Magma

Lore & Background

In the world of Oxygen Not Included, the cross-section is a finite geological column suspended in the void of space, and Magma sits at its very base like a slow-burning furnace that has been lit since the station was first assembled. The Duplicants, tiny engineered workers in their little spacesuits, have no geological training and no respect for the heat gradient that builds with every meter of depth. To them, Magma is simply the red stuff at the bottom that the engineers tell them not to touch.

The colony's relationship with Magma is one of desperate gratitude mixed with genuine fear. Early on, a handful of solar panels and a wind turbine might keep the lights humming, but as the population grows, the oxygen scrubbers spin up, the food synthesizers whir, and the heating systems kick in, power demand climbs past what surface sources can provide. Magma Generators become the answer: plug in a pipe, feed the molten liquid into the reactor chamber, and watch the kilowatts pour in. The trade-off is that the colony must now maintain a vertical shaft through every layer of rock and dirt, a pumping system that can handle extreme temperatures, and a safety culture that treats a single unsealed pipe joint as a colony-ending emergency.

There is a quiet, almost mythic quality to the Magma layer in the minds of long-serving Duplicants. It never dims, never cools, never runs dry. It is the one constant in a world where oxygen levels fluctuate, crops fail, and the pressure in a sealed room can swing wildly. Engineers who have spent months routing insulated conduits around it speak of it with the same wary reverence a sailor might reserve for the open ocean: something vast, patient, and utterly indifferent to whether you survive the interaction.

In Their Own Story

The shaft had been open for three days now, and the heat rising from the bottom was enough to make the air shimmer. Kip, a Duplicant with a smudge of engine grease on her left cheek, crouched at the edge of the excavation pit and watched the Magma pulse its slow, rhythmic glow. It looked almost peaceful down there, that river of orange light crawling across the black basalt floor, like something breathing in its sleep.

"Pump's calibrated," called Rho from the control panel above, his voice tinny through the comms. "Pressure holding at twelve. You good to open the intake?"

Kip wiped her hands on her suit and nodded. Below her, the liquid shifted, and a thin vein of it crept up a crack in the rock face, leaving a faint trail of steam. She could feel the warmth on her face even through the visor. She thought about all the times she'd almost dropped a tool into that pit. About the time the intern had walked right up to the edge just to 'get a better look.'

"Open the intake," she said, and the pumps groaned to life, and the Magma began its long, slow climb up the insulated pipe toward the generator that would keep every light in the station burning for another week.

Reader's Guide

Magma occupies the lowest layer of the cross-section, beneath all rock, dirt, and ice strata. To access it, Duplicants must excavate a vertical shaft through every overlying layer, which can be a significant time and resource investment depending on the depth of the starting layout.

The liquid itself is at an extremely high temperature and will instantly kill a Duplicant on direct contact. It also melts or ignites most solid materials it touches, so any structure, pipe, or storage container in its vicinity must be rated to withstand the heat. Uncontained Magma will spread across the floor of a room and continue to damage anything it contacts.

The primary use of Magma is as fuel for Magma Generators, which convert it into a large amount of electrical power. A typical setup involves a sealed chamber at the bottom of the shaft, a pump to lift the Magma into a pipe, and a short insulated conduit feeding the generator. The generator consumes the Magma, and the remaining liquid can be returned to the pool or stored.

Key hazards to manage: the extreme heat radiating upward through the shaft (which can cook Duplicants working nearby), the risk of a pump failure flooding a lower room with molten liquid, and the fact that Magma will react violently with certain gases and coolants if mixed carelessly. Always build a containment wall around the Magma pool, keep Duplicants at a safe distance, and double-check every pipe joint before pressurizing the system.

Did You Know?

• Magma Generators are among the most power-dense energy sources available in the game, making Magma the go-to fuel for large, late-game colonies.
• Magma is effectively inexhaustible: the pool at the bottom of the cross-section does not deplete, so it functions as a truly renewable resource.
• A single drop of Magma on a Duplicant's suit is enough to kill them; there is no partial-damage threshold to worry about.
• Because Magma sits below every other geological layer, accessing it requires digging through the entire depth of the cross-section, making it the most engineering-intensive resource to tap.