Great Space Farming With Great Soil on Asteroids With Fungi

A Phase 1 NASA NIAC study proposes to create soil from carbon-rich asteroid material, using fungi to physically break down the material and chemically degrade toxic substances. They will use fungi to help turn asteroid material into soil. The basic idea is to inoculate carbonaceous asteroid material with fungi to initiate soil formation. Fungi are excellent at breaking down complex organic molecules, including those toxic to other life forms. For example, oyster mushrooms (Pleurotus ostreatus) have been shown to successfully clean up petroleum contaminated soil by digesting the hydrocarbons making up the petroleum. Fungal hyphae can penetrate long distances into cracks and exert large amounts of pressure, physically breaking down rock – some even live inside rocks. Indeed, evidence indicates that fungi played a key role in early soil formation on Earth.

Above – Graphic depiction of the method for Making Soil for Space Habitats by Seeding Asteroids with Fungi. Credits: Jane Shevtsov

Any large, long-term human space habitat will need to grow most of its own food and recycle nutrients. For easily resupplied missions, growing crops hydroponically makes sense, but soil-based systems possess important advantages in the context of a large settlement that cannot be affordably resupplied from Earth.

One proposed habitat design is a cylinder that rotates to create artificial gravity and houses up to 8000 people, for purposes such as asteroid mining, space manufacturing and research. This habitat is meant to be self-sustaining with regards to food and have ample green space, which both supports crew mental health and functions as part of the life support system. At this scale, hydroponics would run into difficulties with the amount of machinery needed and the concomitant proliferation of failure points such as pumps and tubing. Moreover, hydroponic systems require nutrient solutions and do not easily lend themselves to the recycling of agricultural and human waste, which is readily accomplished in a soil-based system through composting the waste (possibly using thermophilic methods that are effective at killing pathogens) and incorporating it into soil.

Two tasks would be performed during Phase 1. Task 1 will be to identify the leading fungal species for experimental use on simulated asteroid material, followed by study of their soil production rates and the effects of physical parameters such as temperature, humidity and oxygen concentration. Task 2 will be to evaluate a number of different approaches for performing the breakdown of asteroid regolith by fungi in space – ranking them in terms of productivity and estimated costs, as well as sizing them to support a target mission habitat within a reasonable amount of time.

Significance: The research proposed here will support efforts to develop large space habitats with ample green space and robust agricultural systems. These will then open the door to other activities, such as space mining, manufacturing, and scientific research. While an expandable habitat can support many types of activities, our soil-making process is a particularly natural fit for asteroid mining operations targeting volatiles, as they use carbonaceous asteroids and leave behind leftover regolith that should make a suitable parent material for soil production. Our method turns this leftover regolith into a valuable resource. This concept should be exciting to everyone working on off-planet habitats and their applications – a major part of the move toward space commercialization and, in a larger sense, becoming a space-faring species.

Written By Brian Wang

19 thoughts on “Great Space Farming With Great Soil on Asteroids With Fungi”

  1. Yes, it makes more sense if we completely rewrite their 1 sentence description (hardly a firm source I'll admit) to something like:

    A pressurized, flexible walled, digestion chamber contains the asteroid rubble while it is being transformed through biological processing.

  2. The most damaging activity of humans is cultivation, tilling in particular. The notion of moving the damaging things off the planet first may not lead to lettuce from Space anytime soon, but plants are much like solar panels, they really do better in the sunlight of Space. No rational person would choose to needlessly destroy unscraped Earth surface. Did you see the hail come thru the roof and ceiling. It's nature's way . . .

  3. The claim is that such pressure vessels are better than hard metal for micros, by mass. I'm sure the picture in the fungus graphic was to represent an achievable goal, not an actual appearance. This is particularly true when the rest of he article is considered, where holding air around a roid is a small matter. These are not gardens, more like waste treatment ponds.

  4. "A large bag
    in space will remain gas proof for maybe a few hours until it starts to
    get punctured by the hail of micro meteors that will turn the plastic
    sheeting into plastic netting." The Bigelow module has done exactly, remain gas proof, that for years now, under full pressure. So, the problem CAN be solved at least to that extent, and I suspect even better when it is actually being paid for.

  5. The vast difference between planet thinking and O'Neill thinking is showing here. O'Neill people would never think of living in the row crop fields, cultivated. They will live in mimic natural areas, probably trying to have a part of Earth that is threatened (which part is not?) backed up, similar to Musk Mars idea, but practical. Settlements as in the forest. Small, nice. Crops have lighting and temp preferences that are not livable for humans, I suspect.

  6. You are right, it would be shredded netting. Something self sealing seems to be far fetched at this point and any loss to the vacuum of space would be wasteful.

  7. Etymologically, "colony" comes from Latin colonia which comes from Latin colo, colere, colui, cultum "to till the soil, to cultivate," which is particularly appropriate for settlements where you are going to produce soil to enable agriculture.

  8. It is a pressure vessel. It seems to have to be transparent to the light needed by the organisms, if any. Perhaps very low pressure, but still a pressure vessel. Can I invest in your solution?

  9. better than hard metal at absorbing micro energy without failure, for the same mass of enclosure

    Better than a hard metal enclosure of the same mass is damning with faint praise.

  10. However, the past of "colony" as a word is not the reason, or main reason, I support "settlement" instead. It is a matter of precise definition. Colony can be anything remotely controlled, say a mining colony that is rarely visited. Not at all what I have in mind!

  11. People are complaining about *colonies* because of the colonial history *other than* US, Canada and Australia, not because of them. Also, US calls themselves *colonial* to emphasize the fact that we successfully revolted, unlike our less freedom oriented brethren. We *were* colonies. No more under a monarchy. The fact that a few of the dominant colonizing culture nations like to call themselves *colonies* is not the issue. Have you read "The Heart of Darkness"? We Africans have little to be proud of. See Janov for details. "Neurotics are capable of doing anything".

    Also, Bigelow has shown that flexible bags are better than hard metal at absorbing micro energy without failure, for the same mass of enclosure, or pale.

  12. I have reserves about the step of

    Enclosure bag retains atmosphere.

    For one thing, people who are professional grievance experts are already freaking out about use the phrase "space colonies" because that's the same word as was used to establish USA, Canada, Australia etc, and that's bad because of reasons.
    At least one of them will be educated enough to have heard of the enclosure of english farmland and I'll bet they'll get triggered about using the same name there too.

    Second point: A large bag in space will remain gas proof for maybe a few hours until it starts to get punctured by the hail of micro meteors that will turn the plastic sheeting into plastic netting.

  13. I wonder if there could be a combination of organically induced rock/soil breakdown preceding mining/water extraction techniques. Would likely need to be tailored for each class of asteroid. Time scale dependence could be a limiting factor.
    I could see skipping the turning it into soil process and directly producing food from the asteroid and fungi / lichen combination. Flattening out an asteroid to maximize sun exposure could hasten the decomposition process. Constant sun, with a vacuum insulation to keep it within a set temperature range for maximal growth, all enclosed by a plastic bag container.
    Shake and Bake.
    Genetic engineering of particular species in outer space presents less opposition from an on planet use.  Could optimize acid/ breakdown production or protein production – with tailored living conditions. Different successive inoculations depending on the stage of asteroid use and material composition. Possible successive mining interspersed with the different inoculations.
    It could even line the exterior of those o neil habitats constantly, maniacally expounded upon in the comment section. Extra small particle and radiation protection? It could be 'cooking' as it is moved into position from it's orbit.

  14. Methinks that capturing asteroids is relatively easy as long as you can get to them and they are reasonably vacuum-welded together that you can actually push them and not have them dissolve like a clot of milk powder in water… Turning regolith into soil is a far more complex question, especially if you want to do it in shorter time scales than geological. This is probably something that can be developed in parallel with water mining strategies, and probably about as difficult.

  15. teraforming 0.1? seems like a great thing to study. Hopefully they also get good at capturing astroids (I think they are working on that too).


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