Although I enjoyed playing both TAC life support and the life support in better than starting manned I didn't feel like their game play was the best implementation of a life support mod.
This is an ongoing project and is in no way finished yet.
The planned Implantation is to allow life support to get more difficult and complex the longer you need Kerbals to be in space.
1: Breathable_air.
This runs out in seconds to minutes depending the size of the capsule. To make more requires either a end tech hydroponics module or both oxidizer (I'm assuming for this mod it is liquid oxygen) and a way to remove carbon dioxide.
Why have I done it this way and not used both oxygen and carbon dioxide? Humans can't live if either carbon dioxide goes above 3-5% or oxygen goes below a certain percentage. Every breath we crate the same amount of carbon dioxide as the oxygen we use. The two are linked and adding in another resource just clutters the resources screen. What I have added is lithium hydroxide. This is a basic carbon dioxide remover and is used up when used. Basic air scrubbers use this and oxidizer (oxygen) to create breathable air.
2: Water. Kerbals drink water. All pods will start with days worth of water in them. It will be the first thing after air that player will have to think about. There will be water containers. I'm planning to make hydrogen cell for power that make water. Lithium hydroxide also makes water as a by product. Kerbals will also make waste water that can be converted to water at a 60% efficiency in starting water scrubbers 90% in advanced scrubbers and 100% in hydroponics.
3: Food. All pods will start with days to a few weeks worth of food in them. There will be food storage canisters. hydroponics will be the only way to make more.
4: Sanity. Kerbals like space and other Kerbals just like more people. One Kerbal cooped up in a capsule on his own is OK for a while but will eventually go insane and have an "accident" or an accident. Empty seats will provide space for you Kerbals so hitchhiker canisters are good (they only need to be part of the same ship) as are any parts (hopefully including modded parts) that have seats in them. The Kerbals will also want other Kerbals to talk to so bringing a couple of friends (bill and bob should do) should help but for a very long period many Kerbals and lots of empty seats will be required.
5: Radiation. This is difference to sanity in that it is dependent on atmosphere. Kerbin gets no deadly radiation on the surface but will high up. Duna has a thin atmosphere so some radiation will get though. Orbiting planets will cause a high radiation dosage but even with no shielding Kerbals should survive for months. Radiation shielding will be added as a part.
Science bonuses for Kerbal tasks will be added to balance the extra effort though reducing automated science test may also be required.
I would also like to add a science part that is required to be attached to a science lab. This should encourage more lab use. Remember the seat on the lab will also count as extra space.
All of these resources will run whether in focus or not.
So why make a new mod and not just modify another mod? Firstly I would require the makers permission. Secondly none of the mods have some of the mechanics required to run things like sanity. Thirdly I am trying my hand at making parts as well as programing of Kerbal space program and I am attempting to make stock like parts. Fourthly to make the game play work the way I want I would need to remove parts of the mods like oxygen and carbon dioxide as separate resources for TAC.
Progress
Uploaded at the moment is just the oxygen tank. I have a lot more code and modeled but this is the only nearly finished element and I would like advice on it.
Parts Models Textures Unity compiled .CFG
Oxi Tank 100% 100% 100% 100%
Food storage tank 95% 80% 0% 100%
Water tank 0% 0% 0% 0%
Lithium Hydroxide tank 50% 0% 0% 0%
Lithium Air scrubber 50% 0% 0% 0%
Regenerative air scrubber 0% 0% 0% 0%
Water recycler 0% 0% 0% 0%
Advanced water recycler 0% 0% 0% 0%
Hydroponics 0% 0% 0% 0%
radiation shield 50% 0% 0% 0%
Code
Written Tested Active
Can kill Kerbals 100% 50%
Kerbals use resources 80% 50%
Kerbals use resource when not in focus 40% 40%
Sanity drains correctly 40% 40%
Radiation builds correctly 40% 40%
Air works right 40% 40%
Water works right 0% 0%
Food works right 40% 40%
Air scrubbers work right 40% 40%
water scrubbers work right 0% 0%
radiation shields work right 40% 40%
hydroponics works right 30% 30%
Kerbals take resources on EVA 0% 0%
Other (unknown at present) 0%