Kittens now need air, water and food to survive. Plan your supplies, manage your crew and prepare for the challenges of longer missions.
Kittens now need to breathe, drink and eat. Every seated kitten uses oxygen, water, meals and CO₂ scrubber canisters.
This is tier 1 of life support: everything is carried from launch and nothing is recycled yet. Recyclers, greenhouses and living off the land will come in later tiers.
Life support has been done plenty of times before in KSP mods and in other survival games, including our own Stationeers.
So before writing any code I did a lot of research going through what worked, what didn't, and what players said about it.
All that research told me that Life Support boils down to the following rules:
The rates, loadouts and UI shown here are by no means final. The numbers are real human ones for now and will get balanced once there's more to do on a long mission.
The water figure covers drinking (2.0 kg), food preparation (0.5 kg) and hygiene (0.7 kg).
Meals and scrubber canisters are Apollo and Gemini era: about 0.27 kg a meal, and LiOH canisters of 2.3 kg rated for 1.5 kitten-days each.
The capsule's small 0.175 m aluminium bottle holds 5.4 kg of oxygen at 203 bar. The part window shows each gas tank's pressure and rated pressure.
Want more air or water on your vehicle? Tick Air or Water under Role Affinity on any existing tank and it fills with oxygen or water. Air and Water each need a tank to themselves, so ticking one clears the other boxes. A tank that only the crew draw from shows Supply Use instead of Propellant Use.
The two crewed parts are loaded so all four supplies run out together after three days:
Older saves pick up the new supplies too. A capsule's new tanks load full in a save made before life support existed.
There's a new Life Support category in the editor's part picker with two supply lockers that fit into a service module's bays:
To make that work, every service module now has a habitat of its own. It stores nothing and adds no living space but kittens can pass through it. So a service module under a capsule joins the capsule's zone. A locker in its bays joins the same zone and its meals and canisters go into the crew's pantry.
The lockers borrow the bay tank models for now, so a locker and a bay tank look the same until they get models of their own.
PArts that have Habitats attached directly to each other form one zone. Put anything else between them and you have two zones with two separate pantries. Crew passages and service modules carry an empty habitat, so they join zones together.
Close them and the zone splits again. Hatches are closed by default and automatically close when you dock or undock and are persisted in save games.
Either one lists the empty seats in the kitten's zone including a docked vessel's seats through an open hatch. While the menu is open the kitten's current seat is marked in the world with a green dot and an arrow points to whichever seat you're hovering the mouse cursor over.
Crew portrait SEAT menu open, with the arrow from the current seat to the hovered oneKnowing how long you have
It shows in the same places delta-v already does, plus a few more:
As supplies run down the warnings escalate through four states:
The thresholds are fixed times rather than a percentage. I chose this because 10% sounds sensible until you notice it's 7 hours on a 3-day capsule but 73 days on a 2-year ship.
Alerts cover every crewed vessel not just the one you're flying. Vessels not being controlled by the player also consume life support resources and will run out too.
Consumption is linear. So a vessel's supplies are worked out in one step however long the warp step is and the warp step is cut short at the next warning or run-out.
Yes they will die, but it isn't instant.
From the moment a supply runs out each kitten climbs a ladder for that supply, with hours to weeks between the rungs:
The oxygen and CO₂ hours come from how fast cabin air goes bad: CO₂ above about 10% is fatal, and so is oxygen below about 10%. The table is for 2 m³ of cabin per kitten.
The hours scale with each zone's habitable volume so a cramped cabin goes bad faster, while water and food don't scale. The capsule gives its two kittens 0.7 m³ each so without oxygen they're degraded 1.2 hours after it runs out, incapacitated at 2.1 hours and dead at 3.2.
Every kitten keeps its own life support status and countdown clocks and takes them wherever it goes. It counts down against the zone's supplies for the zone that it is currently inside.
So one zone running dry doesn't hurt the kittens in the next zone.
Resupply stops the countdown clocks and the clock then runs back down at the rate it went up. A kitten on EVA recovers too, because the suit supplies everything, and so does a kitten back home. Only death is permanent.
Reaching a rung raises an alert, such as "Juquartz is incapacitated: no oxygen", and drops warp to 1×. Warp lands exactly on each rung so it can't carry you past one.
Hover a greyed-out control and it tells you why.
A vehicle with a probe core keeps flying the vessel so it doubles as a backup pilot.
A NASA Ames study (Jones, 2016) put numbers on it:
Recycling pays for itself after about 80 days. You'd want a spare system that far from home and every spare pushes the break-even out: about 180 days with two systems, 240 with three and 300 with four. Real programmes have moved along that curve:
Even the best loops leak. The ISS gets back 98% of its water since a brine processor was added in 2023, but only about half its oxygen, because the reactor that turns CO₂ back into water vents methane, and with it hydrogen.
Leaky loops are good for gameplay: a recycler buys you time but never makes a ship last forever.
Growing your own food closes the loop further but it's fragile. China's Lunar Palace 1 ran 370 days at 98.2% closure, with all of its oxygen and water and 73% of its food recycled. Biosphere 2 went the other way: oxygen fell below 14.5%, crops failed and the crew lost 16% of their body weight.
So KSA's tiers follow the real progression. Tier 1 is Apollo: carry it all. Each tier after that closes part of the loop and makes longer missions possible. Short trips will keep carrying everything, and long ones will need the hardware.
The Habitat Zones window now lists each zone's storage parts with their meals and CO₂ canisters, under a Supplies heading, with the zone's kittens under a Kittens heading.
In flight each storage part has a Move button. Pick another habitat in the same zone including a docked vessel's through an open hatch, and set how many meals and canisters to move.
A kitten in the zone who isn't incapacitated has to carry them, and the button tooltip will tell you if it cannot.
Hovering a storage part tints it purple on the vessel and while you're moving supplies a purple arrow runs from the source to the destination.
Moving supplies doesn't change what the zone holds. It decides which part keeps them when you undock, decouple or close a hatch.
They now move gases too, so oxygen can be pumped from one tank to another as well as water, which is how you top up a docked vessel's air and water.
With life support off, habitats use nothing, there are no alerts and no failure ladder and the crew portrait's condition lines are hidden.
The readouts stay as information, and nothing is reset, so turning it back on carries on where it left off.
These switches are temporary until there are proper game types and difficulty settings.
Air counts as breathable where oxygen's partial pressure is at least 11 kPa which is about what it is at 5,000 m, near the highest towns people live in all year.
A habitat in breathable air breathes the outside air. It uses no oxygen and no scrubber canisters, only food and water, and its part window shows "Breathing outside air".
The vehicle editor still plans on tanks and canisters since it doesn't know where you're going to fly.
The suit is filled from the zone the kitten leaves and that habitat zone pays for it. A kitten can go out on a part-filled suit with an alert saying how long it will last, but a kitten cannot go EVA with an empty suit unless the air outside is breathable. When that happens both EVA buttons grey out and say why. When a Kitten goes on EVA In breathable air the suit takes only water and food with it.
Out on EVA the kitten lives from its suit. Alerts are produced at 1 hour and 15 minutes left.
If the suit runs out, the kitten climbs the failure ladder at the suit's tiny 0.1 m³ volume. So it goes fast: CO₂ is deadly first about 24 minutes after the cartridge is spent.
Boarding gives back whatever is left over in the suit. Oxygen and water go back into the vessel's tanks and meals into free storage.
Anything there's no room for is thrown away and the Board prompt warns you of this. For example "Boarding throws away what won't fit: 120 minutes oxygen, 2 meals".
The backpack's part window shows the suit's life support like any other habitat. The crew portrait shows "Suit: 5 hours", amber under an hour and red under 15 minutes, or "Breathing External Air" in breathable air.
Hover over this text to get a tooltip showing the suit's oxygen, cartridge, water and food.
In the Habitat Zones window a suit is its own zone, and highlighting it tints the kitten's suit, helmet and backpack.
In amber on the crew portrait and in the Kitten Roster's Condition column: "Thirsty: 3 hours", "Hungry", "Short of air" or "High CO₂", with how long it's been.
The habitat part window lists each kitten's condition too.
Now a kitten on EVA can carry them.
When an EVA kitten is within 2 m of any habitat with storage, a "[G] Supplies" prompt appears. Press G to open the Supplies window which allows you to pick the storage part from a dropdown and take or stow meals and CO₂ canisters.
A kitten carries up to 10 kg: 4 canisters (9.2 kg) plus 3 meals is exactly the limit, or 37 meals on their own.
What it carries adds to its mass so the jetpack works harder when loaded.
A kitten never eats or uses what it carries and it can't carry anything if the kitten is in a degraded state.
Anything still carried gets stored aboard when it boards, with the same warning if there's not enough room.
The crew portrait's suit tooltip shows what the kitten is carrying. This also works between vessels that aren't docked. There's no carry model yet, so for now the load is invisible.
This is tier 1 of life support: everything is carried from launch and nothing is recycled yet. Recyclers, greenhouses and living off the land will come in later tiers.
Life support has been done plenty of times before in KSP mods and in other survival games, including our own Stationeers.
So before writing any code I did a lot of research going through what worked, what didn't, and what players said about it.
All that research told me that Life Support boils down to the following rules:
- Life support should be a limit on mission length and not a chore.
- Every failure should be explained and its cause on screen and available to the player.
- Penalties need a reward. Recyclers, greenhouses and living off the land are unlocks that make longer missions possible, not just add extra costs.
- Time warp and background simulation are the core problems in existing mods and games.
- Punishment versus planning. Life support is about planning, not punishment.
- More detailed life support simluation does not equal more gameplay depth.
- Fully closed loops remove the time pressure.
- Health, stress and habitation mechanics overlap.
- Forecasting and player information decides whether life support feels fair.
The rates, loadouts and UI shown here are by no means final. The numbers are real human ones for now and will get balanced once there's more to do on a long mission.
What a kitten needs
For now kittens use real human rates taken from NASA's Baseline Values and Assumptions Document (BVAD) for an 82 kg reference crew member. We can retune them later.| Supply | Per kitten per day | Where it's kept |
|---|---|---|
| Air (oxygen) | 0.895 kg | Tanks with the Air role |
| Water | 3.2 kg | Tanks with the Water role, drawn in 0.5 L units |
| Food | 3 meals, 0.8 kg | Habitat storage |
| CO₂ scrubbing | 1 canister per 1.5 kitten-days | Habitat storage |
Meals and scrubber canisters are Apollo and Gemini era: about 0.27 kg a meal, and LiOH canisters of 2.3 kg rated for 1.5 kitten-days each.
Oxygen is a gas now
Tanks can now hold gases, so oxygen is stored as high-pressure gas. A tank's rated pressure is worked out from its wall:shape, thickness and the wall material's strength at its storage temperature with a safety factor of 2.The capsule's small 0.175 m aluminium bottle holds 5.4 kg of oxygen at 203 bar. The part window shows each gas tank's pressure and rated pressure.
Want more air or water on your vehicle? Tick Air or Water under Role Affinity on any existing tank and it fills with oxygen or water. Air and Water each need a tank to themselves, so ticking one clears the other boxes. A tank that only the crew draw from shows Supply Use instead of Propellant Use.
Habitats
Any part kittens can sit in or move through now has a habitat. A habitat has a habitable volume which is the space the kittens live in and a storage volume where meals and scrubber canisters are stowed. That's how real spacecraft did it: Apollo had a LiOH locker in the cabin and the ISS keeps its food in bags.The two crewed parts are loaded so all four supplies run out together after three days:
| Part | Kittens | Cabin | Storage | Tanks | Lasts |
|---|---|---|---|---|---|
| Medium capsule | 2 | 1.4 m³ | 0.042 m³ 18 meals, 4 canisters | 5.4 kg O₂ 19.2 L water | 3 days |
| Lander Cans | 1 | 1.76 m³ | 0.021 m³ 9 meals, 2 canisters | Half the capsule's | 3 days |
Packing light
Select a crewed part in the editor and its part window has a Habitat Storage section with a Meals slider and a CO₂ Canisters slider, each from empty up to what the storage holds.
Carrying more: supply lockers
As mentioned a crewed part's storage can only store three days life support resources for the capsule's two kittens.There's a new Life Support category in the editor's part picker with two supply lockers that fit into a service module's bays:
| Part | Storage | Holds | For two kittens |
|---|---|---|---|
| SL-M1 Supply Locker | 0.021 m³ | 9 meals, 2 canisters | 1.5 days |
| SL-M2 Supply Locker | 0.105 m³ | 45 meals, 10 canisters | 7.5 days |
The lockers borrow the bay tank models for now, so a locker and a bay tank look the same until they get models of their own.
Zones and hatches
Life support doesn't run per vessel, it runs per habitat zone.PArts that have Habitats attached directly to each other form one zone. Put anything else between them and you have two zones with two separate pantries. Crew passages and service modules carry an empty habitat, so they join zones together.
- Food and scrubber canisters come from the zone's own habitats. One zone can't eat another zone's meals.
- Air and water come from any Air or Water tank the vessel's plumbing reaches, so zones on one vessel share tanks.
- Scrubbing is per zone, not per kitten. The zone's crew wears down the installed canister, and when it's spent a stowed one is swapped in.
Close them and the zone splits again. Hatches are closed by default and automatically close when you dock or undock and are persisted in save games.
Habitat Zones window
The new Habitat Zones window is available in the vehicle editor and flight. (shortcut Shift+F6). Each zone lists:- Total habitable volume and volume per kitten.
- Storage, meals and canisters.
- Which kittens are in it and how long its supplies last.
- A warning for a crewed zone with no storage, meals or canisters, so you catch it on the pad and not in orbit.
Moving between seats
Until now a kitten could only change seats in flight by going out on EVA through one door and climbing back in through another. Now there's a SEAT button beside EVA on each crew portrait and a Move button beside each kitten in the Habitat Zones window.Either one lists the empty seats in the kitten's zone including a docked vessel's seats through an open hatch. While the menu is open the kitten's current seat is marked in the world with a green dot and an arrow points to whichever seat you're hovering the mouse cursor over.
Crew portrait SEAT menu open, with the arrow from the current seat to the hovered oneKnowing how long you have
Life support UI information
Life support reads as one line: days left and what runs out first.It shows in the same places delta-v already does, plus a few more:
- Editor: a LIFE SUPPORT row under TOTAL dV in the sequence footer with the crew it assumes underneath ("2 kittens assigned", or every seat filled when nobody is assigned yet).
- Resources gauge: four rows pinned under a LIFE SUPPORT divider, for Air, Water, Food and CO₂ Scrubber, with each how much time of each is left.
- Universe Manifest: a life support column so you can check vessels you aren't flying.
- Transfer Planner: a warning under the delta-v when the trip takes longer than your supplies last.
- Part window: a crewed part shows its zone the kittens in it and the time left for each supply.
As supplies run down the warnings escalate through four states:
| State | When | What happens |
|---|---|---|
| OK | More than 1 day left | Nothing |
| Low | 1 day left | Alert, warp drops to 1×, and a "Life support low" line while you're flying that vessel |
| Critical | 1 hour left | Alert, warp drops to 1× again |
| Out | A supply runs out | Alert, warp stops |
Alerts cover every crewed vessel not just the one you're flying. Vessels not being controlled by the player also consume life support resources and will run out too.
Consumption is linear. So a vessel's supplies are worked out in one step however long the warp step is and the warp step is cut short at the next warning or run-out.
What about performance? I hear people saying
It's also cheap. With 121 crewed vessels in orbit the stress test for all of them costs about 0.06 ms of main thread a frame and frame time and sim rate didn't change measurably.What happens when we runs out?
Yes, kittens will DIE and there's no setting to turn it off. IT is expected once we start building game modes and difficulty settings that a lot of these settings and options will be introduced then.Yes they will die, but it isn't instant.
From the moment a supply runs out each kitten climbs a ladder for that supply, with hours to weeks between the rungs:
| Rung | No oxygen | No CO₂ scrubber | No water | No food | Effect on the kitten |
|---|---|---|---|---|---|
| Degraded | 3.5 h | 2.5 h | 1 day | 14 days | Refuses to go on EVA |
| Incapacitated | 6 h | 5.5 h | 3 days | 30 days | Can't move seats. If every kitten aboard is incapacitated and there's no probe core, the vessel can't be flown |
| Death | 9 h | 8 h | 7 days | 45 days | Dies, with an alert naming what ran out |
The hours scale with each zone's habitable volume so a cramped cabin goes bad faster, while water and food don't scale. The capsule gives its two kittens 0.7 m³ each so without oxygen they're degraded 1.2 hours after it runs out, incapacitated at 2.1 hours and dead at 3.2.
Every kitten keeps its own life support status and countdown clocks and takes them wherever it goes. It counts down against the zone's supplies for the zone that it is currently inside.
So one zone running dry doesn't hurt the kittens in the next zone.
Resupply stops the countdown clocks and the clock then runs back down at the rate it went up. A kitten on EVA recovers too, because the suit supplies everything, and so does a kitten back home. Only death is permanent.
Reaching a rung raises an alert, such as "Juquartz is incapacitated: no oxygen", and drops warp to 1×. Warp lands exactly on each rung so it can't carry you past one.
Losing control
A crewed pod needs someone awake to fly it. When every kitten aboard is incapacitated, manual controls, staging, engines and burns lock out, and an alert says the vessel is out of control.Hover a greyed-out control and it tells you why.
A vehicle with a probe core keeps flying the vessel so it doubles as a backup pilot.
Seeing how each kitten is doing
- Crew portrait: now has a line under the radiation doses, "Degraded: no oxygen" in amber or "Incapacitated: no CO₂ scrubber" in red. Hover it for each supply's clock: "No oxygen for 4h, incapacitated in 2h", or after resupply "Has oxygen again, recovered in 3h".
- Kitten Roster: now has a Condition column with the same text and tooltip so you can check kittens on vessels you aren't flying.
- Memorial tab: now has a Cause of Death column for every way a kitten can die: no oxygen, CO₂ scrubber, water or food, radiation, a ground or ocean impact, a collision, g-force, aerodynamic or hydrodynamic forces, a fall on EVA, or an abandoned vessel. It's saved with the game. Kittens lost before this update show it blank.
Carry it or recycle it
Real spacecraft either carry everything they need (an open loop) or recycle some of it (a closed loop). Apollo carried everything. The ISS recycles air and water but still gets its food from cargo ships. Which one makes sense comes down to mission length.A NASA Ames study (Jones, 2016) put numbers on it:
| Approach | Mass |
|---|---|
| Carry everything | ~9.3 kg per crew-day |
| ISS-style recycling | ~730 kg up front + 0.2 kg per crew-day |
| Programme | Approach |
|---|---|
| Apollo | Fully open: everything carried |
| ISS | Air and water partly closed, food carried, cargo resupply |
| Gateway | Mostly open, for 30-day crew stays |
| Mars transit | Closed, and it has to survive a year with no crew aboard |
Leaky loops are good for gameplay: a recycler buys you time but never makes a ship last forever.
Growing your own food closes the loop further but it's fragile. China's Lunar Palace 1 ran 370 days at 98.2% closure, with all of its oxygen and water and 73% of its food recycled. Biosphere 2 went the other way: oxygen fell below 14.5%, crops failed and the crew lost 16% of their body weight.
So KSA's tiers follow the real progression. Tier 1 is Apollo: carry it all. Each tier after that closes part of the loop and makes longer missions possible. Short trips will keep carrying everything, and long ones will need the hardware.
What's next
| Next | What it adds | Waiting on |
|---|---|---|
| Tier 2: recycling | Regenerable CO₂ scrubbers that run on power, and water recovery at rising rates. Losing power starts to matter for air | Power design |
| Tier 3: oxygen | Oxygen from electrolysis and CO₂ reduction | Tier 2 |
| Tier 4: greenhouses | Grow part of your food, at a high power and light cost | Tier 3 |
| Tier 5: ISRU | Water from ice, oxygen from CO₂ atmospheres, using what's on the ground | Tier 4 |
| Locker models | Proper models for the supply lockers in place of the borrowed bay tanks | Art |
| Living space | Cabin volume per kitten as a comfort level. Cramped kittens work slower, comfortable ones a bit faster. It's a modifier, never a death timer. | Science and repair to affect |
| Modding | Rates, meal and canister sizes and the ladder moved into content data, so mods can make life support gentler or harsher | Tier 1 finished. Most likely ends up as difficulty settings |
Addendum · 6 November 2026
What's changed since this update
Since this post went up life support has gained:- Supply transfer.
- Gas transfer between tanks.
- Ability to switch Life Support on or off.
- Breathable air.
- A real EVA suit.
- Early warnings.
- Kittens can carry/move supplies on EVA.
Moving supplies between habitats
Supply transfer, the first item under What's next, is in.The Habitat Zones window now lists each zone's storage parts with their meals and CO₂ canisters, under a Supplies heading, with the zone's kittens under a Kittens heading.
In flight each storage part has a Move button. Pick another habitat in the same zone including a docked vessel's through an open hatch, and set how many meals and canisters to move.
A kitten in the zone who isn't incapacitated has to carry them, and the button tooltip will tell you if it cannot.
Hovering a storage part tints it purple on the vessel and while you're moving supplies a purple arrow runs from the source to the destination.
Moving supplies doesn't change what the zone holds. It decides which part keeps them when you undock, decouple or close a hatch.
Moving air and water between tanks
The transfer buttons in a tank's part window used to move liquids only.They now move gases too, so oxygen can be pumped from one tank to another as well as water, which is how you top up a docked vessel's air and water.
Turning life support off
Life support and radiation each have a switch under Game Type on startup game screen and in the Universe > Rules menu during a game.With life support off, habitats use nothing, there are no alerts and no failure ladder and the crew portrait's condition lines are hidden.
The readouts stay as information, and nothing is reset, so turning it back on carries on where it left off.
These switches are temporary until there are proper game types and difficulty settings.
Breathable air
Atmospheres now have an oxygen fraction. Earth's is 20.95%, and it's the only body with breathable air.Air counts as breathable where oxygen's partial pressure is at least 11 kPa which is about what it is at 5,000 m, near the highest towns people live in all year.
A habitat in breathable air breathes the outside air. It uses no oxygen and no scrubber canisters, only food and water, and its part window shows "Breathing outside air".
The vehicle editor still plans on tanks and canisters since it doesn't know where you're going to fly.
The EVA suit
The suit is now a habitat on the kitten's backpack with the life support a real suit carries for a working day outside:| Supply | In the suit | Based on |
|---|---|---|
| Oxygen | 8 hours | Apollo 15 to 17, the ISS EMU and the latest Orlan all last a working day |
| CO₂ cartridge | 8 hours | A LiOH cartridge, as Apollo and the EMU used |
| Water | 1 L | The EMU's in-suit drink bag holds about 0.95 L |
| Food | 1 meal | One meal bar |
Out on EVA the kitten lives from its suit. Alerts are produced at 1 hour and 15 minutes left.
If the suit runs out, the kitten climbs the failure ladder at the suit's tiny 0.1 m³ volume. So it goes fast: CO₂ is deadly first about 24 minutes after the cartridge is spent.
Boarding gives back whatever is left over in the suit. Oxygen and water go back into the vessel's tanks and meals into free storage.
Anything there's no room for is thrown away and the Board prompt warns you of this. For example "Boarding throws away what won't fit: 120 minutes oxygen, 2 meals".
The backpack's part window shows the suit's life support like any other habitat. The crew portrait shows "Suit: 5 hours", amber under an hour and red under 15 minutes, or "Breathing External Air" in breathable air.
Hover over this text to get a tooltip showing the suit's oxygen, cartridge, water and food.
In the Habitat Zones window a suit is its own zone, and highlighting it tints the kitten's suit, helmet and backpack.
Warnings before it hurts
Kittens now show what they're going without before it harms them.In amber on the crew portrait and in the Kitten Roster's Condition column: "Thirsty: 3 hours", "Hungry", "Short of air" or "High CO₂", with how long it's been.
The habitat part window lists each kitten's condition too.
Carrying supplies on EVA
Zones that aren't connected to each other initially had no way to share food or canisters except directly connecting them by docking and having only habitat parts between them.Now a kitten on EVA can carry them.
When an EVA kitten is within 2 m of any habitat with storage, a "[G] Supplies" prompt appears. Press G to open the Supplies window which allows you to pick the storage part from a dropdown and take or stow meals and CO₂ canisters.
A kitten carries up to 10 kg: 4 canisters (9.2 kg) plus 3 meals is exactly the limit, or 37 meals on their own.
What it carries adds to its mass so the jetpack works harder when loaded.
A kitten never eats or uses what it carries and it can't carry anything if the kitten is in a degraded state.
Anything still carried gets stored aboard when it boards, with the same warning if there's not enough room.
The crew portrait's suit tooltip shows what the kitten is carrying. This also works between vessels that aren't docked. There's no carry model yet, so for now the load is invisible.
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