Colonization

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This article is for the PC version of Stellaris only.

Celestial body

Classification

Colonization

Planetary features

Planet modifiers

Colonization is the process of establishing control over an uninhabited, habitable planet with a Colony Ship.

The first time an empire colonizes another world, it gains 12x engineering output (between 250 ~ 100 000)

Humanoid empire colonizing a new world

Habitability

Habitability is the measure of how comfortably a species can live on a planet. Most species have a climate preference for one of the primary habitable planet types, although more exotic preferences are possible. A planet's habitability for a given species is determined by how closely its climate matches that species' preference. The 9 regular habitable world types are divided into 3 climate categories: dry, frozen, and wet. Ring Worlds, Gaia Worlds, and Ecumenopolises have maximum habitability for all species, while Tomb Worlds, Machine Worlds, and Hive Worlds (except for Hive-Minded species) normally have 0% habitability for biological species.

Tier	Base
Gaia World, Ecumenopolis, and Ring World	100%
Hive World for Hive-Minded species	100%
Relic World or exact match	80%
Habitat	70%
Climate category match	60%
Climate category mismatch	20%
Tomb World, Machine World, and Hive World	0%

• Every 1% reduction of habitability below 100% increases pops' upkeep and amenities usage by +1% and reduces their job output and species growth by −0.5%. It floors at 0% Habitability, giving +100% pop upkeep and amenities usage, and −50% job output and pop growth.
• Homeworlds have +30% habitability for the species originating from them.
• Robot pops have 200% habitability for each planet type.
• Low habitability can trigger various events.

There are four ways to improve habitability:

• Terraforming the planet. This needs a certain technology and may have additional requirements depending on the original planet.
• Using robot pops, which are not affected by habitability. Empires that aren't Machine Intelligences require the Droids technology to build colony ships using robots.
• Genetically modifying the climate preference of the pops, which requires the Glandular Acclimation technology. Since this modifies all pops of that subspecies on the selected world either the planet must be colonized first or an existing world where changing habitability won't be an issue (Gaia World, Ring World, Ecumenopolis, Habitat) should be selected.
• Obtaining alien species with a different climate preference. This can be done by conquest, migration treaty, infiltrating a pre-FTL civilization, uplifting a pre-sapient species, certain events and offers or the Slave Market. Empires can colonize with any species that has migration access to the empire, even if no pops of that species live on the empire's worlds, provided they have the Colonization Allowed species right.

Visual cues

Systems containing habitable worlds will have one or more planet icons that are either green, yellow, orange, red, or blue – depending on the habitability percentage and/or status of the planet(s) in question.

Icon	Meaning
	World is has at least 70% habitability for at least one species in the player's empire that can colonize
	World has 40–69% habitability for at least one species in the player's empire that can colonize
	World has below 40% habitability for all species in the player's empire that can colonize
	World is habitable but not surveyed
	World is currently being terraformed
	World has the Terraforming Candidate modifier

Planets with an anomaly or a primitive civilization cannot be colonized.

Improving habitability

Aside from changing climate preference, there are also various other methods for improving habitability:

Source	Habitability (empire)
Ecological Protection resolution 5	+15%
Environmental Diversification tradition	+10%
Ecological Protection resolution 4	+10%
Ecological Protection resolution 3	+5%
Ascetic civic	+5%
Atmospheric Filtering technology	+5%
Hostile Environment Adaptation technology	+5%
Foreign Soil Enrichment technology	+5%
Eco-Integration Studies technology	+5%
Integrated Cybernetics technology	+5%
Conquer Nature agenda	+5%
Industrial Development resolution 1	−2%
Industrial Development resolution 2	−5%
Industrial Development resolution 3	−10%
Industrial Development resolution 4	−20%
Industrial Development resolution 5	−25%

Source	Habitability (species)
Mechanical trait	+200%
Machine trait	+200%
Lithoid trait	+50%
Nivlac trait	+50%
Robust trait	+30%
Excessive Endurance trait	+30%
Cybernetic trait	+20%
Clone Soldier Ascendant trait	+20%
Extremely Adaptive trait	+20%
Spliced Adaptability trait	+20%
Adaptive trait	+10%
Starborn trait	+10%
Bioadaptability trait	+10%
Nonadaptive trait	−10%

Terraforming

Terraforming is the act of changing the planet classification of a planet in order to make it more Habitable for the empire's species. Terraforming technologies requires significant society research to unlock, and each terraforming project requires large investments of energy and time.

The first time a planet is terraformed, there's a chance of triggering a terraforming event. Terraformed planets cannot receive colony events.

A planet must be surveyed and within the empire's borders to be terraformed. It is possible to terraform inhabited planets if the empire has the Ecological Adaptation technology. Doing so inflicts a −20% happiness penalty on the planet for the duration of the process.

Only the following terraformings are possible:

Original climate	New climate	Cost	Years	Requirements
Frozen	Frozen	2000	5	Terrestrial Sculpting technology
Dry	Dry
Wet	Wet
Frozen	Dry or Wet	5000	10
Dry	Frozen or Wet
Wet	Frozen or Dry
Barren	Dry	5000	10	Climate Restoration technology Terraforming Candidate modifier
	Wet	10000	15
	Frozen	15000	20
Barren (Cold)	Frozen	5000	10
	Wet	10000	15
	Dry	15000	20
Nanite	Any regular climate	1000	1
Frozen	Ocean	12500	25	Climate Restoration technology Frozen Terraforming Candidate modifier Hydrocentric ascension perk
Tomb	Any regular climate	10000	20	Climate Restoration technology
Hive
Machine
All regular climates	Gaia	7500	10	World Shaper ascension perk
Tomb		12500	25
Barren				World Shaper ascension perk Terraforming Candidate modifier
Any habitable	Hive	10000	20	Hive Worlds ascension perk
Barren				Hive Worlds ascension perk Terraforming Candidate modifier
Any habitable	Machine			Machine Worlds ascension perk
Barren				Machine Worlds ascension perk Terraforming Candidate modifier
Toxic	Any habitable except Continental	10000	10	Detox ascension perk Climate Restoration technology Toxic Terraforming Candidate modifier
	Continental		15
All regular climates	Tomb	1000 100 100	10	Relentless Industrialists For Science! Industrialism policy
Gaia		2500 200 200	15
Barren		12500	25	Relentless Industrialists For Science! Industrialism policy Climate Restoration technology Terraforming Candidate modifier

The following planet modifiers are always removed when terraforming a planet:

• File:Bleak.png Bleak
• Irradiated
• File:Hazardous weather.png Hazardous Weather
• File:Dangerous wildlife.png Hostile Fauna
• Wild Storms
•  Second Home

If the planet is being terraformed into either a Machine or Hive World the following modifiers are also removed:

• Atmospheric Hallucinogen
• Atmospheric Aphrodisiac
• Lush
• File:Natural beauty.png Natural Beauty

If the planet being terraformed was a Toxic World, the following blockers will be created:

• Poisonous Algae
• Rotten Soil
• Tainted Snowcaps
• Unpleasant Atmosphere
• Venomous Insects

Some planet modifiers make planet unable to be terraformed by standard methods:

• Unstable Tectonics
• Molten Mineral Rivers

If the planet is terraformed into a Machine World any Pops on the planet without the Cybernetic, Mechanical, or Machine traits are all killed and an Organic Slurry deposit is added.

When and if terraforming a planet to Hive or Machine World, keep in mind that all planetary features, excluding a few rare ones that give access to rare resources, will always be removed.

Alternative terraforming methods

In addition to the regular terraforming mechanics above, certain events, special projects, decisions, or other actions can change a planet's classification. The following is a partial list:

• Armageddon bombardment: if the last pop is killed, the planet becomes a Tomb World.
• Javorian Pox bombardment: if the last pop is killed, the planet becomes a Tomb World. This does not kill robotic pops.
• Deluge Machine Colossus: all pops without the Aquatic trait are killed and the planet is terraformed into an Ocean World. Owned planets can be targeted. If any pops remain, the perpetrator gains ownership of the planet if not already owned.
• Toxic God Colossus: all pops are killed, all deposits and buildings are removed, and the planet is terraformed into a Toxic World. If the planet was previously habitable it will have the Toxic Terraforming Candidate modifier.
• The Worm can terraform all planets and moons in the empire's capital system, habitable and uninhabitable alike, into Tomb Worlds; only Gas Giants, Relic Worlds, and Ecumenopolises are spared. Moreover, the climate preference of every pop living on those planets will be changed to Tomb World climate preference.
• Gaia Seeders: Idyllic Bloom empires can build special buildings that will terraform the world into a Gaia world. They can also build a holding on subjects' worlds to terraform those worlds.
• Every activation of The Last Baol relic allows one use of the Nu-Baol Life Seeding planetary decision that terraforms any colonized planet into a Gaia World in 720 days and additionally creates 4 Baol plantoid pops.
• Relentless Industrialists can build Coordinated Fulfillment Center and Universal Productivity Alignment Facility buildings which terraform planets into Tomb Worlds over time. The first time triggers the Environmental Deterioration situation; if the situation reaches maximum, the planet turns into a Tomb World. After the situations ends, Industrialism policy is unlocked. If the policy is set to Full Steam Ahead or For Science!, next planets with a Coordinated Fulfillment Center will be turned into Tomb Worlds in 30 years and planets with a Universal Productivity Alignment Facility will turn into Tomb Worlds in 15 years, this time without any warning. Only chosing Cleanup policy stops this effect.
• The science ship used the the Astrocreator Azaryn legendary paragon has the ability to terraform 3 planets into Gaia Worlds with the Overgrowth modifier at the cost of 10000 Energy and 10 years. Barren Worlds, even without Terraforming Candidate modifier, can be terraformed too but the time is increased to 25 years. The science ship merely starts the process and does not have to stay there.

Cost reduction & speed

Terraforming cost and speed can be affected by the following:

Source	Cost	Speed	DLC
World Shaper ascension perk	−25%	—
Hydrocentric	−25% to Ocean	—
Secrets of the Baol empire modifier	−15%	—
Shallarian Terraforming Knowledge empire modifier	−10%	+20%
Mask of Transformation empire modifier	−10%	+10%
Terraforming Gases edict	—	+50%
Exotic Gases Shortages situation	—	−20% per stage
Ecological Protection resolution 4	+25%	—
Ecological Protection resolution 5	+100%	—
Cartographer I on council	—	+10%
Cartographer II on council	—	+25%
Cartographer III on council	—	+33%

Colony ships

Colony ships allow an empire to settle habitable planets or megastructures in owned systems. When ordering the construction of a colony ship, the player is given the option of choosing the species or sub-species of the pop(s) that will be sent to the new colony. Species require the Colonization Allowed species rights to be selected for new colony ships. Pops are neither consumed nor transported in this process. Once constructed, the colony ship may be sent to any habitable world within an owned system to start a colony. Colony ships take one year to build and their upkeep cost is maintained throughout the whole colonization process. Colony ships can also be built through the interface of the planet to be colonized, which automatically queues the colonization order as long as the path is not blocked.

The cost of a colony ship depends mainly on the empire's primary species class and governing authority.

Primary species
Biological	200 Alloys 200 Food 200 Consumer Goods	200 Alloys 500 Food	50 Alloys 1000 Food
Lithoid	200 Alloys 200 Minerals 200 Consumer Goods	200 Alloys 500 Minerals	50 Alloys 500 Minerals 500 Food
Robot	400 Alloys

The Frontier Spirit ruler trait reduces the cost of colony ships by −35%.

Alternative colony ships

Meteorite Colony Ship

In addition to regular colony ships, empires with the Corporate Dominion or Private Prospectors civics can also construct Private Colony Ships, which cost 500 energy instead.

Similarly, empires with the Calamitous Birth origin can also construct Lithoid Meteorites, which cost 500 minerals instead, have no upkeep cost, and take only 150 days to build. Lithoid Meteorites also have a much faster sublight speed than regular colony ships. A planet colonized by a lithoid meteorite gains two Buried Lithoids blockers and the  Lithoid Crater modifier.

Colony development

When a Colony Ship lands on a planet, a period of initial development will occur during which a colony is extremely vulnerable: just a few days of orbital bombardment will wipe it out completely and the new colony will not produce any resources nor will pops grow on the world. It is possible to remove blockers while the colony is developing, however their clearance cannot be cancelled or reordered until the colony is fully established. Once the colony has been successfully established, it will have a tier 1 capital building and a single pop of the species selected for the colony ship. It is then possible to develop the planet by constructing districts and buildings.

The  Colonization Fever tradition and the Yuht Cryo Core relic each increase the number of initial pops on a new colony by +1. Machine Intelligence empires' colonies also start with +1 initial pop.

The initial development period lasts about 2 years and 10 months. Colony development speed can also be reduced by the following:

Source	Colony development speed
Habitat	+200%
Evacuation Protocols edict	+100%
AI-controlled Colony Ships technology	+50%
Self-Aware Colony Ships technology	+50%
Ceramo-Metal Infrastructure technology	+25%
Durasteel Infrastructure technology	+25%
Expansion tradition tree	+25%
Superior Colonies agenda	+25%
Expansionist diplomatic stance	+15%

References

Game concepts