Health Factors - GarwelGarwel/KerbalHealth GitHub Wiki

Health factors is what changes a kerbal's health. They can be of two types: ordinary and marginal.

Ordinary Health Factors

  • Stress (kerbal is on a mission): ranges from -0.3 to -2 HP/day, depending on Astronaut Complex level and training (more details here)
  • Confinement: -3 HP/day, scaled in proportion to crew per Living Space
  • Loneliness (only 1 kerbal on the vessel, badass kerbals immune): -1 HP/day
  • Microgravity (orbital/suborbital flight or under 0.1 g conditions, e.g. Minmus): -1 HP/day
  • EVA: -10 HP/day (don't abandon your kerbals outside for long!)
  • Connected (having a working CommNet to home): +0.5 HP/day
  • Home (at Kerbin at altitude of under 18 km): +2 HP/day
  • KSC (kerbal is recuperating in KSC, i.e. available): +4 HP/day

If a kerbal acquires one or more health conditions, the Conditions factor will also come into play.

Health Multipliers

Certain parts can reduce or increase the effect of a health factor allowing for much longer and healthier flights, in exchange for a good amount of EC. A part can give this bonus to a limited number of kerbals. If it affects more than its crew cap, its effect is diminished.

Recuperation and Health Decay

Some parts, such as the Cupola, provide a recuperation bonus. If a kerbal receives, say, a 3% recuperation bonus, he/she will recover 3% of their lacking health (i.e. of the difference between their current HP and the maximum HP) every day. This change works in parallel with the normal health factors above.

Example: A 5-star kerbal (maximum HP = 150) currently has 40 Health Points and is in a vessel that gives him 5% recuperation. The vessel is full, has connection and he has a crewmate. Therefore that he recovers (150 - 40) x 5% = 5.5 HP per day and loses also (0.5 + 5 + 0.5 - 0.5) = 5.5 HP per day. It means that the marginal change balances out the "normal" change and his health will stay around 40 HP (27%) until the situation changes.

As you see, this mechanics may allow some kerbals to stay relatively healthy indefinitely. It may look cheaty, but the point is that: (1) there should be a way to design long-term missions without spamming crew space, (2) it requires a lot of heavy parts and therefore is still difficult, (3) the balanced health level is usually far from 100% and may fall lower if circumstances change (e.g., new crew arrives and fills the station), (4) these bonuses require a lot of EC, (5) radiation still keeps mounting.

Stock Parts with Health Effects

  • Hitchhiker: 0.375x to Confinement for up to 4 kerbals, 2.5 EC/sec per kerbal
  • Mk1 Crew Cabin: 0.50x to Confinement for up to 2 kerbals, 2.5 EC/sec per kerbal
  • Mk2 Crew Cabin: 0.50x to Confinement for up to 4 kerbals, 2 EC/sec per kerbal
  • Mk3 Passenger Module: 0.50x to Confinement for up to 16 kerbals, 2 EC/kerbal
  • PPD-12 Cupola Module: 1% Recuperation, 0.50x to Confinement for up to 2 kerbals, up to 4 EC/sec per kerbal
  • Mobile Processing Lab MPL-LG-2: 0.50x to Sickness effects for up to 2 kerbals (part crew only), 2 EC/sec per kerbal