Greenhouse
Growing plants in a Greenhouse delivers oxygen and food. It can play an important part in human recreation. The sunlight is not bright enough on Mars to allow usual terrestrial plants to thrive, but it provides a valuable part of light energy for plants.
The greenhouse will be constructed from transparent material, allowing maximum sunlight to pass, generating an artificial "greenhouse effect". The spectral properties of the material should be optimized to match the absorption characteristics of chlorophyll, maximizing the energy gain.
Plants need a mix of air pressure and temperature. The greenhouse must be strong enough to hold that air pressure, and it must be insulating to hold the temperature inside.
Additional energy is necessary to light and heat the greenhouse.
Side-lit Greenhouse Concept
The Mars Foundation concept for a greenhouse involves the maximum use of local materials to avoid waste, maximize energy input and optimize space. Spawned from the Hillside settlement design, the greenhouse would most likely be located inside/next to a hill side. Therefore regolith or some other absorbant material could be suspended above the greenhouse to protect occupants and plants from harmful radiation. The source of light would therefore be directed from the side, via and array of adjustable mirrors. A system of vents and ducts would allow warm air to circulate, perhaps even used to heat the main habitat.
Open Issues
- How much greenhouse area is needed per person?
- How much additional energy is needed per square meter?
- What temperature and pressure do plants need?
- What transparent materials match the absorption characteristics of chlorophyll?
