This reminds of Cordwainer Smith's [1] most famous story, Scanners Live in Vain [2]. In the story, a scientist named Adam Stone has found a way to conquer The Great Pain of Space that affects humans who travel into space. To do so he builds a ship whose walls are teeming with life that shields the human inside it:
"I have loaded ships with life."
"Life?"
"Life. I don't know what the Great Pain is, but I did find that in the experiments, when I sent out masses of animals or plants, the life in the center of the mass lived longest. I built ships -small ones, of course- and sent them out with rabbits, with monkeys-"
"Those are Beasts?"
"Yes. With small Beasts. And the Beasts came back unhurt. They came back because the walls of the ships were filled with life. I tried many kinds, and finally found a sort of life which lives in the waters. Oysters. Oysterbeds. The outermost oysters died in the great pain. The inner ones lived. The passengers were unhurt."
"But they were Beasts?"
"Not only Beasts. Myself."
"You!"
"I came through Space alone. Through what you call the Up-and-Out, alone. Awake and sleeping. I am unhurt. If you do not believe me, ask your brother Scanners. Come and see my ship in the morning. I will be glad to see you then, along with your brother Scanners. I am going to demonstrate before the Chiefs of the Instrumentality."
Yes indeed. I can't find this information online but I remember an anecdote according to which Cordwainer Smith had explained the entire timeline of the Instrumentality of Mankind in terms of current goings-on on the international stage. Of (some of) which he had a certain privileged vantage point, of course.
I mainly read his works translated in my native Greek at a time when he was not that well-known among English-speaking SF readers anymore. I consider that lucky, for me, and sad, for everyone else. I think of him as one of the greats, one of the authors of SF whose imagination was not bound by cliché and trope, perhaps thanks to his having a day job, unlike most SF authors. I suspect he never really reached his full potential either, again because that was not his day job. His life experience certainly shaped his writing in any case.
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.
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.
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.
I doubt that radiation-loving mushrooms are edible, and if they produce CO2 rather than scrub it, I can’t consider them to be part of the life-support system.
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.
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.
> 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.
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]
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.
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.
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.
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.
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?
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.
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.
There is a few radioactive isotopes of oxygen that I think could be produced by gamma bombardment, O-15, and a few others. They decay very quickly to nitrogen though. Over time, this could turn into an interesting mix of elements.
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.
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.
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.
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.
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.
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.
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.
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?
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.
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
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.
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.
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.
Anything that can't walk around on its own is obviously a plant. /s
More seriously, the ideal is obviously an actual radiotrophic plant, right? That honestly seems within reach of genetic engineering, if it doesn't already exist.
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.
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.
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.)
> ((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])"
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.
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?
> 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.
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).
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)
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.
"I have loaded ships with life."
"Life?"
"Life. I don't know what the Great Pain is, but I did find that in the experiments, when I sent out masses of animals or plants, the life in the center of the mass lived longest. I built ships -small ones, of course- and sent them out with rabbits, with monkeys-"
"Those are Beasts?"
"Yes. With small Beasts. And the Beasts came back unhurt. They came back because the walls of the ships were filled with life. I tried many kinds, and finally found a sort of life which lives in the waters. Oysters. Oysterbeds. The outermost oysters died in the great pain. The inner ones lived. The passengers were unhurt."
"But they were Beasts?"
"Not only Beasts. Myself."
"You!"
"I came through Space alone. Through what you call the Up-and-Out, alone. Awake and sleeping. I am unhurt. If you do not believe me, ask your brother Scanners. Come and see my ship in the morning. I will be glad to see you then, along with your brother Scanners. I am going to demonstrate before the Chiefs of the Instrumentality."
https://archive.org/stream/ScannersLiveInVain/SmithCordwaine...
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[1] https://en.wikipedia.org/wiki/Cordwainer_Smith
[2] https://en.wikipedia.org/wiki/Scanners_Live_in_Vain