Space Biome

The Space Biome is the exposed outer layer found above the surface of an asteroid. Its upper region is a vacuum, and the lower region is made up of empty space tiles that can be opened to the vacuum when exposed. This biome is not a normal source of food, water, or living space; instead, it serves as the planet’s boundary and the place where solar power, telescopes, and rocket access become relevant.

The biome contains no metal ore, raw mineral, other solids, liquids, gases, plants, or critters in its base form. Surface Crags is the variant with less mass, and meteor showers periodically add more Regolith tiles along with item drops such as Copper Ore, refined Iron, and Gold Amalgam. Ruins near the biome’s border may override Abyssalite, which can create openings for heat transfer and allow Shove Voles to pass through. The biome is also associated with intense light that can be harvested with Solar Panels, but Duplicants exposed to it for too long can get Sunburn.

Space Exposure is the biome’s defining hazard. Any affected tile will continuously remove 100 kg of liquid per second or 100 g of gas per second, converting the area into vacuum. Background buildings such as Drywall or Tempshift Plates can block this effect and preserve nearby gases and liquids. This makes the Space Biome useful for building solar arrays and late-game infrastructure, but dangerous for any construction that relies on atmospheric containment.

A number of planetoid starting variants can alter the surface region. The Mini Metal variant contains more Copper Ore and Carbon Dioxide but no Oxygen, and it includes a Metal Vacuum Room feature in the center. The Mini Water variant similarly has more Carbon Dioxide and Water but no Oxygen, with a Small Lake feature in the center. The Mini Algae variant has an Algae Deposit feature, while the cold versions of these variants shift the temperature downward to around -5 °C. The Frozen variant adds Snow and includes Metal Vacuum Room plus Frozen Lake features.

For space missions, the biome is part of a much larger starmap and rocket system. Duplicants can settle multiple planetoids, and rockets must launch from a Command Capsule over a Gantry with the required fuel and cargo conditions met. In practice, the Space Biome is where endgame exploration begins: it marks the transition from colony survival to interplanetary expansion, and it is the source of solar access, rocket infrastructure, and the hazards that come with opening the colony directly to space.