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 all five PDS classes, how they fight, and how Planetary Shield Generators protect your orbitals.
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 | All PDS has initiative 1 — the lowest possible. PDS fires first in every round, before any ship can act |
| 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 five PDS classes
PDS comes in five classes, mirroring the six ship classes (with no Corvette-class PDS):
| PDS | Class | Targets | Damage | Armor | Cost (Ti / Si / Ur) | Build | Max owned |
|---|---|---|---|---|---|---|---|
| Pulse Laser Array | Fi | Fi → Co | 30 | 100 | 500 / 800 / — | 6 ticks | unlimited |
| Plasma Turret | Fr | Fr → De | 80 | 200 | 800 / 1 200 / 200 | 8 ticks | unlimited |
| Ion Cannon | De | De → Cr | 150 | 350 | 1 500 / 2 000 / 500 | 10 ticks | unlimited |
| Orbital Strike Platform | Cr | Cr → Bs | 300 | 500 | 3 000 / 3 000 / 1 500 | 14 ticks | unlimited |
| Planetary Shield Generator | Bs | — | 0 | 1 000 | 8 000 / 8 000 / 4 000 | 12 ticks | 10 |
Each PDS unit fires once per 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. 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 is enough to one-shot most fighter classes (Stinger 25, 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. The cost-per-damage ratio is the best among single-class PDS.
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 (7 500 per platform), but the only ground-based defense that meaningfully targets Bs.
Planetary Shield Generator (Bs) doesn't fire. It absorbs hits at 1 000 armor each, soaking up Bs-class attacks that would otherwise reach your other PDS. Each surviving Shield Generator also reduces orbital theft — see below.
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 negligible PDS damage, because no other PDS class targets Fighters. 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 only) | Only Pulse Lasers (Fi-target) |
| Pure corvette (Vanguards only) | Pulse Lasers (Co fallback), nothing else |
| Pure destroyer (Pegasus only) | Plasma Turret (Fr-target) only via Pegasus's Fr target — no chain to Ion Cannon |
| Pure capital (Titans only) | Orbital Strike Platforms only |
| Mixed fleet (Fi + Fr + De + Cr + Bs) | All 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 in every class.
This is intentional. It rewards balanced fleet design and punishes mono-class attacks.
Planetary Shield Generators
Shield Generators are special. They have 0 damage — they don't shoot anything — but they do two things:
- They absorb Battleship-class attacks. A Bs-targeting ship that wants to hit your Orbital Strike Platforms has to chew through your Shield Generators first.
- They reduce orbital theft on defeat.
Shield-based theft reduction
When the attacker wins and uses surviving capture ships to steal orbitals, every surviving Shield Generator reduces the number of orbitals stolen:
orbitals_after_shields = orbitals_stolen × (1 − min(shields, 10) × 0.05)
Linear reduction at 5% per shield, capped at 10 Shields (50% reduction). An 11th Shield Generator gives no additional benefit — that's the hard cap.
| Surviving Shields | Reduction | Multiplier |
|---|---|---|
| 0 | 0% | 1.00 |
| 1 | 5% | 0.95 |
| 2 | 10% | 0.90 |
| 5 | 25% | 0.75 |
| 8 | 40% | 0.60 |
| 10 (max) | 50% | 0.50 |
Surviving matters
Only Shields that survived the battle count toward theft reduction. If all your Shield Generators get destroyed during the fight (by Bs-class attacks penetrating your other PDS), you get 0% reduction — full theft.
This means Shields are most effective when paired with Orbital Strike Platforms that thin out the Bs-class attackers before they can reach the Shields. A defender who builds 10 Shields and no OSP risks losing all of them to a battleship wing and gaining no protection at all.
Max 10 Shields
The max_quantity cap on Shield Generators is 10 — enforced at the action level. You cannot build an 11th Shield until one is destroyed. This is also the cap where theft reduction maxes out.
20 000 resource cost × 10 = 200 000 to fully maximize Shield protection. Expensive but powerful — a planet with 10 surviving Shields after a battle loses half what it otherwise would. The increment is smoother than v1's 5-Shield max (5 → 10 → 15 → ...% per shield), making partial Shield investments more rewarding as you scale up.
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 buffs (armor/damage/agility/init) | Do not apply to PDS units. Only your ships get commander buffs |
| 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 at base stats 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 and queue slot.
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
Unlike ships, PDS stats are identical across all four playable races. UEC builds the same Pulse Laser as ODO or ATH or STC. No race bonus applies to PDS construction speed, damage, or armor.
The Void doesn't build PDS — they're NPC garrisons with no permanent infrastructure.
Build cost summary
| PDS | Cost | Build time | Damage per unit | Cost per damage |
|---|---|---|---|---|
| Pulse Laser Array | 1 300 | 6 ticks | 30 | 43 |
| Plasma Turret | 2 200 | 8 ticks | 80 | 28 (best) |
| Ion Cannon | 4 000 | 10 ticks | 150 | 27 (best) |
| Orbital Strike Platform | 7 500 | 14 ticks | 300 | 25 (best) |
| Planetary Shield Generator | 20 000 | 12 ticks | — | (theft reduction) |
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. Mid-tier kill platforms are far cheaper per damage and cover Destroyers + Cruisers. OSP comes online when you have specific battleship threats.
Shields without OSP are wasted. If attackers reach your Shields with Battleships, those Shields die. Always pair Shield Generators with OSPs that can thin out the Bs-class attackers.
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 (Bs) |
| Initiative | 1 (fires first in every round) |
| Rounds active | All 3 (no more pre-round pulse) |
| Damage formula | Same as ships: guns × damage × hit_chance × share × luck |
| Hit chance | Standard (25 + weapon_speed − target_agility) / 100, but PDS has weapon_speed 0 |
| EMP resistance | 100 (immune to freeze) |
| Steal immunity | Yes (cannot be captured by STC) |
| Commander buffs | Do not apply to PDS |
| Destruction | Exact, proportional to incoming damage. No flat percentage |
| Shield max | 10 per planet |
| Shield theft reduction | 5% × surviving shields, capped at 50% (10 shields) |
| Race differences | None — identical stats across UEC/ODO/ATH/STC |
| Void PDS | None — NPCs don't build PDS |
| Build queue | Defense orders, separate from ship queue |
Documentation reflects Orbitarion v2.0. Last updated: 2026-05-29.