How do you make a complete carbon-cycle in a spacecraft?

Discussion in 'Science and Technology' started by Urge, Apr 2, 2012.

  1. Urge

    Urge Lieutenant Commander Red Shirt

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    In startrek they probably have some sort of machine that splits CO2 into C and O2 - but there exist no such machine right now, does it?

    So I was thinking, that if you wanted a complete carbon-cycle in a minimal space, you would still need some sort of photosyntesis on board.

    One idea I had, is that if you have little park of fast-growing trees on the ship, then these trees can be turned into some sort of more digestable tree-pourage (it probably wont taste so good, but Im not planning for a luxury-cruise) with shorter carbon-hydrates, or whatever it is those cellulose-molecules need to be manipulated into in order to be eatable.

    Also, water would have to be destilled in an endless cycle, and all forms of organic waste must be turned into soil for the tree-park.

    If you find the right type of fast-growing tree, and have a way of turning the wood into food without spending oxygen in the process, then you can travel for a very long time without needing fresh supplies? Kind of?

    I imagine that the tree-pourage would need some vitamins and minerals added in order to give the body all it needs, but this will only be a drop of this and a hint of this - so it wont be so space-consuming to bring along.
     
  2. The Dominion

    The Dominion Fleet Captain Fleet Captain

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    If you're going to put trees on the ship, why not other vegetables? I think the key to having a livable environment for a trip into space is to have a fully functioning greenhouse with a variety of plants to use.
     
  3. Robert D. Robot

    Robert D. Robot Fleet Captain Fleet Captain

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    I wonder if tanks of some genetically modified, rapidly growing planktonic algae would do the trick just as well (although would not be as aesthetically pleasing as a nice park of trees!....)

    On the other hand, I believe this was the plot line of a story that
    Harlan Ellison wrote for "Voyage to the Bottom of the Sea" (and it did not wend well!)
     
  4. Asbo Zaprudder

    Asbo Zaprudder Rear Admiral Rear Admiral

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    Fast growing greens such as lettuce would be a good idea to add variety to the diet. Legumes might not be so doable as the bacteria in their nodules rely on fixing nitrogen from the air. Most spacecraft have oxygen-only atmospheres. It would be a good idea to find an hygienic way of turning human waste into fertiliser. You might also need an artificial gravity environment (probably by rotation) as I don't think plants cope well without an acceleration frame to guide their growth (gravitropism) although a directional light source does help to some extent (phototropism).

    http://www.redorbit.com/news/science/122510/growing_plants_in_zero_gravity/
    http://spaceflight.nasa.gov/station/crew/exp6/spacechronicles13.html
     
  5. The Dominion

    The Dominion Fleet Captain Fleet Captain

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    Algea would be a great idea. It's more effective than what trees do actually, and low maintenance. I guess it would be edible too, depending on what kind it is.
     
  6. Robert D. Robot

    Robert D. Robot Fleet Captain Fleet Captain

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    ^ That's what I was thinking. I had heard that someone was developing a nutritious, edible paste made from planktonic algae. I think I'd call it something other than "paste", though... algae jam, maybe? I guess it could be something like Vegemite, but they could get creative and make some form other than paste, too....
     
  7. Urge

    Urge Lieutenant Commander Red Shirt

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    Its important though, that the algea that produces the paste, does not consume oxygen in the process.

    I imagine that the human crew will consume so much oxygen that they can not have any competition from other oxygen-consuming life-forms on board.
     
  8. Asbo Zaprudder

    Asbo Zaprudder Rear Admiral Rear Admiral

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    Blue-green algae (cyanobacteria) released most of the atmospheric oxygen on Earth by photosynthesis. A paste of algae might not be too edible if cyanotoxins are also produced though. Even if such metabolic byproducts are not present, it would be a very bland diet.
     
  9. Urge

    Urge Lieutenant Commander Red Shirt

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    My spacecrew will just have to use a lot of spice.

    A little side-track:

    If those cyano-bacterias in the ocean take C02 and makes oxygen. Could they not work well against global warming? We can make large artifical lakes and make sure they thrive, up to the point were the lakes turn into thick, green, goo.

    And as the algea-bacterias become so numerous that they suffocate in their own poison, the remaining water can probably be filtered out, and then they will sooner or later turn into highly nutritious soil.
     
  10. Asbo Zaprudder

    Asbo Zaprudder Rear Admiral Rear Admiral

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    Iron fertilization.
     
  11. YellowSubmarine

    YellowSubmarine Rear Admiral Rear Admiral

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    We're living on an open spacecraft with a complete carbon cycle. With no limit on the size of the spacecraft, we can simply copy the carbon cycle system from here and hope that it will work. If there's a limit, we can still copy it and watch it fail. In both cases it will be equal fun.
     
  12. Asbo Zaprudder

    Asbo Zaprudder Rear Admiral Rear Admiral

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    Biosphere 2 is one of the places where they've tried setting up a closed ecological system - with mostly disappointing results.
     
  13. JustAFriend

    JustAFriend Commodore Commodore

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    It's real easy to tell who grew up in a city and always ate everything out of a package...

    ;-))
     
  14. Robert D. Robot

    Robert D. Robot Fleet Captain Fleet Captain

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    If they intend to "fold space", they surely will need the Spice! ;)
     
  15. Urge

    Urge Lieutenant Commander Red Shirt

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    Nope. The people on my spaceship will eat "algfu" that comes out of big glass-containers with green water. The "algfu" is produced by the algeas, and then tapped into containers.

    They heat it in a microwave-oven after mixing it with lots of spices, in order to make it eatable. They also drink a lot of distilled water to get it down.

    The maintanence-crew some times add minerals and stuff to the water in order to make sure the algea thrives and make enough algfu for everyone. (I am thinking about having to different types of algea on board, one type that is dedicated to algy-production, and another one that makes oxygen)

    Im thinking "DDR in space" - specially because the ships captain is a stalinist dictator who flee towards Mars (in a very slow spacecraft) with his ministers (and a large crew off course), because the UN hate him.

    All the other people who have quarreled with the UN in the past are already there, so Mars is a being populated by strong-minded dictators of various kinds.

    Please dont copy the idea :-)
     
  16. Asbo Zaprudder

    Asbo Zaprudder Rear Admiral Rear Admiral

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    Sounds like Dune. :p

    Remember, the spice must flow. He who controls the spice, controls the universe!
     
  17. publiusr

    publiusr Rear Admiral Rear Admiral

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    The ship needs to be pretty big, one would think.
     
  18. Santaman

    Santaman Rear Admiral Rear Admiral

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  19. PurpleBuddha

    PurpleBuddha Rear Admiral Rear Admiral

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    This part interests me. I assume that separating carbon from oxygen artificially would currently require a lot of energy so as to make it impractical. Right?

    Not knowing much about plants myself, what type of chemical process occurs in the plant to do the same thing? Can this potentially be artificially replicated in a way that is practical and efficient?
     
  20. Asbo Zaprudder

    Asbo Zaprudder Rear Admiral Rear Admiral

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    In the most general terms, photosynthesis in plants creates glucose (a simple sugar):

    6 Carbon Dioxide + 6 Water + Light → Glucose + 6 Oxygen

    A great deal of research is being done into artificial photosynthesis, but I can't say how far it is from being commercially viable. It appears that natural photosynthesis might rely on quantum entanglement effects to boost its efficiency, and plants are much better at capturing carbon dioxide at atmospheric concentration than are man-made devices that emulate photosynthesis.
     

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