[HN Gopher] Self-replicating radiation-shield for deep-space exp...
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Self-replicating radiation-shield for deep-space exploration:
Radiotrophic fungi
Author : che_shr_cat
Score : 154 points
Date : 2022-01-15 13:58 UTC (9 hours ago)
(HTM) web link (www.biorxiv.org)
(TXT) w3m dump (www.biorxiv.org)
| choeger wrote:
| What is it with all the fuzz a out fungi in space lately? Is
| Discovery so well-liked or is it the other way around?
|
| Serious question: How does the fungus release the energy? heat?
| Could we use them as some kind of biological radiation thermal
| panels on Mars?
| dnautics wrote:
| My guess is that the original paper is artefactual, but there's
| no reason a priori that an organism _couldn 't_ take large
| classes of ionizing radiation and turn it directly into
| chemical energy, ionizing radiation, after all, effects
| chemical transformations.
| nynx wrote:
| Clearly the end goal for this research is figuring out why the
| fungi can block radiation and taking advantage of that for better
| radiation shielding. We're not going to be flying around in
| spaceships coated in fungi.
| Chris2048 wrote:
| Hmm, how would fungi be different from a self-repairing
| expanding foam? Other than needing to be kept alive?
| xvilka wrote:
| Maybe the future of space travel are living spaceships. Some
| kind of crustaceans with outer shell, living main body, and
| human crew inside. Something between fungi, animal, and plant
| even.
| jorvi wrote:
| > Something between fungi, animal, and plant even.
|
| You mean a protista?
| vbezhenar wrote:
| IMO future of everything is replicating nano-robots,
| artificial life-like beings. Nature can't be as good as
| artificially created specialized mechanisms. Right now nature
| have an advantage in self-replicating cells which we can't
| reproduce yet, but I'm sure that we will.
| edgyquant wrote:
| Maybe over 2 billion years nature has created as efficient
| as we can get, and it would be best to have hybrid life
| that is a mix of nano-tech and biological cells. Is it a
| given that we could create tiny factories more efficiently
| than cells?
| IX-103 wrote:
| Nature tends to get stuck in local optimums where things
| are "good enough". For reference see the recurrent
| laryngeal nerve, the "backwards" eye in many animals
| (though not octopuses or their relatives).
|
| We can do better than nature just by taking the best from
| everything, integrating it together, and removing all the
| extra junk. Imagine if we just used it as inspiration.
|
| I'm not saying tiny factories wouldn't end up looking
| like cells, but I expect the similarities to be
| superficial, as we have access to more robust materials
| to serve as feedstock and can have better control of the
| operating environment.
| walleeee wrote:
| cool, like the yuuzhan vong
|
| in a sense a planet is one of these already, just a little
| less maneuverable than we would maybe prefer out of a ship,
| and inverts the hard shell soft interior crustacean-ship idea
|
| for large ships maybe you could literally use a planet, e.g.
| swing a spare one out of the solar system in the direction
| you want to go... if rogue planets can hold down an
| atmosphere and stay geologically active [0] maybe you could
| have liquid water oceans and sea life and atlantean cities
| scattered around the seafloor drawing hydrothermal power
|
| plus you're hidden pretty well flying dark in interstellar
| space, maybe civilizations deem it prudent to leave their
| parent stars for dark forest concerns etc, maybe you could
| even harness earthquakes/vulcanism to (very slowly)
| manipulate the angular velocity vector enough to course-
| correct and navigate
|
| [0]: https://doi.org/10.1038%2F21811
| f6v wrote:
| That's straight out of Farscape, iirc. I remember watching a
| living ship fly though space as a kid and it seemed like a
| giant stretch. But maybe it isn't.
| T-A wrote:
| Good old Moya:
|
| https://farscape.fandom.com/wiki/Moya
| edgyquant wrote:
| Maybe these competing for resources around stars is the
| future of life
| FredPret wrote:
| > crustacean
|
| We'll call it the lob-star
| arcticbull wrote:
| Why _not_ Zoidberg, tbh?
| justinator wrote:
| I call it: delicious!
| whalesalad wrote:
| Why not? I mean, the fungi would die out in space without
| oxygen but if it retained its properties it could be used just
| like any other material: wood, steel, ceramics, etc.
|
| The coolest part about fungus is that it will grow into its
| environment, so I would imagine molds (no pun intended) could
| be used to "grow" a panel, sheet, etc almost like natural 3D
| printing.
| mtsr wrote:
| There are a few companies that produce packaging alternatives
| for EPS that way.
| kortex wrote:
| I mean why not? Hard radiation tends to destroy whatever it
| hits on a molecular/atomic level. If you have a biological
| shield which is constantly refreshing itself, you can possibly
| have a much lighter assembly. Mycelium has also been used to
| purify water. It might be possible to integrate shielding with
| water storage/buffer and recycling.
|
| It'll probably require layering different types of material to
| convert higher energy radiation (like cosmic rays) to more
| manageable spectra.
| FredPret wrote:
| If we had a fungi that could purify water and block out deep
| space radiation, that would be one sweet mushroom.
|
| Better hope it doesn't die halway to Mars!
| kortex wrote:
| Yeah, that would be something we'd want to do long-scale
| simulation tests of before setting sail. Build a simulated
| spaceship, probably in orbit for maximum accuracy, and see
| how everything holds up.
|
| Tbh I'd be more concerned about the humans cracking
| psychologically before the fungus dying. They are hardy
| buggers.
| lallysingh wrote:
| I think the end goal would be a fungi that we can layer between
| hulls and is low maintenance. Or even better, that also
| generates oxygen. Maybe even feeds on human waste.
| abletonlive wrote:
| fungi consume oxygen, or at least, most of them do. not sure
| why people think of fungi as plants.
| ipodopt wrote:
| We don't want a material that builds and repairs itself?
|
| Anyhow, seems like they think it is the concentration of
| melanin in the fungi. The melanin has been sequenced and it is
| the same type found in human skin. Maybe we will see this
| adaptation in space fairing humans... Wonder if current black
| astronauts are less effected by radiation.
|
| EDIT: Probably something that will seem so obvious in
| hindsight.
| T-A wrote:
| Check out the Martian settlers in Spin:
|
| https://en.wikipedia.org/wiki/Spin_(novel)
| hinkley wrote:
| Because fungi are some of the oldest terrestrial organisms on
| the planet. Today they often enjoy shade and humidity, but at
| the time there was melanin and other UV blocking chemicals, or
| wearing other organisms as a hat (lichen).
|
| There's one interpretation of evolution where fungi are the
| original farmers. Everything from lichen up to and including
| trees only happening because it suited fungi to do so.
| MertsA wrote:
| I don't understand the interest here. It's not like fungi are
| magically more effective than virtually any other mass at
| absorbing ionizing radiation and subatomic particles. "Self-
| replicating" is meaningless when it needs to consume water and
| carbon sources to do so which on their own would probably be
| denser and more effective per unit volume at shielding. Chemistry
| has next to nothing to do with radiation shielding let alone
| biology.
| omginternets wrote:
| I imagine this might be interesting for longer distances in
| which broken shielding might not be so easily replaced. In such
| cases, regenerating your shielding via life-support systems is
| a feature, not a bug.
| lumost wrote:
| Why not fly with a pre pulverized shield? There aren't many
| big forces on a long distance space hall and one could
| imagine using electrostatic forces to hold the pulverized
| shielding in place. No need to regrow the radiation shield
| then.
| omginternets wrote:
| Why not indeed. Why not investigate growing a shield as
| well?
| ianai wrote:
| species: Cladosporium sphaerospermum
|
| """
|
| radiation beneath a [?] 1.7 mm thick lawn of the dematiaceous
| radiotrophic fungus was 2.17+-0.25% lower as compared to the
| negative control. In addition, a growth advantage in Space of ~
| 21% was observed, substantiating the thesis that the fungus'
| radiotropism is extendable to Space radiation.
|
| """
| ByThyGrace wrote:
| So what is "growth advantage" and why is the 21% figure
| meaningul?
| plutonorm wrote:
| The fungus grows better in space. Probably because it's
| radiographic (uses radiation for energy). But also possibly
| because it came from space and incidentally populates
| environments on earth (I'm semi serious).
| MauranKilom wrote:
| I don't think the conditions on random meteors are in any
| way comparable to some lab in the ISS...
| ianai wrote:
| Consider on the low end ((2.17-.25)% per 1.7 mm thick) this
| works out to 88.6 mm for 100% coverage or around 3.5 inches.
|
| I'm wondering whether the fungus could actually be grown to
| various thicknesses, or is 1.7mm kind of its natural thickness?
| Might need a layer system of some sort.
|
| I'm really thinking I should burn some time on learning about
| fungi and bacteria. It'd be cool if there were some ecosystem
| of them capable of taking in human waste as input and
| outputting useful things like cleaner water and shielding.
|
| (Replied to myself since the other comment is older.)
| lioeters wrote:
| Book recommendation: Mycelium Running
|
| > Mycoremediation: the use of mycelium for decomposing toxic
| wastes and pollutants
|
| https://fungi.com/products/mycelium-running
| phdelightful wrote:
| Does it actually work like that or does each successive 1.7mm
| multiply the radiation flux by 0.98? And then the inner
| layers will get less radiation and grow less well also?
| version_five wrote:
| This is correct, each incremental layer would block 2% of
| what is incident on it, not knock 2% off the starting
| number
| ianai wrote:
| Yeah if it's like that, I get around .9 meters thick for
| blocking 99.999997%.
|
| I'd like to see what a 10x thicker fungus could block. That
| would help inform how it's likely to flesh out at scale.
| JohnJamesRambo wrote:
| I grew fungi for a living at my previous job. They will grow
| in any shape you like as long as they have food and
| substrate.
|
| The lower levels will get less radiation though.
|
| https://www.buildinggreen.com/blog/greensulate---fungus-
| base...
| lostlogin wrote:
| It could be grown in movable segments so that the less
| exposed parts got a good dose regularity. Sounds like a
| pain to manage.
|
| Either way, you'd need to be checking it regularly as
| having a section die would be bad.
| satya71 wrote:
| You'd need about 400mm thick layer to cut radiation to 1% of
| incident at 2% per layer.
| Voloskaya wrote:
| > ((2.17-.25)% per 1.7 mm thick) this works out to 88.6 mm
| for 100% coverage or around 3.5 inches.
|
| 2.17% is when only one side is shielded: "it can be
| extrapolated that the biomass would reduce total radiation
| levels (of the measured spectrum) by 4.34+-0.5% were it fully
| surrounding an object"
|
| But your assumption that this thing scale linearly is far
| from reality, see for example their estimate for Mars:
|
| "In a case study we estimated that a ~ 2.3 m layer of
| melanized fungal biomass (8.6% [wmelanin/wCWW] melanin-
| content) would be needed to lower Martian radiation levels to
| those on Earth (from 234 mSv/a to 6.2 mSv/a [6, 7, 53])"
|
| ISS is at apporximately 144 mSv/a.
| ianai wrote:
| I think it's probably fair to say this is early research
| and much more would need to be done. I also figure this
| could be done on earth and tested against various radiation
| sources.
| lostlogin wrote:
| > It'd be cool if there were some ecosystem of them capable
| of taking in human waste as input and outputting useful
| things like cleaner water and shielding.
|
| Earth is pretty good. A little large to change its direction
| of travel though.
| yummypaint wrote:
| For the record, here is the correct math for attenuation of high
| energy photons with a nice explanation from NIST:
| https://physics.nist.gov/PhysRefData/XrayMassCoef/chap2.html
|
| The coefficient in the exponential is 0.0161/mm for these data,
| so a 100 mm thick layer will stop 80% of their measured spectrum.
| A 200 mm thick layer will stop 96%.
|
| The same relationship applies for higher energy gammas as well,
| but the coefficents will be energy dependent.
| kangaroozach wrote:
| Encapsulate the entire vessel in a membrane of fungi? No windows
| just fungi-bubble deep-space faring?
| f6v wrote:
| ISS doesn't have that many windows for a reason.
| blamestross wrote:
| Now this is the solarpunk/biopunk future I signed up for.
| Symbiotic radiation shielding fungi for space exploration!
| AndrewDucker wrote:
| It's a fascinating idea.
|
| But 2% lower radiation isn't going to do nearly enough.
| biorach wrote:
| That's with a 1.7mm layer of fungus. This looks to be proof of
| concept research.
|
| Whether thicker layers can be used to provide comprehensive
| protection is for future research to establish. (and it's
| unlikely to be a linear relationship)
| Aspos wrote:
| It is 2% with the current strain of the fungus which may evolve
| in the future.
| ape4 wrote:
| When we meet some aliens they might greet the fungus instead of
| us
| hinkley wrote:
| Why have they decorated their ships with dead bodies? What sort
| of barbarians are we dealing with here?
| MauranKilom wrote:
| Decorating the ship with dead fungi would be very pointless
| though. You could use most any other material for the same
| effect.
| f6v wrote:
| When we meet some aliens they're likely to be fungus, at best.
| kgc wrote:
| Where does the additional mass come from when the fungi
| reproduces in space?
| jxcole wrote:
| IIUC most of the mass required to build plants comes out of the
| air (CO2). Of course, any astronauts wanting to utilize these
| fungi will have to take some amount of other resources with
| them.
|
| The most important measure for any radiation shielding in space
| is weight. We have great technology for blocking all radiation
| today: lead plating. This is obviously way to heavy for space.
| Alternative suggestions have been to surround the astronauts
| with water which presents a lot of challenge in terms of
| plumbing and weight. Having the walls covered in fungi may
| actually be a much lighter option, I certainly hope the idea is
| well considered.
| hinkley wrote:
| The other advantage of fungi might be in the aftermath of a
| micrometeoroid event. Does it make more sense to cut a hole
| in your shielding and use up a store of fungal bricks that
| you brought with you, or to grow a somewhat custom patch with
| the right radius of curvature, and slightly larger than the
| hole, and then recycling any material that gets removed to
| apply the patch.
|
| If the shield is actually alive (say, a layer around your
| emergency shelter), then you can just fill the hole with food
| and let the fungi patch themselves, and any damage caused by
| being exposed to partial vaccuum. Possibly with a mold that
| also acts as a temporary, reusable patch over the worst hit
| areas, so that a subsequent space storm doesn't catch you
| with your pants down.
| meepmorp wrote:
| > IIUC most of the mass required to build plants comes out of
| the air (CO2).
|
| Fungi aren't plants, though.
|
| edit: they're heterotrophs - they get their food from more
| complex materials than autotrophs, which generate their raw
| material largely from carbon extracted from the atmosphere.
| samus wrote:
| For fungi, the carbon source is actually even more
| straightforward than with plants: we can just feed them
| biowaste. Depends on the species of course, and probably
| requires some treatment to not encourage growth of less
| desirable species instead. If they turn out to be edible,
| this could prove to be ideal.
| littlestymaar wrote:
| > edit: they're heterotrophs
|
| Except not these ones! These are autotrophs fungi, they do
| some kind of photosynthesis (it's absolutely not the same
| metabolic path, though) gaining their energy from gamma
| rays instead of food.
|
| Edit: The above comment is wrong, I though autotroph vs
| heterotroph was about energy input (as a matter of fact I'm
| very convinced it was how my college teacher explained it)
| but from wikipedia it looks like I'm wrong, and such fungi
| would be classified as Photoheterotroph[1]
|
| [1]: https://en.wikipedia.org/wiki/Photoheterotroph
| meepmorp wrote:
| Yes, but they're still fungi. They might be extracting
| some amount of energy from radiation, but they still get
| most of their energy (and cellular raw material) the old
| fashioned, biological way. It's not like they suddenly
| evolved replacement pathways to synthesize all the
| products they need.
| andrewflnr wrote:
| Maybe we should think of the fungus as self-managing water
| storage and plumbing.
| beebmam wrote:
| Lead does not block "all radiation". Here's a great video
| that explains common types of radiation and what kind of
| materials are effective at blocking each of these types of
| radiation: https://www.youtube.com/watch?v=iTb_KRG6LXo
|
| There's plenty of radiation that we have no effective way of
| blocking, like neutrino radiation.
| hinkley wrote:
| Short version: sometimes it's not the bullet that kills you
| but the spray or ricochet. There are plenty of types of
| radiation that you want to block with light elements. If a
| high energy particle spalls off some hydrogen atoms, then
| those can be less damaging than a similar collision in
| steel or lead. Fungi is a mixture of mostly light elements.
|
| But that's about the extent of my knowledge.
|
| Do you happen to know if in a composite shielding situation
| (several layers of multiple materials) would you put the
| lead on the outside facing the hard radiation, or on the
| inside?
| formerly_proven wrote:
| Ability to block/attenuate radiation is proportional to
| interaction probability which is generally also
| proportional to biomedical risk: ergo, if we can't block
| it, we don't care about it.
| lostlogin wrote:
| Surely you'd need a lot more water than lead?
|
| At least you can be using the water though.
| samus wrote:
| The water will accumulate deuterium and tritium over time
| though. Eventually, it will degrade to emergency drink
| status. Might be a good way to get at fusion reactor fuel
| though.
| Tagbert wrote:
| Probably water and air. Combine that with the radiation and
| trace elements from the water and you have enough to build
| tissue.
| [deleted]
| hinkley wrote:
| Imagine you're an interplanetary civilization. You're building
| long haul ships not rated for Earth atmosphere, just ferrying
| supplies between planets, or landing on moons and asteroids.
| You might have a shipyard in orbit, though the moon seems more
| likely (too many pulverized metal oxides right there begging to
| be dumped into a smelter) or a carbonaceous asteroid (which can
| still be high in metals). You can still use vacuum rated
| engines to lift it into orbit, although you might have to
| design the ship as a second stage for some lifting platform to
| get the deltaV you need.
|
| Growing shielding could be very good. Especially if you can use
| waste products to do so. The right sort will be easier to find
| on the right asteroid, but could be available on the moon if
| you have a high enough volume of imported supplies being turned
| into effluent streams.
| suifbwish wrote:
| Technically light can be converted into mass, but I'm not sure
| that's relevant here.
| TonyRobbins wrote:
| Kyragem wrote:
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