1. Subscribersonhouse
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    30 Jul '14 10:29
    http://phys.org/news/2014-07-silk-leaf-maker-material-aid.html

    This may be a boon for space travel, efficient recovery of O2 from people's CO2. Would have been a big help on Apollo 13......
  2. Standard memberforkedknight
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    30 Jul '14 14:422 edits
    Originally posted by sonhouse
    http://phys.org/news/2014-07-silk-leaf-maker-material-aid.html

    This may be a boon for space travel, efficient recovery of O2 from people's CO2. Would have been a big help on Apollo 13......
    I'm skeptical.

    How efficient could this possibly be, and what happens to the carbon?

    There are no numbers or even a description of how the photosynthesis process continues to work in the article.
  3. Subscribersonhouse
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    30 Jul '14 15:04
    Originally posted by forkedknight
    I'm skeptical.

    How efficient could this possibly be, and what happens to the carbon?

    There are no numbers or even a description of how the photosynthesis process continues to work in the article.
    If it were 100% efficient, the carbon would just come out as elemental carbon. If it were less than 100% there would be O2 plus some amount of CO, carbon monoxide. So time will tell if it works out. Even if it doesn't it might lead to ways of doing it more efficiently yet. Whatever that works out to be.
  4. Standard memberDeepThought
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    30 Jul '14 15:28
    Originally posted by forkedknight
    I'm skeptical.

    How efficient could this possibly be, and what happens to the carbon?

    There are no numbers or even a description of how the photosynthesis process continues to work in the article.
    He claims to have injected some kind of silk extract with chloroplasts so the carbon will be sequestered as glucose. I'm hugely sceptical, first this is a solved problem, nuclear submarines can stay underwater indefinitely - the only limitation is how much food they can carry to feed the crew with. The second point is that you have to keep the chloroplasts alive, so the problems with keeping a living thing alive have not gone away. Also this guy is a graduate of the Royal College of Arts, so he's not a scientist. The purpose may be artistic, rather in the way that the point of Damian Hurst's bisected shark is to get people to pay to look at a pickled fish. Basically I think it's a hoax for artistic purposes.
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    30 Jul '14 15:36
    As DeepThought says, it looks like wild speculation by someone who hasn't got a clue. For some unexplained reason the writer seems to think that the chloroplasts will continue to work indefinitely without cellular machinery.
    Also the writer seems to think the only alternative plant for space travel is an tree.
  6. Standard memberforkedknight
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    30 Jul '14 15:53
    Originally posted by sonhouse
    If it were 100% efficient, the carbon would just come out as elemental carbon. If it were less than 100% there would be O2 plus some amount of CO, carbon monoxide. So time will tell if it works out. Even if it doesn't it might lead to ways of doing it more efficiently yet. Whatever that works out to be.
    I mostly meant efficient in the "How many do you need to get something tangible?" kind of way.

    Fake leaves that make oxygen are great, unless you need 4 metric tons of them to produce enough oxygen to matter at all.

    There's also efficiency in terms of how many plants you need to kill in order to make a tiny fake leaf, which puts a real damper on the potential usefulness on earth.
  7. Standard memberDeepThought
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    30 Jul '14 22:16
    Originally posted by forkedknight
    I mostly meant efficient in the "How many do you need to get something tangible?" kind of way.

    Fake leaves that make oxygen are great, unless you need 4 metric tons of them to produce enough oxygen to matter at all.

    There's also efficiency in terms of how many plants you need to kill in order to make a tiny fake leaf, which puts a real damper on the potential usefulness on earth.
    Very good point. The article on photosynthesis on Wikipedia doesn't shed much light on how much you'd need, but the stuff under efficiency to do with quantum walk is well worth a read. Also where are they going to get the light from. With an earth orbit it's fine, but further out may not be. I'd hazard a guess that one would need several human body masses per person to be kept alive. Also if plants can do it why not just use cyanobacteria?
  8. Subscribersonhouse
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    31 Jul '14 00:59
    Originally posted by DeepThought
    Very good point. The article on photosynthesis on Wikipedia doesn't shed much light on how much you'd need, but the stuff under efficiency to do with quantum walk is well worth a read. Also where are they going to get the light from. With an earth orbit it's fine, but further out may not be. I'd hazard a guess that one would need several human ...[text shortened]... dy masses per person to be kept alive. Also if plants can do it why not just use cyanobacteria?
    I thought it was some kind of filter like an RO filter or something. So you have to supply it with energy. Well you could still use them say at Jupiter if you concentrated enough light on it, like a big mylar balloon reflecting into the craft. Just throwing things out there.

    How do regular rebreathers work?
  9. Standard memberDeepThought
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    31 Jul '14 20:36
    Originally posted by sonhouse
    I thought it was some kind of filter like an RO filter or something. So you have to supply it with energy. Well you could still use them say at Jupiter if you concentrated enough light on it, like a big mylar balloon reflecting into the craft. Just throwing things out there.

    How do regular rebreathers work?
    They just scrub out the carbon dioxide in the system, using soda lime or some other carbon dioxide absorbing chemical. Typically oxygen is added from a cylinder. There are systems that release oxygen, but have their own problems. A system that cleanly removes carbon dioxide and releases water would be useful for a lot of applications.

    See: http://en.wikipedia.org/wiki/Rebreather
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