Plants in space

Discussion in 'Science and Technology' started by MadaBidyoni, Aug 27, 2013.

  1. MadaBidyoni

    MadaBidyoni Lieutenant Red Shirt

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    Jun 11, 2012
    Hi
    do you know which plants they will use in long space missions? plants that will pure the air, take out co2 & supply oxygen... (& could i buy them to clean the air in my house?;))
     
  2. gturner

    gturner Admiral

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    I've seen some older experiments with algae, which has the advantage of not having an "up".
     
  3. R. Star

    R. Star Rear Admiral Rear Admiral

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  4. RobertVA

    RobertVA Fleet Captain Fleet Captain

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    Don't forget:

    1. Photosynthesis uses light, carbon dioxide and water to make oxygen and sugar
    2. The metabolic process in animals (and plants in low light conditions) uses sugar and oxygen to make energy, carbon dioxide and water. Humans need supplemental water to replace what's lost in respiration, perspiration, and waste elimination
    If you can maintain the proper ration of photosynthesis to metabolism and don't vent materials to space you only need a window to allow sunlight to reach your garden or electricity to operate your grow lights (solar panels, mini nuclear plant etc)
     
  5. gturner

    gturner Admiral

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    I don't have my calculations handy at the moment, but solar cells and LEDs aren't all that far from surpassing direct sunlight for photosynthesis. Plants mainly use a thin band of red and a little blue. Since so little of yellow, green, deep blue, and UV are useful to plants, using a solar cell to gather all the sunlight and then drive narrow band red and blue LEDs can up the overall efficiency of agriculture per square meter of collection area - once the LED's are a bit more efficient than present. As I recall off the top of my head, you're looking for about 30% efficiency when you multiply the solar cell and LED efficiencies for the break-over point. For space applications, once you factor in all the losses in a purely optical solution (windows, mirrors, etc), the breakover should happen a bit sooner.

    From a design standpoint, this is a very good thing, because we need our plant habitats to have some artificial gravity, which of course means spinning. If you're trying to illuminate them with just windows and mirrors, this usually means they'll be spread out over a large surface area, which isn't a particularly efficient structure. It can also create very complicated topologies between the large, outboard collection mirrors and the required windows and light tubes to get the sunlight inside the station and shining on the plants.

    With solar cells, you just put them in space without spinning and snake the power wires into your grow rooms, which can have plants stacked on racks, densely packed for maximum volumetric efficiency.

    As for which plats to grow, grow just about everything you like to eat.
     
  6. Lindley

    Lindley Moderator with a Soul Moderator

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    Some plants require oxygen in the soil in addition to CO2 in the air. Just FYI.
     
  7. JarodRussell

    JarodRussell Vice Admiral Admiral

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    Jul 2, 2009
    Can big plants even grow properly in zero gravity?
     
  8. RobertVA

    RobertVA Fleet Captain Fleet Captain

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    You would probably need to spin the station to maintain the crew's health anyway. For those purposes the acceleration that results form the structure pulling the garden around the center of the spacecraft would be indistinguishable from gravity.

    One issue with many traditional food crops is the relatively small percentage of the plant that would be directly consumed by the crew. If they can be convinced to consume algae bars and/or algae shakes instead of things like broccoli, lettuce and cucumbers the gardens could probably be smaller. With the more traditional crops much of the plant would have to be recycled to fertilize the next generation of crops.