Auto Radiator

A Cosmoteer mod. Radiators stop dumping heat the ship still wants.

The problem

Thermal Canister Missiles are built from the ship's own heat. The game says so itself, in Data/strings/en.rules:

Manufactures guided Thermal Canister Missiles that take thermal energy from their own ship's heat pipe network and inflict it upon the target.

The launcher charges each missile from the heat network — HEAT_PER_MISSILE = 8500, two missiles buffered per launcher. A radiator pulls from that same network, through a component that is behaviourally identical to the launcher's:

	Radiator	Thermal launcher
Type	NetworkResourceOutput	NetworkResourceOutput
Mode	DistributeProportionallyByAvailable	DistributeProportionallyByAvailable
Categories	[ thermal_storage ]	[ thermal_storage ]

Data/ships/priorities.rules defines priorities for crew and supply only — nothing for heat. So the two compete flat, proportionally, and a radiator running constantly is spending your ammunition to make steam.

Why holding heat is safe

Heat storage being full does not hurt you. Damage comes only from overflow. Every overclocked part routes its heat through this (Data/ships/base_part_overclock.rules):

HeatDistributionStorage
{
	Type = MultiResourceStorage
	ResourceStorages = [NetworkHeatInput, OverflowHeatStorage]
	AddMode = InOrder
}

InOrder means the network is tried first, and OverflowHeatStorage only receives what the network refuses. Overflow then applies the cosmoteer.heat status to the producing part's own tiles.

From Data/statuses/heat/heat.rules, that status does nothing whatsoever below 350 per tile (RequireValueRangeForTick = [350, Infinity]). Fire chance ramps from 350 to 2500; thermal damage begins at 700.

An overclocked large reactor produces 2750 heat/sec over its 4×4 footprint — about 172 status/sec per tile while fully overflowing, so roughly 2 seconds of continuous, total overflow before fire risk even arms. Radiators react within 0.5 s (HeatDissipationConverter { Interval = 0.5 }).

At a 98% ceiling on a single 15000-capacity thermal battery, the overshoot during that reaction window is about 625 status heat spread over 16 tiles — roughly 39 per tile, against a threshold of 350. Holding the network near full is safe with a wide margin, and every percent of ceiling given up is ammunition thrown away for nothing.

The genuine constraint is not the threshold. It is total radiator throughput (1100/sec each) versus sustained generation. If you are short on radiators you overflow continuously and no threshold value saves you — which is what the safety net below is for.

What the mod does

Radiators vent when any of these is true:

1. The heat network is not asking them to hold — the thermal battery is at or above 98% full (dropping the hold again at 94%, a deadband so radiators do not chatter at the threshold).
2. No launcher on the network is set to Thermal Canister Missiles. If you are not spending heat as ammunition there is nothing to hoard, so radiators behave exactly as in vanilla.
3. Safety net: some part is actually overflowing heat right now. This reads the engine's own OverflowHeatStorage, so it fires the moment the network genuinely refuses heat — regardless of thresholds, pipe topology, or whether your radiator capacity was ever sufficient. Latched for 3 seconds so a stream of per-tick overflow events becomes one steady signal.

Your manual radiator on/off switch still overrides all of it. The automation can only idle a radiator you have left switched on.

Ships with no thermal battery have no broadcaster, so nothing changes for them. The signal polarity is deliberately "hold", not "vent", so that the absence of any part of this mod's machinery always falls back to vanilla behaviour.

No stat or number is changed. Only when radiators run.

Layout

mod.rules                                  manifest + patch actions
components/thermal_battery_vent.rules      decides when there is surplus
components/launcher_ammo_signal.rules      reports thermal ammo in use
components/overclock_overflow_signal.rules safety net, reports real overflow
components/radiator_auto.rules             combines the signals into one gate
tests/                                     offline validation suite
install.sh                                 validate + copy into the Mods folder

Install

./install.sh

Then enable Auto Radiator in the game's Mods menu. ./install.sh --uninstall removes it. If the script cannot find your Mods folder, set COSMOTEER_MODS_DIR.

Tests

python3 tests/test_mod.py

Cosmoteer applies mod actions to vanilla data at load time. Some mistakes crash the game on startup — an unresolvable path, a misspelled component Type — and the suite catches those by parsing the installed game's .rules tree offline.

The more dangerous mistakes do not crash anything. They load perfectly and silently do nothing; see Status below for the four this project hit and the guard for each. The suite also self-checks its own parser against known vanilla facts first, so a broken parser fails loudly instead of passing everything.

Set COSMOTEER_DATA to point at a different install, and COSMOTEER_ASSEMBLY for the schema checks.

How to tell it is working

There is no separate "auto" mode and nothing to reset. The radiator's on/off switch is an AND gate:

• switch off -> radiator is off, and stays off. The mod never turns it back on.
• switch on -> the automation decides, moment to moment.

An auto-idled radiator shows the "powered off" indicator icon and stops emitting its steam plume. That icon on a radiator you did not switch off is the mod holding heat back for your launchers.

Status

Working, confirmed in game on 2026-08-29 against game data version 0.30.4c.

Getting there took four builds that each loaded without a single error and did nothing, for four different reasons. Cosmoteer reports none of them, so each one now has a mutation-verified test:

Silent failure	Guard
NetworkToggle / NetworkToggleReceiver carry no signal on a physical ship (every vanilla use sets IncludeInPhysical = false)	test_no_blueprint_only_signal_types, plus test_vanilla_marks_those_types_blueprint_only so the premise cannot go stale
A field name that does not exist in the component's real schema is ignored rather than reported	test_component_fields_exist_in_schema, read from the assembly's own metadata
A network component no route reaches never attaches, and reads as absent forever	test_network_components_are_routed
An Overrides value naming a component that is not there reverts the gate to nothing	test_override_values_name_real_components

The third was the actual cause. A network component is only attached if a route reaches it: the part's NetworkPort anchors on one component, and a NetworkRouter bridges that anchor to every other network component on the part. That is how vanilla connects the radiator's own NetworkedThermalDissipationLoadValue, and how the amplification pump reaches the resonance beam turret. Routes now run from each part's anchor — NetworkedHeatBuffer on the radiator through its existing Router, plus a new NetworkRouter on the thermal battery, the missile launcher and base_part_overclock, none of which ships one.

None of this is documented: the wiki's modding pages cover no network components at all, so the game's own .rules files are the only reference.

tools/dotnet_enum.py reads component schemas and enum members straight out of Cosmoteer.dll, which is how the field and type questions got settled. It is useful on its own for any Cosmoteer modding:

python3 tools/dotnet_enum.py /path/to/Cosmoteer.dll PartThresholdToggleRules
python3 tools/dotnet_enum.py /path/to/Cosmoteer.dll MultiToggleMode

Version 1.4.0 in the git history carries a probe build that makes a radiator report its own internal state through indicator icons, if this ever needs debugging again.

Possible additions

• A per-radiator UI toggle for auto/manual, which needs a new ChoiceID wired into Data/gui/game/parts/part_toggles.rules.
• Making the 98% / 94% band configurable.