Revision 3

Overview

Eros Station is the asteroid station where the story of The Expanse: Osiris Reborn begins. The player character is on shore leave from their duties with Pinkwater Security when the station goes into a deadly lockdown, trapping the population inside and triggering a chain of events that launches the entire game. Escaping Eros alive is the first challenge the player faces, and the trauma of what happens there sets the tone for everything that follows.

Physical Description

Eros is based on the real near-Earth asteroid 433 Eros, an S-type asteroid approximately 34.4 by 11.2 by 11.2 kilometers in size. In The Expanse universe, Eros was hollowed out and converted into one of the oldest and most established stations in the Asteroid Belt. Its orbit crosses that of Mars, classifying it as a Mars-crosser rather than a true Belt object.

The station's docks are arranged in five main clusters around the asteroid, with old shipyards extending outward as great spiderwebs of steel and carbon mesh studded with warning lights and sensor arrays. Eros remained a center of ship manufacture and repair even as commerce shifted to Ceres Station. Lower docking fees kept traffic flowing, and the station found other ways to generate revenue, most notably through casinos and entertainment. For ship crews looking for a place to relax and stretch their legs between runs, Eros was a popular port of call.

Population and Culture

At the time of the protomolecule incident, Eros supported a population of approximately 1.5 million permanent residents. The station had a diverse mix of Belters, Earthers, and Martians passing through its docks and entertainment districts. Like most Belt stations, the population was predominantly Belter, but the casinos and docking facilities drew visitors from across the solar system.

Security

Station security on Eros was originally handled by Protogen under a private contract. In the lead-up to the protomolecule experiment, Protogen quietly withdrew its security forces and replaced them with Carne Por la Machina, a front organization Protogen created specifically to facilitate the infection plan. Carne Por la Machina's role was to manage the population during the lockdown, directing residents into contamination cells disguised as fallout shelters.

The Eros Incident

The Eros incident is the defining event that kicks off the game's story. Protogen deliberately released the protomolecule onto the station's population as a controlled experiment. The operation began when a ship was destroyed in the station's docks. Eros went into full lockdown, and the population was moved to what they were told were fallout shelters. In reality, these were contamination cells flooded with radiation and the protomolecule. The entire population was infected within hours.

With 1.5 million hosts, the protomolecule achieved something it could not do with smaller samples: it developed a hive intelligence. The infected population merged into a networked consciousness that integrated with the station's computer systems. The protomolecule life-form on Eros achieved sentience and gained control over the station's spin reactors, using them to maneuver the station through space.

The station, now effectively a living organism, began moving toward Earth. Detective Joe Miller discovered that the infected mind of Julie Mao was at the center of the intelligence, and he convinced the Julie-protomolecule entity to divert Eros away from Earth and crash-land on Venus instead. This saved billions of lives. On Venus, the protomolecule continued to grow and develop, eventually constructing the Sol Ring.

The Player's Escape

The player character is on Eros during shore leave when the lockdown hits. Accompanied by their identical twin sibling J and their engineer Zafar, the player fights to escape the station as chaos erupts around them. The rest of the player's Pinkwater Security team is killed during the escape attempt. Only the player and J survive.

During the escape, the survivors commandeer a Protogen vessel docked at Eros. This stolen ship becomes central to the game's story. The player brings it back to Pinkwater Station, where its Protogen origins and advanced technology draw attention from multiple factions. The ship is eventually identified as one of the most advanced vessels in the solar system, and the player takes command of it as the Gemini.

Eros in the Game Timeline

The Eros escape serves as the game's opening sequence and prologue. After escaping, the player returns to Pinkwater Station to report what happened to their chief. The first playable mission shown to press at Gamescom 2025 was actually the second mission of the game, set on Pinkwater Station during a Protogen attack. Eros itself is experienced in the game's earliest moments, establishing the stakes and the threat that the protomolecule represents.

Key Facts

The Eros Incident as Inciting Event

In the closed beta build, the fall of Eros is the event the whole game hinges on. The first playable mission opens in the immediate aftermath of the incident, and every character the player meets in the opening hours is reacting to what happened on the station. The beta does not stage the incident itself as a tutorial; instead it puts the player on the other side of it, aboard a ship fleeing the chaos, arriving at another Pinkwater outpost with a story to tell and a pursuer closing in behind them. That framing turns Eros from a piece of background lore into the load-bearing pillar of the opening act.

The player character and their twin, J, are Pinkwater Security mercenaries who narrowly escaped Eros with their lives. Most of their unit was lost. Their ship was destroyed. The twins rode a ship they took from the attacking forces out of the station's death throes, and that ship is the one that carries them to Pinkwater Four Station as the beta begins. Before the player has even finished parking at the dock, the station's director is already demanding to know where the old Pinkwater ship is and what exactly this unfamiliar craft is doing in his stable.

What Happened, In The Game's Own Framing

The in-game account of the incident is told in fragments, through environmental VO, crew dialogue, and the debrief that the twins give their director. The mercenary corporation Protogen deliberately released the alien Protomolecule on Eros, wiping out and then reanimating the station's population. Pinkwater Security had personnel in theater at the time, including the crew of a Pinkwater ship called the Piranha, which was destroyed during the attack. Most of the Piranha's crew did not make it out. The twins are among the very few survivors of that engagement, and they carry the debrief for their chain of command back to Pinkwater Four as one of their first duties.

Not every detail of the incident is verbalized in the beta's mission window. Some comes through NPC chatter on the station, where residents trade rumors about what really happened and argue about how much of the public record can be trusted. Some comes through news broadcasts playing on large screens in the station's public spaces. Taken together, they paint the Eros incident as something that has already rewritten the political map of the Belt before the player has fired their first shot in the game, and the pre-incident status quo is not coming back.

A New Perspective on a Familiar Event

For fans of the Expanse universe, the Eros incident is familiar ground. The show and novels follow James Holden and his crew through the same event from their angle, and the beta leans into that connection rather than away from it. NPCs on Pinkwater Four mention Holden and his crew directly. News broadcasts reference the very same figures and events the show drew on. One resident complains that he will not believe the survivors are really alive until he sees another video from Holden. The game is not retelling that story; it is running alongside it, from a new ground-level angle, and using the overlap to anchor the player in a world that is already in motion.

The player's vantage is different. They are not a ship captain or a journalist or a UN operative. They are a Pinkwater mercenary, one of a pair of twins whose unit was caught in the chaos on the station and barely made it off. The beta consistently puts the Eros incident into that smaller human frame. It is not the end of the cold war between Earth and Mars in this account; it is the day the twins lost their ship, their crewmates, and any illusion that Pinkwater's contract work was going to be business as usual.

The Stolen Ship and the Escape

The twins' route off Eros runs through an enemy hull. Rather than flee aboard their own vessel (which was already gone by the time they broke for the docks), they seize a ship from the Protogen-aligned forces that had descended on the station, and they fly out on that. In later dialogue aboard Pinkwater Four Station, that ship is referred to as their ticket off the station. Its origin is not hidden from the other characters; the twins openly describe it as taken from the attackers. The director of Pinkwater Four reacts to the unfamiliar craft in his docking bay with barely concealed suspicion, because it looks nothing like a Pinkwater vessel and everything like a liability.

That ship becomes the Gemini, the player's mobile base for the rest of the game. It carries the shared call sign of the twin crew at its core, and it is the vessel the player returns to between missions. The Eros incident is therefore not just the inciting loss of the Piranha and the twins' old unit; it is also the moment the player acquires the ship that will define the rest of the campaign. The story treats those two halves as inseparable. The only reason the player has the Gemini is that the Piranha did not come back, and the only reason the Piranha did not come back is that Protogen chose Eros as the site of their controlled experiment.

Why Protogen Pursues the Player

The twins did not simply run away from Eros. They took something with them when they went. The vessel they seized is Protogen property, and whatever data and hardware were aboard it are now aboard the Gemini. That changes Protogen's calculus. The corporation's forces now have a concrete reason to pursue the twins personally, rather than simply writing off two more mercenary survivors. They want the ship back. They want whatever it carries back. They want to know who the twins saw and what they are about to tell their chain of command. Those three motives converge on a single destination: Pinkwater Four Station.

That pursuit sets up the central choice of the closed beta's main mission. Protogen catches up to the twins at Pinkwater Four, and the player has to decide whether to convince Oscar O'Connell, the station's director, to resist or to stand down. Both branches trace their pressure back to Eros. If Pinkwater resists, they do so because the twins' eyewitness account of what Protogen did on Eros makes standing aside unconscionable. If Pinkwater stands down, they do so because the twins' account of what Protogen is willing to do tells them exactly how ugly a fight with that corporation will get. Those consequences are detailed further in choices and consequences.

Ambient References Across The Game

Even though the beta build does not return to Eros as a visitable location, the incident threads through the environmental storytelling on Pinkwater Four. News broadcasts playing on large public screens cover the fall of the station and the aftermath. Pinkwater crewmates, technicians, and visiting station residents discuss what they believe happened, and their takes disagree in ways that sound exactly like the rumor traffic the show and novels built out around Eros. Some believe the official story, some believe Protogen was involved, some believe it was an act of war by another faction, and some just want to stop talking about it. Each piece of ambient chatter reinforces the idea that the Eros incident is something that the rest of the solar system is still trying to process.

Conversations the player overhears also reference figures and events pulled straight from the wider Expanse timeline, including direct mentions of James Holden. The game uses those mentions as seasoning rather than as plot points. They are there to tell the player which slice of the timeline they are playing in, and to remind them that what happens in the Expanse universe does not revolve solely around the player's crew. The rest of the system is dealing with Eros too, just off screen.

Eros in the Expanse Universe

For readers of the novels and viewers of the show, Eros's significance predates the incident itself. In the wider Expanse setting, Eros is one of the older stations in the Asteroid Belt. It was hollowed out of its parent asteroid and converted into a population and commerce hub, and its administration and security arrangements shifted between Belt authorities and Ceres Station's sphere of influence over the course of its history. It sits in the broader network of human destinations across the solar system that Osiris Reborn's full campaign intends to visit, alongside Ganymede, Mars, Luna, Io, and the asteroid-belt bunker complexes the developers have named as future destinations.

Within the scope of Osiris Reborn, Eros is treated as the dividing moment. There is the pre-incident status quo, in which Pinkwater's contracts run business as usual and Protogen is just one more well-connected corporation among many. Then there is the Eros incident itself. Then there is everything that follows, which is the game the player is actually playing. Other factions in the setting all have to reposition themselves around the same event, and the closed beta's mission structure reflects that. The twins arrive at Pinkwater Four in a post-Eros solar system, and every NPC they speak to is adjusting to that reality.

Eros and the Closed Beta Build

It is worth being clear about what the closed beta does and does not show of Eros directly. The beta does not let the player walk the docks of Eros, fight in its corridors, or witness the incident in first-person play. The playable window begins after the escape is complete. That means Eros is present in the build primarily as:

• backdrop to the opening dialogue, where the twins describe what they just lived through to their director and to Zafar in passing

• debrief material that the player explicitly speaks aloud when pressed about where the Piranha is and what exactly the new ship in the docking bay is

• ambient environmental storytelling across Pinkwater Four, including news broadcasts, overheard NPC conversation, and Pinkwater crewmates trading takes on what really happened

• motivation for Protogen's pursuit, which shapes the entire Pinkwater Four encounter and bleeds into the airlock sequences outside the station

• thematic framing for the beta's spacewalk and zero-G combat sections, where the player is already leveraging skills they can only have because they just escaped a station turning against them

Eros itself is therefore not a recurring hub in the closed beta. The station where the twins actually walk, shop, talk, fight, and make choices is Pinkwater Four. The Eros incident is the reason the player is there in the first place, the reason they arrived in a Protogen-made ship, and the reason a Protogen strike force will come knocking before the mission is out. For the purposes of the beta, that role as inciting event is the station's primary function.

Narrative Role Within The Larger Story

Looked at from the level of the larger story and setting, Eros establishes three things the rest of the campaign is built on. First, it establishes Protogen as a corporation willing to experiment on a population of more than a million people. That informs every later interaction with Protogen and every later rumor about what else the corporation might be doing in quieter corners of the system. Second, it establishes the twins as survivors who owe their ship and their mission to a catastrophe they did not cause, which gives the player their stake in events beyond simple Pinkwater contract work. Third, it establishes the Protomolecule as something real, active, and present in the setting, which primes the player for every later encounter with its consequences.

The beta therefore treats Eros with the weight the source material gives it, while building the game's own load-bearing narrative on top of that weight. Fans who already know the Eros incident from outside Osiris Reborn will find it leveraged exactly the way the game wants, as a recognizable hinge that the new story pivots around. Players coming in cold will still feel its gravity through the mission design, the NPC dialogue, and the very concrete fact that the ship the player ends the tutorial aboard is a ship they fled Eros on, not one Pinkwater ever assigned them.