The Modification Station is the base crafting facility for Tadpole upgrade modules in Subnautica 2, and unlocking it requires a dangerous trip to the Alien Ruins. Finding the blueprint requires a long push east toward the Alien Ruins, and building the station demands Celestine, a resource that only spawns in that same dangerous biome.
This guide covers how to unlock the Modification Station blueprint, where to farm Celestine, how to build the station, and every upgrade it currently offers.
Subnautica 2 entered Early Access on May 14, 2026. Module recipes, blueprint locations, and crafting requirements may change in future updates. All data in this guide reflects the Early Access launch build.
1. What the Modification Station Does
Modification Station
The Modification Station is a base facility that operates entirely outside the standard Fabricator workflow.
Players who hit the Tadpole’s crush depth limit or try to craft advanced vehicle modules quickly realize the Fabricator offers nothing for upgrades. The Modification Station fills that gap, serving as one of the most important crafting points from the mid-game onward.
Once placed inside a Seabase, the station unlocks every Tadpole upgrade module in the game and both current prototype tool modifications. Its upgrade catalog covers:
- Depth Modules: Raise the Tadpole’s safe diving limit from 250 meters to 450 meters.
- Engine Efficiency: Extend battery life significantly on long expeditions.
- Strike Armor and Cavitation Muffler: Increase your survivability and stealth in hostile zones.
- Photovoltaic Charger: Provide passive power recovery in shallow water.
- Bioscanner and Feedback Resonator: Unlock Biomod scanning, break shielded Cankers, and stun wildlife.
Building the station requires two common materials and one progression-gated resource. That resource, Celestine, only spawns near the Alien Ruins biome, naturally placing the station behind a mid-game exploration wall.
2. How to Unlock the Blueprint
You will not have the Modification Station blueprint by default. You must find and scan a Modification Station inside one of the abandoned structures in the eastern part of the map.
There are two potential scan locations. The Alien Ruins Research Outpost is the earliest accessible scan point, encountered during normal story progression roughly 1,300 to 1,400 meters east of the Lifepod.
A second scannable station is found inside the Cicada Wreck (EVA Prep), near the Karakorum Power Plant, during the Iso blackbox objective. One scan at either location is enough to unlock the blueprint.
2.1. What to Bring Before You Go
The Tadpole
The Alien Ruins biome sits over 1,300 meters from the Lifepod and is one of the most hazardous zones in the current build. Making the trip without the right tools risks losing progress and materials. Prepare the following before setting out:
- Scanner: Required to scan the station and unlock the blueprint. Nothing works without it.
- Sonic Resonator: Needed to harvest Celestine nodes on the way back. Celestine cannot be broken by any other tool.
- Tadpole or Extended Oxygen Support: The trip is 1,300 to 1,400 meters one way. Swimming the full distance without a vehicle is extremely risky.
- Repair Tool: The Tadpole takes damage from creature strikes and wall collisions near the alien biome. Carry one at all times.
- Habitat Builder: You do not need this for the Alien Ruins trip, but have it ready at your Seabase so you can place the Modification Station as soon as you return with the materials.
- Inventory Space: Leave room for at least 5x Celestine (two for the station itself and three for the Depth Module Mk. 1). Collecting both in one trip eliminates a return run.
2.2. How to Reach the Alien Ruins Research Outpost
Before leaving, enable landmark signals in the character menu so the Alien Ruins waypoint appears on your HUD. Bring enough oxygen support for the trip if you do not yet have a Tadpole.
- Navigate East: Exit the Lifepod and head east using your compass.
- Travel Distance: Swim approximately 1,300 to 1,400 meters in a straight line.
- Spot the Landmark: Look for a tall tower structure to act as a navigation anchor; the Research Outpost sits nearby.
- Enter the Outpost: Locate the broken Modification Station inside the main room.
- Scan the Station: Equip the Scanner and scan the station once to unlock the blueprint.
3. Where to Find Celestine
Celestine is the bottleneck material for the Modification Station. It does not appear in the early biomes near the Lifepod and is found exclusively in the Alien Ruins biome.
Three confirmed farming zones exist: the region surrounding the Karakorum Power Plant, the area near the Alien Observatory, and the cliffs around the Karakorum Metal Farm.
Celestine appears as blue-silver jagged crystal clusters attached to rock walls, cliff edges, and deeper seabed formations. It requires a Sonic Resonator to harvest, as standard tools cannot break the nodes.
Given that both the Modification Station and the Depth Module Mk. 1 together require 5x Celestine, plan to collect at least that much in a single trip to avoid an unnecessary second run.
3.1. Best Celestine Farming Spots
The most reliable location is approximately 200 meters southeast of the Alien Ruins research base, down the cliffside. Nodes cluster here at around 250 meters deep.
A safer alternative lies 290 meters south of the Alien Ruins waypoint, at a depth of 250 meters. This spot keeps you away from denser Needler patrols and yields Creature Enamel, which you will need for the Depth Module recipe.
Setting up a small secondary base with a Scanner Station in the alien biome makes repeat farming much faster. The Scanner Station tags every Celestine node within 300 meters, removing the guesswork.
3.2. How to Farm Celestine Safely
Celestine Crystal Cluster
The alien biome is highly hostile. Two Needlers actively patrol the main farming cliff, and the Collector Leviathan controls the stretch of ocean between the hot biome and the eastern zone.
- Vehicle Prep: Bring a fully charged Tadpole with a Repair Tool accessible.
- Required Tool: Equip the Sonic Resonator before diving; Celestine cannot be harvested without it.
- Depth Management: Park the Tadpole at 225 to 245 meters and swim the remaining depth manually.
- Evade Threats: Move quickly near Needler nests and stay close to rock cover to limit the duration of aggression windows.
- Farm Efficiently: Gather at least 5x Celestine to cover the station and your first Depth Module.
- Processing: Celestine can also be processed into Strontium at the Processor, which is needed for Strike Armor, Cavitation Muffler, and the Feedback Resonator.
4. How to Build the Modification Station
Modification Station Recipe
The Modification Station is an Interior Facility, meaning it must be placed inside a Seabase room using the Habitat Builder. A working Seabase with at least one room is a prerequisite.
To build the Modification Station, you need:
- 2x Titanium
- 2x Celestine
- 2x Copper
Titanium and Copper are readily available in the starting biome, so Celestine is the only material requiring a dedicated trip. Once all three are in your inventory, equip the Habitat Builder, select the station from the interior facilities list, and place it against a wall.
Place the station near your storage lockers and Processor. Tadpole upgrades often require multiple refined materials, and keeping your crafting stations close together saves significant time on every upgrade run.
5. All Upgrades Available at the Modification Station
Engine Efficiency Upgrade
The Modification Station is the exclusive crafting point for all Tadpole upgrade modules and prototype tool modifications. Nothing from this station can be crafted at the base Fabricator.
The Modification Station handles upgrade modules that slot into the Tadpole’s four module slots. It does not cover Tadpole chassis variants such as the Scout Ray or Haul. Those are structural attachments built at the Vehicle Fabricator and operate as a separate upgrade category.
Each upgrade requires a field scan or Recipe Data Card pickup before it appears in the Modification Station menu.
5.1. Tadpole Upgrade Modules
Every module here is installed into the Tadpole’s upgrade slots. The Tadpole has four upgrade slots, and modules can be swapped freely between dives.
| Module | Module Effects | Blueprint Location |
|---|---|---|
| Depth Module Mk. 1 | Raises crush depth from 250m to 450m. Does not stack. | Needler Nest cave, bearing 165 from the Alien Base NOA Terminal |
| Depth Module Mk. 2 | Raises the crush depth from 450m to 800m. Does not stack. Currently available only in Creative Mode, not Survival Mode. | N/A (not accessible in Survival Mode) |
| Engine Efficiency | Reduces power draw by 20% per module. Stacks can be applied up to 4 times, resulting in a maximum reduction of 80%. | Alien Ruins Research Outpost |
| Photovoltaic Charger | Recharges the battery passively in shallow water during the day. | Cicada Wreck (EVA Prep) |
| Strike Armor | Increases physical resistance to attacks and collision damage. | Platform north of the Rosetta Stone |
| Cavitation Muffler | Reduces engine noise to avoid attracting hostile creatures. Does not stack. | Metal Farms area |
5.2. Key Crafting Recipes for Tadpole Modules
System Chip
Once a blueprint is unlocked, gather these materials to craft the module:
- Depth Module Mk. 1: 3x Celestine, 2x Enameled Glass, 1x System Chip
- Depth Module Mk. 2: 2x Dedicated Core, 2x Troilite, 2x Mangalloy Ingot (Creative Mode only)
- Engine Efficiency: 1x Titanium Ingot, 2x Glass, 1x System Chip
- Photovoltaic Charger: 1x Copper Ingot, 1x Strong Acid, 1x Troilite
- Strike Armor: 2x Enameled Glass, 2x Strontium
- Cavitation Muffler: 3x Titanium, 2x Strontium
Note that Strontium is not found in its raw form in the world. It must be processed from Celestine at the Processor. Two Celestine units yield one Strontium unit.
5.3. Best Upgrades to Craft First
Tadpole Depth Module Mk. I
With the station built and blueprints in hand, prioritize these upgrades first based on immediate progression payoff:
- Depth Module Mk. 1: The single most impactful upgrade on this list. It raises the Tadpole’s crush depth from 250 meters to 450 meters and directly unlocks every biome route the story pushes players toward. Build this first without exception.
- Engine Efficiency: The best quality-of-life upgrade for long trips. Running two copies reduces power draw by 40%, effectively doubling the usable range per Power Cell charge.
- Cavitation Muffler: Most valuable in hostile zones. Fit this before Strike Armor if your exploration routes regularly pass through the Metal Farms or deeper alien areas.
- Photovoltaic Charger: Best suited for surface transit and shallow daytime runs. Lower priority for deep-dive builds but strong for open-water travel between distant base locations.
- Strike Armor: Useful in creature-dense zones, but only worth slotting once the Depth Module and Engine Efficiency are already installed.
5.4. Tool Upgrades
The Modification Station also handles two prototype tool modifications. Both are mid-to-late game crafts that require Conduit Crystals from the Karakorum Power Plant area.
- Bioscanner: An upgraded Scanner that lets you scan flora and fauna to unlock Biomods at the Biolab. Find the blueprint inside the Cicada Wreck (EVA Prep). Recipe requires 1x Scanner, 2x Enameled Glass, 3x Conduit Crystal.
- Feedback Resonator: Fires a projectile wave of sound to break shielded Cankers and stun wildlife. Scan fragments at the Cicada Wreck (Therapy Room) and Metal Farms area. Recipe requires 1x Sonic Resonator, 2x Enameled Glass, 2x Conduit Crystal, 2x Strontium.
6. How to Install Tadpole Upgrade Modules
Installing modules is quick once they are crafted. The Tadpole’s upgrade compartment is separate from standard storage and is accessible directly from outside the vehicle.
- Locate the Panel: Swim to the Tadpole and position yourself above it.
- Find the Compartment: Look for the upgrade compartment on top of the vehicle, just above the Power Cell hatch.
- Open the Bay: Interact with it to open the module bay panel.
- Install Upgrades: Drag crafted modules from your inventory into the available upgrade slots.
- Confirm: Close the panel, and the upgrade takes effect immediately.
Keep these stacking rules in mind when planning your module loadout:
- Slot Limits: Only four slots are available per Tadpole.
- Depth Limits: Depth modules do not stack. Installing two Depth Module Mk. 1s provides no extra benefit.
- Power Stacking: Engine Efficiency stacks up to four times, providing an 80% reduction in power draw.
- Stealth Limits: Cavitation Muffler does not stack; a second copy has no additional effect.
