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 }).

With ~2000 status heat of headroom left when venting starts, one overclocked large reactor takes about 0.7 s to consume it, against a 0.5 s radiator reaction time — so the overshoot lands well under the 350-per-tile threshold at which anything begins to happen. Holding the network near full is safe with a wide margin, and headroom given up beyond that 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.

What the mod does

A radiator vents when either:

1. The heat network is running out of room. The radiator measures this itself, with a bare NetworkResourceInput — the same way the heat exchanger decides whether it can still push heat (heat_exchanger.rules: IsNetworkHeatNonFull). Vent below ~2000 status heat of remaining headroom, hold again above ~6000, a deadband so radiators do not chatter.
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.

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

The design is fail-safe: holding heat requires positive evidence that the network has room to spare. Anything missing, disconnected or unmeasurable ends up venting, which is vanilla behaviour. Headroom is measured in absolute heat rather than as a percentage, because what actually matters is headroom against your generation rate — 2000 status heat is under a second of one overclocked large reactor.

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

Layout

mod.rules                              manifest + patch actions
components/radiator_auto.rules         measures network headroom, decides, acts
components/launcher_ammo_signal.rules  reports thermal ammo in use
tests/                                 offline validation suite
tools/dotnet_enum.py                   reads component schemas out of Cosmoteer.dll
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

Partly confirmed. Against game data 0.30.4c, as of 2026-08-29:

• Confirmed: the gate closes and idles a radiator when thermal ammo is in use.
• Confirmed: with no launcher on thermal ammo, behaviour is vanilla.
• Not yet confirmed: the release path. v2.0.0 held heat forever — thermal batteries visibly full, parts taking heat damage, radiators still idle.

That failure was the dangerous direction, and it came from reading the wrong thing. v2.0.0 put a percentage threshold on a thermal battery's own HeatStorage, which is wrapped by a NetworkResourceStore; that local read never crossed its ceiling however full the network got. v2.1.0 measures the network's remaining room directly instead, from the radiator, using the same bare NetworkResourceInput the heat exchanger uses — and the polarity is now fail-safe, so an unmeasurable signal vents rather than holds.

Getting this far took five builds that each loaded without a single error and misbehaved silently. Cosmoteer reports none of these, so each 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
A percentage threshold on a network-wrapped ResourceStorage never crosses, however full the network is	no test — avoid the pattern; measure the network, not a part's storage

Routing was the cause of the first three builds doing nothing. 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. Many parts ship no router at all.

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.