Defence station

A Defence station is a Station subtype dedicated to combat. It hosts defence modules (turrets, missile batteries, defence drones), patrol fighters, and acts as the strategic stronghold of a sector. Defence stations don’t produce wares — they exist to deny enemy movement.

This page documents Defence-station-specific behavior. For all general station behavior (creation, ownership, hull, dockingbays, events), see the parent Station page.

Identification

Flag	Meaning
.isdefencestation	Currently a defence station
.isplanneddefencestation	Planned/in-construction to be a defence station

For early detection during construction, use .isplanneddefencestation (vanilla factionlogic_stations.xml:241).

Properties (defence-station-relevant)

All accessors live on the parent station datatype (scriptproperties.xml:848). There is no separate defencestation datatype.

Property	Type	Description
.isdefencestation	bool	Currently a defence station
.isplanneddefencestation	bool	Planned to be a defence station
.dps.all / .dps.turrets.all	hp/s	Combined DPS — typically very high on defence stations
.maxcombatrange.turrets	length	Max turret reach
.hasarmeddefencedrones	bool	Has armed defence drones available
.iscapturable	bool	Defence stations are typically not boardable (large hull, high resistance)
.alertlevel	alertlevel	Red / yellow / green — drives turret activation

Common defence-station-relevant patterns

”Find the nearest defence station"

<find_station_by_true_owner name="$Candidates"
    space="player.galaxy"
    multiple="true"
    sortbydistanceto="player.ship"/>

<set_value name="$found" exact="null"/>

<do_for_each name="$station" in="$Candidates">
    <do_if value="$station.isdefencestation">
        <set_value name="$found" exact="$station"/>
        <break/>
    </do_if>
</do_for_each>

"Bias fight-mission offers at defence stations”

<set_value name="$Chance_Fight"
    exact="$Chance_High"
    chance="100 * $OfferObject.isdefencestation"/>

Pattern from vanilla genericmissions.xml:313 — defence stations bias mission offers toward combat tasks (parallel to pirate bases).

”Filter pure defence stations (not wharf/shipyard hybrids)”

<do_if value="$station.isdefencestation
    and not ($station.iswharf or $station.isshipyard)">
    <!-- pure defence — no shipbuilding -->
</do_if>

Pattern from vanilla gmc_retrieve_dead_drop.xml:2292.

”Watch for player capturing a defence station”

<cue name="WatchDefenceCapture" instantiate="true">
    <conditions>
        <event_object_changed_owner/>
        <check_value
            value="event.object.isdefencestation
                and event.param == faction.player"/>
    </conditions>
    <actions>
        <write_to_logbook
            text="'Player captured defence station: '
                + event.object.knownname"/>
    </actions>
</cue>

NPC population behavior

Defence stations have special NPC instantiation rules (vanilla npc_instantiation.xml:1634, 2057). Most defence stations have minimal civilian NPCs — only a defence NPC, a representative-of-sorts, and maintenance crew. Player-owned defence stations get the full NPC complement; NPC-owned ones stay sparse to save resources.

If your mod adds custom NPCs to defence stations, be aware: the engine may cull them during sparsification if not isplayerowned.

Construction macros

Defence stations are constructed using:

• Group: defence_<faction_3-letter-code> (e.g. defence_arg, defence_tel) in libraries/stationgroups.xml.
• Plan: e.g. arg_defence in libraries/constructionplans.xml.

A typical defence station has many defence modules, several storage modules (for ammo and repair supplies), connection modules, and habitation for crew. Production modules are absent.

Common gotchas

• ⚠ .isdefencestation is FALSE during construction. Use .isplanneddefencestation for early detection.
• ⚠ Defence stations can be hybrid (shipyard / wharf / equipment dock combined). Don’t assume mutual exclusion. The pure-defence filter is .isdefencestation and not (.iswharf or .isshipyard).
• ⚠ Defence stations are typically NOT capturable. .iscapturable=false for most macros; high boarding resistance, no signal leak. Don’t write mods that assume the player can board them.
• ⚠ NPC-owned defence stations have reduced NPC population. Engine sparsifies — your custom NPC additions may get culled. Check .isplayerowned before injecting characters.
• ⚠ Turret activation depends on alert level. A defence station at alertlevel.green has turrets deactivated. Set alert state via set_alertlevel if your mod needs guaranteed combat readiness.
• ⚠ A faction can lose its defence station mid-game. Sector ownership flip → defence station likely destroyed. Listen for event_object_destroyed on watched stations.

Architectural context

• How factions decide where to build defence stations: Architectural overview Faction goals — factiongoal_hold_space evaluates sector value; defence stations placed at chokepoints (entry gates).
• Static defence positioning: Architectural overview Static defence positioning — factionlogic_staticdefense.xml scores each gate by destination ownership, places defence assets accordingly.
• NPC sparsification: Architectural overview NPC instantiation — engine-side rule that defence stations get fewer NPCs to manage performance.

Related

• Station — parent abstraction (all general properties/actions live there).
• Faction — owner; faction goals drive placement.
• Shipyard — sibling; some defence stations are also shipyards (rare).
• Wharf — sibling; defence + wharf combo possible.
• Defence module — the contained part providing combat capability.
• Sector — what the defence station defends.

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Pattern — IS-A subtype

Same pattern as Shipyard / Wharf / Equipment dock — this page only documents Defence-station-specific behavior. General station behavior lives on Station.