Merry Christmas (belated) everyone! Presenting my first mod here. This adds a module to grow plants using other planets' atmospheric resources and get science out of it. You'll be able to run this experiment on Kerbin, Duna, Eve, Laythe, and Jool, and any modded planets where there is atmosphere present (if it doesn't work with the modded planet you're trying, and it does have an atmosphere, mention it!).
The design is based on that of the #LettuceOnMars team's submission for Mars One 2018 lander university payload competition. You can read more about them and how their project works here (yes, the project, in real life, passed a technical review):
This mod has been slightly KSPified in certain cases; you'll know when they happen. The modded experiment takes considerably shorter time to run than a few weeks, for example.
To install: Drag the LettuceOnMars folder to the GameData folder.
Little Q&A for those interested in the technical details:
Don't plants need oxygen to start germination?
> The design this is based on carries its own water, and either uses electrolysis or decomposes nitrous oxide to produce oxygen. The carbon dioxide is is obtained from the atmospheres of other planets, and so can the nitrogen or buffer gas. On certain large and gaseous planets, however, there is no carbon dioxide or buffer gas and the "explodium vapour" present might result in an energetic redox reaction with the oxygen produced. Here in KSP you can still put the experiment or two on a Jool descent probe and see what happens.
Where does the buffer gas come from:
> In real life, there's an open design choice between supplying a buffer gas (inert gas like nitrogen or argon) from chemical decomposition or extracting it from a planet's atmosphere. On a planet like Mars, the nitrogen content can be enriched using membrane filters, which are light, cheap, safe, and are in-real-life used in just about all but the most massive nitrogen production plants. For this mod, the buffer gas (Squad hasn't elaborated on what this gas is called) system uses the one best suited to the planet.
What about air pressure?
> A compressor is carried along to build up the pressure. That said Duna has a lot thicker atmosphere than Mars.