This article is for the PC version of Stellaris only.
Exploration is one of the most important tasks for a spacefaring empire. At the game's start nobody will know anything about the universe beyond their home system. To learn more about anything beyond it, an empire will need to send their science ships out to survey them. Early game exploring is key for an empire to start growing rapidly, however caution is warranted for the various events and anomalies associated with exploring can bring either great boons or banes with them. Part of the Discovery tradition tree is focused on exploration.
- 1 Science ships
- 2 Situation log
- 3 First Contact
- 4 Galaxy Map
- 5 Unique Systems
- 6 Habitable Worlds Survey
- 7 References
Players can build science ships from the start of the game, and every player starts with a pre-built science ship which is ready to be sent out to survey. Every science ship must be assigned a scientist for the science ship to perform tasks such as surveying, assisting research of a planet, exploring uncharted hyperlanes or researching a special project (the ship can still move around without being assigned a scientist).
By default science ships are set to "evasive" stance, which means they will flee any system where hostile ships or spaceborn life forms are present. They can be set to "passive" stance instead, which lets the ship continue its current orders even if the system it is in contains hostile aliens.
Science ships cost 100 alloys. They are built at starbase shipyards, like all other ships. They do not have weapons but are automatically equipped with the latest sensors, engines, reactors, armor and shields based on your current technology. Science ship components are automatically upgraded as your technology advances without the need to refit them at shipyards.
Science ships can do the following actions, all which require a scientist to be assigned to the science ship:
- Surveying gives detailed information about a celestial body, namely deposits, habitability and anomalies.
- Researching Anomaly will investigate an anomaly, the investigation time being dependent on the level of the scientist and of the anomaly. For more details see Anomaly.
- Assist Research allows science ships to boost the research output of the planet, by an amount depending on the skill level of the scientist.
- Automatic Exploration requires the Automated Exploration Protocols technology and explores the galaxy automatically.
- Experimental Subspace Navigation requires the Speculative Hyperlane Breaching technology and makes the science ship travel directly to any destination as MIA.
In order to survey a planet, select a science ship and right click on the planet and select the "Survey" option. The player may also select the "Survey System" option to order the science ship to survey every celestial body in the system. From the galaxy map, the player may queue survey mission by holding down "Shift" key and right clicking on a system and selecting the "Survey System" option one by one. The science ships can only survey systems that are within their reach. Science ships can be ordered to explore the galaxy automatically once the Automated Exploration Protocols technology has been researched.
Surveying celestial bodies such as stars, planets and asteroids allows for the discoveries of resources such as energy credits, minerals, strategic resources, research points or a primitive civilization or pre-sapient species on them. The player may then send a construction ship to build mining and research stations to harvest them, provided the system with the resources are within their borders. Starbase outposts can only be constructed in systems that have been fully surveyed.
Scientists may also come across anomalies (unusual things in the galaxy that require further study and analysis) when surveying a celestial body. These anomalies can be investigated by any scientist, but have a greater chance of success if the scientist has a high skill level. When an anomaly is found, the player gets an alert at the top of their screen. Clicking on this alert will bring up a screen which has the option to direct a scientist to research the anomaly immediately. The scientist will return to their current assignment once he or she has complete investigating the anomaly.
Planets surveyed by an empire within its own borders do not have to be surveyed by other empires. However planets within Fallen Empire borders will have to be surveyed once border access is gained one way or another. The same applies to Marauder systems in Apocalypse.
The situation log helps to keep track of special projects and anomalies, which are discovered when venturing out into the galaxy and exploring, and allows individual projects and anomalies to be tracked on the map. For democratic Governments it will also display Election Mandates. If there is an update to the Situation Log, it will glow in orange.
Most projects are centered around a location (often a planet, but it could also be an object in space), and many of which requires the presence of a science ship with a highly skilled Scientist assigned to the science ship before the projects can be researched. However, some of the projects may require something other than a science ship such as a military warship, or a troop transport, or something else entirely. Some special projects are timed while others will remain present until resolved.
Eventually ships belonging to another empire will be encountered. Diplomatic interactions will not be available until their language is translated so the only decision that matters is whether to attack unprovoked or to take a peaceful stance unless attacked. Hostile action can only be undertaken if the First Contact Protocol is set to aggressive (the default for xenophobe, fanatic xenophobe, militarist and fanatic militarist empires) and only with an explicit order. A hostile action will have a permanent -25 opinion towards that empire while capturing any of their worlds will mark it as a first contact war and give a permanent -75 opinion instead.
After the first contact the option to investigate and translate the language of the newly encountered empire will become available. Should you focus on other projects the alien empire will translate your language shortly after the encounter.
Note that the ethics-based replies available after a peaceful first contact do not affect opinion.
The layout of star systems is determined by the galaxy shape. All systems are connected by hyperlanes in clusters connected by choke points. The latter will never be a home system nor will they house anything that will stop an empire's expansion. The systems at the very edge of the galaxy will always be isolated, with a single hyperlane connection.
The number of choke points is set at galaxy generation.
Nebulae tend to have fewer habitable planets within them, but the chance of finding Strategic Resources is increased by 50%. Nebulae block all sensor coverage originating from other systems, meaning that it's impossible for an empire to see what is within and beyond a nebula's hyperlanes without having a ship or station therein. Nebulae are named and visible on the galaxy map from the start of the game.
|Available only with the Distant Stars DLC enabled.|
Some Black Hole systems are home to L-Gates. These heavily modified gateways cannot be activated with the Gateway Activation technology. Upon first encountering one, the L-Cluster entry will be added to the Situation Log, requiring the collection of 7 L-Gate Insights. Insights can be obtained from investigating anomalies, defeating certain enemies, researching the rare L-Gate Insight repeatable Voidcraft technology or asking the Curator Order for an insight every decade (-5000 Energy).
Once 7 L-Gate Insights have been collected, the technology L-Gate Activation will become available for research. The empire will have to own a system with an L-Gate before it can access the L-Cluster. Finally, a special project will be added to activate the L-Gate, taking 180 days for a science ship to open the gate.
Opened L-Gates grant access to the L-Cluster, a cluster of stars located north-east of the galaxy and entirely inaccessible through the regular hyperlane network or experimental subspace navigation and too far for Psi Jump Drive range. The L-Cluster contains a unique Strategic Resource: Nanites. If a ringworld is built inside the L-Cluster, then while its construction will remove the planets in the system and make the original resources unavailable, the uninhabitable sections of the ringworld will contain some of the the resources instead as the habitable sections are completed, sometimes more than there were originally.
Once the first L-Gate is activated one of four things will be found, with the following weights:
|Outcome||Weight||Opens all L-gates|
The outcome is rolled at the start of the game so reloading a previous save will not alter the result.
Up to 10 L-Gates can exist in a galaxy and new ones cannot be constructed. Only one L-Gate is located in the L-Cluster, in the Terminal Engress system, and as a result any L-Gate in the galaxy will connect to the same gate in Terminal Engress but the Terminal Engress gate can be used to travel to any L-Gate inside the galaxy.
|Available only with the Utopia DLC enabled.|
Completed Sentry Arrays cannot grant vision of the L-Cluster before an L-Gate is activated. After that, it will grant visibility inside the L-Cluster as well.
A common outcome of the L-Gate activation is an invasion from the L-Cluster. All L-Gates in the galaxy except the first one activated will open at the same time and bring an invasion force. In a tiny galaxy with only one L-Gate the empire that activated it will endure the invasion instead.
Nanite fleets are composed of one titan and 5 cruisers, all equipped with energy weapons and strike craft. As such, fleets with shields and point-defenses are the counters. Nanite ships have equal amounts of tier V armor and shields, making every offensive approach quite balanced.
The Gray Tempest home system contains a factory station twice as strong as the usual fleet that creates a new fleet every 10 years. If the factory is destroyed all Gray Tempest ships will dissolve and all Nanite Worlds will get the Terraforming Candidate planet modifier.
Another possible outcome of the L-Gate activation is finding an empire called the Dessanu Consonance inhabiting the entire L-Cluster. Upon discovery the Dessanu will provide the empire that opened the gate +1 Living Metal, Exotic Gases, Rare Crystals and Volatile Motes. Their only request is that no ship will enter the factory trinary system at the heart of the L-Cluster and that they are not asked about the Nanites. The Dessanu will never leave the L-Cluster even if they become hostile, nor will they build new fleets.
Each time a ship or fleet enters the factory system the Dessanu will demand that it leaves within 60 days. Refusing to do so or inquiring too much about nanites will make them hostile, as will attacking them.
Each Dessanu system contains at least one Gaia World. However if a planet is successfully invaded and occupied it will turn into a Nanite World with the Terraforming Candidate planet modifier. All armies will safely retreat back in orbit. If the factory is destroyed the same will happen to all Dessanu worlds.
If the L-Cluster is abandoned a random Nanite World will have a Level 3 Surface Signature anomaly. Investigating it will reveal a nanite entity taking the form of a member of the species discovering it. Asking it to join you will add Gray to the Contacts menu. Gray can take three forms at any time:
Should Gray be destroyed it will merge back in 10 years.
This outcome leaves only one L-Gate activated, all the others coming online afterwards one every one or two years. This gives the empire that activated the first L-Gate a significant headstart.
The only outcome of the L-Gate activation seemingly unrelated to nanites is the spawning of L-Drakes. Each L-Gate in the galaxy will activate and bring an L-Drake which will travel to a random system three hyperlanes away and nest there. It will not be hostile even if its nesting system is claimed. If an L-Drake is attacked all L-Drakes will become hostile towards the attacking empire but each L-Drake killed adds a moderate reward of Influence and Minerals. If the empire that opened the L-Gate takes this stance it will also gain moderate Engineering and Society research for each killed L-Drake. L-Drakes fights identically to the Young Drake from the Leviathans DLC.
If the empire that opened the L-Gate enters a nesting system with a science ship it will have the option to start a special project to tame the L-Drake residing there, gaining control of it. The option is not available if the empire is Fanatic Xenophobe or genocidal.
This outcomes leaves all L-Gates activated and leading to an abandoned L-Cluster, allowing everyone access.
These rare systems can only spawn once per galaxy and have a unique event or anomaly related to them. They have the following spawn chances:
|Galaxy Size||Sanctuary spawn chance||Zanaam spawn chance||Leviathans systems spawn chance||Distant Stars systems spawn chance||Guaranteed systems|
|Tiny||4%||6%||16% for each system||16% for each system|| Sealed Wormhole System|
At least one Curator Enclave system
At least one Artisan Enclave system
XuraCorp Trader Enclave system
|Small||8%||12%||32% for each system||32% for each system|
|Medium||12%||18%||48% for each system||48% for each system|
|Large||16%||24%||64% for each system||64% for each system|
|Huge||20%||30%||80% for each system||80% for each system|
Unique systems will never spawn in choke points.
- Main article: Precursors
Guaranteed, location-based event chains with level 10 anomalies.
Sanctuary is a system containing an abandoned ring world of previous Enigmatic Observers. Originally created to act as a nature preserve and house primitive life, the system was abandoned but left guarded by multiple defense platforms of approximately 42k fleet power. Upon discovering the system an empire is contacted by the automated defense facility, which explains the history and purpose of the facility. Every message ends in "Do not approach this facility under any circumstances" and indeed the defenses will fire upon any ship that approaches it.
The Sanctuary defenses contain the following stations:
| 1 Sanctuary Core
||4 A-1 Fortresses||11 A-2 Outposts|
Despite having no engine modules, stations are, in fact, mobile, and therefore cannot be engaged with artillery ships from a safe distance, one by one. Defeating them may prove a challenge but destroyed platforms are not rebuilt, allowing the system to slowly be overtaken.
The ring world is almost completely intact and each habitable segment houses a randomized pre-FTL species, none of them advanced beyond the Steam Age. Any empire that manages to defeat the platforms can lay claim to the extremely valuable system and decide the fate of the inhabiting species. It should be noted that since the species have evolved and reached sentience on the ring world they have the Ring World climate preference which hampers their ability to colonize without compensatory methods.
A rare special system contains Zanaam, a size 25 Gaia world with the unique Valley of Zanaam Planetary Feature, the system is guarded by a strong fleet of 11k fleet power, which can drag out taking the system. Aside from the namegiving planet, the System has 3 broken worlds, an asteroid ring and 6 shipwrecks. The planets can have random anomalies as usual.
The Fleet guarding it consists of 24 Guardian Class Destroyers, named from Alpha to Omega, which look like Ancient Mining Drones but use far more advanced components.
Upon entering the System, the player is given a message stating they will be destroyed. The Fleet is hostile, however it is not set to aggressive stance, simply blocking any approach to the planet. After they are defeated the planet can be colonized as usual.
A random system in the galaxy will contain an asteroid field where one of the large asteroids is orbited by an Ancient Manufactory identical to the Mining Drone stations. Surveying the asteroid will reveal a level III anomaly. Investigating it will bring the option to either:
- Leave the manufactory alone. Xenophobe and Fanatic Xenophobe empires will gain 100 Influence from this option.
- Start a Special Project to restore the manufactory. Not available to Fanatic Xenophobe empires. Outcomes include turning the manufactory into a mining station, creating a Teldar Crystals deposit to the asteroid, launching the manufactory into the star and awakening 3 hostile Ancient Mining Drones or Crystalline Entities.
Distant Stars systems
|Available only with the Distant Stars DLC enabled.|
Twin Tomb World Civilizations
This star system contains two Tomb Worlds, both with humanoid Bronze Age civilizations. Surveying the second Tomb World will reveal a level III anomaly. Investigating it will grant a moderate amount of Society research. The species are always the following:
This system will not spawn if primitives have been disabled.
One anomaly in the galaxy might be called called The Vechtar Zavonia when successfully investigated, describing a planet called Paridayda and a species called Mardak Vol. Choosing the option to search for the planet will start a special project. Finishing it will create a neighbor system and point to a Barren World inside. Choosing to investigate further when entering the system will start a special project to investigate the planet with a science ship. Finishing the special project takes 60 days and will reveal the planet as a size 25 Gaia World with the Stone Age Mardak Vol civilization.
20 days after the system has been claimed a species called the Vol will arrive with a fleet to purge the Mardak Vol. Accepting will destroy the civilization and add a removable district blocker to the planet. Refusing will have the fleet attack the system. If their fleet is not defeated they will bombard the planet with the Armageddon stance. Once all Mardak Vol pops are killed by bombardment all tiles on the planet will get 4 removable district blockers.
Accepting is the recommended course of action as not only does it avoid the fight but the Mardak Vol would take a long time to enlighten or remove Stellar Culture Shock and have the Gaia World climate preference. In addition if the planet is colonized the colonists will gain +10% Happiness for 10 years.
Paridayda has a unique planet modifier granting it the following:
A random pulsar system in the galaxy might contain a Tomb World planet called Ruinous Core orbited by a Tomb World moon called Lost Encampment, as well as various debris thorough the system. A similar nearby system will contain three Tomb Worlds: Silent Colony, Decayed Hub and Crumbling Borough. A second nearby system will contain a Tomb World called Fallen Outpost. Unlike other Distant Stars systems, these systems will give a notification when one is entered for the first time. Surverying Ruinous Core will reveal a level II anomaly. Investigating it will grant a significant amount of Society research. The planets are filled with Junkheap buildings, which don't do anything.
A few decades after the first system has been entered a species called Ketling will emerge in any of the three systems that haven't been claimed by an empire. A special project will be added to investigate any Tomb World in one of those systems and doing so will grant a large amount of Society research.
Planets with Ketlings cannot be colonized but can be invaded. If invaded they will suffer a 5 years Culture Shock identical to invading an Early Space Age civilization.
Another few decades after the Ketling have emerged they will become the following Federation Builders empire:
|Ketling Star Pack|
All their planets will be filled with tier IV buildings and they will get 10 armies and a fleet of 8 cruisers, 8 destroyers and 10 corvettes.
Sealed Wormhole System
This pair of systems will be present in any game regardless of the Wormhole Pairs setting. A system will be linked to the rest of the galaxy and when first entered a signal will come out from the wormhole, something that does not happen in other wormhole systems. Exploring the wormhole will reveal its connection to a trinary star system disconnected from the galaxy. Said system is guarded by a Corrupted Psionic Avatar which must be defeated to allow science ships through. The avatar has strong shields, no armor and weak hull making weapons that bypass shield extremely effective against it. The first planet of the system is a Shrouded World with a 4 Physics deposit. The second planet is a Gaia World with a Mysterious Tanker in orbit. The third planet is a Gas Giant an Exotic Gases deposit. Surveying the second planet will reveal a level V anomaly. Investigating it will grant access to the Neural Tissue Engineering technology to organic empires or a very large amount of Society research if Machine Intelligence.
Alternatively a science ship can be set to Passive stance and guided around the Corrupted Psionic Avatar to scan the planets without entering its weapons range.
|Available only with the Utopia DLC enabled.|
While the sealed system is not visible on any sensor until the wormhole has been opened, it will be detected by a completed Sentry Array.
Abandoned Observation Post: This class F star system contains an Abandoned Observation Post orbiting a habitable world. Surveying the planet will reveal a level IV anomaly. Investigating it will bring the option to either:
- Investigate the observation post with a science ship to gain a moderate amount of Society research.
- Leave the observation post alone for 60 Influence.
Abandoned Star Platform: This system contains an Abandoned Star Platform orbiting a pulsar star. Surveying the star will reveal a level IV anomaly. Investigating it will bring the option to start a 60 days special project to either:
- Repair the platform with a construction ship to add a 6 Energy deposit to the pulsar.
- Salvage the platform with a science ship to gain 20% to the next level of lasers technology.
Gaia Civilization: This class M star system contains a Gaia moon orbited by a derelict station. Surveying the moon will reveal a Stone Age molluscoid civilization as well as a level VI anomaly. Investigating it will grant a significant amount of Physics and Society research. The primitive civilization has the Gaia World climate preference, as well as the Extremely Adaptive, Slow Breeders and Sedentary traits.
Shielded World: This class B star system contains a Shielded World. Surveying the planet will reveal a level IV anomaly. Investigating it will bring the option to either:
- Repair the shield with a science ship to add a 8 Physics and 4 Society deposit to the world for a few decades.
- Interrupt the time loop with a science ship, gaining a small amount of Physics research. There is a 50% chance of the world turning into a tomb world and a 50% chance of creating a Fanatical Purifier Prikki empire.
- Leave the planet alone and gain a small amount of Physics and Society research. Around a decade later a Fanatical Purifier Prikki empire will emerge.
The Veil This binary star system contains a planet that will appear either as a Gaia World or a Shrouded World. Surveying it will reveal the Phase-Shifted planet modifier (-50% Planet Build Speed) and the only level X anomaly besides certain precursor anomalies in the game. Investigating it will describe how every 3 months the planet shifts between a Gaia World and a Shrouded World and grant a moderate amount of Physics. Once the system has been claimed you will be given the option to either:
- Leave the planet for a moderate amount of Influence.
- Start a special project to use a science ship to freeze the phase-shift. The project takes 180 days and finishing it permanently sets the planet to a Gaia World. It will also grant a moderate amount of Physics research.
Rudimentary Robots: This star system contains a single habitable world among other uninhabitable planets. Surveying the planet will reveal a level I anomaly. Investigating it will reveal 3 or 4 Robot pops and primitive buildings on the planet. Shortly after colonizing the planet you will be given the option to either:
- Dismantle the robots and gain 100 Minerals.
- Keep using the robots. 90 days later a special project to investigate the robots with a science ship is given. Finishing the special project takes 30 days and gives a large amount of Society research.
Regardless of the chosen option, around 5 years after the planet has been colonized a number of colonists will gain the Erratic Behavior modifier, giving -25% to Happiness, Governing Ethics Attraction and Resource Production, and a special project to investigate it will be added, costing 60 Society research. Finishing the research project grants a random Biology technology. If the special project is not completed in 4 months three enraged colonists armies will form and attempt to occupy the planet.
Sea of Consciousness: This class A star system contains a size 24 Ocean World among other uninhabitable planets. Surveying the planet will reveal a level II anomaly. Investigating it will give the planet a deposit of 5 Society. If the empire is not a Machine Intelligence it will also grant a moderate amount of Society research and start a special project to build a research station over the planet. 6 months later you will get three options:
- Allow the scientist Leader to leave. One year later it will bring a large reward of Physics and Society research as well as a random psionic technology.
- Disallow the scientist Leader to leave. 3 months later the Leader will send a message and die 10 days afterwards.
- Remove the scientist Leader, ending the event chain.
Caretaker Escape Pod: This binary star system has as its last planet a Gas Giant with escape pods in orbit. Surveying the planet will reveal a level III anomaly. Investigating it will bring the option to either ignore the pod for a small amount of Influence or hail it and get the following options:
- Valid if AI is not outlawed: Accept Caretaker AX7-b as a leader, gaining a level 4 governor Leader.
- Valid if AI is not outlawed: Examine Caretaker AX7-b for a moderate amount of Engineering research.
- Valid if AI is outlawed: Destroy the pod for a small amount of Influence.
- Valid if Machine Intelligence: Recycle Caretaker AX7-b for a small amount of Minerals and Engineering research.
Habitable Worlds Survey
Accepting the event will issue a special project that requires surveying any 8 habitable planets. The task is completed especially quickly on games with a higher percentage of habitable worlds set up. Completing the event will grant up to 500 Energy and Society research. Refusing the event will grant 20 Influence instead.
If the Habitable Worlds Survey special project has been completed a few years later the Alien Specimen Procurement event will start. Accepting it will issue a special project to collect specimens with a Science Ship on all 8 surveyed planets. Each time a specimen is collected it will grant a small amount of Society research. Completing the event will grant a moderate reward of Energy, Society research, Influence and Unity.