[Space] What’s the minimum resources required for Asteroid or Comet habitats?

[Johnny1A.2]

Originally Posted by Mysterious Dark Lord v3.2

Life-sustaining chemicals - Hydrogen, oxygen, carbon. All very common in asteroidal ices, comets, and on moons of outer system worlds. Combine them in a variety of manners, and you get water, fertilizer, plastic, fuel, etc.

True, but the combining process is non-trivial, and the necessary trace elements are very necessary.