Ostranauts Life Support Guide

Where to read atmosphere

Open the PDA atmosphere overlay or click a room tile and inspect gas breakdown. The O2 alarm triggers at <20 kPa even though its tooltip mentions 16 kPa — treat 20 kPa as your engineering setpoint so auto pumps stop buzzing.

N2 is optional for survival (hyperoxia is not fully modeled) but filling to ~80 kPa N2 plus ~20 kPa O2 gives stable total pressure and buffers CO2 swings.

Why CO2 kills before O2 does

You exhale CO2 into a closed room. Without a CO2 scrubber and empty outflow canister, CO2 climbs while O2 canisters still read full. Crew complain, sleep quality tanks, then capnia thresholds hit. Scrubbers need power, a cartridge, and somewhere for CO2 to go — usually a gas canister on the scrubber outflow tile.

CO2 scrubber vs Contaminant AtmoScrubber

Standard CO2 scrubbers pull carbon dioxide into a canister. The Contaminant AtmoScrubber (controlled by a Contaminants Pressure Alarm) handles hazardous trace gases if your salvage haul vented something nasty. Most starter tugs only need CO2 gear until you pressurize exotic cargo.

Alarms as automation triggers

When an alarm enters alert state, linked pumps turn on; when O2 returns to safe (≥20 kPa), pumps stop. Click the pump, open its control panel, use the link tool on the terminal screw, then click the matching alarm — no confirmation UI, but the squiggly wire cursor means you are linking correctly.

When scrubbers are overkill

Ships that vent atmosphere after every EVA (no proper airlock recovery) or run vacuum habitation short-term can skip scrubbers temporarily — but any multi-day hab with crew needs CO2 control. Pair this section with the reactor guide so scrubber breakers survive startup spikes.

Air pump vs turbo pump in practice

At equal settings, a turbo pump without turbo enabled behaves like a normal pump. Turn Turbo on when you need to vacuum a compartment for hull surgery (community timings: medium hull ~15 in-game minutes from ~45 kPa to ~3 kPa) or rush-pressurize after repairs. Leave turbo off on everyday O2/N2 maintenance pumps.

Two-pump "comfort" layout

Advanced layout: one O2 canister + O2 pump + O2 alarm and one N2 canister + N2 pump + N2 alarm, both set to Auto. Total pressure lands around 40–100 kPa depending on targets, with breathable O2 partial pressure — many captains run ~5–8 "units" O2 display (~50 kPa equivalent) plus N2 fill.

Airlock pump orientation

A classic leak: turbo pump in the airlock set to recover air but wired outlet to space. You vent the entire hab every cycle. Recovery pumps should draw from the airlock and push into the ship, or capture airlock gas into a spare canister if you want emergency RCS feedstock.

Heater and cooler placement

One heater per hab compartment often suffices on a loan tug; add a cooler when you install a Sulaiman ICFR or stack powered fabricators. Wire heaters/coolers through a Thermostat (not a bare temperature sensor alone) if you want hands-off comfort — same automation layer as O2 alarms for pumps.

"Running 3 coolers and still heating up"

Check whether heat inflow exceeds removal — reactor rooms dumping waste heat into adjacent tiles, unvented machinery bays, or a cooler breaker tripped offline. Coolers only sink heat to space through valid vent paths; a cooler in a sealed closet with no exhaust routing just moves the problem.

Power vs heat

Brownouts turn off coolers first if you share breakers with optional loads. Keep life support and climate on a protected branch that stays up during reactor laser-cap charges — the same lesson as scrubbers in the reactor guide.

Immediate post-fire steps

Vent hot gas if crew are suited or the room is disposable: manual pump Reverse into canisters, or open an exterior vent if your layout has one. Replace damaged tiles — charred walls leak heat and atmosphere. Run coolers at full draw once power is stable.

Why it feels stuck

Large hab volumes, multiple crew bodies, and running reactors all add heat faster than passive radiation removes it. Split the ship: isolate the burned compartment with powered doors, cool the hab deck separately, and do not restart fusion until core temp and room sensors trend down.

Prevent the next fire

Electrical faults, overloaded conduits, and welding in a pressurized O2-rich room are common igniters. Depressurize before cutting torches, keep fire suppression tools in the workshop, and review DmgViz after every salvage boarding where stray bullets flew.

Editor recalc workaround

Developer-confirmed fix: manually turn the O2 pump ON from its control panel until rooms sit above 20 kPa, then let auto mode hold. Alternately, save and reload — the editor auto-fills closed rooms to 20 kPa on load.

Compartment geometry rules

Floors are not required under every exterior wall for airtightness — wiki *Managing Atmosphere* notes floors under walls mainly add HP / micrometeor protection. You do need floor under doors, and a continuous pressurized room shell. Phantom leaks usually mean a missing door floor, open airlock, or hull hole — not "wall without underfloor."

Sensor placement

The O2 alarm must sit in the same room as the pump output. Big ships need two pump + sensor pairs on opposite hab wings — otherwise one end sits at 25 kPa while the other hovers at 19 kPa and never stops beeping.

Finding leaks

Watch total pressure trend on the PDA, listen for hissing, and use DmgViz to highlight cracked tiles. EVA outside and visually trace dark hull damage. Interior frost or fog sometimes marks rapid expansion zones.

Patching under pressure

Welding plates or swapping floor/wall tiles requires planning: isolate the compartment, optionally vent to safe pressure, or suit up. Carrying spare tiles from salvage beats dying mid-patch when the room hits vacuum.

Decompression discipline

Powered doors fail open or closed on brownouts — another reason life support and doors share critical breaker design. Before cutting a wall, check the Atmo tab on adjacent rooms; one wrong cut vents the bunk deck.

Ship-side vs station refill

OKLG vendors sell O2 and spare bottles if your hab stack is not built yet. Long-term, run a dedicated slow pump labeled for suit service so nobody turbo-fills during panic prep.

Budget O2 for EVA + hab

Every salvage minute burns suit O2. Refill before undock, carry a spare bottle in suit storage, and abort at ~50% remaining — the salvage guide's EVA abort rule pairs directly with this refill loop.

Sleep shift duration

Roster shifts — Work, Free, Sleep, Untime — gate what AI crew obey. Sleep shifts let characters rest unattended; Work shifts mean they follow orders including repairs. Insomniac traits and high CO2 can still wake crew early — fix atmosphere before blaming the bunk brand.

Bunk room as life-support unit test

If thermal comfort fails in the bunk while the bridge reads green, you have a vent routing or compartment split problem. Treat the bunk room sensors as your canary — same logic as the 19.02 kPa O2 bug.