Rust

Rust is an element resource used primarily with the Rust Deoxidizer and as a source of iron. It is found in the game’s space-related renewable points of interest, where it can be harvested on rocket missions from Oxidized Asteroid Fields and Radioactive Asteroid Fields. It also has a second major use as a raw material for melting: when heated above its melting point, Rust converts directly into liquid iron at a 1:1 ratio, which can then be cooled into refined iron.

Rust Deoxidizer processing turns Rust and Salt into Oxygen, Chlorine, and Iron Ore. The conversion rate is 750 g/s Rust + 250 g/s Salt = 570 g/s Oxygen + 30 g/s Chlorine + 400 g/s Iron Ore. This makes Rust a useful late-game input for both life support and metal production, especially when a colony has access to space harvests or a large stockpile of Rust from asteroid mining.

Melting Rust is more efficient for metal output than using a Rust Deoxidizer. Heating it past its melting point and refining the resulting liquid iron into refined iron is 87.5% more efficient than the deoxidizer route, but it does not produce Oxygen or Chlorine. Because of that tradeoff, the two methods serve different needs: the deoxidizer is valuable when a colony wants oxygen and chlorine alongside iron ore, while melting is better when the goal is maximizing metal yield.

A few practical notes apply when building around Rust processing:

• Rust can be harvested from renewable space points of interest, with much higher yields in Oxidized Asteroid Fields than in Radioactive Asteroid Fields.
• A Rust melter can be designed so that the heat from produced iron is reused to preheat incoming Rust, greatly improving heat efficiency.
• A properly designed Rust melter can later be adapted to process most other Metal Ores faster than a standard Metal Refinery, or even converted into a Regolith melter.
• Liquid Steel can be used as a coolant in a Metal Refinery to reach the temperatures needed to melt Rust.
• Since the deoxidizer outputs both Oxygen and Chlorine, Rust is especially useful in bases that need controlled amounts of each gas rather than pure oxygen production.

Before the Launch Update, this resource’s associated attribute was named Mining.