Asteroid Impact

Lore & Background

In the world of Oxygen Not Included, the colony is built on or within a rocky body orbiting a distant star, surrounded by a field of smaller fragments and debris. The game's narrative makes clear that this is not a settled, peaceful frontier; the environment is indifferent and the sky is a source of constant, low-level danger. An asteroid impact event crystallizes that danger into a single, catastrophic moment.

When the impact occurs, the visual and audio design shifts dramatically: a bright streak crosses the viewport, the ground shakes, and structures within the blast radius crumble or crack. Dust clouds fill the affected area, and colonists may be thrown or injured. The event is deliberately loud and disorienting, contrasting with the otherwise methodical, grid-based planning that defines most of the gameplay.

For the crew, the impact is a reminder of why they carry repair tools, why they stockpile materials, and why the mission briefing warned them that the frontier does not negotiate. It is the universe saying, in one blunt sentence, that you are still small and the rocks are still falling.

In Their Own Story

Nancy was mid-sip of her recycled coffee when the warning klaxon tore through the habitat. The screen she'd been monitoring—oxygen levels, CO₂ scrubbers, the usual—flickered and went dark. Through the reinforced window she could see it: a tumbling chunk of grey rock, maybe the size of a shipping container, catching the pale starlight as it tumbled end over end toward the eastern wall.

"Everyone down!" she shouted, already sprinting for the inner corridor. The impact hit two seconds later. The whole base groaned like a living thing. Dust poured through the ceiling tiles. Somewhere downstream, a pipe burst and the hiss of escaping gas filled the air. She pressed her palm against the wall, feeling the vibrations die out, and listened. Silence. Then, faintly, a cough from behind the supply rack. She exhaled. They were still here. The base was still here. Mostly.

She pulled her tablet from her belt. The structural integrity readout was a mess of red. She started marking repair priorities with a quick, steady hand. The coffee was gone. The day was gone. But the colony would hold. It always held. Barely, but it held.

Reader's Guide

The Asteroid Impact event triggers randomly during active gameplay, typically after the colony has been running for a period of time. There is no player input required to initiate it; it simply occurs.

Upon impact, a visible meteor streaks across the screen and strikes a point on the colony's terrain. Structures within the blast radius take damage or are destroyed outright. Terrain in the immediate area may be displaced or cracked. Dust particles fill the affected zone, temporarily reducing visibility and potentially clogging ventilation if the area is enclosed.

Colonists in the blast radius may take injury and be temporarily incapacitated. Those outside the radius will react with alarm and may need to be redirected to safety.

The player's response is to assess the damage: repair or replace broken structures, clear displaced terrain, ensure life-support systems (oxygen generation, CO₂ scrubbing, power) are still functional, and treat any injured colonists. If critical systems are destroyed, the player must improvise or rebuild before the colony's atmosphere becomes untenable.

There is no explicit "win" or "lose" condition tied to the event itself. The colony either recovers or, if the damage cascades into a full atmospheric failure, the run ends. The event is a stress test, not a binary challenge.

Did You Know?

• Oxygen Not Included's event system is designed to interrupt the player's routine, forcing a shift from long-term planning to immediate triage and repair.
• The game's grid-based terrain means that even a single impact can cascade: a destroyed wall can let in vacuum or toxic gas, turning a localized hit into a colony-wide emergency.
• Colonists in ONI have individual stress and health stats, so the psychological shock of an impact event can compound the physical damage, affecting their work efficiency for a period afterward.
• The game encourages players to build redundancy—multiple oxygen sources, backup power, and structural depth—precisely because events like Asteroid Impact make single points of failure fatal.