Making a space RPG feel authentically lived-in requires more than just slapping zero-G animations onto character models. Owlcat Games understands this, which is why they brought in former NASA astronaut Leroy Chiao to consult on The Expanse: Osiris Reborn. The developer diary released November 19, 2025, showcases new gameplay footage while Chiao explains how his personal spaceflight experience shaped everything from spacewalk mechanics to how firearms would behave in vacuum. Set in The Expanse universe created by James S.A. Corey, this third-person action RPG puts players in command of a Pinkwater Security mercenary trapped in a conspiracy on asteroid Eros, launching later for PlayStation 5, Xbox Series X and S, and PC with a beta test coming soon for founder pack purchasers.
Why Hire a Real Astronaut
Leroy Chiao spent 230 days in space across four missions between 1994 and 2005, including commanding Expedition 10 to the International Space Station. His experience provides invaluable perspective that no amount of research alone can replicate. According to the dev diary, Owlcat wanted to portray life in space in a way that would feel right to anyone familiar with actual spaceflight while remaining accessible and fun for players.
The challenge involves striking balance between realism grounded in science fiction and avoiding tedious simulation. Chiao explained that his role centered on sharing the scientific aspects of living and working in space alongside his personal emotional experience. Then Owlcat’s team took that knowledge and translated it into reactive gameplay that maintains authenticity without becoming clumsy or frustrating.
One specific example discussed involves spacewalking. During real EVA operations, astronauts use safety tethers attached to the spacecraft to prevent drifting away. In a video game, constantly managing tethers would create awkward movement and break immersion. Owlcat’s creative solution implements mag boots that allow characters to walk on hull surfaces while maintaining the fundamental fear of becoming detached and drifting into the void.
Chiao validated this compromise as realistic within The Expanse’s established technology while preserving the emotional core of spacewalking, that primal terror of separation from your ship. This philosophy extends throughout the game’s systems, finding creative ways to honor reality without sacrificing playability.
Space Combat and Physics
The dev diary revealed that even firearms behave differently in Osiris Reborn’s space environments. Chiao noted that weapons would produce different results in vacuum versus pressurized habitats. Newton’s third law becomes dramatically relevant when firing high-caliber weapons in zero-G, as the recoil could send you spinning uncontrollably without proper bracing or mag boot attachment.
The gameplay footage showcased third-person cover-based shooting that accounts for these physics considerations. Characters brace themselves before firing, use cover not just for protection from enemy fire but also for stability during engagement, and demonstrate weight and momentum when moving between positions. The combat feels grounded in a way most sci-fi shooters ignore.
Sound design also reflects space’s unique acoustic properties. In vacuum sections, weapon fire produces muffled sounds transmitted through your suit and helmet rather than the atmospheric crack of gunfire. Inside pressurized areas, acoustics change based on environment size and composition. These details create immersion through authenticity rather than Hollywood-style space explosions that scientifically make no sense.
The Story and Setting
The Expanse: Osiris Reborn takes place within the universe created by Daniel Abraham and Ty Franck writing as James S.A. Corey, known through both the bestselling novel series and acclaimed Amazon Prime television adaptation. The game’s timeline positions it during the books’ continuity, allowing familiar locations and factions while telling an original story that doesn’t require players to have read every novel or watched every episode.
You play as a Pinkwater Security mercenary taking shore leave on Eros, a massive asteroid converted into a rotating habitat providing artificial gravity through spin. What should be a brief rest spirals into catastrophe when the station enters lockdown and you find yourself trapped in a conspiracy affecting the entire solar system. Survival requires adapting quickly while taking command of the most advanced ship available.
The plot structure follows Owlcat’s RPG pedigree from Pathfinder: Wrath of the Righteous and Rogue Trader, where player choices meaningfully impact narrative direction and character relationships. Your background as Earther, Martian, or Belter affects how NPCs respond and which faction allegiances feel natural versus requiring significant roleplay justification.
Iconic Expanse locations appear including Ganymede, Ceres, Mars, and Luna. You’ll explore ruined habitats alongside political strongholds, talk to locals caught in the system’s fragile power balance, and potentially encounter familiar faces from the books or show. The solar system looks different from every planet and asteroid, with some locations visibly falling apart while others hide their decay behind polished facades.
Squad-Based Combat System
Combat follows third-person action RPG conventions with cover mechanics and special abilities. Two companions accompany you into field missions while other crew members provide remote support by hacking systems, creating distractions, or manipulating environmental elements. You issue real-time commands to squadmates, requiring tactical thinking beyond simply shooting everything that moves.
Your crew consists of specialists with distinct skills, personalities, and personal agendas. Relationships flourish or deteriorate based on your decisions and leadership style. Some chase redemption for past failures. Others hide dangerous secrets. The ship becomes your home where trust must be earned through consistent actions rather than given freely.
The companion system draws obvious comparisons to Mass Effect, which Owlcat acknowledged as inspiration alongside The Expanse’s source material. Building genuine relationships with crew members creates emotional investment beyond stat optimization, making you care whether they live, die, or betray you when loyalties conflict.
Character Creation and Customization
Character creation lets you customize your captain’s appearance, background, and origin as Earther, Martian, or Belter. Each origin provides different starting perspectives on the solar system’s political tensions. Earthers represent established power and bureaucratic authority. Martians embody disciplined military culture and terraforming ambitions. Belters know exploitation and scarcity, fighting for basic dignity in harsh conditions.
These aren’t merely cosmetic choices. Your origin affects dialogue options, how factions perceive you, and which solutions feel authentic to your character’s worldview. An Earther might leverage UN connections where a Belter would rely on OPA relationships, creating distinct playthrough experiences beyond simple stat differences.
The dev diary didn’t detail progression systems or skill trees, but Owlcat’s RPG background suggests robust character building with meaningful specialization choices. Expect the studio’s signature depth where builds drastically alter playstyle rather than offering minor numerical variations.
Owlcat’s RPG Pedigree
Owlcat Games earned their reputation through Pathfinder: Kingmaker and Pathfinder: Wrath of the Righteous, complex isometric CRPGs praised for faithful tabletop adaptation, deep systems, and reactivity to player choices. Their recent Warhammer 40,000: Rogue Trader continued this tradition in the grimdark future, proving they could handle licensed sci-fi properties with respect for source material.
The Expanse represents their first third-person action RPG rather than isometric CRPG. This shift in perspective and combat systems demonstrates willingness to evolve beyond their established formula. Hiring Leroy Chiao and conducting extensive space research shows commitment to authenticity matching their dedication to Pathfinder and Warhammer lore accuracy.
Fans hope Owlcat brings the same narrative complexity and meaningful choice consequences that defined their previous work. The Expanse’s morally gray universe where every faction has legitimate grievances and flawed solutions suits Owlcat’s strength in creating difficult decisions without obvious right answers.
Beta Access and Founder Packs
The dev diary teased that upcoming beta access will showcase the results of NASA consultation and research. Players who purchased Miller’s Pack or Collector’s Edition founder packages gain early access to this beta, allowing them to experience space mechanics firsthand before general release.
Founder packs follow Owlcat’s standard approach of offering tiered pre-purchase options with escalating rewards. These typically include beta access, digital artbooks, soundtracks, in-game cosmetics, and other exclusive items. Specific pricing and exact contents for Osiris Reborn’s founder tiers haven’t been publicly detailed in the dev diary.
The beta serves dual purposes: rewarding early supporters with exclusive access while gathering valuable feedback to polish systems before launch. Owlcat historically uses beta periods to identify balance issues, technical problems, and gameplay friction that internal testing might miss.
Release Window and Platforms
The Expanse: Osiris Reborn targets PlayStation 5, Xbox Series X and S, and PC via Steam and Epic Games Store. No release date has been announced, though the existence of playable beta builds suggests development has progressed beyond early prototyping. Given typical beta-to-release timelines, sometime in 2026 seems plausible though purely speculative.
The game won’t release on previous generation consoles, allowing Owlcat to leverage current hardware capabilities without compromising for seven-year-old systems. This decision makes sense for a space RPG requiring detailed environments, complex physics simulations, and potentially large-scale space battles.
Frequently Asked Questions
When does The Expanse Osiris Reborn release?
No release date has been announced yet. The game is coming to PlayStation 5, Xbox Series X/S, and PC, with beta access available for certain founder pack purchasers.
Who is developing The Expanse Osiris Reborn?
Owlcat Games, the studio behind Pathfinder: Kingmaker, Pathfinder: Wrath of the Righteous, and Warhammer 40,000: Rogue Trader, is developing the game.
Did a real astronaut work on the game?
Yes, former NASA astronaut Leroy Chiao consulted on The Expanse: Osiris Reborn, sharing his spaceflight experience to inform realistic zero-gravity mechanics, spacewalking, and space combat.
What type of game is Osiris Reborn?
It’s a third-person action RPG with cover-based shooting, squad mechanics, and deep narrative choices. Think Mass Effect meets The Expanse universe.
Is this connected to Telltale’s Expanse game?
No, The Expanse: Osiris Reborn by Owlcat Games is separate from The Expanse: A Telltale Series developed by Telltale Games and Deck Nine. They’re different games set in the same universe.
Do I need to know The Expanse books or show?
While familiarity helps with lore appreciation, the game tells an original story designed to be accessible to newcomers while respecting established canon for fans.
What platforms is it coming to?
The Expanse: Osiris Reborn launches on PlayStation 5, Xbox Series X, Xbox Series S, and PC via Steam and Epic Games Store. It will not release on PlayStation 4, Xbox One, or Nintendo platforms.
Conclusion
The decision to consult actual astronauts and conduct extensive research into spaceflight realities demonstrates Owlcat’s commitment to authenticity that defined their previous RPG adaptations. Whether that dedication translates into compelling third-person action alongside their signature narrative depth won’t be clear until players experience the beta and eventual full release. For fans of The Expanse hungry for interactive stories in that universe, or Mass Effect devotees waiting for spiritual successors, Osiris Reborn represents one of the most promising sci-fi RPGs on the horizon. Just remember to check your mag boots before stepping outside the airlock.