≡ Menu

Agricultural Resources Beyond the Earth

Gaining a human foothold on another world — Mars is the obvious first case, but we can assume there will be others — will require a search for resources to support the young colony. In today’s essay, Ioannis Kokkinidis looks at our needs in terms of agriculture, whether on a planetary surface or a space-borne vessel like an O’Neill colony or a worldship. Happily, his first reference, to Lucian of Samosata, has deep science fiction roots. The author of several Centauri Dreams posts including Agriculture on Other Worlds, Ioannis graduated with a Master of Science in Agricultural Engineering from the Department of Natural Resources Management and Agricultural Engineering of the Agricultural University of Athens. He holds a Mastère Spécialisé Systèmes d’informations localisées pour l’aménagement des territoires (SILAT) from AgroParisTech and AgroMontpellier and a PhD in Geospatial and Environmental Analysis from Virginia Tech. He now lives in Fresno CA and works for local government, while continuing to pursue his interest in sustaining human life outside our own planet.

By Ioannis Kokkinidis



About noon, when the island was no longer in sight, a whirlwind suddenly arose, spun the boat about, raised her into the air about three hundred furlongs and did not let her down into the sea again; but while she was hung up aloft a wind struck her sails and drove her ahead with bellying canvas. For seven days and seven nights we sailed the air, and on the eighth day we saw a great country in it, resembling an island, bright and round and shining with a great light. Running in there and anchoring, we went ashore, and on investigating found that the land was inhabited and cultivated. By day nothing was in sight from the place, but as night came on we began to see many other islands hard by, some larger, some smaller, and they were like fire in colour. We also saw another country below, with cities in it and rivers and seas and forests and mountains. This we inferred to be our own world. We determined to go still further inland, but we met what they call the Vulture Dragoons, and were arrested. These are men riding on large vultures and using the birds for horses. The vultures are large and for the most part have three heads: you can judge of their size from the fact that the mast of a large merchantman is not so long or so thick as the smallest of the quills they have. The Vulture Dragoons are commissioned to fly about the country and bring before the king any stranger they may find, so of course they arrested us and brought us before him. When he had looked us over and drawn his conclusions from our clothes, he said: “Then you are Greeks, are you, strangers?” and when we assented, “Well, how did you get here, with so much air to cross?”

— Lucian (ca. 125–180 AD), True Story, chapters 9-11 translated by A. M. Harmon (1913).

Lucian of Samosata’s most famous work, True Story, defies easy categorization. He most likely wrote it as a parody of the travel novels popular during the Antonine Era and more specifically Antonius Diogenes’ now lost The Wonders Beyond Thule. Modern critics have called it the first surviving work of both Science Fiction and Fantasy, and ironically it is the only work of both genres that is part of the school curriculum in Greece today.

We can see that already from the earliest work of science fiction space colonization, war and agriculture are important themes. Alas, unlike Lucian’s description, who like Herodotus implores us to go and travel to the places he just described to see for ourselves that he is telling the truth, neither the Sun, nor our Moon nor Venus have an Earth-like biosphere. The use of technology, though, can allow us to produce agricultural products necessary for human survival on other celestial bodies, provided that these bodies can provide in easily available form the resources that agriculture needs. This article at first describes in general terms what sort of resources agriculture can provide, and then lists the important elements and their forms necessary for an artificial ecology to function.


When designing planetary colonization we should take note that the biosphere of Earth provides resources and ecosystem services to people through large scale cycles that are hard to replicate. It is very hard, though, to create a completely enclosed system; resource inputs of several forms will be necessary in order to maintain a system that can sustain human civilization. On Earth cultivated plants assimilate carbon from the atmosphere during the growing season, which is then released back in the short term after the end of the growing season and in the long term through the geologic carbon cycle. Until a colony reaches a very large size, which it might never reach, we will most likely try to maintain our crops in a permanent growing season, planting a crop as soon as the previous is harvested, which in turn would mean that we need to be constantly adding resources instead of allowing them to be slowly released by decomposition.

Furthermore even if we do reach a balance of agricultural inputs and outputs in our artificial ecosystem, it will likely still require a large buffer, far larger than what is being cycled every year. For example if we only use agriculture to grow food and we grow our food exclusively from plants, we only consume a small part of a plant, less than 50% of aboveground biomass for annual crops and an even smaller part of tree crops. It is simply not possible to plan to colonize a body that does not contain in significant quantities easily available elements that we need, unless we set up large scale resource transfer from outside it. I believe that I am not the first person to raise the issues below, though I have not done a systematic search in the literature. All suggestions are welcome.

Image: A fictionalized portrait of Lucian taken from a seventeenth century engraving by William Faithorne (1616-1691). Credit: Wikimedia Commons.

Resources from agriculture


Food, sustenance in all forms for the colonists, is the most readily available reason given to engage in agriculture in space. Any food grown is food that does not need to be transported from Earth, not to mention that there are a variety of psychological benefits from seeing it grow. We can divide edible crops into two categories, autotrophic organisms such as plants and heterotrophic organisms such as fungi and animals. Over the last 10 millennia we have domesticated a huge number of plants of which we eat a very wide variety of plant parts but rarely the entire plant. With heterotrophic organisms we can take advantage of the non-human edible parts of a plant and convert it into edible sources, though again we do not eat entire animals, except perhaps octopuses and their relatives. There is no such thing as the perfect diet for all conditions; we need to balance the macro and micronutrient needs of humans with the available resources and the need to maintain a healthy population. Also since plants produce their edible parts on an irregular basis we also need to store and preserve food, especially to guard against crop failure.


Usually when we talk about plants providing food and fiber, by fiber we often mean wood fiber. While we will likely see trees planted in arboretums, we are not likely to see forest style plantations for harvesting timber; colony space is too valuable and tree growth rate is too slow. Unless we can find a celestial body with forests, wood furniture will likely remain a luxury item reserved for the well off or for very specific uses where it is indispensable. Another use of wood fiber for which we will need a ready substitute is paper, it being much easier to produce paper than a factory making electronics. There is already on the market tree free paper made from bagasse, a byproduct of sugarcane processing, and several other plant waste fibers. Historically, before the invention of paper by the Chinese and its introduction by the Arabs in the 11th century to Europe, papyrus and vellum were the writing material, although it is highly unlikely that we will see vellum used in a non-ceremonial setting in space.

Moving on to other fiber uses, the most obvious one is for cloth making. Cotton fiber is the most popular of the vegetable fibers used, though other plant fibers are also used, such as flax, jute and hemp. Among animal fibers wool is the most popular, though silk and leather are also fine choices. On earth biologically derived fibers are today more expensive than petroleum derived fibers such as polyester. In practice, with the exception of Titan, celestial bodies are not known to harbor large bodies of hydrocarbons from which we can derive artificial fibers. The specific planting of crops and the selection of animals to be used in space will depend on the needs of the colony and the related infrastructure such as cotton gins that are needed to produce usable materials.


Before the industrial revolution most materials used for energy purposes were derived from the active biosphere, e.g. firewood. Today fossil fuels, biogenic in nature, mostly cover the energy needs of human civilization. There has been effort, though, to produce biofuels to substitute for fossil fuels since the oil crises of the 1970s. In Europe, which does not have large petroleum resources, coal has long been mined, and biofuels are subsidized by the Common Agricultural Policy. The purpose is not so much to cover energy needs with European resources but to keep farm prices from dropping too low and thus creating unhappy farmers that block the highways demanding better prices. In the US corn biofuel policy is more related to the political cycle, such as the first in the country Iowa caucus and its voters; after all the US is one of the largest petroleum producers in the world. The most successful bioenergy program in the world is considered to be that of Brazil, blending sugarcane derived ethanol into gasoline and thus abolishing the need for importing oil (Brazil is an oil producing country).

The use of biofuel in space is tied to the selection of the energy cycle for the colony. It is highly unlikely that we will use internal combustion engines to power a colony. Most likely energy sources will be either photovoltaics, which in the long term will require a plant to produce them out of silicon wafers, or nuclear, which requires an entire cycle of mining, refining and isotope enrichment. It is possible that we will see hydrocarbons as energy sources in the colony. Already there are plans to use abiotic processes to produce methane as rocket and rover fuel in future Mars colonies, and there it is possible to produce RP-1 from biological sources if a rocket is to require it. In general, though, I see biofuels occupying a niche source in a future colony. We might create biodiesel out of waste edible oils but we are unlikely to see entire sunflower plantations intended for biodiesel production.


According to Wikipedia there are over 300,000 tons of bioplastics produced each year, or 0.1% of the total global plastics production worldwide. Modern technological civilization is very dependent on a variety of plastics, even inside a greenhouse (e.g. drippers). Unless the celestial body colonized has prodigious amounts of easily available hydrocarbons available such as Titan, we will need to create very early an infrastructure to produce bioplastics for colony needs or else set up a logistic chain for plastics from Earth. Generally for bioplastics the feedstock is readily available plant material, such as cellulose or dextrose, though some animal sources such as casein (a milk protein) have been used. The harder part will be creating a production line for these bioplastics from the local raw material.

Elements for agriculture

What follows is a list of major elements that are necessary for plant growth. Some 17 elements are necessary for plants to survive, though the majority are required in minute amounts often easily available in the soil or as impurities in the fertilizers. Carbon, Hydrogen and Oxygen combined are responsible for 95% of plant mass. Often, though, due to pH element deficiencies can arise despite the presence of the element in the soil.


Carbon enters the biosphere when it is assimilated by plants through photosynthesis in the form of CO2. While there are a few methanotrophic bacteria known, it is unlikely that we will require carbon in any form except CO2 for agriculture. Plants can oxidize CO in the presence of O2 to CO2, but cannot use raw carbon. Thus if carbon is available in the environment but not in the form of CO2, we will likely need to set up processes to produce CO2 before plants can assimilate it.


Plants assimilate hydrogen mostly in the form of water. Water has an important function in plants both as the solvent of biology but also as the stream that allows the transport of elements inside the plant.


Oxygen as an element is assimilated by plants in the form of water and CO2. It is released to the environment in molecular form by photosynthesis, which is critical for the survival of animal life. Plants also use molecular oxygen from the environment during respiration, however they produce far more O2 than they consume, and this allows heterotrophic life to exist.


Image: The colors in the spectra show dips, the size of which reveal the amount of these elements in the atmosphere of a star. The human body on the left uses the same color coding to evoke the important role these elements play in different parts of our bodies, from oxygen in our lungs to phosphorous in our bones (although in reality all elements are found all across the body). In the background is an artist’s impression of the Galaxy, with cyan dots to show the APOGEE measurements of the oxygen abundance in different stars; brighter dots indicate higher oxygen abundance. Credit: Dana Berry/SkyWorks Digital Inc.; SDSS collaboration.


Plants require this element in a variety of forms but unlike the previous three they cannot assimilate it from the atmosphere. Rather they take it through the roots, more specifically through the soil solution in the form of nitrate. Nitrates, though, are highly mobile in the soil, which is why we also fertilize with ammonia, which is converted to nitrate by soil microorganisms over time. Both forms of nitrogen are typically produced in chemical factories on Earth using atmospheric nitrogen as a feedstock. In parts of the outer solar system they are available as rocks and ices.


Phosphorus is another element that is assimilated from the soil solution. Unlike nitrogen, though, it is not found in the earth’s atmosphere, rather we mine phosphate rocks and fertilize with phosphate salts. Some 80% of global phosphate mining exploits deposits of biogenic sedimentary rocks of marine origin. The other 20% is of igneous origin in the form of apatite. Outside earth it is this phosphoric apatite that will likely provide our phosphorus needs


Just as with phosphorus, potassium is mostly mined from sedimentary rocks, more specifically evaporites. While evaporites have been found on Mars and are likely present on Venus, for other bodies of the solar system we will need to locate other forms of the element and process it into the salts that plants require.


Iron has an intermediate position between micro and macronutrients, required in quantities that are small for macronutirents but large for micronutrients. Plants assimilate iron in ferrous (Fe++) form, often from organic iron complexes that contain ferric (Fe+++) form with the expenditure of energy by the plant. Since the concentration and availability of ferrous and ferric iron depend on the soil pH and other ion antagonists in the solution, very often we see plants with iron deficiency despite a large iron concentration in the soil and the parent rock. In hydroponic fertilization and urgent deficiency interventions we tend to use organic iron so as to provide a highly available form to the plants. Organic iron, though, is not necessary if we take pains to control the pH and antagonists such as calcium, phosphorus and carbonates.


Calcium is a micronutrient, not necessary in large quantities for agriculture. However it is often applied in macronutrient quantities in order to control soil pH. In areas of high rainfall such as the eastern US and western Greece we will find many soils that are calciferous in origin but have a low pH, because rainfall washes the Ca++ ions, lowering the pH to acid levels. Calcium is used in hydroponics to raise solution pH and it is likely necessary to stockpile and use calcium for this purpose rather than for the specific need of the plant for this element.


Sulfur is the opposite of Calcium in that it is used to lower soil pH. There is no shortage of sulfur concentration in agricultural soils on Earth; fossil fuel use has spread it far and wide. Pollution control measures have reduced atmospheric deposition in developed countries and it is likely that in a few decades sulfur fertilization will be necessary in some areas. So far, though, we are more likely to see sulfur in hydroponics, raising pH when it falls too low. Just as with calcium, plants do not require large quantities, but we may need to stockpile it for the same reasons.

Other micronutrients

The rest of the elements necessary are required in minute quantities and while pH is very important for their availability, their limited requirements mean that we will not need to seek them specifically. In general, micronutrient fertilization can become necessary and critical if we choose an agricultural system where we remove the entirety of the plant mass from the soil or substrate and do not allow any plant decomposition to take place, which is what we will do at first. The decomposing remains of the previous harvest are often the primary source of micronutrients for the next, even in intensive agriculture. If we remove the entirety of the crop each time, we will need to provide the elements that were mined in the process, though again, it is unlikely that we will need to search for extensive quantities.


This contribution was inspired by news reports of the first NASA Mars landing site selection symposium. They mentioned that along with geologists seeking interesting formations there were also colonization specialists arguing to select sites with mineral resources for metallurgy in the future colony. They did not mention plant specialists looking for areas having resources to grow plants. I did not write this contribution with Mars specifically in mind; it is intended as a general guide for all celestial bodies. Bodies with carbon dioxide in the atmosphere will not require creating it from other elements. Bodies with nitrate rocks are advantageous to those with only gaseous nitrogen in the atmosphere.

Also, while we are fortunate enough to know the surface composition of several bodies of the solar system, we just don’t know enough about exoplanets to be able to judge which are more suitable for colonization. At best we have managed to infer the presence of some elements in the atmosphere of a few exoplanets but we are nowhere near a full resource guide. Human civilization has always been dependent on agriculture for a variety of resources to survive and thrive. This will continue to be true when we move beyond Earth.


Comments on this entry are closed.

  • Michael February 3, 2017, 16:21

    It looks like Ceres offers most if not all of these elements.


    • Coacervate February 5, 2017, 9:19

      I am just asking … how many watts/square meter does Ceres receive from the Sun? It is enough to grow plants?

      • Michael February 5, 2017, 14:17

        It is around 200 – 250 W/m^2 which is enough for some plants to survive on but not all, using mirrors will increase the light concentration substantially.

        • Coacervate February 5, 2017, 17:00

          And there are no cloudy days :) Except maybe near the odd cryovolcano.

          • Michael February 6, 2017, 4:40

            If life originated in comets or was carried by them there may not be a better place to find them, Ceres has been exposed to them for billions of years.

            • Coacervate February 6, 2017, 13:35

              Would you not expect to have found some in the moon samples?

              • Michael February 6, 2017, 16:18

                The moon is bone dry except at the poles, Ceres has water ice, clays and ammonia which could aid life if it fell upon it.

      • Sean Robert Meaney February 9, 2017, 0:52

        Is it more viable to mine Ceres and dump the contents into Mars atmosphere? Planet building is what we are facing. I can see the need to go as far as using a small asteroid to alter the trajectory of a large asteroid to move a small moon to shift the orbit of Mercury to alter the orbit of Venus so its as far from the Sun as Earth but on the opposite side of the Sun from us.

  • Charlie February 3, 2017, 17:05

    I’ve got to hand it to you, Paul – you been batting three for three in the last set of articles that you placed online, in the topic that you have been dealing with. At least that’s the way I see it.
    I find it a lot more interesting (from my perspective, at least) in the technical difficulties and challenges that will be facing manned or unmanned spacefaring adventures from the technical perspective. At least I find it a lot more interesting than dry articles on how much dust clouds surround alpha Centauri or whatever may be the situation at the destination that we may be choosing; even though I realize that certainly that information is important to whomever or whatever may be actually taking the voyage. Certainly it’s of no importance to me in that regard, since I’m not the one going.
    But this is certainly one of the most pressing issues for those going is the environment and how to maintain it on long stellar voyages. If people are going to in any sense be the ones to do the traveling. I’ve been looking forward to some discussion on this level for a considerable period of time.

  • Alex Tolley February 3, 2017, 17:06

    Nitrogen is fixed by bacteria. There is research in adapting crop plants to create root nodules so that they can fix their own nitrogen. More likely we will fix it by chemical processes that are well established.

    Nutrient recycling is going to be very important. Phosphorus is already coming up against production shortages on Earth.

    I disagree that wood will be rare. Some trees grow very fast. While there may not be oak furniture, I would expect wood products, e.g. OSB to be available, perhaps using bamboo as the fiber.

    Speaking of bamboo, it is now used for fabrics. It is surprisingly soft.

    Growing crops will likely be mostly hypo- and aeroponic. Indoor crop production is now a thing. Expect something like the underground marijuana farms for size.

    Food technology is rapidly advancing. Muscle cell culture for meat is close to commercialization. This reduces waste. Similarly, algae reduce wastes, if you can process it to be acceptable as food. Algal biofuels are an active area of research and a good way to make such materials in the absence of cheap fossil fuels.

    Don’t forget magnesium, the primary metal for chlorophyll. Rocks should be a good source.

    • Ioannis Kokkinidis February 3, 2017, 18:00

      Nitrogen is fixed by bacteria, if we use soil and if the air has Nitrogen. In hydroponics, including aeroponics, all the nitrogen is provided in the solution, not in the substrate which in any case does not contain significant populations of N-fixing bacteria. Fast growing tree is relative, half the students in Remote Sensing were from Forestry so I know that a fast growing tree is the sort that produces wood for particle boards 20 years after it has been planted. Even if we reduced this to 10 year it is still excessive to grow entire plantations just for wood. Maybe we will get tree fiber from oil palm trees along with the oil, though to be honest I am not familiar with this culture so I could be wrong. Muscle cell culture looks great, until you realize that the sort of consumables required for vat meat production also require quite a bit of infrastructure to grow in turn. As for Magnesium, according to the link below from the university of Wisconsin we need 50 mg/kg of live plant material. So, if a person eats 1 ton of food a year (that is how much the average American does) and it comes from 3 tons of plants, we need 3 grams of Magnesium per person/year.


      • Alex Tolley February 4, 2017, 16:09

        You make some good points.


        1. Your forest colleagues are probably thinking of standard commercial tree plantations or natural forests. Trees are far faster growing and harvestable.
        I think trees would be an excellent resource in the colony. They provide visual interest, support climbing plants, and harvested for wood and paper. Wood is also a very versatile material that can be worked with very simple tools. Engineered woods are now being considered for sustainable multi-story office buildings and condominium complexes.

        2. While animals are lower tech than tissue culture, as was pointed out in your last post, how exactly are you going to transport cows to Mars. Rabbits and chickens maybe. Tissue culture will certainly require some complex feedstocks which might prove difficult to do until the colony is industrialized, but I want to know how you can get meat animals to Mars before this is abandoned. Fish, molluscs and crustacea might be much easier to get started, especially as they can be transported as eggs and convert fast-growing algae and zooplankton to edible flesh. They are also containable. Insects might be theoretically a good choice, but the problems of inevitable escape are a problem. Even tribbles cannot get behind wall panels. ;)

        3. On a related note, how are crops going to be pollinated? By humans? Robots? If you use insects like bees, they will need to be contained. If they escape into the colony living areas, you cannot open a window to let them out.

        4. The more you rely on traditional farming methods for meat production, the more you will need to manage the extended ecosystem, such as microbiome required bacteria and viruses, diseases, trace elements, etc. Earth provides ecosystem services for free, but they won’t be available on Mars. You may need to ship chunks of Earth to Mars to get an Earth environment working in the habs. An unexpected crop failure could be disastrous without a multi-year buffer of food supplies.

        • Ioannis Kokkinidis February 6, 2017, 1:04

          1. Are we going to keep any plant in the greenhouse for more than 3-6 months? Do we want to keep the greenhouse occupied, including adding all sort of resources such as light and fertilizer, with a plant that only produces a product which we can substitute with easier to produce product? What is less resource intensive in the colony, creating a wooden desk or a metal desk? If wood is as indispensable as food, I do see plantations, otherwise not really.

          2. Why the same way it was done in Firefly: Captain Raynolds will load them on the back of his ship and carry them :)
          Now, adult cows do not fit on the Orion, though calves probably do. They do fit though on a second generation Martian spaceship like Elon Musk’s ITS. I do not see cows on Mars on a 10-20 person colony, but when we get to hundreds of people carried by a spaceship that carries tens of people we can carry bovines

          3. I am thinking parthenocarpic crops, self pollinating varieties at first. Eventually we will bring bees.

          4. Historically agrarian societies could sustain a year of crop failure but not a second. I am pretty sure that they will keep a sufficient buffer.

          • Douglas Loss February 7, 2017, 16:39

            I’m no expert, but I would think pigs and rabbits before cows, just for the efficiency (kg. of meat/kg. of feed).

      • Coacervate February 5, 2017, 8:49

        This is really important and fascinating article. Thanks! I would add the following:

        The nitrogenase enzyme systems in legume root nodules are poisoned by oxygen. On Earth, the plant/bacteria symbionts protect against O2 poisoning using a special form of haemoglobin called leghemoglobin. it is almost identical to animal hemoglobins but its affinity for O2 is so high it effectively sequesters and prevents damage to the nitrogen fixing process. In fact, active root nodules take on a bloody red appearance.

        So this is one aspect of an O2 deficient atmosphere that may turn out to be beneficial with respect to nitrogen fixation. Also, leghemoglobin contains haeme iron which is efficiently absorbed and has high bioavailability.

        Finally, from a nutritional viewpoint there is no good reason to consume animal products on Earth or anywhere. The evidence supporting an eating plan based on whole, minimally processed plant foods has been building since the early work of Dean Ornish, Nathan Pritikan and a long list of others. I know this idea is rejected by many even ‘cum experiment’. Nevertheless, there it is. We have an opportunity to leave a host of ‘lifestyle’ diseases such and diabetes, heart disease, cancers and their myriad knock on effects.

      • Eric Hughes February 5, 2017, 12:47

        > Even if we reduced this to 10 year […]

        Ten years has been standard practice for hundreds of years already using the practice of coppicing. Species such as ash and hazel will resprout directly from roots. The principle here is that you’re treating the underground root system as the underlying resource and the visible saplings as the product.

        To my knowledge there’s never been a plant breeding program to develop coppicing varieties with high specific yields. Even without using GMO I would hazard to guess that simple breeding could yield significant improvements.

        The present article doesn’t get into the carbon cycle, but there will have to be match between animal activity that produces CO2 and plant activity that fixes it. If the entirety of that biomass is in short-lifespan agricultural crops, you get a relatively less stable system than if you have a reservoir of long-lifespan woody plants.

        • Ioannis Kokkinidis February 6, 2017, 1:09

          In the carbon cycle we see sequestered carbon released by decomposition after the end of the growing season in the short term and through sedimentary rock recycling in the long term. If we sequester carbon in woody plants a massive release after a fire can be catastrophic. We can only speculate though how an artificial ecology will look like outside earth.

          • Eric Hughes February 6, 2017, 14:31

            Dealing with a carbon impulse from fire is a problem no matter what the plant partition of carbon is.

  • Geoffrey Hillend February 3, 2017, 17:14

    Biofuels can be used for the energy cycle of a space colony as the author has written, and they are not used in combustion engines which are only thirty percent efficient since they have to have a radiator to cool them since they are used as heat sink. Hydrogen fuel cells are seventy percent plus heat efficient and the fuel they use is completely recyclable or renewable. Space Frontier, Von Braun.

    Hydrogen fuel cells have already been used for a long in space stations including the international space station. The Hydrogen and oxygen which make electricity and water and the water can been recycled by being broken down by an electrolyzer. https://www.nasa.gov/centers/glenn/technology/fuel_cells.html

    • Ioannis Kokkinidis February 3, 2017, 18:05

      I agree we are unlikely to see internal combustion engines running hydrocarbon fuels. Hydrogen though also has its own issues such as explosiveness and storage. Power options in general do not look that great: PV requires sun and in the long term a cell fab. Nuclear power a full scale nuclear cycle, from mining to enriching to a complicated power plant. Internal combustion engines require fuel and oxidizer.

      • Michael February 5, 2017, 17:00

        Alcohol could be used in fuel cells and it does have other medicinal properties. And there are oils from crops that can be used to run internal combustion engines. Hydrogen is just a little too dangerous for my liking.

  • DCM February 3, 2017, 17:57

    This is vital because space biospheres are an absolute necessity even when planets are colonized.
    Experimentation needs to be going on now, beginning with bacteria and similar life that can refine raw materials into usable soil.

    • Eric Hughes February 5, 2017, 12:55

      This research is already happening, although not targeted at space. It’s the topic of desertification and its reversal. The Sahara is full of laboratory space to practice building soil out of abiotic material. (Well, only largely abiotic for many Terran deserts.) Also of interest, however, is the process of desertification of the Sahel, because it demonstrates where resource usage from the land overtaxes its recovery capacity and leads to degradation.

      • DCM February 7, 2017, 12:26

        The small enclosed environments in space will allow us a wide range of experimentation.
        That will help us here on the ground as well as future space inhabitants.

  • JohnHunt February 3, 2017, 19:47

    The first priorities should be the first bridge that we will be crossing. So, initially food will be grown indoors under grow lights starting with salad-type vegetables of which most all of it will be consumed (e.g. sprouts, lettuce, cabbage, spinach, celery, onions, etc). Hydroponics are excellent for these types of foods and so the issue of the toxicity of regolith can be delayed and avoided. People will be working within the hydroponic greenhouses and so they will need significant shielding even if the plants do not. So, with the regolith shielding overhead, continuing to use grow lights using electricity makes sense.

    • Jens Knudsen February 4, 2017, 11:46

      The areas needed for sustaining just a few humans are very large.

      • Coacervate February 5, 2017, 8:56

        Could you give this a little more exposition? An important aspect food production by any means.

        • Ioannis Kokkinidis February 6, 2017, 1:13

          In hydroponics on earth the rule of thumb is 250 m2 of growing space per person assuming 1 growing season. If we grow more than one crop per year we can reduce that figure. Be aware that we have no idea how crops would grow in a reduced gravity environment, though the German have a satellite going up next year called EuCROPIS to do testing.

          • Jens Knudsen February 6, 2017, 13:22

            There are two things I think about that deserves some attention here: 1) It worries me if we go for a food/resources production scheme that makes maximum use of hyrdophonics, because it is so intensive. What if something fails? This is a fragile way of sustaining a human outpost on Mars. We must make the ‘farm’ sufficiently robust, so that things can go wrong without having the crew starving to death. 2) I wish we could send some robots out there in advance, so that they could spend some time building rough, sturdy structures to make it possible to ‘build’ ‘farmland’, comparatively large areas that could sustanin damage without losing their usefullness. In some kind of a colony, these very critical pieces of infrastructure must be very durable?

            • Ioannis Kokkinidis February 6, 2017, 16:00

              1) We keep as much redundancy as possible. Enough spare parts to build all moving machinery from scratch. Several substrates. On top of that let’s have a few pots growing edible food in the habitation area if all else fails. Habitable space is going to be a premium in an extraterrestrial environment, especially at the beginning, we need to be intensive.
              2) We do need robots to do early work but there is no automated farm anywhere on earth yet, even in place of very expensive labor. If anything the history of spaceflight has proven, robots go first and do first everywhere.

  • Joe February 3, 2017, 22:04

    The National Geographic Channel had a miniseries last fall about settling Mars. Is was quite well done, and yes, the colonists grew plants inside one of their structures.

    • Ioannis Kokkinidis February 4, 2017, 13:56

      The National Geographic series’ habitat was more driven by the dramatic needs of the show than actual studies. There are far better reviewers than me but, let’s just say I would not pick the kind of colonization plan they do. In any case we are never quite told where their fertilizer comes from.

  • ljk February 3, 2017, 22:33

    A link to the complete Lucian story online, in both Greek and English:


    Truly one of the first science fiction stories in the modern sense of the word.

    • Ioannis Kokkinidis February 4, 2017, 14:05

      True Story is considered the oldest surviving science fiction story though being a 2nd century AD text you can easily miss several of his homages unless you are familiar with ancient Greek literature. The days he sails beyond the Pillars of Hercules (Gibraltar) are based in the Odyssey. As I mentioned he channels Herodotus when he calls on his readers to visit to the far away place and see them for themselves. The king of the sun is arrayed in battle in the same way that the Persian kings were in Xenophon. On the way back to earth they get emissaries from Cloud Cuckoo Land, a homage to Aristophane’s Birds. After the moon trip there are quite a bit of adventures which I would rather not spoil but let us say that they have nothing to do with scifi.

      • ljk February 6, 2017, 12:10

        The site I link to above which contains the translation of Lucian’s story also annotates his references. Sadly a number of them are lost to history.

        This is yet another reminder of how important it is that we preserve humanity’s cultures and our knowledge for future generations before we suffer another dark age. More than just historians will thank us for thinking ahead.

  • Harold Shaw February 4, 2017, 11:12

    The uses you list for fiber could be met with bioplastics. A 3D printer could print cloth, avoiding the need to build specialized equipment like cotton gins and looms or maintain the expertise to use that equipment. The expertise required to run 3D printers would be much easier to maintain. As a colony grows, fibers such as flax, hemp, cotton may fill a luxury niche and provide employment for artisans.

    I think the same goes for wood. Processing trees requires massive, specialized equipment, loads of energy and often lots of water. I can’t think of any wood products that could not be printed with plant pulp or bioplastics instead. That being said, bio-engineering may deliver dwarf trees that could be grown as giant bonsai. I’m picturing short trees with thick trunks and minimal foliage that could be worked by hand.

    • Ioannis Kokkinidis February 4, 2017, 14:09

      A cotton gin is far simpler machinery to have than a bioplastics refinery. I see 3d printers used everywhere but we must first consider this: Where does their feedstock come from? What does it take to produce it? Space manufacturing in all its forms is still somewhere in its infancy so all we can really do is speculate.

      • Harold Shaw February 6, 2017, 11:50

        All good questions but also questions we see being answered here on Earth. Clothing and structures can be printed and the range of feed-stock materials continues to grow. I do not think it is ‘too’ speculative to project that trend into the future.

  • Jim Early February 4, 2017, 11:30

    An excellent and accurate article. As an aside, the term “plant food” as used by your typical weekend gardener would be more accurately related to the human daily vitamin and mineral pills (particularly familiar for us in the older ages). As the author noted 95% of the real plant food is O,C & H which is usually served as water and CO2 (with photons for energy). These three elements will likely dominate the economic and engineering challenges.

    With some external energy oxygen is widely available everywhere from various oxides. The oxides of silicon, magnesium and iron constitute about 95% of the earth as well as the rocky planets and smaller bodies. The primary challenge for space agriculture will be supplying the carbon and hydrogen probably from H2O and CO/CO2 ices. If we supply the photons and “daily mineral supplements”, most plants can work directly from these ices.

  • Charlie February 4, 2017, 17:17

    @Ioannis Kokkinidis
    have you considered thinking really, really outside the box ?
    Perhaps the way to approach this is to cut out the middleman in all this particular productions of food stuffs and may I suggest another route? While this might be thinking quite far in the future it might be possibly closer than we can imagine.
    Do you think it might be possible to synthesize all the basic materials we need to consume in some kind of gel cap form or perhaps a pill type of delivery, which contains all the essential amino acids as well as trace minerals. I know that this is been suggested many, many times before, but the difference would be that research might show a way to find a drug or drugs that would effectively acted appetite suppressant’s and permit the individual to feel like they had consumed an entire meal without being dissatisfied ?
    Given the fact that this direct synthesis of the required food essentials would be done in a industrial setting would undo all the need for a inefficient plant to animal to human consumption cycle that would be required. I realize this would be not quite ready for prime time activities. If we are to go to Mars are some other planet, but at least it would serve to condense and trim the the biological energy cycle that we are not trapped in with regards to this specialized problem. What do you think?

    • Ioannis Kokkinidis February 6, 2017, 1:22

      Where would the amino acids come from? Inorganic synthesis is not as efficient as biological synthesis. We eat meals made out of food not just because that is what agriculture produces but also because that is what our bodies are evolved to assimilate. We do want food with texture and volume so that we can please the palate and exercise the digestive tract. In any case psychological experiments in confined environments, whether prisons on Earth, Mars analogues or space habitats show that people pay an inordinate amount of attention to what they are eating and can get very agitated if the food is not due to their lacking. Running out of one particular kind of cookies is believed to be a major contributor to the outbreak of the Strike in Space in Skylab 4.

      • Antonio February 6, 2017, 19:14

        “Running out of one particular kind of cookies is believed to be a major contributor to the outbreak of the Strike in Space in Skylab 4.”

        Definitely, there are no explorers today.

        “Wednesday, November 28, 1520, we debouched from the strait, engulfing ourselves in the Pacific Sea. We were three months and twenty days without getting any kind of fresh food. We ate biscuit, which was no longer biscuit, but powder of biscuits swarming with worms, for they had eaten the good. It stank strongly of the urine of rats. We drank yellow water that has been putrid for many days. We also ate some ox hides that covered the top of the mainyard to prevent the yard from chafing the shrouds, and which had become exceedingly hard because of the sun, rain, and wind. We left them in the sea for four or five days, and then placed them for a few moments on top of the embers, and so ate them; and often we ate sawdust from boards. Rats were sold for one-half ducado apiece, and even then we could not get them. The gums of both the lower and the upper teeth of some of our men swelled, so they could not eat under any circumstances therefore died. Nineteen men died from that sickness.”

        Antonio Pigafetta, one of the 18 survivors of Magellan’s 234 men expedition

  • Geoffrey Hillend February 4, 2017, 17:28

    Hydrogen does does not explode unless is has oxygen to combine with it. If it is stored in a air free environment it won’t explode which is not hard to do in a rocket or space station in space or even on Mars.

  • Antonio February 4, 2017, 18:21

    “Resources from agriculture

    Fuel (methane/oxygen bipropellant, CO/O2 bipropellant, and others) can be easily made on Mars without agriculture, using CO2 from the atmosphere and H2O from the permafrost.

    Same for plastics. Plastics can be made from ethylene, that is the basis for today’s plastic industry. And ethylene is made this way on Mars (citing from Zubrin’s “The Case for Mars”, with some rewriting):

    First, electrolyze water to obtain hydrogen and oxygen. Then, make hydrogen react with CO2 this way:

    6 H2 + 2 CO2 -> 2 H2O + 2 CO + 4 H2 (1)

    (Yes, I know that I can divide by 2 and simplify, but bear with me for a moment.) Now let the water condense, remove it, and send the remaining hydrogen and carbon monoxide mixture to another reactor with an iron-based catalyst:

    2 CO + 4 H2 -> C2H4 + 2 H2O (2)

    Et voila, we have ethylene!

    Reaction (2) is strongly exothermic and can be used as a heat source to provide the energy the endothermic reaction (1) needs. It also has a high equilibrium constant, making the achievement of high ethylene yields possible.

    Ethylene has a boiling point, at one atmosphere pressure, of -104°C. But, under a few atmospheres pressure, it is liquid and storable without refrigeration at Mars average ambient temperatures. Ethylene can be used as fuel for rovers and rockets, but it can also be used as an anesthetic, as a ripening agent for fruits, and as a means of reducing the dormant time of seeds. These features will all be very useful to the developing of a Mars colony, but its more important use will be for making plastics.

    Ethylene is the basic feedstock for a range of processes to manufacture polyethylene, polypropylene, and numerous other plastics. These plastics can be formed into films or fabrics to create large inflatable structures (including habitation domes) as well as to manufacture clothing, bags, insulation, and tires, among other things. They can also be formed into high-density, stiff forms to produce bottles and other watertight vessels both enormous and minute, tableware, tools, implements, medical gear, and innumerable other small but necessary objects, boxes, and rigid structures of every size and description, including those that are both transparent and opaque. Lubricants, sealants, adhesives, tapes, can all be manufactured–the list is nearly endless.

    Plastics are, of course, among the most central materials of modern life. They can be made on Mars because of the ubiquitous presence there of carbon and hydrogen. This should give pause to those who believe the prospects for settlement on the Moon are superior to those on Mars. The Moon has no significant quantities of carbon and hydrogen; they exist there only in parts per million quantities, somewhat like gold in seawater. The manufacture of cheap plastics will never be possible on the Moon. In fact, on the Moon for a long time to come, plastics would literally be worth their weight in gold.

    • Ioannis Kokkinidis February 6, 2017, 1:27

      To use ethylene as fuel is assumes that you have oxygen to burn. I am open to using non biologically derived plastics, the list was mostly intended to show what we can get from agriculture. Which of the two is more efficient: Creating plastics out of polymers from biologically derived sugar or crating them out of abiotic ethylene? If the answer is that latter, why not?

    • Michael February 6, 2017, 15:57

      My problem with ethylene production by chemical means is CO and hydrogen are both dangerous, there are bacteria that can produce ethylene naturally.

    • Antonio February 6, 2017, 18:35

      Ioannis Kokkinidis:

      Of course oxygen is needed to burn the fuel. Of course biofuels need oxygen too. And, as I said in my first sentence, hydrogen is obtained by electrolysing water. So… well… you know what is obtained in that electrolysis too…

      Oxygen can also be obtained from the Martian atmosphere in several ways. For example, you can use the Sabatier reaction to obtain methane and water from hydrogen and carbon dioxide, then electrolyze the water, take the oxygen and recycle the hydrogen back in to the Sabatier reaction chamber. After some passes, from the initial CO2, all the carbon is in the methane and all the oxygen is free. You can use the methane as fuel, or you can pyrolyze it into carbon and hydrogen, and reuse the hydrogen. The remaining carbon is in the form of graphite, that can be given some industrial use or combined with CO2 while the graphite is still hot, obtaining CO, that can be vented to the atmosphere or used someway.


      What do you mean by dangerous? They can only explode/burn in Earth’s oxygen-rich atmosphere. And anyway biofuels have the same problem. Also, the hydrogen will be stored only in the form of water, since it’s expensive to store cryogenic hydrogen, even on cold Mars. And water will be electrolyzed only when hydrogen is needed.

      As for toxicity, carbon monoxide is toxic when inhaled, but so are many other gases, and I can’t imagine any credible scenario where the astronauts would inhale it. They will not walk without a helmet near the tanks.

    • Antonio February 6, 2017, 18:43

      Ioannis Kokkinidis: As for efficiency in making plastics, well, currently almost all of our plastics are abiotically made. I can’t quantitatively compare them with biotically made plastics because the later are very rare today. So, put simply, you could develop a lot of new bacteria and industrial processes and use them on Mars, or you could simply use current processes and technologies to produce plastics on Mars as they have been produced for decades on Earth.

      • Ioannis Kokkinidis February 6, 2017, 23:27

        Plastic derive from prime material that is extracted by a very biological material: petroleum. They are made abiotically but the prime material is biotic. The idea behind bioplastics is to sustainably reproduce the biological prime material, to limited effect

        • Antonio February 10, 2017, 5:50

          But people didn’t have to produce petroleum, so that efficiency doesn’t count.

    • Eniac February 18, 2017, 13:01

      On the moon, and many other places in space, metal, glass, and ceramics are much more accessible than plastics. And that is just fine, they make excellent materials for nearly everything.

      As has been said, there is no need for fuel. Thin film photovoltaics are not that hard to make, especially given free vacuum, and all energy will be electric.

  • Geoffrey Hillend February 4, 2017, 18:45

    In other words, hydrogen needs oxygen to burn and explode.

  • Coacervate February 5, 2017, 9:13

    I do not understand this: “There is no such thing as the perfect diet for all conditions; we need to balance the macro and micronutrient needs of humans with the available resources and the need to maintain a healthy population.”

    Do you intend for the second sentence to follow from the first? Available resources are limiting factors agreed but that does not imply anything about the former statement.

    I think you mean that humans working in extreme environments are likely to require higher caloric intake by eating say a larger proportion of rice or of course Watney’s Potatoes ; ) But if you mean that ” everyone’s chemistry is different” I disagree. This get repeated often but it just not true. We may variations in our genes but all share the same biology.

    Or perhaps you are including individuals with genetic diseases that require special diets?

    I suggest anyone interested in further investigation start with Dr. Michael Geger’s book “How Not to Die”. I mean, who can resist such a title!

    I hope to see more of your articles here. Very important indeed.

    • Alex Tolley February 5, 2017, 13:41

      But if you mean that ” everyone’s chemistry is different” I disagree. This get repeated often but it just not true. We may variations in our genes but all share the same biology.

      You are forgetting the microbiome. Different gut populations can alter our ability to obtain nutrients from food. For example, the Japanese have gut bacteria that can help digest seaweed, bacteria that are absent in most populations.

      Which suggests that just possibly, rather than changing the human genome with unforeseen consequences, perhaps a better route is to engineer bacteria, that can become part of our microbiomes, to help us adjust to some limitations of off-planet life. Synthesizing some essential vitamins for example.

      • Coacervate February 5, 2017, 17:24

        This is a common misconception. Our diets present a selective medium to the myriad background bacterial species/strains that we are all exposed to all the time. The Japanese seaweed eaters are a case in point.

        Engineering is fine but it is much better to select the best diet to encourage the best types of bugs. This guy says it better than I can:


        • Alex Tolley February 5, 2017, 21:48

          If I understand your point correctly, doesn’t that mean that all bug types have to be present in all geographic areas so that the appropriate ones can colonize your gut based on your diet? Is that really the case? If that was the case, then changing diet would dramatically change your gut flora, but AFAIK that isn’t the case. Those flora have to be provided, e.g. via fecal ingestion. We also don’t even know where we get our gut flora from. Recent work has suggested the mother is not the source, at least around birth. (Maybe breastfeeding is a route?)

          But yes, a good diet is definitely the best approach. Fortunately, the largely plant diet recommended is going to be the easiest for Martian colonists. Lucky we aren’t carnivores.

    • Ioannis Kokkinidis February 6, 2017, 1:34

      When I was doing my PhD my professor’s other graduate student was working on a project to grow local food. In the end the question of growing food locally boiled down to what people actually eat: The Mediterranean diet is I think the best diet (I am biased) but it is in the optimized for a Mediterranean climate and environment. In Northern Europe you need more meat in order to survive the winter cold. Olive trees do not grow north of the Alps, hence fat becomes butter and pork lard rather than olive oil However eating a North European diet in the Mediterranean stresses the environment because it cannot support the kind of animal density a north european diet assumes. This is what I mean: no perfect diet for all environments, optimize diet based on what you can actually grow there as much as local preferences.

      • Coacervate February 6, 2017, 14:35

        Ioannis, I encourage you to look into the large body of evidence that is in direct contradiction to your assertions about Northern European caloric requirements. I do not stand to gain anything from my nutrition research. Rather I am only trying to sort out the real science from the funny science that gets funded by ‘interest groups’ like Coke or the Texas Cattlemen’s Association to help my family and friends who seem trapped in a maze of misinformation.

        You said “Optimise diet based on what you can actually grow there as much as local preferences.” I am, with respect, in opposition to this statement. When an individual goes to space now and for the foreseeable future, they are riding on the taxpayer’s dime. Or perhaps, Mr. Musk’s billions. Either way their ‘local preference’ in this case is irrelevant. Your admitted bias is what concerns me. The pitfall would be to transmit our bad habits to the new pioneers. A lot of educated people think we should eat like cavemen, whatever that means. Many are slurping down “Atkins” meals thinking they are lucky to have found something that fits with their personal bias.

        I say that They must eat the most healthy diet that current science can describe. They must grow plants even if they need to amend the medium to do that. Of course it must be done within practical limits. If you can’t grow kale then grow rocket, heh. But if you can’t grow plants in general then better stay on Earth.

        We know without experiment that to live independently of Earth we must be able to grow plants. Feeding those plants to animals falls over on many levels. It is not efficient, not healthy and it is in opposition to the notion of sustainable agriculture. Consider 250 m2 of hydroponics compared to manyfold times that to feed/grow meat animals.

        I emphasise that I am not promoting an agenda based on morality around killing and eating animals. This is all strictly from a nutritional viewpoint.

        Supplying calories with any kind of fat (plant or animal) lays down an underlying, low-grade, systemic state of inflammation. The knock on effects of inflammation are still being elucidated but we already have a good idea of just how harmful it really is. The best health and longest living groups are among those who meet their caloric needs by eating complex whole starches such as potato, rices and other whole foods.

        The following is just a small sample from the published record. I would value the opportunity to make my case to you by direct contact. I think Paul would pass my email to you if asked. I am a PhD biochemist ( with MS in Food Science) with some 30 years experience trying to unlearn the “truths” foisted by the US Academic/Industrial/Pharmaceutical complex.

        I’m sure it is clear that I am passionate about this subject and overjoyed to see this topic developing on CD. It would be fun to hammer out an exposition on the current science and see if we can align that with the needs of our little space sprogs as they mature into reality.

        I do not mean to overwhelm with this reference list. I can provide my (and other leading scientist’s) reviews of these and much more with respect to optimal nutrition and how it should be applied to space exploration and colonization.

        I think you would agree with me that we have an opportunity to shape an optimal eating plan for our extraterrestrial offspring that spares them from the afflictions that modern eating patterns cause. In short we can virtually eliminate the number 1, 2 , 3 …..n killers for a brave new generation.

        D C Willcox, G Scapagnini, B J Willcox. Healthy aging diets other than the Mediterranean: a focus on the Okinawan diet. Mech Ageing Dev. 2014 Mar-Apr;136-137:148-62.

        A Drewnowski, J Hill, B Wansink, R Murray, C Diekman. Achieve Better Health With Nutrient-Rich Foods. Nutrition Today: January/February 2012 – Volume 47 – Issue 1 – p 23–29.

        D C Willcox, B J Willcox, H Todoriki, M Suzuki. The Okinawan diet: health implications of a low-calorie, nutrient-dense, antioxidant-rich dietary pattern low in glycemic load. J Am Coll Nutr. 2009 Aug;28.

        S Davinelli, D C Willcox, G Scapagnini. Extending healthy ageing: nutrient sensitive pathway and centenarian population. Immun Ageing. 2012 Apr 23;9:9.

        B J Willcox, D C Willcox. Caloric restriction, caloric restriction mimetics, and healthy aging in Okinawa: controversies and clinical implications. Curr Opin Clin Nutr Metab Care. 2014 Jan;17(1):51-8.

        M Poulain. Exceptional Longevity in Okinawa:: A Plea for In-depth Validation. Demographic Research;Jul-Dec2011, Vol. 25, p245.

        N S Gavrilova, L A Gavrilov. Comments on Dietary Restriction, Okinawa Diet and Longevity. Gerontology. 2012 Apr; 58(3): 221–223.

        B J Willcox, D C Willcox, H Todoriki, A Fujiyoshi, K Yano, Q He, J D Curb, M Suzuki. Caloric restriction, the traditional Okinawan diet, and healthy aging: the diet of the world’s longest-lived people and its potential impact on morbidity and life span. Ann N Y Acad Sci. 2007 Oct;1114:434-55.

        D C Willcox, B J Willcox, H Todoriki, J D Curb, M Suzuki. Caloric restriction and human longevity: what can we learn from the Okinawans? Biogerontology. 2006 Jun;7(3):173-7.

        G E Fraser, D J Shavlik. Ten years of life: Is it a matter of choice? Arch Intern Med. 2001 Jul 9;161(13):1645-52.

        D C Willcox, B J Willcox, Q He, N C Wang, M Suzuki. They really are that old: a validation study of centenarian prevalence in Okinawa. J Gerontol A Biol Sci Med Sci. 2008 Apr;63(4):338-49.

        M Suzuki, B J Wilcox, C D Wilcox. Implications from and for food cultures for cardiovascular disease: longevity. Asia Pac J Clin Nutr. 2001;10(2):165-71.

        M Suzuki, D C Wilcox, M W Rosenbaum, B J Willcox. Oxidative stress and longevity in okinawa: an investigation of blood lipid peroxidation and tocopherol in okinawan centenarians. Curr Gerontol Geriatr Res. 2010;2010:380460.

        J G Fodor, E Helis, N Yazdekhasti, B Vohnout. “Fishing” for the origins of the “Eskimos and heart disease” story: facts or wishful thinking? Can J Cardiol. 2014 Aug;30(8):864-8. http://www.ncbi.nlm.nih.gov/pubmed/25064579

        P Bjerregaard, T K Young, R A Hegele. Low incidence of cardiovascular disease among the Inuit–what is the evidence? Atherosclerosis. 2003 Feb;166(2):351-7.

        M R Zimmerman. The paleopathology of the cardiovascular system. Tex Heart Inst J. 1993;20(4):252-7.

        J Dyerberg, H O Bang, N Hjorne. Fatty acid composition of the plasma lipids in Greenland Eskimos. Am J Clin Nutr. 1975 Sep;28(9):958-66.

        I M Rabinowitch. Clinical and Other Observations on Canadian Eskimos in the Eastern Arctic. Can Med Assoc J. 1936 May;34(5):487-501.

        E C Rizos, E E Ntzani, E Bika, M S Kostapanos, M S Elisaf. Association between omega-3 fatty acid supplementation and risk of major cardiovascular disease events: a systematic review and meta-analysis. JAMA. 2012 Sep 12;308(10):1024-33. doi: 10.1001/2012.jama.11374.

        R De Caterina. n-3 fatty acids in cardiovascular disease. N Engl J Med. 2011 Jun 23;364(25):2439-50.

        • Ioannis Kokkinidis February 6, 2017, 17:24

          Back in the 1960’s the first diet book were published in Greece, translations of American diet book. My mom told me a story about a diet that became rather fashionable (I do not recollect which one) whose originator was divorced by his wife. The reaction in Greece was if he forced people to eat just an apple for lunch, he had it coming. In Greece like in most of the Mediterranean lunch is the main meal of the day, where you get the majority of the calories, preferably (but not always) followed by siesta. In Anglosaxon countries it tends to be dinner. In Germany it is breakfast. In high latitudes you try to catch as much sun as possible during winter, lunch is an impediment, eat a lot early, a lot after sunset and work as much as possible. Anyone who has been in a Mediterranean summer knows that working outside at noon is downright dangerous because of the heat, 40 C. Physicians have found that it is healthier to have the siesta as opposed to a one block 8 hour sleep at night. Why am I talking about sleep? Because the optimum diet also depends on your sleeping habits. Half my classmates in Greece ate their lunch after 3 pm, as I did when I was working in Crete from 7.30 to 15.00. Do we have any idea what will be the schedule of off planet colonists? Do we know when they will eat? The requirements of a meal that will sustain you for 8 hours and must be digested rapidly is very different than that of a meal that you give yourself hours to digest before getting to work. I have learned to be wary of the implicit assumptions of optimum diet studies: Is diet A which was found best in a schedule of strong breakfast, weak lunch, strong dinner better in a schedule of weak breakfast, strong lunch, weak dinner? I may live in the US several years now but lunch is still the main meal of the day for me, even if it is not for my coworkers. In any case, I am very skeptical of a diet that does not consider bougatsa and chocolate milk to be the best possible breakfast possible :)

  • Coacervate February 5, 2017, 9:39

    Here we have an example of the ‘frontline’ in the battle between science and ethics. We have an ever-improving command of genetic engineering, much of which is restricted by ethical concerns (in the USA at least). For example consider Stem Cell research. While government-funded research on the use of fetal tissues languished in the USA, other countries attracted the top talents to continue this work. Is it important and urgent? Of course. Yet it was stopped cold.

    We all know that a biological revolution is upon us, and yet the idea of re-inventing people into a better fit with resp/ to extraterrestrial habitats didn’t even rank a nod. I wonder how other contemporary societies (not often represented here at CD) are viewing this moral dilemma, if they see it as dilemma at all? Perhaps it is time to re-assess our bourgeois obsession with maintaining our existing core moral hierarchies.

    BTW, the Elements of Life chart is brilliant. I need this poster for my office!

    • Ioannis Kokkinidis February 6, 2017, 1:40

      In Europe transgenic crops are viewed extremely negatively, even by the farmers, but people are more open to stem cell therapies for the simple reason that abortion is not a controversial thing. When I think of what is ethical and proper for research and applications, I divert to what we were taught in 11th grade Ancient Greek: We were doing Plato’s Protagoras which in the end comes to the following proposition: All science removed from virtue (αρετη) is wickedness and not wisdom. When we are doing research, are we pursuing αρετη? If the answer is yes, keep doing it

    • Harold Shaw February 6, 2017, 14:33

      I think homesteading will select for an explorer character type and will make demands that a homesteader must negotiate. The risk of CRISPR tools to human health are easy to manage while the risk to wider ecosystems is more difficult. With homesteading there is no risk of GMOs to a wider ecosystem. With homesteading there may be more risks to mothers and fetuses, and also here a lesser risk to a larger ecosystem.
      Ways to successfully modify the human genome will require failed attempts.

  • Harold Shaw February 6, 2017, 12:19

    Forgive me if this lowers the bar for discussion, but I am going to talk about poop.

    I think the type of animals transported to Mars or off Earth colonies will depend a lot on the amount and type of waste generated by an animal and our ability to manage waste en route. If we attempt to transport cows in micro-gravity, the ship’s crew may decide to change course for the sun or they may require years of counseling. Even the waste generated by something as small as a rabbit will be difficult to manage in micro-gravity.

    We may not see Martian cows until we have ships such as the Spacecoach concept capable of simulating gravity and processing a lot of waste. Animals could be anesthetized whenever gravity couldn’t be simulated.

  • Charlie February 6, 2017, 13:54

    @Ioannis Kokkinidis
    thanks for the reply; yes, I do believe that inorganic synthesis of these amino acids would in fact be more difficult than biological, and perhaps the initial synthesis step could be conducted by say by yeast or algae or something like that. But my previous comments were directed to the idea that foodstuffs derived totally through some kind of synthesis method could serve to condense this complicated and error-prone biological methods that would consist of growing and harvesting and ultimately returning non-edible portions of the foodstuffs back to the soil, etc. etc.
    I realize that it is human nature to have a meal or many meals if you wish, and the enjoyment is of course something that makes part of life what it is. But I did say that a strong appetite suppressant might be developed which in fact would curb the need for excessive calories which would be extremely crucial in spaceflight.
    This is, after all, astronauts that we are talking about not restaurant diners who are going about and having a grand meal. The astronauts are going to have to work as hard as possible under the current scenario, just to produce enough calories for the every day, bodily needs of the individuals there and doesn’t seem that a way to reduce the process down to its most elemental basis is a way to help these people?
    I’m not saying I have all the answers but I can easily imagine that when it comes down to farming on some foreign planet, the people there are going to be doing that and perhaps very little else. And that’s not why they are setting up colonies. Food is part of the equation that will be make being a colonist endurable. But if you are constantly working to get that pleasurable aspect of life. It becomes less pleasurable when you must go to access to obtain the food that you enjoy. That’s what I was trying to get across

    • Ioannis Kokkinidis February 6, 2017, 17:38

      A few months ago NASA posted this very interesting lecture on youtube: https://www.youtube.com/watch?v=bjuN15J59io

      It is worth watching all two hours of it. Astronauts are humans. What we want them to do in the name of efficiency is very different from that they actually do with their food. I am pretty sure that it belongs to the realm of the possible to create an entirely artificial food pipeline. Would people actually want to be subjected to it? Soylent does prove that there are people that in the name of efficiency are willing to sacrifice the finer parts of life. Think though of how small is the percentage of people in the general population willing to replace their diet with Soylent.

  • Harold Shaw February 6, 2017, 14:25

    A colony able to refine the materials needed to build the structures needed to sustain agriculture wouldn’t necessarily need agriculture to provide structural materials. I think the role of agriculture will evolve as homesteading evolves. The focus will be edible food and therapeutic common gardens. We can assume a reliable way to produce 3D printed hydroponics systems, root mediums, and aquaponic tanks systems, perhaps as a rack system. Engineers are working on printed LEDs for homeworld demand.
    I think there is a transportation filter for meat where only or dominantly, eggs can be transported. There is a lot of variety in the category: insects, aquatic invertebrate…many suitable to a rack system.
    Common space would certainly influence the design of colonies and produce an architecture of independent estates connecting to large common areas. That common area would grow until a being a Martian or Mooner lumberjack was a thing.

  • James Stilwell February 6, 2017, 16:42

    A good post…this information will come in handy when by 2100 11 billion people on earth will need to know all these things…for earthlings…UN suggests we will have to stop eating meat by then, unless Memphis Meats gets going with their synthetic meats project.

  • stan erickson February 6, 2017, 16:49

    Before considering agriculture on Mars, decades in the future, it might be beneficial to consider agriculture on Earth. Will be we doing it a century or two in the future, or will everything we need for nutrition come from black boxes with wires and organics going in and nutrients and debris coming out? If agriculture is destined to become extinct here on Earth, why worry about its revival on other planets?

    • Ioannis Kokkinidis February 6, 2017, 23:24

      Agriculture is not going away on earth anytime soon. We will see transformations in the same way that man plows were replaced by animal plows and nowadays tractors and no till, but we will not see a change in the basic core: We grow a plant or an animal to produce a good we need. While I cannot guess centuries in the future, food fabs will still require agriculturally produced prime materials.

    • DCM February 7, 2017, 5:04

      We better maintain some traditional agriculture so the skills won’t be lost. A big catastrophe or one that has a swift cascade effect could destroy industrial food production.
      Transferring this to other planets will be a good idea once we can do it. Who knows what might happen there?

  • Geoffrey Hillend February 6, 2017, 17:37

    I think that batteries of some kind will always be needed at least for emergency back up power and stored energy. The same is true of solar cells. Looking to the future, submarines have nuclear reactors and at some point a small one might be launched into space or built in space and used to power VASIMR or some ion powered craft. If the reactor has to be shut down, then there must be an auxiliary power source.

    Also GMO’s are not liked because are harmful to people and animals. They also have been engineered to resist pesticides which increases the use of pesticides etc. They are sometimes engineered to kill bugs that attack them.

  • Harold Daughety February 7, 2017, 1:38

    On wood and fiber, bamboo is a quick-growing plant that can be hand worked. Fast growing willows and ornamentals could provide materials for carving simple implements. On food, small plots of food crops – legumes , potatoes, squash, fertilized with night soil has been practiced for millennia. Pollination by hand is easily accomplished. Okra is a high protein food that is easy to grow and can be eaten raw. Cotton can be ginned with a simple hand- turned mechanism and spun into thread and woven into cloth – all low tech operations. The seed is a source of vegetable oil and the seed kernel is an excellent nitrogen fertilizer. Low tech is far more forgiving than high tech when one is a gazillion miles away fro repair parts..

  • Epibeemie February 7, 2017, 17:17

    Does the same follow for humans? We need certain elements for nutrition, so here, sonny, here’s some coal for your carbon, a tank of hydrogen and some sand for your silicon. Our bodies eat food. That’s how they can access and use these elements. Plants need humate, mulch, etc., in a matrix w water and micro organisms. Please don’t mislead the planetary scientists into thinking that identifying where elements are is the same as identifying places that plants can grow. NPK fertilizer is a gross oversimplification of plants’ nutritional needs.

    • Ioannis Kokkinidis February 7, 2017, 21:03

      Plants assimilate elements in different way than animals. Plants take most elements as ions in the nutrient solution in their roots. Animals get their elements through their stomachs. If you want to add sulfur, one way is to add gypsum to the soil Animals do not mostly eat gypsum, though granted chickens eat stones though mostly to grind the meal in their stomach. Now it is true that plants are likely to assimilate complexes rather than naked elements (though it is naked elements they assimilate in hydroponics) but still complexes are produced by microorgamisms in the soil starting with the raw element

  • Andrew Palfreyman February 8, 2017, 14:29

    A big, fat, juicy steak.
    Just saying.

    • Bruce Mayfield February 8, 2017, 17:44

      And not grown in a chemical vat, thank you very much. But hey, what else could I say, I’m from Texas.

      It is good to be omnivores though. It gives us the adaptablity to make it in a wide range of environments.