Planetary Defense Systems
Planetary Defense Systems — PDS — are stationary defensive structures built directly onto your planet. They fight automatically in every battle, can't be moved or sent on missions, and provide the only fleet-independent defense against incoming attacks.
If you've ever sent every ship you own on an attack and come home to find your planet still standing, that was PDS. They are why a planet is never truly defenseless.
This page covers the four combat PDS classes, the Planetary Shield Generator, and how they fight. For orbital-theft protection, see the Orbital Shield.
What PDS does
PDS used to fire a single "pre-round damage pulse" before combat, then sit out the rest of the battle. This is no longer true in v2.
In the current battle engine, PDS participates as stationary defender units alongside your ships:
| Behavior | Detail |
|---|---|
| Joins the defender side | Every PDS unit you own is loaded into the battle alongside your ships and any allied defend fleets |
| Initiative 1–2 | Pulse Laser Arrays and Plasma Turrets fire at initiative 1, Ion Cannons and Orbital Strike Platforms at 2 — ahead of almost every ship in every round (only Odonari ships with First Strike act earlier, in round 1) |
| Three rounds | PDS fires in all 3 combat rounds (not just one pre-round pulse) |
| Targets ship classes | Each PDS type targets specific ship classes (see below) and falls back to a secondary class when the primary is depleted |
| Takes proportional damage | When attackers target your PDS class, they kill PDS units the same way they kill defender ships — exact, not blanket |
| Stays where it is | PDS never leaves the planet. It doesn't follow defend fleets or return missions |
A planet with no ships at home but a full PDS stack still gets three full rounds of stationary fire against incoming attackers. PDS is the floor of your defense.
The PDS classes
Combat PDS comes in four classes, mirroring the ship classes Fighter to Cruiser, plus the Planetary Shield Generator structure:
| PDS | Class | Targets | Guns × Damage | Armor | Init | Cost (Ti / Si / Ur) | Build | Max owned |
|---|---|---|---|---|---|---|---|---|
| Pulse Laser Array | Fi | Fi → Co | 2 × 30 | 150 | 1 | 300 / 400 / — | 6 ticks | unlimited |
| Plasma Turret | Fr | Fr → De | 2 × 80 | 300 | 1 | 500 / 600 / 100 | 8 ticks | unlimited |
| Ion Cannon | De | De → Cr | 3 × 150 | 525 | 2 | 900 / 1 100 / 300 | 10 ticks | unlimited |
| Orbital Strike Platform | Cr | Cr → Bs | 3 × 300 | 750 | 2 | 1 500 / 1 500 / 700 | 14 ticks | unlimited |
| Planetary Shield Generator | structure | — | — | — | — | 8 000 / 8 000 / 4 000 | 12 ticks | 1 |
Changed in 4.5: the 999 cap on combat PDS is gone, and every combat class got 50% more armour (Pulse Laser 100 → 150, Plasma Turret 200 → 300, Ion Cannon 350 → 525, Orbital Strike Platform 500 → 750).
Each PDS unit fires its guns every round at its primary target class. If the primary class has been completely destroyed (or wasn't present), it falls back to the secondary class; if neither is present, it fires at the most numerous enemy class at 40% effectiveness, like a ship. Damage is calculated identically to ship damage — see Combat.
Class-by-class roles
Pulse Laser Array (Fi → Co) is your anti-swarm defense. The 30 damage per gun (two guns) is enough to one-shot most fighter classes (Stinger 23, Probe 30, Cutlass 30) and chew up corvettes. Build these against neighbors that field cheap mass-fighter fleets.
Plasma Turret (Fr → De) punches into mid-tier ships. 80 damage destroys enemy frigates in two-three hits and contributes meaningfully against destroyers.
Ion Cannon (De → Cr) is the heavy-armor breaker. 150 damage chews through destroyers and cruisers. Required if you expect attacks from players running heavy Pegasus/Tempest/Hornet/Subjugator fleets.
Orbital Strike Platform (Cr → Bs) is anti-capital. 300 damage per hit means a small stack can threaten incoming battleship fleets. Expensive (3 700 per platform), but the only ground-based defense that meaningfully targets Bs.
Planetary Shield Generator doesn't fight at all. It is a permanent structure, max 1 per planet, that can't be targeted or destroyed — building it unlocks research of the Orbital Shield, which is what protects your orbitals.
Targeting cheat sheet
| Attacker class | First targeted by | Fallback |
|---|---|---|
| Fighter | Pulse Laser Array | — |
| Corvette | Pulse Laser Array (as fallback target) | — |
| Frigate | Plasma Turret | — |
| Destroyer | Ion Cannon · Plasma Turret (fallback) | — |
| Cruiser | Orbital Strike Platform · Ion Cannon (fallback) | — |
| Battleship | Orbital Strike Platform (fallback) | — |
A pure-fighter attack against a planet with no Pulse Lasers takes much less PDS damage: no other PDS class targets Fighters, so the rest fire at them at only 40% effectiveness. Similarly, an Orbital Strike Platform shoots Cruisers first; against a battleship-only attack it falls back to Bs.
Build for the threat profile you expect, not "one of each." A defender expecting fighter-heavy ODO neighbors should overbuild Pulse Lasers. A defender expecting UEC capital-ship sieges should overbuild Orbital Strike Platforms. Spreading thin across all classes leaves gaps.
How destruction works
PDS units take damage the same way ships do. When an attacker targets your PDS class, hits land, armor is overcome, and the unit count drops by exactly that many.
After the battle resolves, the planet_defenses table reflects the new quantity exactly. There is no flat percentage destruction (no "lose 30% of all PDS on a defeat"). If your Pulse Laser stack took 50 kills in a fight, you have 50 fewer Pulse Lasers when the dust settles. If your Plasma Turrets weren't targeted at all, they're untouched.
A battle that focuses on fighter-class targeting can leave your heavy PDS completely intact. Conversely, a heavy capital-ship attack can rip through Orbital Strike Platforms without scratching your Pulse Lasers.
Destroyed PDS does not regenerate or repair. You rebuild from scratch through the same defense order queue that built them originally.
Punch-up principle
Because PDS is targeted just like ships, the natural punch-up principle of ship targeting applies. An attacking fleet has to reach the PDS class through normal targeting chains.
| Pure attacker fleet | Reaches PDS class? |
|---|---|
Pure fighter (Falcons, Fi > Co > Fr) |
Pulse Lasers and Plasma Turrets |
Pure corvette (Vanguards, Fi > Co > Fr) |
Pulse Lasers and Plasma Turrets |
Pure destroyer (Pegasus, Fi > Co > Fr) |
Pulse Lasers and Plasma Turrets — no chain to Ion Cannon |
Pure capital (Titans, Cr > Bs > De) |
Orbital Strike Platforms and Ion Cannons |
| Mixed fleet (Fi + Fr + De + Cr + Bs) | All combat PDS classes |
This means a defender's PDS stack can survive an attacker that fields too narrow a fleet composition. To completely strip a fortified planet's PDS, the attacker must bring ships whose target chains cover every PDS class. (A ship only fires at a class outside its chain — at 40% — when none of its three target classes is left on the field.) The Shield Generator can never be hit.
This is intentional. It rewards balanced fleet design and punishes mono-class attacks.
Planetary Shield Generators
The Shield Generator is a permanent structure, not a combat unit:
- It never fights — no guns, and it is not loaded into battles at all.
- It cannot be targeted or destroyed, so it never soaks fire meant for your other PDS.
- Max 1 per planet. A built Shield Generator is required before you can research the Orbital Shield.
The old theft-reduction mechanic (−5% stolen orbitals per surviving Shield, stackable to 10) is gone. Orbital-theft protection now lives in the Orbital Shield — a researched, chargeable planet-wide barrier that blocks theft entirely while it holds 60%+ charge, and drains by a fixed percentage per attack based on the attacker's fleet value.
If you read strategy advice about "stacking Shield Generators", it predates v3.1.0 — one is all you can build, and all you need.
PDS immunities
PDS is immune to several mechanics that affect ships:
| Mechanic | Effect on PDS |
|---|---|
| EMP freeze | Immune — PDS has emp_resistance = 100 |
| STC ship-stealing | Immune — boarding hardware can't capture PDS |
| Commander and race buffs | Armour, agility and initiative bonuses do not apply to PDS. Your commander's damage and crit bonuses do apply to PDS fire |
| Orbital theft by capture ships | Capture ships steal orbitals, not PDS. PDS is destroyed only by ship attacks during combat |
This makes PDS reliable. Whatever exotic mechanic the attacker brings — EMP-heavy ATH fleets, STC steal-fleets, fully-buffed commander fleets — your PDS keeps shooting every round.
Building PDS
PDS is built through your planet's defense queue, similar to ship construction but separate. Each PDS class has its own build time. You can run up to 5 defence build orders at once (5 production halls); one order can hold any quantity. Alliance-tier and Renown build discounts apply to PDS like they do to ships.
Research prerequisites
Each PDS class unlocks through research:
| PDS | Required research |
|---|---|
| Pulse Laser Array | Basic Defense Systems |
| Plasma Turret | Basic Defense Systems |
| Ion Cannon | Advanced Defense Systems |
| Orbital Strike Platform | Orbital Defense Platforms |
| Planetary Shield Generator | Orbital Defense Platforms |
See Research for the full Defense Engineering tree.
No race differences in stats
Unlike ships, PDS stats are identical across all four playable races. UEC builds the same Pulse Laser as ODO or ATH or STC, and no race bonus changes PDS damage or armour. The one race bonus that touches PDS is speed: UEC builds defences 20% faster.
The Void doesn't build PDS — they're NPC garrisons with no permanent infrastructure.
Build cost summary
| PDS | Cost | Build time | Damage per unit (guns × damage) | Cost per damage |
|---|---|---|---|---|
| Pulse Laser Array | 700 | 6 ticks | 60 | 11.7 |
| Plasma Turret | 1 200 | 8 ticks | 160 | 7.5 |
| Ion Cannon | 2 300 | 10 ticks | 450 | 5.1 |
| Orbital Strike Platform | 3 700 | 14 ticks | 900 | 4.1 (best) |
| Planetary Shield Generator | 20 000 | 12 ticks | — | (structure) |
Cost-per-damage favors heavier PDS — but they also target narrower threat profiles. Choose based on the attack profile you actually face, not the most "efficient" line.
Tactics
Don't over-invest in one class. A 50-Pulse-Laser fort is unbeatable against fighters and worthless against capital ships. Spread investments to cover the threat profile you actually face.
Lead with Pulse Lasers and Plasma Turrets. Cheap PDS in volume creates a baseline floor. A few dozen Pulse Lasers means no neighbor can casually fighter-rush you.
Build Ion Cannons before Orbital Strike Platforms. Ion Cannons unlock a research tier earlier, cost less per unit and cover Destroyers + Cruisers. OSP — the best damage per resource — comes online when you face cruiser and battleship threats.
PDS doesn't replace a home fleet. A well-defended planet has both. PDS gives you a floor; home fleet gives you a ceiling. Together they multiply.
Replacing destroyed PDS is slow. Each unit takes 6–14 ticks to rebuild and costs significantly. Plan your defense investment for long-term standing rather than per-battle restoration.
Watch what neighbors are scanning you for. Attackers usually scan before they commit. If you see scans, the attack is coming — accelerate any defense orders, recall fleets if possible.
Quick reference
| Concept | Detail |
|---|---|
| PDS classes | Pulse Laser (Fi) · Plasma Turret (Fr) · Ion Cannon (De) · Orbital Strike Platform (Cr) · Planetary Shield Generator (structure) |
| Armour | 150 / 300 / 525 / 750 (since 4.5) |
| Max owned | Unlimited (999 cap removed in 4.5); Shield Generator 1 |
| Initiative | 1 (Pulse Laser, Plasma Turret) · 2 (Ion Cannon, Orbital Strike Platform) |
| Rounds active | All 3 (no more pre-round pulse) |
| Damage formula | Same as ships: guns × damage × hit_chance × target_mult × share × luck |
| Hit chance | Standard (25 + weapon_speed − target_agility) / 100; PDS weapon speed 45 / 45 / 48 / 50, agility 5 / 5 / 4 / 3 |
| EMP resistance | 100 (immune to freeze) |
| Steal immunity | Yes (cannot be captured by STC) |
| Commander buffs | Armour/agility/initiative: no · damage/crit: yes |
| Destruction | Exact, proportional to incoming damage. No flat percentage |
| Shield Generator | Max 1, never fights, cannot be destroyed — unlocks Orbital Shield research |
| Race differences | Identical stats; UEC builds PDS 20% faster |
| Void PDS | None — NPCs don't build PDS |
| Build queue | Defense orders, separate from ship queue, max 5 at once |
Documentation reflects Orbitarion v4.6.0. Last updated: 2026-10-13.