Regolith

Regolith is a granular, non-combustible material found on the surface and in space biomes that serves as both a resource and a filter medium in the game. It appears as loose soil piles and behaves thermally and mechanically like other elements: it can be moved by conveyors and messengers, dug up by mining, and harvested on rocket missions. Regolith is distinct from Dirt and Sand by its specific interactions with machines and creatures, and it is commonly used to process polluted liquids and gases or to generate heat when melted.

Regolith melts into Magma Biome when heated to 1411.85 °C (melting point + 2 °C). When flash-melted by volcanic Magma Biome or the core Magma Biome, the transition releases a very large amount of heat because the Magma Biome has roughly five times the heat capacity of Regolith at the same temperature. This makes excess Regolith a convenient heat source: the heat can preheat incoming Regolith, drive steam generation for Steam Turbines or Steam Rockets, or be harnessed to cook Petroleum. Cooled Magma Biome solidifies into Igneous Rock, which can be fed to Hatches to produce additional resources and power.

Regolith is a standard filter medium for purification machines and interacts with fauna:

• Water Sieve converts Polluted Water into Water using Regolith (or Sand) as the filter medium. The recipe is: 5 kg/s Polluted Water + 1 kg/s Regolith = 5 kg/s Water + 0.2 kg/s Polluted Dirt.
• Deodorizer converts Polluted Oxygen into Oxygen using Regolith as the medium. The recipe is: 0.1 kg/s Polluted Oxygen + 0.13333 kg/s Regolith = 0.09 kg/s Oxygen + 0.14333 kg/s Clay.
• Shove Vole consumes Regolith and excretes Regolith tiles equal to half the mass consumed; they can be used to passively recycle large stocks of Regolith if kept fed.

Regolith can be obtained from several sources. It is harvestable as a renewable resource on certain Space POIs obtained via rockets: Gilded Asteroid Fields yield Regolith at roughly 30–90 kg per cycle. Meteor showers also deposit Regolith; the Regolith arriving from meteor showers is often at elevated temperatures.

Practical notes and best practices:

• Heated Regolith from meteor showers or deliberate melting can overheat nearby equipment (for example, telescopes). When dealing with falling or accumulated hot Regolith, place sensitive buildings above an automated horizontal Mechanized Airlock to allow Regolith to fall through, or use Robo-Miners to clear deposits.
• Use hot Regolith to generate steam for early Steam Rockets or to supply a steam chamber beneath rockets; while not especially efficient, this method can bootstrap initial steam power.
• When using Regolith as a filter medium, plan for the byproducts: Water Sieves produce Polluted Dirt and Deodorizers produce Clay. These byproducts require storage or disposal and can be further processed or used as inputs elsewhere.
• Consider thermal buffering when melting Regolith into Magma Biome: the high heat release can be harnessed, but uncontrolled melting will damage structures and create hazards; channel heat into dedicated steam generation or heat exchangers and allow Magma Biome to cool into Igneous Rock where useful.

Regolith’s combination of filtration utility, thermal energy potential, and availability in space makes it a versatile midgame-to-lategame resource when managed with attention to temperature and byproduct flows.