Functions (Habitation)
Habitation is measured in "Kerbal-Months" (30 six-hour Kerbin-Days). All parts that have crew capacity provide 1/4 of a Kerbal-Month of habitation per seat (For example, the Mk1 Command Pod provides 7.5 six-hour days of Habitation). Habitation time is divided equally by all kerbals on board. For example, a Mk1-2 Command Pod has 22.5 kerbal days of Habitation time for one kerbal (7.5 days x 3 seats / 1 kerbal). When that pod is full, each kerbal only has 7.5 kerbal-days of hab time available (7.5 days x 3 seats / 3 kerbals). More specialized parts may provide additional Habitation.
For example: the Hitchhiker Can provides 660 kerbal-days of Habitation (in addition to the 30 kerbal-days provided by its 4 seats).
This page covers the key concepts for habitation.
The kerbal-months provided by your habitat space are multiplied by the vessel's total Hab Multiplier value. Every vessel has a base Hab Multiplier of 1. Any additional multipliers provided by parts are added to that to get the vessel's final Hab Multiplier. If the number of kerbals on board is higher than the 'crew affected' stat of a part, the multiplier provided will be divided by crew/crew affected.
For example: a Cupola has a Hab Multiplier of 1.76. If a vessel has two Cupola, its final Hab Multiplier is 1 + (1.76 * 2) = 4.52. If the vessel provides a base Habitation of 100 kerbal-months, the Hab Multiplier increases the ship's total Habitation to 452 kerbal-months. However, if the vessel has five kerbals on board, the overall multiplier will be reduced to 1 + (((1.76 / (5 / 1)) * 2) = 1.704, giving a disproportionately low 34.08 kerbal-months per kerbal.
Kerbals can only stay in a confined space away from home for so long before bad things happen. Each kerbal has two running clocks which determine this time limit. These values are displayed for each active kerbal in the USI-LS window.
- Hab time - how long the kerbal will be happy on his current vessel
- Home time - how long the kerbal will be happy before getting homesick for Kerbin
Hab time is reset every time a kerbal enters a new vessel. It begins with the vessel's provided Habitation time, divided by the number of kerbals present, and counts down to zero. The concept of Hab time is how comfortable your kerbal is with his current vessel. He can't live in tight spaces for long, and he gets tired of staying in the same place.
Home time never resets of its own accord and starts counting down from the moment of launch. However, it is increased by the highest amount of Habitation ever experienced by the kerbal. The concept of Home time is how homesick the kerbal is. Spacious vessels will help him stay positive for a longer time, but eventually he's going to miss home. However, this timer can be reversed if there is a functioning colonization module present. See Functions (Med Bay and Colony Supplies) for more info. The hab/home timers can also be paused indefinitely if habtime per kerbal exceeds 50 years or 1 year if the kerbal is a pilot/scout, or is on a planet with a kolonisation rating of over 500%. In addition, the total amount of habitation a kerbal has is multiplied by the Kolonisation rating2.
For example, imagine we have a rocket (Habitation = 30 days) with an attached lander (Habitation = 5 days) and a space station (Habitation = 1000 days). When Jebediah launches (alone) his Hab time and Home time both start at 30 days and begin counting down. He arrives at the Mun 5 days later with a Hab time and Home time of 25 days each.
Then he moves to the lander. His Home time will be unaffected (still 25 days, counting down), but his Hab time will be reset/decreased to 5 days (because the lander is only able to support a kerbal for 5 days).
Jeb visits the surface of the Mun and returns to his ship in orbit after 4 days. At this point his Hab time is 1 day and his Home time is 21 days. When he moves back to the rocket his Hab time will reset to 30 days, but his Home time will remain at 21 days.
Jebediah then travels to the space station for 10 days (Hab = 20 days, Home = 11 days). When he enters the space station, Hab time is reset to 1000 days (a nice new station for him to stretch his legs in). His Home time is also increased, but not to 1000. He has already been away from home for 19 days at this point, which means his Home time will be reset to 981 days (19 days shy of 1000).
After 100 days on the station he boards the rocket again (Hab goes down to 30, Home is unaffected and at 951) and heads back to Kerbin, where he is recovered.
For the tables below: ‘Months’ is habitation months added by the part in that mode. ‘Multiplier’ is the habitation multiplier applied by the part in that mode. ‘Affects’ is the number of Kerbals affected by the multiplier in that mode.
| Part | Name | Hab mode | Crew | Months | Multiplier | Affects |
|---|---|---|---|---|---|---|
 |
'Ranger' Inflatable Habitation Module | Hab Quarters | 4 | 83.6 | 0.00 | 0 |
|
'Ranger' Inflatable Habitation Module | Hab Common | 4 | 0.0 | 5.20 | 4 |
 |
'Tundra' Expandable Habitat 2.75m | Hab Quarters | 6 | 19.8 | 0.00 | 0 |
 |
'Tundra' Expandable Habitat 4.25m | Hab Quarters | 6 | 77.0 | 0.00 | 0 |
 |
'Tundra' Habitation Ring | Hab Quarters | 10 | 497.5 | 0.00 | 0 |
 |
'Duna' Kerbitat | Hab Common | 2 | 2.3 | 1.40 | 4 |
 |
'Tundra' Kerbitat (2.5m) | Hab Quarters | 2 | 18.5 | 0.00 | 0 |
|
'Tundra' Kerbitat (2.5m) | Hab Common | 2 | 0.0 | 2.35 | 4 |
 |
'Tundra' Kerbitat (3.75m) | Hab Quarters | 4 | 65.0 | 0.00 | 0 |
|
'Tundra' Kerbitat (3.75m) | Hab Common | 4 | 0.0 | 5.42 | 6 |