Habitat
The internal habitat of a vessel is modeled as a set of individual parts flagged as habitats. Each part has an internal volume and an external surface, deduced automatically from their bounding box or specified by the part author.
From these basic properties, more complex ones are deduced and made available as modifiers to the rule framework.
Pseudo-resources¶
Some pseudo-resources are added to each habitat. Each one is used to simulate the individual properties of a vessels internal habitat volume and surface area. Their flow state is synchronized automatically from the habitat enabled/disabled state.
| RESOURCE | CAPACITY | USE | DENSITY (per-unit) |
|---|---|---|---|
| Atmosphere | Set by volume | Pressure | 1 m³ of Nitrogen at STP |
| WasteAtmosphere | Set by volume | CO2 level | 1 m³ of CarbonDioxide at STP |
| Shielding | Set by surface | Radiation shielding | 0.075 (alloy composite shielding) |
Atmospheric control¶
Atmospheric conditions inside a vessel are regulated by Life Support Systems fitted into manned parts or by the External Life Support Unit. Each vessel has a number of configurable LSS slots that can be configured into an assortment of different LSS processes. The number of slots is upgradeable by purchasing the Slot Upgrade in the Electronics section of the Tech Tree. Also as you progress through the Tech Tree more options become available for the LSS slots.
The internal atmospheric pressure is regulated by the Pressure Controller, this unit is used to overcome the losses from leaks and for pressurizing inflatable habitats.
The CO2 level is regulated by the Scrubber, this unit is used to scrub from the atmosphere the CO2 that the Kerbal's exhale. The greenhouse can also be used to remove CO2 from the atmosphere.
Radiation shielding¶
The user can choose the level of Shielding for each individual habitat part in the editor. The overall Shielding level on all enabled habitat parts is then used to reduce the environment radiation. It is possible to influence the level after launch by producing the Shielding resource.
Enable/disable habitats¶
The user can enable and disable habitat parts individually, both in flight and in the editor. This is used to configure and reconfigure the vessels internal volume, to influence its properties as the need arise.
Equalization and venting¶
When a habitat transitions from the enabled to the disabled state or vise versa, special care is used to avoid abrupt changes to the overall pressure of the whole vessels internal habitat. This is accomplished by two temporary states, in addition to enabled and disabled. These are equalizing that first matches the part pressure with the rest of the vessel and then switches to enabled and the other being venting that depressurizes the part completely by dumping the removed atmosphere either into the rest of the vessel, if there is room, or outside.
Inflatable habitats¶
If a habitat is inflatable, its inflate/deflate animation will be driven by the actual pressure of the part. Note that pressurizing a large habitat with a small pressure controller can take a long time. For example the Mk1 pod's pressure control will take approx 12 days (3 Earth days) to inflate the Gravity Ring. So remember to add enough pressure controllers for the job.
And by the way, you also should bring enough nitrogen. To estimate how much, look at Volume in the Habitat section for the part. It takes 1,000 units of nitrogen to fill 1 cubic meter. So for a habitat volume of 19 cubic meters you will need 19,000 units of nitrogen just to inflate. You wouldn't want to blow up a bouncy castle with your mouth :/
To inflate an inflatable habitat on a celestial body surface with breathable atmosphere the "Air pump" should be used. Every crewable habitat got an air pump, including the non-inflatable ones. The more air pumps are enabled, the faster the inflation proceeds. Inflating the Gravity Ring with the air pump of the mk1 pod will take approx 3.5 hours. (Of course you will not bring the gravity ring to a planet's surface, or will you? This was just a comparision...)
Comforts¶
Comforts are provided by some vessel conditions, and parts implementing the Comfort module.
| COMFORT | CONDITION | PART |
|---|---|---|
| firm-ground | vessel is landed/splashed; a Gravity Ring is deployed on a powered vessel; or whole-vessel spin meets the seat-coverage thresholds below | Gravity Ring |
| not-alone | more than 1 crew member in the vessel | |
| call-home | vessel can communicate with DSN via an antennas science rate | |
| exercise | Kerbal's can ride a bike or use a treadmill etc | Hitchhiker |
| panorama | Kerbal's can look out of a big window | Cupola |
Firm ground from whole-vessel spin¶
Besides landing/splashing or a deployed Gravity Ring, a vessel can earn firm ground by spinning as a whole so that enough crew seats sit at useful artificial gravity.
Kerbalism does not track which Kerbal is sitting where. It assumes the crew can move around the living volume. What matters is capacity:
- For each crewable part with live
CrewCapacity(disabled or still-inflating Habitats count as zero), compute artificial gravity from the vessel spin rate and the part’s cylindrical radius about the spin axis through the vessel CoM. - Seats that meet the configured minimum g are qualifying seats.
- Firm ground is granted when qualifying seats cover enough of the aboard crew and the spin rate stays at or below the configured maximum RPM (to limit Coriolis discomfort).
Defaults (difficulty / Kerbalism Comfort preferences, also overridable via Settings.cfg keys):
| OPTION | DEFAULT | MEANING |
|---|---|---|
| Vessel Spin Firm Ground | off | Master toggle for this source of firm ground |
| Minimum Spin Gravity | 0.25 g | Seat must reach at least this much artificial gravity to count |
| Maximum Spin Rate | 3.0 rpm | Whole-vessel spin must stay at or below this rate |
| Spin Seat Coverage | 100% | Fraction of aboard crew that must have a qualifying high-g seat |
Example: 8 crew, 100% coverage, 0.25 g / 3 rpm → you need at least 8 seats that reach ≥ 0.25 g while spinning no faster than 3 rpm. Airlocks and other near-axis seats usually do not qualify; they do not “punish” the ship either — they simply do not help.
The VAB/SPH Planner shows a spin estimate: qualifying seats / seats needed, innermost relevant radius, gravity at max RPM, and the RPM required to hit the target. It picks the root-part principal axis that covers the needed seats at the lowest RPM.
A Gravity Ring remains the compact shortcut (part + EC, whole vessel gets firm ground while deployed and powered). Whole-vessel spin is free of that part cost but needs geometry: enough seats far enough from the spin axis at an acceptable RPM.