Could spaceships just put a bunch of plants on board to produce all their oxygen and get rid of the carbon dioxide?
In: Biology
This process requires light, and in that regard it’s pretty inefficient. Even assuming that 100% of light that you produce by some fixture is absorbed by the plants’ leaves. Most of that light simply heats the plant, and among that, a significant portion of the absorbed energy goes to running biochemical processes other than absorbing CO2 and producing oxygen and carbohydrates.
The other issue is that plants require massive amounts of water, which is another source of inefficiency. That water is evaporated from their leaves. In a spacecraft this can be recycled as condensation but this also consumes large amounts of energy.
Oxygen can be easily produced by running an electric current through water containing a small amount of acid as a catalyst.
This is vastly more efficient and much simpler than relying on plants.
Growing plants on spacecraft might be a useful activity for another reason, for producing food. But there are any number of other more serious technical issues with long term spaceflight that still open questions.
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