# Kerbal Health
This mod introduces many aspects of astronauts' health management to KSP. It makes the game more challenging but also more realistic, encourages smarter mission planning, and adds to the fun. It works well alongside most popular mods.
The following factors may affect kerbal's health:
These values, like most others in the mod, are adjustable in Difficulty Settings. They also depend on quirks of a particular kerbal. You can check current values for a specific crew member in Health Monitor.
Certain parts (such as Hitchhiker and crew cabins) can additionally reduce the effect of a health factor (Confinement in this case) allowing for much longer and healthier flights. It often requires EC though. Hab rings in some mods can help overcome Microgravity issues for long-term stations and interplanetary missions. All these features can be changed using ModuleManager patches.
One of the drains on kerbals' health is Stress. If you have training disabled (recommended for new players), Stress is reducced based on your Astronaut Complex facility level:
If you have training enabled, you should first train your kerbals for missions. In the Editor, assign crew to the ship you are going to launch, open the Health Report and click Train button. All kerbals in the list will start training, if they are at least 90% healthy. You can check the time required for training and the effects of training in the Health Report. Then save the vessel and exit the Editor (don't launch it yet!).
Wait for the kerbals to finish their training. Training time depends on the number of trainable parts (as of now, it is those with crew capacity) and whether the kerbal has previously been trained for this part type. After the crew has been trained, load the vessel and launch it.
Untrained kerbals will slowly get used to a vessel they are in, but it will take more time than in KSC (and they will suffer from higher Stress all that time).
Certain parts (such as the Cupola) provide Recuperation bonuses. If a kerbal receives, say, a 1% recuperation bonus, he/she will recover 1% 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 70 Health Points and is in a vessel that gives him 2% recuperation. The vessel has 10 units of living space and he has connection and he has a crewmate. Therefore he recovers (150 - 70) x 2% = 1.6 HP per day and loses also (0.5 + 3 x 2 / 10 + 1 - 0.5) = 1.6 HP per day. It means that the marginal change balances out the "normal" change and his health will stay around 70 HP (47%) 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 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 (see below).
Recuperation is not stacked and has crew cap. It means that one Cupola provides 1% Recup for 2 kerbals, 2 Cupolas give 1% for 4 kerbals (not 2%!), etc. If you have more kerbals than the crew cap, Recuperation will be split among them evenly (e.g. 4 kerbals with 1 Cupola will get 0.5% Recup).
Decay is the opposite to Recuperation: for every percentage point of Decay, your kerbal will lose 1% of their remaining health per day. Fortunately, it is very rare.
All kerbals on missions are affected by radiation, which slowly but permanently reduces their maximum HP. Radiation is measured in banana equivalent doses (when you eat a banana, you get approximately 1e-7 Sv of radiation). 1e7 (10,000,000) bananas reduce max HP by 10%; 1e8 (100,000,000) bananas kill a kerbal.
The amount of Radiation a kerbal receives depends on many factors. Most importantly, it is determined by their location. Many planets and some moons have magnetic fields that stop some radiation; atmospheres are also very effective in shielding it (see wiki for more). Being close to a celestial body helps screen some rays too. E.g., radiation level at Kerbin's sea level is 1,000 times lower than in interplanetary space just outside Kerbin's SOI. Cosmic radiation is also a bit higher closer to the Sun. To check environment before sending astronauts, you can use magnetometers and Geiger counters provided by supported mods or embedded in advanced stock probe cores.
Being on EVA takes away all the protection your ship provides and dramatically increases radiation level. Artificial radiation is created by certain parts like atomic engines and nuclear reactors.
You can protect kerbals from radiation (both cosmic and artificial) by adding shielding to the vessel. It is provided by some parts, like structural panels, heat shields and mk3 cargo bays. These parts and most crew pods can be improved by adding Radiation Shielding to them in the Editor. You can never eliminate all radiation, but you can reduce it to non-dangerous levels.
Beware of solar radiation storms! They can blast your kerbals in a planet's SOI or in interplanetary space with amounts of radiation ranging from high to enormous. You will be warned, usually, a few hours in advance and the kerbals will automatically take cover in the shelter, if there is one. The shelter is determined as the most protected part (or set of parts) that can fit the entire crew. You will see shelter exposure in the Health Report and Health Monitor details. The frequence of solar storms depends on the phase of the solar cycle going (on average) from one storm every 6,667 days to one storm every 437 days.
If you have Kerbalism installed and enabled "Use Kerbalism Radiation" option in the settings, Kerbal Health's radiation calculations will be replaced with those of Kerbalism (but Kerbal Health shielding will still apply). Kerbalism has a more realistic and complex radiation model, but its balance is very different from Kerbal Health's.
It is possible to cure radiation by decontaminating a kerbal, but it is hard. To start decontamination, the kerbal has to be at KSC at full health and with no health conditions. You also need fully upgraded R&D Facility and Astronaut Complex. Every decontamination costs 100,000 funds (in Career mode) and 1,000 science points (in Career and Science mods). It cures 100,000 banana doses per Kerbin day and stops if you send the kerbal on a mission. The kerbal undergoing decontamination temporarily loses 75% of their health and will need to rest afterwards. As always, each value can be adjusted in-game.
Whenever a kerbal levels up, there is a 25% chance that he or she will acquire a health quirk (unless he/she already has two). Discovering an anomaly can also grant a free quirk. These can be positive or negative and usually affect kerbals' vulnerability to various health factors and dangers. Chances of getting some quirks depend on courage and stupidity of a particular kerbal. The full list can be found in the Kerbal Health Wiki.
Kerbals' organisms, like ours own, are not always predictable. Sometimes, not very often, you may see unexpected events that can impact your whole mission. Kerbals acquire (or lose) certain conditions as a result of these events. Having parts with a Sick Bay (such as the stock Science Lab) helps alleviate the symptoms.
Conditions can be disabled or their chances and effects changed in game settings. You can also easily add, modify or remove conditions (see wiki for details).
Kerbal Health should work well alongside most other mods and will try to adapt to them with smart MM patches. Some have better, manually balanced support though:
Making History is supported but not required.
If you would like to include special support for your (or your favorite) mod, let me know.
This mod has been created by Garwel and is distributed under MIT license.