decent number of planets in a line than to use a starbase to "bootstrap" your route through an uncolonizable gravity well. Note: The only type of gravity well that cannot be chained onto a trade route (or fortified) is a Magnetic Cloud, where starbases cannot be built because all vessel abilities are disabled there -- this includes the "construct starbase" ability of starbase construction vessels.
With research, starbases gain a variety of special abilities, many of which do not directly relate to combat. Additionally, many of these abilities will come in handy at uncolonizable gravity wells where they are generally the only way to simulate the presence of normal logistics structures (also see above).
The "utility" abilities of starbases include, for example, the Auxiliary Government upgrades, which all races have available (albeit under different names) and which prevent the loss of a planet through bombardment. As long as the upgraded starbase exists, the planet that hosts it cannot fall from your control through having its health reduced to zero. This includes both conventional bombardment and Novalith Cannons. It can, however, turn neutral if enemy culture overwhelms it -- planet retention starbase upgrades have no effect whatsoever on cultural subversion. Nevertheless, once the planet has turned neutral, if the upgraded starbase remains, the planet can only be recolonized by you, denying it to the enemy and forcing him to assault the starbase directly. The only thing in the game that completely ignores these upgrades is Repossession, the ultimate ability of the Advent Loyalists' Coronata Titan (available from level 6 of the titan).
Additionally, each race has unique "utility" upgrades: for example, the Advent can increase maximum planet loyalty through starbase upgrades, as well as make a starbase function like a culture broadcast center. The Vasari can turn a starbase into a temporary phase stabilizer or use it to substantially increase planet population, and the TEC can use it as a frigate factory and as a repair station.
Starbases by race
- Main article: Argonev Star Base
- Main article: Transcencia Star Base
- Main article: Orkulus Star Base