A celestial body is a named object (such as a planet or large asteroid) occurring within a star system. Celestial bodies may have resources which can be harvested by orbital stations. Planets may also be habitable and capable to be colonized by empires with the right suitability or technology.
When any owned ship enters a system or passes within its sensor range, any habitable planets in the system will be revealed along with their world type. To see further details about the celestial bodies in a system, it is necessary to survey them with a science ship. This will reveal all of the orbital resources associated with each planet or asteroid. For habitable worlds this will also reveal more detailed world information including: size, surface tiles and their resources, and the habitability percentage for each species in the player's empire. Additionally, surveying worlds has a chance to reveal anomalies.
- 1 Summary of celestial body types
- 2 Planetary details
- 3 Tiles
- 4 Habitability
- 5 Barren Terraforming Candidates
- 6 References
Summary of celestial body types
A habitable world is any celestial body that can harbor advanced organic life. These are the only worlds that can be colonized and terraformed, besides some notable exceptions. Their suitability ranges in accordance to a given species' homeworld, which affects the rate of population growth.
A planet's habitability (and subsequent future terraforming costs) is determined by its climate system. The 10 habitable worlds are divided equally into 3 climate categories: dry, frozen and wet, with Gaia worlds being notable exceptions.
A Gaia world will always feature 100% habitability for any species and generally has only beneficial modifiers, making it the best habitable world available. However the Holy Guardians consider some of these worlds holy (easily identifiable from their special names) and colonizing them will incur their ire.
An uninhabitable world is any celestial body that cannot harbor advanced organic life, that are not stars. These worlds can't be colonized or terraformed, but can still be lucrative sources of common and strategic resources.
A special world is any celestial body that does not follow the standard rules of procedural generation and are, in many cases, only created by events.
|AI||This planet is created by the AI Rebellion.||Rocky world covered with artificial structures. The thin atmosphere consists mostly of industrial pollutants. There are strong energy emissions coming from across the entire surface, but no organic life signs.|
|Crystalline Asteroid||Multiple such asteroids are present in a unique Guardian system. They have a very large amount of minerals per asteroid, but attempting to mine them will awaken the hives.||A large asteroid covered in some kind of crystalline outcroppings.|
|Infested||Created when habitable worlds are infested by the Prethoryn Swarm. Successful bombardment turns the planet into a barren world that can be terraformed.||The surface of this world is covered by some kind of biological contaminant.|
|Shielded||Found inside Militant Isolationists Fallen Empire territory. The shield can be brought down through a special project, with different possible outcomes (mothballed fallen empire ships, a captive admiral or a group of Void Clouds).||This entire world is encased in some kind of impenetrable energy barrier. It blocks all scans of the surface.|
|Shrouded||Created after the 50-year Covenant with the End of the Cycle finishes. All shroud-marked worlds are turned into this type of world. Afterwards, an inhabited world can be turned into a shrouded world by the Warped Consciousness Reckoning, though worlds that do not have intelligent life on them are spared. Cannot be recovered.||Our sensors are unable to penetrate the thick fog surrounding the planet. Ships that enter it do not return.|
|Tomb||A habitable world can be turned into a tomb world by game events, such as a pre-FTL species starting a nuclear war during the Atomic Age. These worlds are habitable but feature the poorest base habitability rating.||A rocky world with a nitrogen-oxygen atmosphere. It is currently experiencing a nuclear winter, with dense layers of sooty aerosols in the atmosphere. High levels of surface radiation. Minimal signs of life.|
Note: It is also possible to repair a damaged ring world in the base game (but not constructing a new one).
A star is a celestial body that usually composes the center of a star system. They are classified based on their spectral characteristics. Some star systems can however be more special, like a black hole, pulsar, or a neutron star. The star type influences the generation of the solar system.
While basic resources (energy, minerals, research points) are randomly and evenly distributed across the galaxy, strategic resources only appear on certain types of celestial bodies. If allowed, basic resource deposit can exist both in orbit and on surface of a habitable world, although each planet may have only one orbital deposit. Food deposits and mixed deposits with food will only appear on surface of habitable planets. Strategic resources spawned with energy or minerals require mining stations, while collecting those accompanied with research points needs research stations. Garanthium, Lythuric Gas, Engos Vapor, Teldar Crystals, Pitharan Dust and Orillium will spawn in clusters, which mean they are rich in some sectors but rarely found in rest part of the galaxy. Betharian stone and alien pet are no longer collectible, but they will serve as prerequisite to construct certain planetary buildings.Habitats will not contain except for one tile containing the orbital resources.
In the table, if not specified, habitable worlds means it can be any of the followings: 9 types of primary habitable worlds, gaia world, ring world and tomb world. Strategic resources have a higher chance of spawning in nebulas
- See also: Traits#Habitability traits
Every species has a preference for one of the primary habitable world types. A planet's habitability (and terraforming costs) is determined by its climate system. The 9 habitable worlds are divided equally into 3 climate categories: dry, frozen and wet. A species' homeworld will always have 100% habitability while other planets of that type will have 80% habitability. The other two planet types in the same climate category will have a base rating of 60% habitability. Planets of other climate categories will have a rating of 20% habitability.
Gaia worlds have a thriving biosphere with many climatic zones, and are 100% habitable for all species. Tomb worlds contain toxic waste and ruins from an earlier civilization and have very low habitability for all species. If they must be colonized for strategic reasons, it is often best to use robots or an uplifted irradiated species until technology for tomb world adaptation in researched.
Worlds of any type may have features which either increase or decrease their habitability. If present, these features will be identified when the world is surveyed by a science ship.
Colonization of habitable worlds is the most common way for a player to expand their control of the galaxy. Therefore, it is critically important to have a solid understanding of the role of colonization in expanding an empire and developing it into a powerful military, economic, and social engine. There are five primary tools for increasing the number of habitable planets available to the player:
An empire can choose to use one or all of these tools when seeking to expand the number of habitable planets available.
Not all planets are equally habitable by all species. Each species has a trait which gives it the highest habitability rating on its home planet type, then reduced (but still acceptable) levels on other world types. A population's happiness is capped at the habitability of the planet for their species. Habitability cannot exceed 100%.
Habitability is spread out on five tiers, with the homeworld of a species always starting at 100%. Furthermore, certain planetary modifiers can modify habitability. There are also traits and various other sources that can improve habitability for certain pops (such as 'Adaptive', described further below on the page).
|Gaia, Ringworld, or Habitat||100%|
Systems containing surveyed or non-surveyed habitable worlds will have a planet icon that is either green, yellow or red, depending on the habitability percentage of the most suitable world that the system contains.
- Green: At least one world in the system is >70% habitable for at least one species in the player's empire.
- Yellow: The best world in the system is 40-69% habitable for at least one species in the player's empire.
- Red: All of the worlds in this system are less than 40% habitable for all species in the player's empire.
Sometimes other factors can prevent colonization of a world. Some common reasons for not being able to colonize an otherwise habitable world are:
- The world has not yet been surveyed
- There is an anomaly on the world which has not yet been researched
- The system is within another empire's borders
- The world is colonized by a pre-spaceflight civilization (excluding pre-sentients)
Note: a species can only colonize a certain planet if its habitability there is more than 40%.
Zooming in to the system and mouseing-over the planet icon may reveal useful information about what is preventing the player's empire from colonizing the world. e.g. If the tool tip says the world is 'controlled by Unidentified Empire' or 'belongs to someone else', another empire is in control of the system. In this case, surveying the world will reveal the empire that controls it. This action can cause the player's science ship to be missing in action for up to a year, so it may be preferable to avoid surveying the world.
Since different species can have different world type preferences, it can be better for an empire to populate its worlds with other alien species, genetically-engineered subspecies, or even robots/synthetics.
It is also possible to terraform habitable worlds, though this is a costly and time consuming process. Only planets of the main types (continental and such) can be terraformed, in addition to tomb and barren worlds with the "Terraforming Candidate" modifier.
A habitable world may have between 10 and 25 tiles. Each tile can hold up to one population and one building.
Each tile has a chance to have base resources. These can be gathered by a population even without a building. If a building is built on the tile, any resource type that is produced by or associated with the building stacks with the base tile resource, but all other resource types are suppressed. Betharian stone and Alien pets will also spawn on the surface of a few planets. They will be generated randomly on energy and society research tiles, but cannot be collected as other resources. Instead, Betharian Power Plant and Xeno Zoo are limited to be built on these tiles. The basic resources (energy, minerals, food, research) spawn in amounts varying from 1 to 3. Not all tiles will have resources on them.
Tile blockers are obstacles that block tiles. The player cannot move populations onto or create buildings on top of tiles that have blockers, and thus cannot exploit the resources of blocked tiles. Blockers can be cleared for a modest cost in minerals, energy, and time, if the player has researched the required technology. There are 9 such technologies, one for every normal blocker type, and they are all relatively easy to research. All normal blockers cost the same amount of resources to remove.
Two special blocker types, sprawling slums and industrial wastelands, are automatically generated on every player's homeworld in a new game. They don't require technology to be removed, but initial resources may be better spent on other things. The remaining tile blockers appear much more rarely across the galaxy - some are result of particular actions (bombardment craters), other are tied to events. Event-related tile blockers aren't posted here to not spoil the dramatic events surrounding them.
It is possible to avoid researching the individual removal techs by taking Mastery of Nature ascension perk. The perk grants all removal techs at once in addition to removing the cost associated with the removal.
In general almost all blockers provide no benefits and are merely obstacles, only a few blockers may be useful for adjacency or unique effects. Other than that, the player is free to remove regular tile blockers without any risk or downside (other than resources spent on clearing them).
Habitability is the measure of how well a species can live on a habitat. It has massive effects on Colonisation.
- Habitability is primarily derived from a Species Habitability Trait. This is defined by a Species Homeplanet, usually picked at empire creation.
- A planet must have at least 40% Habitability before it is considered to be "Liveable" for a species. A species can not be Colonist of, Migrate to, or be Resetteled on a non-Liveable planet. If a planet or species turns non-liveable, pops are automatically displaced.
- Habitabiltiy acts as a Cap on Happiness. This can force Unrest at the minimum Level of habitability and lock out Happiness bonuses even on higher levels.
- Every point of Habitability under 100% also increases the growth cost of a new Poplation Unit by 1%. This can thus increase growth cost up to +60%.
- Habitats, Ringworlds and Gaia class planets have a fixed Habitability. However the respective Habitability traits grant habitability for no Planet type, making them the weakest 'Homeplanet' type.
- Homeworlds have a +30% habitability for the species originating on them.
- Low Habitability or Happiness can also be the Trigger of Events.
Home Planet and Habitability Categories
- 100% Habitability is ideal, but also extremely rare. A homeworld of a species is usually 100% habitability for that species, unless the planet class has been changed. Gaia planets, Ringworlds, and Habitats, are always 100% habitability for all species. Habitability can also be increased to 100% with several species traits and/or other stuffs.
- 80% Habitability is the default for all Planets of exactly the same planet class as the species Homeworld. This is called Primary Habitability Category.
- 60% Habitability is the default for all Planets that are in the same Hydrosphere Group, but not of exactly the same planet class as the Home Planet. This is the Secondary Habitability.
- 20% is the default for all Planets that can be picked as Homeworlds, but do not fall into one of the Higher Categories. This is the Tertiary Habitability.
- 0% is the fallback habitability for all colonizable planet classes that are undefined in the habitability trait of a species. The most common example is the Tomb Worlds, they have 0% habitability by default.
Terraforming allows the change of the Climate class to be one more suiteable for the intended Colonists. However the process is very costly, requires decades of time and requires special technology if it is not only from a secondary to the primary habitability.
As of 1.6 this step can now be done retroactively on an already colonised planet.
This strategy does not care for Habitability, as long as it is (just) above the threshold. This approach is obviously a poor choice for Empires looking for high Happiness. But if low Happiness is already expected/compensated for, this will hardly be a hindrance. However the Growth penalties do still apply fully and will increase the time until the colony becomes fully productive.
With the combination of Tertiary habitability and +20% Habitability bonus, every planet without penalty would become a viable choice for this empire.
Not really a colonisation strategy, but a strategy to enable one of the others. One pop with just the Minimum Habitability is used to colonise the Planet. The goal is not to actually populate the Planet with that species (in some cases the pop migrating off might even be wanted) but to have a colony to attract or create another, better suited (sub)species for this purpose.
Using Genetic modification, one can create a subspecies of the empires primary species that is suitable for the Climate in question. However this needs either the first-in approach (so they can be changed on the new Planet) or a staging area with increased Habitability regardless of current Climate Preference (Ringworld, Habitat, Homeworld, rare modifiers).
Changing a habitability trait was always cost free, and as of 1.6 the base cost for genetic engineering has been dropped.
With all the possible habitability types, there are bound to be some Aliens that can life comfortably at least on planets not available to the primary species. The main disadvantage is that Xeno Pops have increased Unity cost per pop and might not have favorable traits. There may also be unwanted Xenophile attraction/Faction interactions from this path.
Both via Conquest and Migration Treaties, one can add Xeno Pops to the Empire to use as colonists. If the Empire is Xenophobe, the rights Limitations for Xenos will make the pops also considerably less happy. The Migration Approach requires a "First-in" colonist.
Genetic Uplifting, Enlightenment and Infiltration can be used to acquire a Xeno Species as well. With the first one, it might even be possible to get a rare Habitability like Tomb Worlds. Very rare species native to Tomb Worlds are extremely adaptive and can thrive on any kind of planet (every normal class is secondary). The usual way of obtaining these species as subjects is finding them as upliftable semi-sentients on Tomb Worlds and uplifting. The event chain Horizon Signals can also create a subspecies of your main species with this trait. Alternatively, pops of your main species on Tomb Worlds may mutate and develop into their own species native to Tomb Worlds.
All levels of Robots have 100% Habitability on every kind of Celestial Body. However, only the T2 Robots can actually be Colonists, while not being good at many tasks. Synth level Robots are good to superior in all tasks, but also increase the Unity costs. Robot pops furthermore have a massive draw towards Materialist Ethics, both for themselves and other pops on the planet.
While the initial growth might be slower than a pure biological species, once the pop count is sufficient, Robots will also grow a lot quicker than Biological Species. Droids or Synths make particularly good "first in" colonists, if they can be moved off or Materialist attraction is acceptable.
Maximizing habitability of a species
For most species on a planet with no special modifiers and ignoring rare strategic resources, the maximum increase is currently 35% with about 25~30% attainable by the mid-game. With all reliably obtainable conditions fulfilled, this can be increased to 85% (while preserving the biological nature of the species). Further increases must come from planetary modifiers, events, and rare coincidences such as obtaining an uplifted Starborn species who has been first modified with Robust by a biologically-ascended empire, then also Cybernetic by a semi-Synthetic empire.
- The species trait Adaptive or Extremely Adaptive increase their habitability on all words by +10% or +20%, respectively. If a player decides to go down an ascension path the traits Robust or Cybernetic becomes available (with their respective asendancies).
- The Tradition Dynamic Ecomorphism from the Diplomacy tree will provide +10% habitability on all worlds in your empire, for all species. The next tradition below, Alien Tourism grants Visitor Centers that provide a further 5%
- A total of 20% is available from four technological advances at 5% each: Atmospheric Filtering, Hostile Environment Adaption, Foreign Soil Enrichment and Hostile Climate Adaption. In addition, Tomb World Adaption provides 20% specifically for that world type.
- The strategic resource Engos vapor increases habitability by 5%, although usually very few spawn in a given galaxy. Additionally, Xuragel can be purchased from XuraCorp trader enclaves for a +5% increase as well.
- See also: Genetic modification
Celestial body modifiers
There is a small chance that a celestial body will have modifier(s). Modifiers can provide various bonuses and also maluses, such as to habitability. They will be found when surveyed or through anomalies and (accompanying) events.
Barren Terraforming Candidates
A special anomaly with 0% failure risk can be found on Barren Worlds. Researching the Anomaly will reveal that the planet has the conditions necessary for terraforming, once the Climate Restoration technology has been researched. It gains the Terraforming Candidate modifier and can be terraformed into any habitable planet other than a Gaia world. The Sol system planet Mars is guaranteed to possess this anomaly, due to having had a biosphere in the past and still having frozen water. Infested Prethoryn Planets that have been cleared and transformed into barren worlds as well as worlds that have been devoured by the unbidden will have the Terraforming Candidate modifier.