This article is for the PC version of Stellaris only.
A starbase is the primary space station used throughout the game and is used for determining the ownership of a given star system, construction, repair and maintenance of ships, collection and transportation of Trade Value in addition to it acting as a strategic fortress during warfare.
A starbase's most fundamental function lies in asserting ownership over a star system. Doing so requires fully surveying the desired system and then constructing a starbase in it. The build cost is 100 Alloys and an additional influence cost on top of that. The influence cost is determined by a fixed cost which is then multiplied by the shortest path of hyperlane jumps (gates and wormholes act as "shortcuts") between the target systems and the empire's closest owned system.
Once built, the starbase will appear orbiting the center point of the system. It cannot be destroyed by any regular means but it can still be dismantled by its owner during peacetime if it is of no more than outpost level (higher-level starbases will need to be downgraded to outpost in order to be dismantled). If a starbase is dismantled, the system reverts back to being neutral and unclaimed and can then claimed by any empire.
Besides the initial influence cost, upgrading the starbase to a higher level above outpost level will cost only alloys. Aside from making the starbase more powerful due to better base stats and the addition of more weapon components, the upgrade also allows the owner to fit the starbase with different buildings and modules to increase its defensive capabilities and improve its contribution to the empire beyond its basic role of system control and defense. One such important module is the Shipyard which enables the construction of military ships in the starbase. Having multiple shipyards on a starbase allows it to effectively act as a "fleet manufactory" by constructing several ships in parallel, simultaneously. Shipyards build order is independent from the main build order of starbase.
Though it is not possible to design a starbase, its components will be auto-fitted with the latest advanced technology as soon as they are made available (at no additional cost to the owner).
Systems with starbases bigger than outposts require a higher influence cost to claim (25 influence). Consequently, those starbases grant a higher war-score if occupied successfully (10 occupation value). An additional benefit of upgraded starbases manifests in them including an FTL inhibitor which, as long as the starbase remains active, prevents enemy ships from leaving the system via any hyperlane other than the one they arrived through. This allows an FTL inhibitor-equipped starbase to turn strategically important systems into efficient choke points, delaying hostile fleets from leaving the system and advancing further by forcing them into an engagement which may last long enough for reinforcements to arrive.
During war, an attacker must disable the enemy's starbase within the system in order to be able to seize control of any planets within said system. As starbases cannot be destroyed, this is achieved by reducing their Hull points down to 0, disabling them. The starbase will then remain incapacitated for a duration of 30 days (after the latest attack), during which time any military ships in close proximity to the starbase will be able to gain control over it. If the starbase is left unoccupied and is not attacked, it will enter a self-repair phase and become operational again as soon as it regains 5% Hull points. If there are multiple empires fighting on one side of the war, the newly-occupied system will then be assigned to the empire with the strongest claim, even if the system wasn't conquered by them.
Occupied starbases are fully operational and can repair ships of the side that controls it, inhibit FTL for "enemy" ships, and manage defense platforms, all empire-wide bonuses will also be applied, including home territory modifiers (The Eternal Vigilance ascension perk's platform cap of the original owner is also temporarily retained). However their buildings and modules cannot be changed, and they cannot be upgraded or downgraded, although they can be returned back to the owner.
It's worth noting, that auto-upgrading a starbase can "gift" higher tech components to occupied starbases (including FTL inhibitors!), while keeping their own more advanced components. They will stay equipped even if said starbase is reclaimed back, so repeated re-conquering might become harder both sides.
Systems containing an unoccupied starbase or unoccupied colonized planets will not be transferred in a forced status-quo peace.
Because starbases are vital targets during warfare, an empire must ensure that they can maintain control over their own starbases to prevent their opponents from seizing control of the system. Investing resources into arming a starbase can allow to function as a strong deterrent to enemy invasions, a powerful supporting power during a fleet battle in the system and a starbase that is heavily armed enough can potentially even repel an entire enemy fleet by itself. Successfully maintaining control over every single starbase in the empire is by itself enough to allow an empire to end the war through a status-quo without losing any systems, earning them a defensive victory.
When initially constructed, an Outpost-level starbase is armed with just a single Guided weapon slot for self-defense, which combined with the starbase's complete lack of Evasion, makes it rather weak. Every upgrade level above outpost, however, will add in +2 medium weapon slots (except for the last upgrade level, which adds +6 medium slots), making it stronger and more capable of defending itself against enemy ships.
A starbase's self-defense capabilities can be further reinforced with the construction of defense platforms. Defense platforms are smaller military stations that are deployed around the starbase and act as weapons platforms. Defense platforms have two sections for weapon slots which can be outfitted with a wide variety of weapon configurations. They will engage any incoming hostile ships, effectively acting as a supporting weapon, by attacking and distracting them from focusing their efforts on the starbase itself, allowing the starbase to engage the enemies and support the defense platform(s). When compared with ships, platforms are situated between Destroyers and Cruisers classes, their hull and armament slightly better than the former, while their armor-potential is equivalent to the latter. However, due to them having no Evasion whatsoever, individual platforms are still very vulnerable, and if a strong, sustainable firepower is a priority it is wiser to put more turrets on the base itself and only add in Defense platforms once the starbases available armaments have been maxed out.
As opposed to the auto-fitting of the starbase's components, defense platforms can be altered through the ship designer allowing for several designs to be built based on the different needs in each front and upgraded based on this designs. However, unlike ships, their designs cannot be switched once built, necessitating dismantling and complete rebuilding. It also renders any transferred platforms non-upgradeable. Economically defense platforms are, again, comparable to destroyers, but they cost no alloys upkeep.
Each starbase can support only a certain number of defense platforms based on its level. However, the defense platform capacity can be increased with the following:
- Globally: +5 Eternal Vigilance, +4/+8/+12 Strategic Coordination Center galactic wonder
- Locally: +8 Defense-Grid Supercomputer
If all of these modifiers are applied for a total of +25 platforms, a single starbase can support up to 40 Defense platforms when upgraded to Citadel level.
|Available only with the Apocalypse DLC enabled.|
In addition to the regular defense platforms, a citadel-level starbase is also capable of hosting a more powerful platform type that carries a singular weapon, which is stat-wise identical to the Perdition Beam weapon. This means that it is capable of destroying an enemy warship of any size (except for Titans) in a single shot from very far away and cannot be changed. It is titan-class hull-wise, but only battleship-class armor-wise. Economically it is also comparable to the latter without alloy upkeep, and it is deployed quite slowly.
An ion cannon platform is equivalent to 8 defense platforms in terms of capacity slots and can only be constructed on citadel-level starbases.
- Defense platform modifiers
Additional modifiers which affect various defense platform parameters are summarized below:
|+10%||Synchronized Firing Patterns|
|+25%||Secure the Borders|
|+500||Improved Structural Integrity|
|Armor hit points|
|−15%||Secure the Borders|
An empire can in theory have as many starbases as their economy can support but an empire can only maintain a limited number of upgraded starbases bigger than outposts. The number of upgraded starbases an empire can support is dictated by the Starbase Capacity and exceeding that capacity will cause all upkeep costs for starbases to increase by +25% Upkeep for every starbase exceeding the cap. This is an empire-wide modifier, and thus affects all starbases owned by the empire. This modifier also affects the maintenance of any modules and buildings on the starbases. Regardless of their level, each starbase bigger than an outpost occupies only one capacity slot and if the need arises, an empire can always downgrade existing starbases back to outpost level to reduce the number of upgraded starbases to within the cap limit.
The base Starbase Capacity is 3, which can be increased by the following:
- +1 for every 10 systems owned by the empire
- +2 adopting the Supremacy tradition tree
- +2 Stellar Expansion technology
- +2 Manifest Destiny technology
- +4 Trading Posts civic
- +5 Grasp the Void ascension perk
- +10 Covenant: End of the Cycle
- +1 Interstellar Expansion repeatable technology (can only be researched 5 times)
- +2 for each Strategic Coordination Center level
A starbase is auto-fitted with the latest components as soon as they are available to the empire. This is done automatically and has no additional cost for the empire - as such this also does not affect a starbase's level upgrade cost.
The weapon slots are fitted with the most effective kinetic and energy weapons (though not necessarily by equal division). The utility slots are divided equally between shield and armor components (auto-fitting does not add hull components here), while the auxiliary slot uses standard auto-fitting of a shield capacitor or auxiliary fire-control (whatever is available in order of priority).
Upgrading a starbase can only be done in a sequential order - meaning that if one were start with a basic outpost and wants to upgrade it to a citadel, they have to go through every single level in between in order to get to the desired level. Downgrading a starbase, however, reduces its level to the basic outpost level (outpost) straight away - regardless of what level the starbase initally was - and removes any present buildings, modules, and any defense platforms over the outpost's capacity limit. Any resources invested into the starbase prior to downgrading will not be refunded.
Starting from the starport level all starbases can repair docked ships (regardless of whether or not it has a shipyard onboard) and have an FTL inhibitor onboard if technology is available.
Note: The table lists the base properties of each starbase level. The actual values themselves will differ due to one's progress in-game (technology, tradition, and etc.), existing modifiers (if any) as well as individual starbase composition (buildings, modules, and etc.).
Additional modifiers which affect various starbase parameters are summarized below:
- Construction and maintenance modifiers
|Outpost influence cost|
|−10%||Reach for the Stars|
|Outpost build cost|
|+25%||"Exceeding starbase capacity" modifier|
- Upgrade related modifiers
|−33%||The Great Game|
|−15%||Corps of Engineers|
|+25%||Corps of Engineers|
- Military properties related modifiers
|+20%||The Great Game|
|Armor hit points|
A fully upgraded starbase can support up to 6 modules. It is possible to construct multiple modules of the same type and the starbase will be called in the outliner accordingly.
Modifiers affecting module build cost include:
A fully upgraded starbase can support up to 4 buildings. Unlike modules, it is only possible to construct a single building of any type. Building cost is reduced by −25% by the Modular Engineering technology.