5 ms·

"but there are substantial areas of future work." Well, yes. Most plant mass comes from air and water, not the ground. Carbon, hydrogen, oxygen, and nitrogen

"but there are substantial areas of future work." Well, yes. Most plant mass comes from air and water, not the ground. Carbon, hydrogen, oxygen, and nitrogen all come from the atmosphere. This is why farms don't dig themselves into the ground. If air and water can be made from asteroids, that's most of the raw materials problem by quantity. Hydroponics already works. Direct synthesis of food from hydrocarbons has never really caught on, although it's been done experimentally and is an area of active research.[1] DARPA has a project.[2] "To address vulnerabilities in food supply chains across a variety of operational and humanitarian scenarios, Cornucopia will demonstrate the capacity to produce all four human dietary macronutrients (protein, carbohydrate, fat, and dietary fiber) in ratios that target Military Dietary Reference Intake (MDRI) daily requirements for complete nutrition. Outputs will be in multiple food formats (e.g., shake, bar, gel, jerky) that meet military nutritional standards and palatability requirements in a system minimizing inputs, handling, and footprint." [1] https://www.sciencedirect.com/science/article/abs/pii/S0924224424002851 https://www.sciencedirect.com/science/article/abs/pii/S09242... [2] https://www.darpa.mil/program/cornucopia https://www.darpa.mil/program/cornucopia

gus_massa 2y ago
Their plan is to use the asteriod material to feed bacterias (it's hidden in the introduction, but explained in the main text). The advantage of using something more complex than air and water is that he bacterias can get energy from it, interad of using light like plants. I guess it's more similar to the method used to cultivate fongus. --- Anyway, you made me wonder if we can feed plats with sugar instead of light. Can we inject sugar into a potatoe and keep the rest of the potatoe plant happy in a dark place? Anyway^2, I don't expect plants to be happy with the mix from the asteriods. It's probably some weird combination of small organic molecules. But some bacterias may eat et gladly and produce more usual organic molecules that we can eat.
- hansvm 2y ago
  Variations of that idea definitely work. Light is optional for plants with adequate nutrient uptake from mediums like agar.
Simon_ORourke 2y ago
> Hydroponics already works. I read something on wired last year on why urban vertical farming never really took off, and one of the reasons was, if I remember, that these kind of environments increase the likelihood of plant disease and the density makes it difficult to arrest any spread. So, I'm not too sure that hydroponics at scale is completely solved.
- Iulioh 2y ago
  It's a price problem, not a technical one
  - mandmandam 2y ago
    Um. Doesn't technological innovation often make things cheaper? Is this a distinction without a difference, or am I missing something?
    - Iulioh 2y ago
      Uhm. "cheaper than before" usually yes. But we are talking about different production methods, maybe hydroponics could never be cheaper than growing stuff in dirt because the production method can be optimized only so much. An "advanced" (different) production methods is not inherently cheaper than a "traditional" method.
      - versteegen 2y ago
        Hydroponics usually isn't competing on cost, it's competing on other axes, such as having a greater amount of control. Just the same as greenhouses vs growing in the open. Farming is mostly about dealing with or preventing everything that could go wrong.
    - SideburnsOfDoom 2y ago
      It's a hard ask to make space in high-rises in cities cheaper than farmland.
adrian_b 2y ago
Plants feed on oxidized compounds, i.e. water, carbon dioxide and dinitrogen, plus solar energy. Because carbon dioxide and dinitrogen are very volatile they must be taken from atmosphere. Reduced organic compounds, like hydrocarbons, are not food for plants, but for fungi or similar organisms, which, like humans, need only dioxygen from the atmosphere. There already are genetically-modified fungi that can produce the complete proteins required by humans (i.e. whey proteins or egg-white proteins) when fed with cheap carbohydrates and ammonia or a simple amino-acid. There are also fungi that can feed on hydrocarbons. Creating genetically-modified fungi able to feed on hydrocarbons and produce glucose and proteins for human consumption is not far from the already existing technology. With a serious effort in this direction, this could be solved in a decade or so. The glucose and proteins produced by fungi would be used not only for direct consumption, but also for feeding other microbial cultures that are needed for producing vitamins and essential fatty acids, using the techniques that are already in use today for this purpose.
- thaumasiotes 2y ago
  Do plants take nitrogen from the atmosphere? There's plenty of it available, but my understanding was that molecular nitrogen likes being molecular nitrogen and is difficult to react into a useful form. If plants took nitrogen from the atmosphere, there would be no issue of fixing nitrogen in the ground. But instead, that's a huge issue. We also provide nitrogen fertilizer, which is another way of getting it into the ground. Why would we do that? And similarly, I was pretty sure that most plants got their hydrogen and oxygen from water, which they draw out of the ground with special, purpose-dedicated organs called "roots". Their stylized interaction with the air is carbon dioxide in, molecular oxygen out. That's a source of carbon and maybe a little oxygen. The atmosphere doesn't even contain any significant amount of hydrogen.
  - adrian_b 2y ago
    Plants in the strictest sense, i.e. the terrestrial descendants of green algae, or even in some wider senses, e.g. all green plants or all eukaryotes that have chloroplasts whose origin is in a primary symbiosis or even all eukaryotes with chloroplasts, cannot take nitrogen from the atmosphere by themselves. Nevertheless, some plants have symbionts that are various kinds of bacteria and which can take nitrogen from the air. The most important of these plants are the legumes, i.e. beans, peas, lentils and all their close relatives. The ancestor of the chloroplasts, which are the parts of the plant cells that capture the solar energy, were free-living blue-green algae a.k.a. cyanobacteria, which had been able to take nitrogen from the atmosphere for billions of years. However during the integration of the chloroplasts into the nucleate cells of the plants, when they have lost their ability to live independently, the chloroplasts have been simplified and among the lost features was the ability to take nitrogen from air. Thus the plants do not have this ability and they have remained dependent for nitrogen on bacteria that either live independently or in symbiosis with plants. Before humans have started to convert nitrogen from the air into ammonia, for fertilizers and other applications, all organic nitrogen came ultimately also from the air, through the blue-green algae or through other kinds of bacteria. The nitrogen content of natural rocks is negligible. All the rocks with nitrogen, e.g. saltpeter, come from the decomposition of bodies or excretions of living beings. In all planets that are not cold enough for ammonia to become a liquid or an ice, the nitrogen is almost entirely in the atmosphere.
evoke4908 2y ago
I'm extremely amused (and totally unsurprised) that the military has palatability requirements for soldier chow
- Ekaros 2y ago
  Well soldiers tend to be armed and trained. Unlike say inmates or school children or hospital patients....

gus_massa 2y ago

Their plan is to use the asteriod material to feed bacterias (it's hidden in the introduction, but explained in the main text). The advantage of using something more complex than air and water is that he bacterias can get energy from it, interad of using light like plants. I guess it's more similar to the method used to cultivate fongus. --- Anyway, you made me wonder if we can feed plats with sugar instead of light. Can we inject sugar into a potatoe and keep the rest of the potatoe plant happy in a dark place? Anyway^2, I don't expect plants to be happy with the mix from the asteriods. It's probably some weird combination of small organic molecules. But some bacterias may eat et gladly and produce more usual organic molecules that we can eat.

hansvm 2y ago
Variations of that idea definitely work. Light is optional for plants with adequate nutrient uptake from mediums like agar.

Simon_ORourke 2y ago

> Hydroponics already works. I read something on wired last year on why urban vertical farming never really took off, and one of the reasons was, if I remember, that these kind of environments increase the likelihood of plant disease and the density makes it difficult to arrest any spread. So, I'm not too sure that hydroponics at scale is completely solved.

Iulioh 2y ago
It's a price problem, not a technical one
- mandmandam 2y ago
  Um. Doesn't technological innovation often make things cheaper? Is this a distinction without a difference, or am I missing something?
  - Iulioh 2y ago
    Uhm. "cheaper than before" usually yes. But we are talking about different production methods, maybe hydroponics could never be cheaper than growing stuff in dirt because the production method can be optimized only so much. An "advanced" (different) production methods is not inherently cheaper than a "traditional" method.
    - versteegen 2y ago
      Hydroponics usually isn't competing on cost, it's competing on other axes, such as having a greater amount of control. Just the same as greenhouses vs growing in the open. Farming is mostly about dealing with or preventing everything that could go wrong.
  - SideburnsOfDoom 2y ago
    It's a hard ask to make space in high-rises in cities cheaper than farmland.

adrian_b 2y ago

Plants feed on oxidized compounds, i.e. water, carbon dioxide and dinitrogen, plus solar energy. Because carbon dioxide and dinitrogen are very volatile they must be taken from atmosphere. Reduced organic compounds, like hydrocarbons, are not food for plants, but for fungi or similar organisms, which, like humans, need only dioxygen from the atmosphere. There already are genetically-modified fungi that can produce the complete proteins required by humans (i.e. whey proteins or egg-white proteins) when fed with cheap carbohydrates and ammonia or a simple amino-acid. There are also fungi that can feed on hydrocarbons. Creating genetically-modified fungi able to feed on hydrocarbons and produce glucose and proteins for human consumption is not far from the already existing technology. With a serious effort in this direction, this could be solved in a decade or so. The glucose and proteins produced by fungi would be used not only for direct consumption, but also for feeding other microbial cultures that are needed for producing vitamins and essential fatty acids, using the techniques that are already in use today for this purpose.

thaumasiotes 2y ago
Do plants take nitrogen from the atmosphere? There's plenty of it available, but my understanding was that molecular nitrogen likes being molecular nitrogen and is difficult to react into a useful form. If plants took nitrogen from the atmosphere, there would be no issue of fixing nitrogen in the ground. But instead, that's a huge issue. We also provide nitrogen fertilizer, which is another way of getting it into the ground. Why would we do that? And similarly, I was pretty sure that most plants got their hydrogen and oxygen from water, which they draw out of the ground with special, purpose-dedicated organs called "roots". Their stylized interaction with the air is carbon dioxide in, molecular oxygen out. That's a source of carbon and maybe a little oxygen. The atmosphere doesn't even contain any significant amount of hydrogen.
- adrian_b 2y ago
  Plants in the strictest sense, i.e. the terrestrial descendants of green algae, or even in some wider senses, e.g. all green plants or all eukaryotes that have chloroplasts whose origin is in a primary symbiosis or even all eukaryotes with chloroplasts, cannot take nitrogen from the atmosphere by themselves. Nevertheless, some plants have symbionts that are various kinds of bacteria and which can take nitrogen from the air. The most important of these plants are the legumes, i.e. beans, peas, lentils and all their close relatives. The ancestor of the chloroplasts, which are the parts of the plant cells that capture the solar energy, were free-living blue-green algae a.k.a. cyanobacteria, which had been able to take nitrogen from the atmosphere for billions of years. However during the integration of the chloroplasts into the nucleate cells of the plants, when they have lost their ability to live independently, the chloroplasts have been simplified and among the lost features was the ability to take nitrogen from air. Thus the plants do not have this ability and they have remained dependent for nitrogen on bacteria that either live independently or in symbiosis with plants. Before humans have started to convert nitrogen from the air into ammonia, for fertilizers and other applications, all organic nitrogen came ultimately also from the air, through the blue-green algae or through other kinds of bacteria. The nitrogen content of natural rocks is negligible. All the rocks with nitrogen, e.g. saltpeter, come from the decomposition of bodies or excretions of living beings. In all planets that are not cold enough for ammonia to become a liquid or an ice, the nitrogen is almost entirely in the atmosphere.

evoke4908 2y ago

I'm extremely amused (and totally unsurprised) that the military has palatability requirements for soldier chow

Ekaros 2y ago
Well soldiers tend to be armed and trained. Unlike say inmates or school children or hospital patients....