Caesium

Caesium

Caesium adds a hidden ore to Factorio 2.1. Pegmatite, the caesium ore, is never placed by map generation and doesn't show on the map: you find it with survey stations, mine it at small outposts, and sort the pollucite out of the rock. A little caesium then goes a long way, into catalysts, photocathodes, scintillators, atomic clocks and atom traps.

Factorio 2.1.23 or later. Space Age and all other mods are optional.

How it plays

1. Survey. A survey station samples one chunk every 10 seconds, nearest first. When it finds a pegmatite, the patch appears, is charted and tagged, and you get a map alert and a highlighted discovery message with an ore icon, ore amount, clickable map link and notification sound. Every planet with pegmatites has a starter patch 3–6 chunks from spawn; after that, about 1 chunk in 150 holds one.
2. Mine and sort. Patches are small (30–70 tiles), scattered, and richer the further out they are. Drills feed an X-ray ore sorter at the mine: 20 ore give 1 pollucite and 16 stone. You can sort the first handful by hand.
3. Refine. Leach the pollucite in sulfuric acid to caesium alum, make caesium carbonate, and reduce it to the metal, sealed in glass ampoules because it ignites in air. About 100 ore make one caesium; one drill gives about 18 an hour.
4. Push outward. A patch lasts a few hours of steady mining, and later machines need more caesium. The magnetometer station reaches 12 chunks, seismic charges survey wherever you throw them, and each survey satellite automatically surveys one new chunk per second for ten minutes: 600 chunks per launch. Satellites share an outward frontier from the planet's origin, skip previously surveyed chunks, and leave found deposits permanently on the map. Launch replacements to keep surveying; /caesium-survey shows remaining mission time. Richer patches wait further out, in biter country.

Every player on the same map finds the same patches: where a pegmatite is, and how big and rich it is, comes from the map seed.

Buildings

• Survey station (3×3, Geological survey, red + green in vanilla): 6-chunk range, 10 s per chunk, 250 kW. Alt-mode shows shared survey coverage in its range and its own discoveries, for example "Area surveyed 42 / 169 · Own finds: 2".
• Magnetometer station (3×3, Caesium metal): 12-chunk range, 5 s per chunk, 500 kW. It upgrades the survey station in place.
• X-ray ore sorter (3×3, Caesium processing): the mine building. Pegmatite sorting runs only here, at one sort every 2 seconds. Built with two fast inserters for material handling; hand sorting is optional. With Neodymium, it also sorts 4 washed heavy mineral sand into 1 copper ore in 4 seconds, with small tin and lead chances where installed; no operating magnets needed.
• Well treatment station (3×3, Well treatment): brings tired oil and gas wells within 8 tiles back toward full yield with formate brine. Each treatment uses 10 brine and restores 2,000 to a well that can absorb the full dose. The station waits for at least 2,000 depletion, avoiding wasted brine near full yield. Completed doses wait if another station fills the well first. It treats infinite wells only.
• Space Age: the ioniser and ion thruster, and the orbital survey array (below).

What caesium is used for

Optional:

• Caesium catalyst: sulfuric acid with 60 acid instead of 50 from the same sulfur, at half the pollution. The catalyst is lost in 1 craft out of 50.
• Well treatment, as above.

Required in existing recipes:

• Photocathodes: 1 per laser turret and personal laser defense for their optical receivers; also night-vision equipment where its research comes after blue science.
• Scintillators: 1 per centrifuge and 2 per nuclear reactor for radiation monitoring.
• Atomic clocks: 1 per beacon as its radio frequency reference; 10 per satellite (5 with Space Exploration); 1 per space platform starter pack with Space Age.
• Atom traps (Space Age): 1 per quantum processor and 1 per 10 cryogenic science packs.

Space Age

• Pegmatites on Nauvis, Vulcanus (richer), Gleba and Fulgora (rarer); none on Aquilo.
• Ion thruster: burns caesium plasma from an ioniser (2 MW): a third of a thruster's thrust on a tenth of the fluid, with no thruster fuel or oxidizer. About 3.6 caesium an hour per thruster. Suits slow supply shuttles.
• Orbital survey array: a platform building that surveys the planet the platform is parked over, one chunk every 5 seconds.
• Fulgora: reduce carbonate with solid fuel from scrap. Gleba: carbon replaces coal, and optional pollucite bioleaching uses sulfur, bioflux and water in a biochamber without productivity.
• Machines: electromagnetic plants make clocks, photocathodes and atom traps; cryogenic plants run Caesium chemistry. Original assemblers and chemical plants remain available.
• Aquilo has no pegmatites. After Lithium processing, a chemical or cryogenic plant takes caesium carbonate out of lithium brine and returns 90 % of the brine. Local solid fuel can reduce the carbonate; atom traps still need imported processing units and steel.
• Platforms import caesium. Ionisers work there, and ion thrusters replace normal thrusters in place.
• Caesium refining productivity: infinite +10% metal yield per level, including Phosphorus distillation, using red, green, blue, space and cryogenic science. A tip and Factoriopedia notes list the planet sources.

Space Exploration

• Pegmatites on planets and moons, never in orbit. Core miners don't find them.
• Gamma-ray detectors take scintillator crystals, observation frames take photocathodes, SE quantum processors take atom traps, and satellites take atomic clocks.

Build a precision-instrument factory