Because Centauri Dreams focuses on the outer system and beyond, I haven’t had much to say about Mars, knowing how many good sites there are that cover developments there. But today’s post is timely not only because of recent depictions of Mars in film but also because long-term sustainability is critical to a lasting human presence off-world. Dr. Ioannis Kokkinidis is a native of Piraeus, Greece. He 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. Have a look now at what we could do to sustain a human settlement on another world.
By Ioannis Kokkinidis
I believe most readers of this blog have seen Ridley Scott’s The Martian and perhaps have even read Andy Weir’s book. Our hero Mark Watney is stranded on Mars and has to overcome a series of crises in order to survive, including growing food. Entertainment aside, the question of how could we grow crops on other worlds is a serious one. As an agronomist, a practitioner of the scientific discipline that conducts analysis and experiments so as to offer advice to farmers, I offer here my take on the subject.
The issue of growing food on other worlds seems to be generally neglected in science fiction. It tends to be brushed over through the use of replicators, miraculously processed food that turns into a scrumptious meal with a few drops of water or other similar plot devices. Until these devices are invented it is better to speculate using existing technology. The majority of the suburban and urban populations are not aware of modern agricultural practices, having a mental image of a rural utopia that reflects decades or centuries past.
Also, farming practices in each country tend to reflect its socioeconomic conditions and level of development: the best method to grow food in the confined and limited space of a colony is often not the one practiced by farms near where you live. For this article I will give a special emphasis on Mars, because our knowledge of the planet is better than that of other heavenly bodies and because of its relative suitability compared to other worlds. This article is divided into two parts dealing with plant and animal production.
Plant Production
Plants require some 30 or so elements to grow. C, H, O, N, P and K are required in large quantities and are called macronutrients, Fe is an intermediate case and the rest are called micronutrients, required in minuscule quantities. Carbon is absorbed from the atmosphere in the form of CO2. Hydrogen is absorbed through the roots in the form of water. Oxygen enters through CO2 and H2O, while the rest of the elements are absorbed through the roots dissolved in the liquid solution. A common misconception about plants is that soil is necessary for their growth: it is not. What is necessary is a liquid solution containing the necessary elements to grow. The practice of growing plants in a soil-less medium is known as hydroponics and was the subject of my undergraduate thesis, which I conducted in Portugal as an Erasmus student. The very specific case where instead of a medium the root is suspended in midair, with the solution sprayed to the root, is called aeroponics.
Hydroponics dates to plant nutrition experiments in the late 19th century. The first major applications appeared during WWII when it was used to grow fresh food by the United States armed forces in the Pacific for garrisons in bare islands that were too isolated for effective resupply. Commercially it was first used in the Netherlands during the 1960’s in greenhouses, where after decades of using the same soil there were too many disease vectors for use. Over the decades it has become a relatively popular method to grow crops in greenhouses, preferably in places that are densely populated and have significant available capital. While all crops can be grown hydroponically, commercially it is limited to high value crops such as vegetables and flowers: Field crops receive free ecosystem services from the environment; in a hydroponic greenhouse we need to provide and/or supplement them artificially.
Plants convert radiation into biomass through photosynthesis. In lower plants such as blue green algae this biomass is in the form of undifferentiated cells. In higher plants there are differentiated organs such as tubers, fruits, stems and leafs. While algae is consumed whole after treatment, we often consume parts of plants, the specific part depending on the species.
Furthermore, there is no such thing as a superplant able to provide the entire needs of human nutrition on its own. We will need to grow a mix of species to provide the various needs of the colonists. A major problem though is that we do not know what the actual nutritional needs of the colonists will be. An office worker on Earth needs 2000-2500 calories per day; a manual laborer can easily consume over 5000. We do not know what the effect of lower gravity is in caloric consumption or the relative requirement on each food component. However, there have been various studies proposing crops mixes for future colonies.
I envision the future Mars plant growth facility as a greenhouse. Since Martian surface pressure is very close to a vacuum, this greenhouse will need to be a pressure vessel. The closest thing yet constructed to a high transmittance pressure vessel is the ISS Cupola. The alternative option is to build a completely enclosed facility with artificial illumination. I am more in favor of a facility with windows, as the inside of a greenhouse is a very corrosive environment and in my opinion it is better to have the option of the sun than to be completely reliant on artificial light sources. That being said, at Mars levels light intensity is lower than that of Earth on clear days, though pretty similar to cloudy days in Northern Europe. In Northern Europe the lack of solar illumination is compensated through supplementary artificial lighting. In my native Greece light intensity is such that farmers will actually put stucco on their greenhouse’s covering material in late spring so as to reduce illumination and the solar heating it causes. This is unlikely to be necessary on Mars.
Image: An artist concept depicts a greenhouse on the surface of Mars. Credit: NASA.
Cover materials for greenhouses on Earth tend to fall into three categories: PET, glass and clear PVC. PET (polyethylene terephthalate) is the most popular material because of its low cost and the light greenhouse structure it requires. It comes in various quality levels, ranging from a thin flexible material that lasts only one season until it is yellowed by UV radiation to relatively thick panels that are rated to last 10 years and in practice can last a bit longer. PET is susceptible to yellowing due to UV radiation and is completely clear to IR radiation. Glass is material that is bristle, easy to break but is known to last for centuries so long it is cleaned. Due to its fragility it requires a heavier structure greenhouse. Clear PVC (polyvinyl chloride) combines the lightness of PET with the longevity of glass. Unfortunately it is a very expensive material, making its uses on Earth rather rare. While I am unaware of any experiment to test long term survival of greenhouse cover material under simulated Martian conditions, my educated guess would be that clear PVC would be the best option for a Martian cover material.
The inside of a high end modern greenhouse contains quite a bit of machinery. Artificial lighting has been mentioned, which will be necessary not only for increasing radiation but also in order to control day length: many temperate species will not set flowers and fruit unless a specific day or night length is met. This phenomenon is known as photoperiodism. On the flip side, the greenhouse will also require a shade to extend night length. In order to reduce heat losses during the night we will most likely need a thermal blanket.
Now in Athens from March on, on a sunny day the temperature inside a greenhouse can reach 40° C. This is not a tolerable temperature for most plants, which is why we keep the doors and windows open on a greenhouse from 10-11 am up to sunset. On Mars of course that is impossible, so should this problem arise we will need a system to remove heat during the day.
We will also need a system to add heat during the night, which even on the Martian equator in the summer can be lower than Earth’s Polar Regions. While on Earth we can rely on ambient air to introduce the CO2 which is removed by the plants, on Mars we will need to provide it. A greenhouse full of mature plants can assimilate the entirety of its atmospheric CO2 within a couple of hours from sunrise. Putting CO2 in excess of atmospheric concentration is a known method to accelerate the life cycle and increase yield in plants, called carbon fertilization.
Usually CO2 is pumped to the 1500 ppm level around sunrise, and the plants will often assimilate this by noon. Since workers often need to enter the greenhouse to work they will do so around the time CO2 drops below ambient concentration so as to bring new atmospheric CO2 in the facility. The Martian atmosphere is fortunately 96% CO2, however higher plants do not usually tolerate more than 4% concentration. Algae can survive up to 70% concentration, which is why it has been used for carbon sequestration in power plants on earth. CO can also be a problem for workers though not for the plants; they can oxidize it to CO2 and assimilate it. In general plants act as water pumps, carrying water from their roots and releasing it in their leaves. On earth we lower humidity by exchanging air, for Mars we will need to do so through machinery. We will need, though, pumps of the mechanical kind to circulate the irrigation water.
Image: From The Martian, astronaut Mark Watney (Matt Damon) works inside a flourishing greenhouse. Credit: Twentieth Century Fox Film Corporation.
Over the last few decades agronomists and farmers have tested a variety of substrates for hydroponic use and have almost always found the material suitable. There is no reason to believe Martian regolith will not be found suitable as substrate, but it would be better for the first colonists to also bring from Earth material proven to work, such as rockwool or cocopeat. While we’ll have a few plant rows working with the proven material, we will have a few experimental rows trying to discover the best methods for the regolith.
As mentioned, hydroponics plants require a nutrient solution to provide their needs. There are two types of nutrient systems available: open loop (also known as run to waste) where the solution is dumped after it passes once through the row, and closed loop, which still dumps about 20% of the solution after loop. Although we will most likely require a N fertilizer production facility anyway, since we will be dealing with limited resources, it is better to adopt a closed loop system despite the issues this creates with plant protection. In a hydroponic greenhouse the solution for each of the elements is produced in large vats where the worker mixes each fertilizer with water. The automation pumps each solution in a new vat where it is mixed to contain the element mixture we wish and pH is regulated using acid or base. Then it is sent to each row for plants to use. Plants selectively assimilate each element depending on the soil and water pH; often element deficiencies are caused not due to lack of the element in the solution but by the inability to assimilate it at the solution’s pH or competition with other elements.
Another phenomenon typical in regions with bad quality water such as Cyprus is precipitation of the micronutrients as a sediment that can block the water emitters. Future Mark Watneys will have their day full just trying to bring their crop into production.
Another issue that future Mark Watneys will need to face is plant protection. Crops on earth get attacked by a variety of pests and diseases. Much as we can try to keep an aseptic environment on Mars, this is likely to happen eventually. We have no idea what the interaction between potential indigenous Martian lifeforms and our plants could be. What we do know, though, is that it is very likely we will bring pests from Earth; already Scott Kelly had to combat a mold on the Veggie experiment on the ISS. By controlling humidity and temperature we can control the growth of pests. However, for major infestations we will likely need to use chemicals and this raises all sort of issues. For one thing we are talking about complicated molecules which we will either need to ship from Earth or synthesize locally. Also, we will need to make sure that they do not enter the air of the human habitat. The best line of defense, though, is polyculture, growing a variety of crops. If one particular crop fails, there will be food from the rest.
Photosynthesis is not the only way to grow food; we can grow calories from decomposition of plant material. Pleurotus mushrooms are an easy way to turn hay into high quality nutrition. All that is required is hay and a dark room without any sunlight. The hay stack (which could be the stem of the plants grown) is inoculated with mushroom spores, placed in a cubic plastic tarp with slits and we harvest every week the growth coming out of the slits. In the end we have both high quality nutrition and a material which can be used for compost at the mushroom’s roots. Soil compost, which we can also create with other biological materials in the habitat will help detoxify soil and thus move towards soil based agriculture on Mars.
Image: NASA plans to grow food on future spacecraft and on other planets as a food supplement for astronauts. Fresh food, such as vegetables, provide essential vitamins and nutrients that will help enable sustainable deep space pioneering. Credits: NASA.
Animal production
A completely vegan diet cannot easily provide all the necessary nutrients for survival in the long term. While at first we can expect animal derived products to arrive with resupply missions, in the long term we will need to engage in animal production to meet the needs of the colony. Meat is an integral part of the Western diet; however, the availability of cheap food mostly reflects the large grazing ground of the US West or the Argentinian Pampas and the policies of the EU Common Agricultural Policy. Growing animals off Earth will mean adopting the model of the Concentrated Animal Feeding Operation (CAFO) rather than low intensity pastoral agriculture.
The most important number in a CAFO is the feed conversion ratio (FCR). It is defined as the quantity of animal feed required to produce one kilogram of body mass. It varies by species, facility, feed composition, climate, age of the animal and production facility. Wikipedia has an interesting article on the subject. FCR ranges from under 2 for crickets, tilapia and some chicken facilities, around 3 for pigs and rabbits, and at least 4 for sheep and cattle.
Now, to achieve these high numbers requires optimized genetic stock, optimized feed and optimized environmental conditions. Modern efficient chicken farms require the use of high yield chicken hybrids that are provided as week old hatchlings to the CAFO. There they are kept in temperature controlled facilities, often in cages with 6 animals per cage. Feed is constituted of high yield grains which must meet specific food group mixture ratios and often includes antibiotics in sub-therapeutic concentrations so as to increase FCR. After 7-8 weeks, when the animals are immature sexually but have reached the expected weight they are harvested and sent to the slaughterhouse.
Losses of 5-10% of the original animal population are typical. Simply put, it requires a very large infrastructure with large breeding flocks so as to minimize the possibility of incest (and the drop in FCR it brings) just to provide these hatchlings. Another thing to note is that we do not eat whole animals or fishes, only part of them. Typically the commercial cuts of the animal are in the order of 50-55% of the body mass. In other words animal production is very inefficient. However, there are a few advantages to animal production. For one thing, we do not eat the entirety of the cultivated plant. Traditionally animals consume first what people do not.
Assuming a Harvest Index of 1, typical for small grains, producing 1 kg of grains will also produce 1 kg of above ground biomass, mostly the plant stem. With a feed conversion ratio of 3 this will convert to 333 g of animal. With a commercial cut ratio of 51% this means that 170 grams of meat can be produced along with 1 kg of grains. In practice an FCR of 3 is unrealistic for any animal only fed on hay and we are likely to lose animals during production. Still, we can presume the possibility of a diet composed of 10% meat by weight in the long term of the colony without significant dedicated plant growth for feed.
If we wish to have 50% of meat in our diet by Mars-grown animals, this means that with an FCR of 3 and an edible weight ratio of 0.5 and assuming that the stem is not used for the feed, we will require 3.5 times the growth area in the farm than for a 100% vegan diet. This is on top of the necessary veterinary support for the animals or the need to manage animal wastes of all kinds. Furthermore, while we can select plant varieties that are parthenocarpic and/or self-pollinated, animals only reproduce sexually, which means that we will need to maintain a flock of sufficient genetic diversity.
Conclusion
This essay has tried to deal with some of the issues that come with growing food away from earth in a gravity environment, with an emphasis on Mars, from the perspective of an agronomist. Several of the concepts can be used in other worlds too, though it will require coming up with sources of carbon dioxide and photosynthetic radiation which are available on Mars. The MIT study of the Mars One concept mission came to the conclusion that the space allocated in the concept (80 m2 per colonist) was insufficient to provide enough calories for the colonists, while increasing to a more realistic 250 m2 led to oxygen poisoning around the time the plants were in full bloom. Bas Lansdorp replied that his plan was to use an oxygen concentrator to remove the excess oxygen from the growth facility.
There have been comments that the model that MIT used to calculate the production of oxygen overestimated how much is actually produced. As an agronomist, though, I am inclined to believe that even if that particular model has bugs, the consumption of the entire CO2 of the habitat in a day by photosynthesis in a greenhouse housing plants in the full growth stage is consistent with earth behavior of greenhouses. With this article I try to highlight for potential planners, engineers and enthusiasts the kind of issues that will realistically be encountered when designing a food growth system for a small closed colony.
@Paul Gilster
In the beginning of the post ,in the part “Plant production” you can read “. . .Fe is an intermediate case and the rest are called macronutrients. . .”. It is a mistake ,of course it is “micronutrients” .
Now I will resume my reading !
And Paul thanks for your incredible work day after day !
Thank you for those kind words, galacsi! And as for the ‘macro/micro’ problem, I’ve just now fixed it.
An informative article, thanks.
I’ve heard some say Martian perchlorates would make Mars regolith toxic to plants. You don’t see this as a problem?
Watney used poop to help the potatoes grow and learned to endure the stench. Unusual in that sewage isn’t often examined in detail in sci fi closed ecological support systems. It seems to me sewage would need to be recycled or unacceptable amounts of organic compounds would be disposed of.
On earth we have a lot of volume, air, soil and water in which bacteria and other processes can convert sewage back into potable water, breathable air and food. Given a spacecraft’s mass and volume constraints, I’ve always suspected effectively recycling waste would be a major obstacle.
The perchlorates can be washed out of the regolith and immobilized by controlling the pH of the nutrient solution. In the long term it is not a problem. However we need to experiment on actual Martian regolith to discover its other pedological properties such as Cation Exchange Capacity. We use house insulation, the sort that is between the walls of your house/apartment as substrate to grow plants hydroponically. I don’t see why we cannot do that with regolith, after experiments to develop an appropriate protocol.
A dirty “secret” that we do not advertise is the use of biosolids as fertilizer and soil amendment. Biosolids, also known as activated sludge, is the solid part that come out of the municipal biological treatment plants after the (mostly) human waste has been treatment. There are entire volumes on the use and reuse of biosolids for agriculture, available at the library of the nearest land grant university. We can use the biosolids as they emerge out of treatment, or convert them to soil compost through composting.
Obviously the sewage, both from humans and from livestock, must be reused as plant fertilizer.
The discussion on perchlorates seems secondary, as the main claim is that we do not need any soil at all, Martian or otherwise. Hydroponics is established enough to remove any doubt on this issue.
Soil has an almost romantic association with agriculture, and as a consequence the well-proven notion that it is simply not needed for growing plants is difficult to establish as common sense.
(My wife and I have two different Orchid plants that are as old as our children… 12yrs and 9yrs… and those plants have never been anywhere near any soil in their entire lives. You’re correct to point out the common misconception)
As much as the focus in this article is on agronomy, you always have some kind of ecosystem in a greenhouse, with the vast majority of species being microbes. The adaptations that bacteria have made for metabolism has astonishing variety. Not surprisingly, there are bacteria that can “eat” perchlorate anions; I know this because the first page of search results was bountiful on the matter. The links below were the result of a less-than-ten minute research effort.
A Wikipedia article on the enzyme group involved: https://en.wikipedia.org/wiki/Perchlorate_reductase
Article “Ubiquity and Diversity of Dissimilatory (Per)chlorate-Reducing Bacteria” http://www.ncbi.nlm.nih.gov/pmc/articles/PMC91710/
Article “Quantitative Detection of Perchlorate-Reducing Bacteria by Real-Time PCR Targeting the Perchlorate Reductase Gene” http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2268300/
I would guess that the most cost-effective way of dealing with perchlorate is to breed bacteria specifically for remediation. I mean “breed” lightly; the genes are known and could conceivably become part of some E. coli. strain(s), perhaps even transported within the guts of the colonists.
As a former agronomist, graduate of the agro of Paris I can say this is a simple but good post on a very important subject : Growing food.
Just for nitpicking I have a minor issue with this greenhouse thing and I have the same with domes which are a stapple of science fiction.
Even if the pressure inside the greenhouse is low ,it will be a very difficult task to buid and maintain one. Pressure X surface = Forces. Many tons of forces able to ripoff and destroy the greenhouse. Or you build a king of cupola aka windows in a bunker. So ,enclosed facility with artificial illumination are the only way to go , IMO.
That was an issue I had with The Martian; Closing the opening left by the lost airlock with plastic sheet and duct tape? At the lowest feasible pressure, the forces involved would have been enormous. It would never have worked.
I agree. This is the most glaring error in the movie.
I envision a “greenhouse bunker” with minimal windows but those windows are supplied concentrated light from numerous tracking reflectors out on the surface and the light is distributed around the entire greenhouse.
Hello Ioannis, thanks for this interesting article.
I was surprised by your preference for a greenhouse with windows on Mars. I would think the corrosion and various machinery problems would be more tractable than trying to build a transparent pressure vessel. In addition to dealing with the pressure differential the greenhouse would have to handle the high martian radiation and the thermal losses.
I expect an underground grow room will be the best solution, LED lights will easily replace the sunlight that reaches Mars and avoid most of the other problems.
This also an answer for the previous commentator galacsi: I favor greenhouses above ground mostly because there are what I was taught in class. I am not philosophically opposed to underground facilities beyond the psychological reasons for the farmers. However be aware that the inside of a greenhouse is a highly corrosive environment: We use galvanized aluminum structural beams rather than iron because iron get very rapidly corroded. Also there are very strong attacks from the biosphere inside the greenhouse to the various materials. Glass and plastic have the advantage of being (relatively) biologically inert; using as much plastic as possible helps prolong the survival of the greenhouse structure. We do not know how long artificial lights can survive inside the highly corrosive environment of a greenhouse on Mars, I feel more comfortable with the 24 1/2 hour day cycle of Mars. I know that building pressure vessels is far harder than building a light greenhouse on Earth, but the ISS Cupola can help show the way of how we can build something similar for Mars
Several times you’ve mentioned that there’s an associated “highly corrosive” component in greenhouses; what’s the source of the corrosion? Are you referring to the chemical injection system, to incidental fertilizer (or other) aerosols, or?
On the issue of calcium perchlorate: I’m wondering about “washing” it off, which of course requires some sort of chemical as a wash, perhaps water. Others point to the 0.5% calcium perchlorate in the soils- high enough, given the nature of the compound, to term it pervasive and certainly poisonous- as a huge impediment to successful colonization as it’s very toxic to people and animals. Adjusting pH might work, but as you pH can drastically affect the ability of plant material to absorb nutrients (some crops are notably tolerant of pH values, to be sure).
Perhaps you’re dismissing this perchlorate issue a bit too quickly?
The main source of corrosion is the high humidity and the biological organisms inside the greenhouse. Greenhouses are bioreactors, a wonderful growth environment for all organisms which in turn try to survive by taking advantage of all energy sources, including corroding everything that can be corroded. Also do not underestimate the corrosive power of high humidity, especially considering that most greenhouses spend the night at 100% humidity and in condensing conditions. Look at the most recent electronic device that you bought and look in the manual good operating conditions, it will tell you that it does not do that great in high humidity. Fertilizers can also be corrosive, but inside the greenhouse they are most often in the form of a water solution, which is set at levels friendly to the plants.
I am thinking of washing out perchlorate with water. Flooding soils before seeding to wash out the salts is a very common practice in dry areas of the world. Before planting the germinated plants (we rarely plant seeds in the greenhouse) let’s try several experiments of flooding to see what is necessary. That is what agricultural experimentation is about, try 4 or more things, along with control (both unwashed regolith but also rockwool and cocopeat) to see what works. Among the things required of pedologists is to clean up soils that have been used to dump industrial waste, there is quite a bit of literature on how to do it, and it can be adapted for our purpose
Very interesting article… A subject not discussed very often… Biggest potential problem I see on Mars is the lower light levels… Artificial lighting requires a huge amount power. Large solar reflecters might help. Most crops have been designed or selected by humans for fast growth and large yields. which requires alot of water and sunlight to accomplish…Which we take for granted in an Earth environment…
I also think I recall reports of salts in tbe soil on Mars (ancient oceans). We assume there are huge expanses of permafrost and possibly underground aquifers… Better find out if that’s salt water (although it would be fairly easy to de-salinate that water)
As Ioannis mentions, Mars sunlight is about as good as a cloudy day in Europe, and quite sufficient for growing most plants. That said, even on Earth we often use artifical light to grow plants, as the large market in growing light will attest to. My guess is that if the colony is solar powered, agriculture will use su light, if it is nuclear powered, it will use artificial illumination. LEDs are the lamps of choice, these days, I hear.
Martian soil contains a fair amount of perclorate, which is poisonous to most life. It can be removed fairly easily by mixing with organic compounds, which it oxidizes, but I was wondering if it could be used to sterilize the hydroponic waste water thereby allowing it to be 100% recycled.
The issue with hydroponic waste water is that plants selectively uptake the nutrients in the solution. We through away part of the nutrients so that we also have the volume to reconstitute the original nutrient mixture. Generally we do not want high Cl concentration in the nutrient solution, plants do not require it in high concentrations, it mostly adds salinity and can bring sediment formation. However it is something for the future experiments on Mars
Fascinating article! It’s great to see Centauri Dreams exploring the real-world biological challenges of inhabiting other worlds like Mars. Growing food may be somewhat less glamorous than rocket engines and super-technology, but in the long run figuring out how to raise plants on Mars will be a vital step in settling space.
I’d like to point out that while Western cultures are rather partial to meat, in my personal experience it is not so very difficult to provide all the nutrients a person requires using plants alone. I am not partial to meat and never it eat it, but I am hardly suffering from malnutrition. The key is to simply to provide a mix of grains and vegetables that together supply the necessary nutrients. Potatoes alone would not, of course, provide future Mark Watneys with all the nutrition they need, but a sufficiently varied diet will.
Very likely Martian colonists will have to accept some changes to their diet. Meat will likely be a much rarer food, making up only a fraction of the settler’s meals. Perhaps real meat will be mixed in with simulated meat as is portrayed in James S.A. Corey’s excellent Leviathan Wakes. But even with very little meat available, a varied plant-based diet will keep the astronauts healthy. Meat will likely be more of a luxury than a necessity.
Another dietary prejudice of Western culture is the revulsion towards eating insects. Nonetheless, many other cultures find nothing wrong with a bowl of fried crickets or nutritious caterpillars. If we can overcome such prejudices, Entemophagy will lend itself to raising food in relatively small areas. Insects don’t require that much space, unlike cows. Ioannis touches upon this when he mentions cricket’s high feed conversion ratio.
I think future astronauts will appreciate being able to raise animals on Mars, if we are ever able to do that. While I don’t tend to eat meat I do use such animal products as eggs and honey (forbidden to vegans) and I wouldn’t want to give up on those forever. Speaking of that, has anyone examined whether we could raise bees in space colonies? Bees can range quite a great distance in search of forage, which doesn’t bode will for efforts to keep them anywhere outside of the largest space colonies. They probably require quite a few flowering plants, as well. Perhaps honey will be the rarest of luxury foods in future space colonies.
The answer I usually give about veganism is that if we were intended to be vegans we would have appropriate stomachs (cows have 4). That being said I do go vegan when I am fasting. My grandmother used to tell me that as recently as the 1950’s most Greeks could only afford to eat meat only once a week, usually Sunday after church. The Mediterranean diet is meat poor because people could not afford to buy meat, when Mediterranean people became richer more meat entered the diet. The proportion of meat in the current US diet is higher than even that of traditional populations of hunters. Unless growing food on Mars becomes as cheap in terms of resources as in the United States , which after all has some of the most competitive farmland in the world and large pasture grounds, meat eating will be associated with feasting, just as in traditional societies.
At Agronomy we were taught how to kill insects rather than how to raise them for food, so I cannot really judge on how feasible it will be. What I can say is that modern agriculture is a very high intensity process, often divorced from traditional agricultural practices. What I can tell you though is that bees are often a necessary insect for pollination of vegetables, I see Martian grown honey before I see Martian grown meat.
I have read Leviathan Wakes in the Expanse and I have to say that you do not need to grow fungus that tastes like beans, beans are autotrophous so you can raise them directly. Fungus that tastes like meat or eggs, yes, that sound reasonable though it will take research until we get there, we are there yet. Eggs and milk are a mechanism through which people could get animal derived food and the necessary nutrients in contains that cannot be found is plant based food (such as vitamin B12) without killing the entire animal. Animals were traditionally slaughtered only parts of the year, and the calendar of the lents reflects that. Milk though you could get any time of the year so long cows were pregnant or had recently had calves. Modern animal production practices can be adopted for Mars, but it will not be more efficient than just growing the animals for meat
Then again, if we were truly adapted as carnivores we should have sharper teeth and be better able to digest meat without cooking it! And maybe had some claws as well. We seem to be poorly adapted for anything without our agricultural technology, food preservation, and cooking, at least compared to animals. I am not vegan, since veganism calls for using NO animal products which I cannot do, and I agree that there is no “natural” foundation for veganism. Humans are omnivorous, not herbivorous. For me, avoiding red meat is a preference, and I was pointing out that it is quite possible to build a balanced diet with plants alone if necessary.
I’ll admit that I have some negative associations with meat. The proportion of meat in the American diet is one of the highest in the world (I didn’t know it was higher than traditional hunters, though!), and obesity has become a major national health problem. Perhaps too many easy calories and proteins with two little work done getting them can be a bad thing.
Yes- you are quite right, I forgot that bees are often kept in greenhouses as they are necessary pollinators. Tomatoes can be pollinated by wind and vibration but most other vegetables need bees. If we have bees we will have honey. I do not know much about raising insects for food, but I have heard that insects are both much more efficient than animals at converting feed to body weight and require a lot less space, so I think entemophagy deserves a careful look for space agriculture. The biggest problem may be cultural prejudice against viewing insects as food.
Leviathan Wakes is sort of hard-ish SF in that it seems well researched, yet the writers aimed for an engaging story more than an ultra-realistic depiction of space travel. I missed the beans thing, though now that I think of it there is no need to grow fungus to replace a plant. Meat and eggs, yes, but not a plant we can raise directly. I think we tend to spot erroneous details in things we are familiar with, and simply accept the things we aren’t. For instance, it makes no sense to coat gauss rounds with teflon as is described in the book! And the fictitious Epstein drive seems to ignore fuel and propellant constraints.
Sometimes in science fiction, the idea of grown meat in a vat is described. This is called “carniculture”. Do you think such an idea might ever actually be tried? The only person I know of who raised animal cells outside of the body was Alexis Carrel in his experiment with the chicken heart.
Miller eats rice and fungi-beans while still on Ceres, and recycles the plate half eaten when his door rings. You are right, we notice more what we know. The problem with growing cells outside an animal is the nutrient broth and inducing the cellular signals to differentiate. Last year there was an entire public demonstration of a vat grown burger from cellular growth. It was rated by reporters as rather tasteless because it completely lacked fat. Also you could just use the broth to keep the cells growing in far more efficient ways. Plant requirements are rather simple to grow, sun, nutrients and water. Animals are far more complex. As it currently stands it is much easier to grow the animals than carniculture. However if that will be true in another hundred years, I cannot guess.
I don’t think we are very far at all from being able to grow artificial organs by themselves. A trachea has been successfully grown and transplanted, as I recall. As a corollary, it should eventually be economical to grow animal muscle, aka meat. It would require a minimal practical substitute for blood, plus extra growth hormone.
I imagine that if carniculture becomes competitive with traditional methods of raising meat, it will be doubly so in space colonies where space and resources are at a premium. Personally, I consider it unnecessary to have meat so I’d much rather have the whole animal for eggs or milk, but if all you want is the chicken breast or wing it may make more sense to simply grow that part. But that technology is not yet ready, as you pointed out.
There’s one thing that’s missing in your analysis though. How are we to get the animals to our Mars colony in the first place? It isn’t practical to herd cows into a launch vehicle and send them on a nine-month Hohmann transfer to Mars. You’ll have to deal with all sorts of issues, from animals panicking in microgravity (a cow in zero-g?) to the sheer cost of launching that much mass. Maybe it is doable with chickens, fish, and smaller mammals, but not with larger animals. Also, we need to send enough animals to provide enough genetic variety, driving up costs. If the animals are not in some kind of hibernation, they will be consuming resources and life support on the transfer to Mars. This all sounds utterly impractical and wildly expensive.
If we have artificial wombs, we could just send frozen embryos and bring them to term at Mars. But if not- I don’t really see how we are going to get a whole cow out there. Maybe bring only infant animals and sedate them for the whole trip? That doesn’t sound healthy, unless Aliens-style hibernation is possible. This all seems very clunky and inefficient when we don’t even need a hamburger on Mars.
I submit that initial Martian colonists are better off learning to be happy with a predominately plant-based diet. If you want to colonize Mars, you are going to have to accept some changes to your diet. I’m sure that this will result in a unique Martian cuisine that will be as rich and interesting as any on Earth, as well as adapted to conditions on the red planet.
I agree that transporting anything much larger than rabbits is going to be a non-starter.
Fish are much easier to transport – just fertilized eggs kept cool, or unfertlized eggs frozen and fertilized on arrival. No artificial uterus needed. Birds might be possible, and I’ve always liked Clarke’s image of live canaries as sensitive gas detectors on space stations. Not sure how to transport chickens or other poultry easily.
I agree that Martian food will be predominantly plants. With gene engineering, there will be many new types, including those tasting just like chicken or beef, even if the texture isn’t at all “meat-like”.
As a colonist, I’d be growing as rich an assortment of spicy and flavorful plants as possible.
What a great article!
Maybe it would be possible for chooks and fish to cryopreserve eggs and sperm, or fertilised eggs and transport these? It seems to me that chickens would be easier to raise than (say) cattle and wouldn’t need artififcial wombs, merely incubators or hatcheries.. Chickens would be relatively easy to feed as they are omnivores, eating food scraps, etc.. Even if not for meat, their eggs would be great food.
Chickens or maybe fish might be beneficial for the “pet” aspect as well. That could be very important for morale. tending plants would also have good effects on morale.
In terms of transportation of animals I am of the opinion that we will most likely transport fish first, who are probably better adapted since they live in water. We can set a closed recirculating system on the transportation ship, also I think that we can transport live frozen juvenile forms. We can transport chickens as fertilized eggs; though I am not sure how long they live in that status. We could though incubate them along the way. Chickens on Mars though have a major issue, they will very likely be airborne, which means we need to clip their wings.
As for higher animals, we have managed to transport them across the Atlantic and to Australia, trips that took several months originally. I think we can get them on a 6 month trip to Mars when the time comes, most likely on a rotating ship. But anything bigger than rabbits belongs deep in the future
Fish, chickens, and rabbits are indeed better adapted to space travel then large mammals. They will be far easier to transport and won’t require large amount of space at the destination colony. In fact, both fish and quail chicks have flown in space already. I imagine that transporting eggs would be quite easy if there was a way to keep the eggs from hatching during the months of space travel. Maybe some method of cold storage could do this? Even if not, we have already flown chicks aboard the space station, so they could live aboard a Mars-bound ship.
It’s important to keep in mind that we will be even better at modifying lifeforms to suit our needs than we are now by the time any of this comes to pass. Assuming we are bringing modern fish and animals is probably unwarranted. We may create new food animals better suited to space using genetic engineering. Perhaps we will create animals that can hibernate during transport, adapt to smaller spaces, and make more efficient use of resources.
Transporting cows and the like across the ocean is an entirely different matter to transporting them from Earth to Mars. Launching anything into space requires a good deal of energy and remass, as does sending it anywhere with rockets once you get up there, and that will cost something even well into the future. Additionally, life support is not free aboard a spaceship – unlike early sailing ships, where a breathable atmosphere and survivable temperatures were taken for granted. Ocean and space travel aren’t the same sort of thing at all, and we can expect both payload mass and life support to be limited resources.
In light of these limitations, it’s likely that future humans will find a more practical solution than the clunky notion of bringing live cows on a spaceship. That far in the future, we can expect carniculture or suitable meat substitutes from algae or fungi to be available.
Additionally, not everyone agrees that exporting our habit of slaughtering other lifeforms for meat should be exported into space. However, this asks the question of what constitutes ethical behavior, which is a bit outside of a discussion of the sheer practicalities!
“In light of these limitations, it’s likely that future humans will find a more practical solution than the clunky notion of bringing live cows on a spaceship. That far in the future, we can expect carniculture or suitable meat substitutes from algae or fungi to be available.”
Take a look at http://www.memphismeats.com/. They and other companies like them are working on the carniculture process that would be much better suited to replication on Mars. Much lower transport costs, much lower input costs, much less waste.
Interesting company. I know that new food companies, such as this one or others that intend to create fully vegan substitutes for meat have raised millions in venture capital funding. What I do remember from microbiology is how hard it can be to keep cell lines free of disease and productive. I wish them the best of luck, but until it is a proven technology we should not make it an integrated part of our plans
True. However, in that case, the space colonists will probably grow plants, fungi, and what smaller animals they can easily transport and fit into their colony. And they’ll probably have some good meat substitutes. Asides from the issues of transport I mentioned, I’m sure that trying to bring modern meat production methods to a pressurized environment will entail even more problems with hygiene, disease, and life support as carniculture faces with microbiology. Don’t forget that modern intensive animal farming creates health risks for workers and nearby communities. Not something you want to have in an enclosed habitat where you have to recirculate all your air and water.
I strongly suspect that whatever farming methods we take into space will have to be the exact opposite of factory farming. Modern factory farms care little about the negative impacts they have on our environment. In a space colony, any such mismanagement would be fatal. Every possible impact, from pollution to the spread of infectious diseases to bioaccumulation of pesticides and fertilizers would have a far greater impact on such a tiny ecosystem. Do you have any thoughts regarding maintaining ecological balance in the habitat and ensuring both humans and animals remain healthy? This is not something we can ignore and get away with for even a short time in space.
Space farming will have to be intensive to make the best use of space, but it will also have to be carefully planned to maintain the habitability of our environment. This is true on Earth as well, but we will notice it a lot faster when we are responsible for maintaining a habitable environment in a tin can.
@Christopher Phoenix
This is a great post , you sumarize well the ecological
issues of a martian agriculture. And in fact one cannot put a line between agriculture and other activities. The whole life on Mars must be thought as an integrated ecological project , because as you said one cannot be careless in such a tiny ecology.On the ISS when their clothes are dirty they just throw them out and order others . On Mars you are not so rich ,you wash them and patch them and in the end you compost them. Or burn them , maybe. But these clothes will be made of bio cotton or bio linen or bio hemp because you cannot afford to poison yourself somewhen in their life cycle.And everything in the life of the colonist would have to be thought this way.
What an extraordinary experiment a Mars colony would be.
It is safer to begin nearer Earth like in L2 or on the moon. Because this is all new and potentially very dangerous.
The other food related item I remember from Leviathan Wakes, was just how expensive and desirable cheese was. That and ecosystem services might make a good motivator for getting a herd of goats established in the longer term.
Thanks for this well-written article on an important subject.
I would really like to see more experiments with these concepts being carried out on Earth. The closest simulation that’s been done so far was the two-year run in Biosphere 2 in Arizona, and that was over twenty years ago (1991-1993). It’s way past time that more biosphere simulations should be picking up the research, and very frustrating that the conventional Mars analog expeditions done by the Mars Society, NASA and ESA are focused on simulating a sortie mission, in which the bulk of the food is pre-packaged.
Stephen
Oxford, UK
While I have moved at graduate school towards Remote Sensing and GIS in agriculture there have been quite a large number of experiments after Biosphere 2. Biosphere 2 BTW was more heavily publicized rather than a true experiment for Mars. This article was created with input that I had after discussions at the NASASpaceFlight forum, and the pointed me out to experiments at Johnson Space Center, about some of which I had already read in Acta Horticulturae back in Portugal. The ESA has conducted the MELiSSA project, more oriented towards making a biological life support system rather than growing food which has however been implemented in the Concordia Station in Antarctica. Most recently, last week for that matter, Wageningen University, arguably Europe’s best agricultural university, conducted an experiment to grow vegetables on simulated Martian agricultural soil (as soil rather than as hydroponics). Stateside the University of Arizona has a Lunar Greenhouse experiment intended to grow half the food a person would need and all the oxygen he would need in a year from a self contained foldable greenhouse. That particular project has been funded by the Space Grant consortium which shows its relatively low priority, if there was a real priority to study crop growth in a gravity environment it would have been funded by NASA HEOMD or USDA NIFA rather than the consortium. I agree that we need to add a greenhouse to some of the Mars simulation facilities, and HI-SEAS, which has a 24 hour day night cycle seems more appropriate to me than those in Arctic regions. However I am nowhere near the ear of decision makers
Ioannis, thanks very much for your detailed reply. Does somebody keep tally of all these various experiments, listing the numbers of people involved, the length of time for which they lived in full isolation from the terrestrial biosphere, and which life-support cycles were closed during their isolation period and which were not? Or should I draw up that list myself, if I want to follow progress?
For all its faults, Biosphere 2 did lay down a clear data point for 8 people isolated for 2 years (and 20 minutes) with full recycling of food and water, and near-full recycling of air.
Stephen
I became aware of them in posts at the NASASpaceflight.com forum. I am not aware of people keeping a list of them. If a conference ever takes place I would like to attend, though I am not in any listservs or mailing lists talking about this subject. If you draw up your own list and create your own website you will do a great service to people interested.
Astronist you wrote: “Does somebody keep tally of all these various experiments…”
As far as I know there is no summary or tally of the Mars Analog experiments. I think it would be great if someone did that.
Most of them are not closed echo system experiments, they seem to be more interested in psychology. Also an important topic. I would like to see more closed ecosystem experiments; it would be a sign we are getting serious about space settlement.
This is a vital issue that most fictional treatments overlook.
This article started off particularly well (quite interesting – although missed the obvious point that mirrors can increase sunlight ‘for free’) and then went into a long detour trying to justify eating meat.
I’ll say this quite plainly: The human nutitional requirement is for a sensibly diverse diet. There is no known nutritional reason for humans to eat meat, or pretty much any animal product. All of the supposed arguments as to meat’s necessity have been known for a long time to be wrong.
These are just extravagent luxury items which much of the population (unfortunately for the planet) has habituated itself to eating. Habituation does not imply necessity.
The fact that millions of people currently eat vegan diets (and many times that simply abstain from meat, ie. vegetarian) permanently and without health or other issues, demonstrates this fact pretty clearly.
Considering that producing meat for human consumption is notoriously grossly inefficient (way worse than stated in the article) and wasteful; and poses massive logistical issues of all kinds (not to mention perpetuating the current barbaric treatment of farmed animals, on another planet – witness the battery cage conditions used as a reference point in the article), frankly it should be completely off the table as far as any early colony on Mars or anywhere else is concerned.
I fear that the preoccupiation with the contrary is just a reflection of the biases of those who eat meat.
Rather than take the fascistic attitude that meat should be denied the colonists, I would suggest that, given the inefficiencies you mention, meat proteins for an enjoyable but conservative diet be provided from Earth.
What was not covered in the article is whether raising the food locally on Mars makes any economic sense at all. While at interstellar distances, it would be obviously necessary, Mars’ proximity to Earth and the cost of lifting, assembling and maintaining a greenhouse structure of adequate size may cost more than a decade’s worth of Earth supplied food.
And, thanks for the wonderful article.
A launch window between Earth and Mars opens every 26 months. The average American eats 1 (metric) ton of food per year. True, we can shrink that weight freeze drying the food and by eating less than the average American but still, it is a huge logistic endeavor. A four person colony would require some 9 tons of food, possibly shrunk to 4.5 tons which is still 6 times the weight of Curiosity. Also there are nutrients that do not survive canning well especially vitamins, which are best supplied by fresh food. Also there are other nutrients that can only be supplied by animals, such as Vitamin B12. As someone who has done animal physiology in college, if we were intended to be herbivores we would that physiological adaptations of herbivores, such as multiple stomachs (e.g. cows) or coprophagy (e.g. rabbits). For safety reasons we will be eventually growing more food than we can consume, is it better to compost it or to turn into to high quality dense food, a.k.a. meat?
What would you expect a 1000 square meter greenhouse (based on 250m2 per person) and all it’s supporting infrastructure to weigh? A pressure vessel that size that can withstand 10 years of mars isn’t going to be light.
Also, I think your estimate for annual weight of food need is higher than would be needed for a couple reasons: Americans waste a third of the food they eat (something much more controllable on the colony). And, and that 1 ton statistic probably includes a lot of liquid refreshment. I would think that, with selective usage of dehydrating, it would be more like 1-2 tons of weight per year for a colony of 4. That assumes water is manufactured/sourced on Mars.
I think that even an established colony is going to get a significant percentage of it’s food from off-planet.
If we must bring much of our food from Earth, we are never going to much more than visitors on Mars, or indeed anywhere else in space. And interstellar travel is going to be pretty much out.
However, your assumption that the greenhouse must be taken from Earth is unwarranted. The raw materials are available on Mars to build our colony structures and greenhouses. If we aren’t building much of what we need from local materials, we aren’t going to have anything more than an exceptionally expensive output that will likely be abandoned once people tire of paying for a crewed presence on Mars.
It is exactly that sort of trade-off that has me skeptical of enclosed LSS also being agricultural. Freeze dried or frozen gourmet meals are going to be an important morale booster compared to trying to grow crops that are bland and worse, prone to failure. Growing fresh fruit and vegetables to supplement food rather than as staples makes more sense to me.
I agree that at least at the start the colony will mostly be getting its food from Earth. Problem is when the food resupply requirement gets to 100 tons it will make more sense to grow food on Mars. An expanding colony on Mars will require ever more complicated machinery and spare parts from Earth and 3D printing is no miracle solution, some things simply cannot be printed. Food is much easier to grow than it is to create an industrial base.
As to how much a Martian Greenhouse would weight, well I would say look at the ISS cupola and also at the BEAM module of the ISS. As an agronomist rather than an aerospace engineer I cannot judge if the optimum solution would be a heavy metal vessel with windows or a version of BEAM made of transparent plastic, but they should give you a ballpark figure of what is currently possible.
I am no a vegetarian and I agree B12 can only come from animal sources.
Surely though B12 supplements or B12 fortified foods would achieve the same purpose?
Technically, Vitamin B12 comes from bacteria, not animals. For efficiency reasons (space, energy) I would estimate that it would be better to supplement it from bacterial sources than to actually raise animals in a Mars colony.
“There is no known nutritional reason for humans to eat meat, or pretty much any animal product.”
Vitamin B12. It’s sole source is animal food products. The human body stores quite a bit of it, and very little is needed, but strict vegans who do not take supplements eventually run out of it, and the consequences are rather horrible.
I point this out not to suggest that it’s actually necessary, in a technological society, to eat meat. B12 can be synthesized, and the daily requirement is only a few micro-grams. But the idea that humans are not biologically required to consume animal products is wrong.
Of course, the idea of raising animals as a protein source creates some logistical complications, however, the prospect of a bunch of Mars settlers locked up together in small habitats eating beans … Well, lets say, you may have to devise a way to deal with the excess “methane production” if you know what I mean…
That excess “methane production” will be even worse if we are sharing the hab with a bunch of cows! *laughs*
Cow flatulence is not just a laughing matter, it was a major design constraint when designing Bovine CAFOs. I remember that there was also research in the Agricultural University of Athens to harvest this methane for use as biofuel on farms.
Aquaponic systems would allow meat and plant production to share a footprint and facilities. An integrated system could be duplicated more often, making it less costly to manage the risk of facilities failing. Fish also have a very high feed conversion rate. Imo, snails would also be a great candidate.
I would be concerned with how raising and slaughtering unnaturally/heavily confined animals would effect the psychology of humans who will also be spending most of their time unnaturally/heavily confined.
My paternal grandmothers side were Turkish speaking Greeks, survivors of the Greek genocide, refugees of 1922. As such they got some of the most undesirable jobs, working at the abattoirs of the city of Serres in Greece and living pretty close to their workplace. Some where pretty skilled, called to skin a puma that had died from a circus. I would say that they turned out OK, so long there is music available, delicacies to eat when feasting and a policeman around to make sure that they did nothing stupid with the butcher’s knifes they lived and prospered
I doubt we will take animals into space for food, 3D printing of foods using selectively grown cultures will be used instead.
http://3dprinting.com/food/
As for the greenhouses, as mentioned earlier, the pressures involved can be quite high, mirrors and light tunnels will most likely be used. There is also the possibly of using artificial light, (specific wavelength LED’s) as not all of the spectrum is actually used by plants.
https://en.wikipedia.org/wiki/Grow_light
I missed this comment before posting mine. Michael @ 7:19 also has some good ideas.
I think the earliest Moon and Mars settlers will depend on prepared food sent from Earth. The earliest settlers on either world will become very practiced at processing regolith and soil. A greenhouse on Mars will have access to a range of sufficiently prepared natural mediums.
We think of Mars as a dry place, but its likely there are vast reserves of water under the surface… Aside from using the H2o as a source of oxygen and fuel, fish could farmed in a large underground pool … There have been alot of research on recirculation systems (filters) and hydroponics utilizing the fish waste products directly… Fish are fairly good at feed conversion, but having said that, they do need feed of some kind… Some types like tilapia or carp can subsist on algae, however carnivorous varieties like trout require a large portion of protein. In the wild they eat bugs and smaller fish… However, there are ongoing efforts to produce strains that can digest a primarily grain diet (feed pellets)… If it comes to raising bugs for food, my vote is to pass them through the digestive tract of a fish first… Besides, its easier to flip a fish on a bbq grill… The meal worms just fall through..
Actually tilapia have a better FCR when consuming grain pellets than when consuming algae. Modern aquaculture depends on soybeans and other similar crops for its feed in peletized form rather than algae. Underwater aquifers on Mars are more likely to be like those on Earth, i.e. rocks with miniscule pores, rather than lakes inside voids. After all we have no evidence of Karst on Mars. I agree, fish are much nicer to grill than mealworm
Fascinating.
OK what if the glasshouse is set into the ground reducing pressure on sides and profile to storms.
What if the roof is a glass lens, or family of them, sintered from silicon on site as suggested by Cory Doctorow. this way you can use different focal intensities to increase light to specific areas. you could move the plants or move the lenses depending on what was best for the system? this could also be used as part of a coms system? Telescopic infrastructure interesting in a low light low tmosphere context?
the approach to agriculture seems a bit monolithic and blunt and uses assumptions based on monoculture and industrial agriculture rather than mixed polycultures with different ripening states and mixes of species. Use of fungi is a great idea. There will be solid waste in any biological system so seeing that as potential soil is a way to turn it to an asset. This reduces the need for fine water delivery and reliance on water fine tuning. How do worms fare in space? what do http://www.permies.com/ suggest re mix of species with different ripening and decomposition states balancing out? Why not use smaller species for food. fish, smaller mammals, chooks are good value for eggs and also have a good relationship to soil health and eating food waste. They are resilient in small spaces but are happier with legroom. I think if you default to a form of agriculture which looks for happiness of the species you are farming you are likely to get a system which is tuned for long term success with latitude for short term adaptations if there is a need to confine them in the short term due to leaks or whatever. Packing things in small spaces is a point of failure because biology works more towards health in a mixed context and tends towards failure or probability of a failure when you have masses of the same thing in one space – eg. 25000000 salmon dead in Chile due to algal bloom.
You need to have systems which understand the nutritional and environmental preferences for each of the species in the mix and treat humans as an input and output and not as the end point of the system? They are not external to the cycle.
It may be that given some challenges the humans have more capacity to adapt to a shift in diet because they are bigger and omnivorous so they need to be one of the possible things to adjust if one of the other species is under stress.
I know that understanding soil health is more complex than water or air mix but that challenge is still core to the system because that is how life works. Decay becomes soil. It is alchemy. =)
We can’t make lens from silicon (optical ones), unless you mean a surface onto which we spray a reflective film as in a parabolic mirror. Sintering of sand is quite possible on mars as the air density is quite low, the Martian air can also be removed very easily by cooling been mostly carbon dioxide. As for the pressure reduction technic on the greenhouse the whole structure would need to be underground to provide effectively forces to restrain the internal air pressure.
I have to agree with others that it would make more sense to have LED lighting inside a solid structure like a cave or lava tube. Firstly we already have experience growing plants under these conditions and knowledge is growing rapidly. Secondly the mass to manufacture or process is much smaller, no panes of glass from quartz sand. Thirdly we can be sure that radiation levels are minimal. Fourthly we can control the illumination level and cycle times. Finally, very similar designs can be used on a variety of worlds, – the Moon. Mars, space habitats, etc.
As for meat eating, there was quite a lot of work done in the 1970s and 80s by the Earth Island Institute among others designing systems that grew Tilapia and filtered the water as a nearly complete ecosystem. I see no reason why these ideas couldn’t be adapted for off-world agriculture. Fish also cannot escape into our environment, as might other mammals, so that control will be easier.
If anything, pollination might be one of the harder issues – use insects, hand pollinate or have machines do the work.
As for Martian soil, I wouldn’t use it except as processed material for structures and media. The particles are unlike terrestrial ones, of different shape and prone to damage delicate machinery. I would keep raw Martian “soil” outside.
One of the most ludicrous “greenhouses” was that in “Mission to Mars”. A flimsy greenhouse that could not have withstood the necessary pressures to keep water liquid and the plants warm and bathed in dense enough gases.
From a broader perspective, we been doing experiments growing plants since the 1960s, yet progress has been slow. My sense is that the ISS and similar structures should be used now to conduct useful experiments on practical crop growing. While I don’t foresee this are part of a spacecraft enclosed LSS, we should be working on then for large space structures and off-world bases, ultimately colonies.
This.
Radiation is a serious danger even on the surface of Mars. You wouldn’t see humans working in a surface greenhouse with big glass or plastic windows as their cumulative dose would put them out of commission in just a few months. That’s lifetime cumulative dose. Permanent colonists will keep their surface activities to an absolute minimum out of necessity. Light pipes are fine and may be useful as supplements, but LEDs are not optional.
Lava tubes would be ideal, but ‘trench and cover’ tunnels with sintered arch blocks could also be used to produce a large volume of structurally sound and radiation-shielded space. Spray-on polymer sealant with a foil-lined nomex or kevlar mesh layer would suffice to make an airtight seal that can handle prolonged high humidity.
The trick to animal protein is to commit only your vegetable waste to animal feed. As mentioned in the article, about half of a plant’s biomass is edible on average. The other half has to go somewhere. First feed some of it to black soldier fly larvae or another high-performing insect species, yielding a high-protein high-fat paste. (This same step can include some types of biowaste, reducing the load on sanitation systems. If the mix of species is properly chosen they can also serve as pollinators.) Mix this revolting paste plus some chlorella or spirulina into the remainder of the vegetable waste in the required proportions to make fish feed and chicken feed. Chickens don’t need to be raised on a six-week slaughter schedule to be efficient; they have a reasonable FCR even if you only consider eggs. Fish such as tilapia can be integrated into the hydroponics system, simplifying the overall nutrient recycling requirements. The animal waste can become insect feed with appropriate processing, and anything left over after all of these recycling loops can be passed through a supercritical water oxidation reactor.
This combined system can be more space and energy efficient for protein production than plants alone, even high performers like soya and peanuts. It can also simplify the design and operation of the facility’s sanitation equipment.
I could not find a percentage value on the efficiency of LEDs but I remember that sodium fluorescent lamps, the technological peak when I was an undergrad, where around 40% efficient. At 50% efficiency from the photovoltaic panel to the greenhouse light we will need twice as much area just to have Martian illumination. Since I assume that we want more than Martian noon and we would store energy to extend day length we would need maybe 4 times the size of the greenhouse are in PVs just to provide the lighting underground.
Lava tubes are not a given! If we have found them on Mars and they are easy to seal of and pressurize, please let me know, but my thinking is that this is not the case. Now as far as I know there are two systems to dig, cut and cover and with tunnel boring machines. In the first case we would need to actually start building the non transparent roof anyway after the digging is over. If we have an underground digging machine we would need to get rid of the tailings anyway. and create air for the chambers we just dug. I am not sure how that would work.
NASA JSC has done the experiments on the radiation tolerance of agricultural plants and using the value that Curiosity measured they could survive a Martian Greenhouse, it is within their survival tolerance. After all we want a plant to survive all the way to reproduction and product production, we don’t mind if it withers afterwords, unlike for people.
I am arguing on the use of Martian soil as a hydroponic substrate, not as a soil with an entire microbial ecosystem. All that you need for a proper substrate is appropriate mechanical qualities, i.e. silt, clay, sand percentage, porosity profile etc and lack of poisonous substances. This is a far lower bar than living soil and I believe that Martian regolith can surpass it.
The problem will be that each generation will be more radiation damaged unless you are intending to send fresh seeds from Earth for each generation. It is teh accumulated radiation dose that is a major issue.
As regards lava tubes, there are expected to be plenty on Mars. However, [ digging a trench, ] inflating a cylindrical pressure vessel and covering it with regolith works well too. In a worst case scenario, the work would be done by hand and power tools, but not heavy machinery. 1 atm can support a lot of mass, especially on Mars, even without supporting structures. Whether chemical or biologic fixing of Martian carbon is used, I would expect that this would then be used to manufacture more pressure vessels for living in. Now if there turns out to be reserves of organic carbon on Mars, then that would be a great site to start a colony designed for expansion.
I’ve always liked the idea of stone buildings on Mars. Their primary role is to support mass for radiation protection of an enclosed pressurized habitat. A set of stone working tools would seem like a good investment to me.
I think that it is realistic to expect a constant exchange of seed and multiplication material in general between Earth and Mars, just as there is this exchange of Earth. For a very long time variety improvement will be impractical on Mars, so we can except improved seeds to come from Earth..
Ioannis Kokkinidis, I agree that the presence of lava tubes where you want them is not a given. I do see a problem with natural lighting that I haven’t seen a comment on. The loss of light through glass (or any glazing) is not trivial. The loss through glass thick enough to withstand internal pressure is quite large. For insulation, the glazing will have to be triple-pane. Add to that the thickness required for radiation reduction and even glass will end up being effectively opaque. Some of this can be overcome with outside shielding and mirrors, but it seems almost impossible to grow plants in a greenhouse on Mars with just natural lighting.
JSC has studied an inflatable greenhouse, where the difference in air pressure keeps the greenhouse inflated and there is no external structure. I agree that glass (or more likely plastic) will need to be thicker than on Earth, but on the other hand thicker material also survives UV losses better so we would not need to replace it that often. Having a greenhouse is always a battle against entropy
Inflatable greenhouses, yes, but none that use natural lighting. At least none that I have found.
Great article! Raising meat seems to be pretty expensive. How would you transport a few head of cattle or goats to Mars? 3D printed meat substitute as someone else mentioned would be a fantastic solution if enough suitable raw material could be located. Have you considered raising fish? That should be a lot easier.
Also (speaking of fish) and I think this is the most glaring omission, the article completely ignores the harvesting of fresh fish and other indigenous aquatic creatures from the planet-wide network of Martian canals.
I have asked the same question myself. *grin* Cows on a launch vehicle don’t sound like a very practical concept. Carniculture would be a far more likely way to get meat in space, if we insist on having it.
But… you aren’t serious about the Martian canals? You know that was made up, and that there are no bodies of water at Mars’s surface? And that the air pressure is too low for any water to remain in liquid form at the surface (well, except for those extremely saline droplets reported by the Phoenix lander, not exactly conducive to life)?
Canal fishing…ha ha ha… brilliant!
There are some hardy algae’s that can thrive in cold temperatures, low pressures and high salinity mediums. A glass (UV protective)/plastic (thermally insulating) container with moderate/low pressure and local nutrient (rocks/water) could do the trick. There are no clouds to speak of on Mars so heating by solar energy would be easier. Perhaps aerogel could be used as well as it is transparent and highly insulative and could be used between the glass and plastic parts.
Taking this farther, we could gengineer organisms that can survive Martian conditions.
Once we determine that Mars is sterile I can not see a problem with this.
Grow animals? No. They are trophically inefficient and require living area. They also compete for oxygen and produce malodorous wastes. I anticipate use of microbes that have been gengineered to produce fats and proteins that resemble animal products. 3D printing of ersatz steaks and chops may also be involved.
That animals eat the same things humans do, and are inefficient, is a feature, not a bug. With animals as part of the food production system, you get added robustness; in the event of an agricultural shortfall, you slaughter the animals, and directly eat their feed.
Leave them out of the system, it’s more efficient, but you lack a response to unexpected shortfalls. You can, of course, routinely overproduce and stockpile vegetable foods, but that sacrifices some of the efficiency.
And most people, bluntly, like eating meat.
It’s still more efficient to stockpile plant food than produce meat. We are talking about an order of magnitude here, so even if you produced twice as much as needed in order to always stockpile, it’d be more efficient than raising (big*) animals.
*Insects might be as efficient as plants, however.
Growing animals indeed are inherently inefficient compared to plants, which after all are autotrophous. However assuming that we have a large quantity of leftover food near expiration and we have enough fresh food anyway, would it not be better to save/conserve it as animal biomass and take advantage of animal nutrients? I am not proposing cows, fish or even insect can also be a good sink.
Just a note, from someone who has worked at a mushroom farm: It isn’t actually necessary for mushrooms to be grown in the dark, they’ll grow just fine under light.
They’re typically grown in the dark because otherwise you tend to get algae growing on them, and customers are put off by running into the occasional green mushroom.
I’d assume on Mars they’d be mostly grown in the dark anyway, just because any light would have to be deliberately provided. But no special efforts would have to be made to keep light off of them.
My experience with mushrooms comes from a farm near Ierapetra that we visited as undergrads. Its intention was to produce product for the market so yes, if it is ugly but tasty, we can certainly eat it. No need for pretty food on Mars
We must not repeat in space the same error we did on Earth. Humans should stop raise raise animals for food well before colonizing other worlds. Veganism is perfectly healthy while eating animal products clearly is not. We don’t deserve to be a space-faring civilization unless we stop abusing animals.
On Martian greenhouses: A standard atmosphere is 100kPa. Materials such as steel, glass, and some of the better plastics offer a yield strength of more than 1GPa. That means that a 10m wide cylindrical greenhouse will require a wall strength of 1 mm, only. If the material is transparent, no structure at all is necessary, since the pressure will be more than sufficient to hold it up.
The covering would not have to be continuous, of course: You could have 1 cm thick non-transparent cables spaced 10 cm apart, which would let 90% of the light through. A relatively thin paneling of clear plastic or glass would easily bridge those 10cm gaps and otherwise not need to hold the full pressure. Flexible plastic would probably be the way to go.
If the colony was solar powered, it would make little sense to operate solar cells to power grow lights: The combined efficiency of such a setup could hardly be more than 20%, so whatever is saved in transparent greenhouse covering will have to be paid for 5-fold in solar panels. As Scott Gordon mentions, if more light is needed, reflective panels erected outside the greenhouse can enhance lighting 2-3 fold, easily.
Finally, standing in a 10 m high and wide transparent greenhouse would be much like standing in the open air of Mars, a fantastic experience, I bet. One that might make life otherwise cooped up in pressure vessels more bearable.
I don’t see any increased value in using solar reflectors for greenhouse illumination vs increasing the illumination of solar panels.
While PV efficiency is about 20-25%, plant efficiency is much lower. In addition, plants don’t need full earth sunlight. Therefore you are just as well off being careful to stack plants and direct sunlight to the stacks, rather than allow shading. LED works just fine and is simpler.
Surface greenhouses are vulnerable to catastrophic failure, while a lava tube is likely to be more stable, and certainly not likely to be prone to failure.
Radiation levels are much reduced below the surface, which will be important, especially for those algal growth tanks.
Clearly there are mass tradeoffs, and it is unlikely that LED light or PV panel manufacture will happen soon on a mars colony, requiring imports, whilst plastic or glass panels might be made locally with quite primitive technology.
lava tubes can be immense. Paint the ceiling white and project cloudy skies on the ceiling. It will look quite Earth-like, probably more reassuring than a pink sky.
If I was living on Mars, an underground habitat, well shielded from radiation , insulated to provide a comfortable temperature, and equipped to prevent catatrophic blow outs would be my preference over an exposed greenhouse, even if that greenhouse was only entered when working in it.
Alex: I am not sure you got my point about the efficiency. In terms of bringing the sunlight onto the plant leaves, a transparent greenhouse cover should be over 90% efficient. PV panels and LEDs would be (optimistically) 20% efficient. So, to grow the same number of plants, you would need 5 times the area of PV panels compared to the area of transparent greenhouse cover. The efficiency of the plants themselves does not figure into this calculation at all. I am not sure why you brought it up. To further tip the balance, PV panels are much more expensive per area than greenhouse covering. All this is extremely strong incentive to go with open greenhouses for solar powered colonies. Considerations may be different if nuclear power is available, but that does not seem likely at this point.
As has been said before, Martian radiation is nothing that plants cannot deal with. With properly automated systems, humans do not have to spend much of their time tending the plants, and can live in underground shelters the rest of the time, as much as necessary or desirable. In general, like most health standards, radiation exposure limits are chosen very conservatively, and it is likely that routine living in space will lead to the adoption of less stringent standards, eventually. It is also plausible that advances in medicine will allow alleviating the effects of radiation exposure. In the unlikely case there is a problem with plant germ line preservation in the face of Martian surface radiation, seeds can be bred in separate, much smaller underground incubators or simply imported from Earth.
@Eniac – you are not analyzing this at a granular level. Yes, a roof lets in most sunlight, but plants cannot use all that sunlight. Firstly there is the problem of distribution – too much sun for the topmost leaves, too little for those shaded below. You need to use mirrors or light guides to distribute the light, and that adds mass. But secondly, plants only use a very limited part of the spectrum. By trapping much of the spectrum, but remitting it in just the most useful wavelengths for photosynthesis, you can optimize the energy for production. Solar cells are being developed to capture more of the spectrum, so efficiency increases, while LED lights emit in the optimized spectrum for plants. Distribution is much simpler for lighting racks, as we have seen in urban vertical farms. Lastly the conversion approach can even out the energy over time, whilst that cannot be done with sunlight.
We would need to determine overall efficiency, but the experience of vertical farms as well as other factors discussed suggests to me that PV is the way to go, especially if you are using PV to power the colony as well.
Radiation for a greenhouse can be minimized with a trench greenhouse. Run the trench East-West and mirror the sides. The dirt on either side would reduce radiation enough for plants. Top glazing to keep the dust out and the glazing at the bottom would have to hold the pressure. The problem is that sunlight at the martian equator is only 50% that at Earth, and after passing through two layers of glazing it will be down to 40%. Top glazing is not an issue since the Sun arcs across the sky every day. If the greenhouse is not at the equator, it would have to be a periscope trench, aligned to the equator.
There is a misunderstanding here about radiation, that we actually want seeds from the plants that are growing in the greenhouse. We do not. The high yield seed is on the F1 generation, which is the one grown on the greenhouse. We can have a smaller facility underground for seed production with P1 and P2 plants to provide the F1 seed. We do not harvest the F2 seed coming out of the F1 plants, it has yield at the P1 or P2 level, not at the F1 level.
Plants are divided into C3 and C4 plants depending on the photosynthetic path. C3 plants, and most cultivated plants are C3 plants, do quite well with low photosynthetically active radiation (PAR) and saturate photosynthesis and high PAR levels. C4 plants, corn is one of the few cultivated C4 plants, do indeed function better at high PAR and do have issues at low PAR. Also leaves are actually optimized to work at 80% ambient level, outer leaves saturate at 120% of their design but inner leaves works very well. There is no need for a system to distribute light, plants have the physiological adaptation.
PAR is very broad, ranging from the red edge to the ultraviolet. We could use LEDs that do not provide radiation below the red edge, but then again we would likely need to heat the greenhouse more
Ioannis, I understand the point you are making about growing hybrids since they are more productive, but that raises another question about creating viable agriculture on Mars.
I wonder how hard it will be to get the hybrid seeds to plant on Mars? They will have to be transported from Earth to begin with. What is their shelf life, and how hard will they be to transport? What is needed to produce new seeds on Mars? What is lost by using non-hybrid plants on Mars, so their seeds can be used to grow the next generation?
Ioannis, radiation protection in the greenhouse isn’t just for the plants, but also for the workers. People will spend a lot of time tending the plants. In Westland, NL and Almeria, ESP greenhouses, cheap labor is everywhere. On Mars, the scientists will all be part time farmers.
Eniac,
I agree working in a transparent greenhouse on Mars would be a great experience. However I am still not convinced that is the best way to go. Mars is cold, so the greenhouse would have to be heated. In addition the radiation environment on Mars is much harsher than Earth’s. Above ground greenhouses would not handle those problems well. It would be easier to manage those in an underground greenhouse.
You wrote “…require a wall strength of 1 mm, only.” Is mm the right unit for strength? Did you mean wall thickness?
Yes, I used strength in the sense of thickness. I’ve heard it used that way, but I should have been more clear.
As noted by many , it will be very difficult to build a hothuse capable of withstanding any kind of realistic pressure .
One solution is of course to build underground food-factories where plants get LED-light in the specific wavelength necesary for photosyntesis .
Another solution is to create transparent ,thermoisolated pressure vessels , something like a giant softdrink bottle in which algae can be grown . A temptating idea would be to look for an algae species capable of producing a the raw material for a polyethylene -like material , which could then be used to make much larger quatities of ‘algae-bottles’ , and this might not be very difficult . A similar system has already been investgated on earth by a private company , hoping to produce comercial quatities of alcohol from sewage water . The idea was to separate the alcohol from the watersolution by lowering the pressure , or ‘sucking’ it out of the solution by wacum pumps …..They used scaled up extrusion machines very similar to the ones used in every village to produce soft drinks , 1,5 meters in diameter and 50 meters in length .
On earth ,contamination from the environment is THE major problem of growing a mono-culture algae . On Mars , sterilisation is automatic , quic and cheap .
Growing algae on mars is not just a food process , but also a way to start up a production of industrial organic materials . Of course many problems remain to be solved , such as producing a transparent AND thermoisolating material from alcohol , but if these can be solved the potential i limitless .
JSC has done experiments with an inflatable Mars greenhouse. Other have already note that it will have quite powerful tensile strength. Plants take most radiation in the visible range to photosynthesize, from NIR to UV. They are quire reflective in NIR, on the visible range at Green though not as much as NIR so we will need full visible spectrum. Algae will be part of any colony, but what function they will have is to be determined. There is no point in growing raw material if getting the industrial process requires a huge expenditure in machinery and resources.
Its not very scientific, but its a truism that people are going to want to eat food that’s satisfying to them… Especially under demanding and stressful conditions. No amount of rationalizing the “efficiency” is going to change that. You are not going to find alot of volunteers that are willing to go on a multi year mission, after you tell them , “oh by the way, we built a state of the art, 100 billion dollar facility, but you’re going to have to eat yeast cakes, algae crackers and mealworms for the next 4 years…”
I imagine Mars exploration in 3 stages… The first landings and small habitats will bring their own food and have resupply missions. The 2nd stage will be akin to an antarctic research station, and those people will probably raise a limited amount of hydroponic vegetables to supplement their rations, and improve morale with fresh food. The 3rd stage will be a small city, complete with self sustaining greenhouses, intensive gardening, and probably small scale animal husbandry… Poultry, rabbits, fish, invertebrates… (And yes, bug larva )…
In the far future, I can imagine re-enacting the Firefly scene, where they delivered a load of cattle to one of the outer planets… Although they implied that terraforming was achievable in that time frame.
Poultry, rabbits, fish, invertebrates… (And yes, bug larva )…”
Rabbits, fish and some invertebrates yes. Poultry might be hard to get established due to transport issues. I’d be against introducing most insects as they will inevitably escape. Pollinators should be considered, but they must be contained carefully.
OTOH, we will need to replace a lot of our parasites/symbionts if we intend to keep mars fairly sterile. All those flakes of skin need to be digested. :)
Poultry should be much easier to transport than mammals, just take the eggs and hatch them when there. Insects can obviously not live under Martian conditions (no oxygen), so them escaping from the colony is not really a concern. Insects escaping inside the colony is nothing that a flyswatter could not take care of, so I am not sure why you are against introducing them.
Re: Poultry transport. Eggs cannot be put into “stasis” for the length of the journey AFAIK, so this would be problematic. Eggs have to be kept warm as birds are homeotherms. The best way might be to have a few birds transported with frozen eggs which are then implanted with IVF to get the bird population started. If you can reduce journey times to just a few weeks or days, then that is a different story.
Insects: I think you are far too sanguine about pest control on the colony. They will infest everything if they escape, and you won’t be able to use conventional means of chemical control due to the lack of air changes. Cockroaches have never been eradicated in NY buildings, and I suspect other insects will be similarly problematic.
The big problem may be that we will need other insects and arachnids to maintain the ecology of the base if it is to be more than just a grounded space station.
Murphy’s Law will always apply. :)
Well, it would be our choice which insects to introduce, so they do not need to be the worst of pests. I also think we can expect a space settlement to be a lot cleaner than the typical New York apartment, so cockroaches would probably starve. And since there is no way to leave the “house” and return, pest control of any kind would be a lot more effective. You could, say, evacuate a section for a while and then refill with fresh air after the pests have suffocated or evaporated.
I’m also thinking about small animals that we need to bring if we want to maintain an Earthlike ecology. Soil is full of organisms that are involved in recycling material, many of which may be needed. I personally would go for hydroponics and aeroponics to avoid this, but that implies that all recycling of human and processing wastes must be done by other means. Maybe we can do this with siloed biology, I just don’t know for certain, as we rely on so many hidden environmental services on earth that supplement our efforts.
This is all grist for some good experiments. It isn’t like we are going to Mars any time soon, so experiments that last a decade could be started soon to test out the needed technologies and discover the problems.
You are right, eggs by themselves cannot be stored long and still hatched. It should be possible, though, to extract embryos and freeze them in the same way as is routine with mammalian embryos. Then, upon arrival, thaw the embryos, transplant them into suitably preserved unfertilized eggs and hatch normally.
To the best of my knowledge that hasn’t been done yet in birds, but it seems just a matter of time.
In effect you are saying freeze a fertilized egg. However we might be able to take the fertilized egg at a much earlier stage when they are much smaller, freeze them, and then implant them so that they continue their growth cycle.
Having said that, has anyone ever tried rapid freezing an egg and thawing it, just to see if there is any viability?
I was thinking about that problem of transporting animals… I assume that by the time we are building city sized Mars habitats (200 years?) spacecraft will be much more advanced, capable of very fast direct flights, carrying huge payloads (I hope)… In the nearer term it probably wouldn’t be too difficult to transport lower forms of life as eggs, or the newly hatched stage… I have some experience with aquaculture… Slowing down maturation of salmonid eggs could probably be done… In any case, newly hatched fish wouldn’t be affected by weightlessness… And they’re very small, you can fit a lot in a small space. Same goes for raising invertebrates, crayfish, oysters, snails… Dont forget frogs…
Elon Musk has promised to present at this year’s IEEE the Mars Colonial Transporter, capable of transporting 100 people to Mars. Considering that the most we have managed to have in space in one place at the same time has been 13 at STS-127 visiting the ISS, 100 people breathing and feeding for 6 months on the way to Mars is a big stretch. With a ship of this class we can transport animals along with people.
Thank you Dr. Kokkinidis for the thought-provoking article and your patient responses to comments.
Any issues regarding meat production and consumption on Earth of course are beyond the focus of Centauri Dreams. The only pertinent issues here arguably should concern the practical suitability of meat production for an off-world settlement.
That is, practicalities aside, the question of whether Martian settlers individually or collectively should opt to forego meat production and consumption on purely moral grounds ultimately should be made by the settlers themselves. Much the same can be said for any number of the “hot button” issues of the day that divide folks back here on Earth.
To paraphrase the line from The Last of the Mohicans movie, settlers who hack their lives out of an off-world wilderness with their own two hands (and, OK, biennial resupply) will have a natural disinclination to live by the leave and the moral judgments of people over thirty million miles away.
From the moment that previously Terran boots set foot on Martian regolith for permanent settlement, their wearers will become a breed apart, not necessarily beholden to the moral judgments of people on a distant planet that they never may walk on again.
All that said, I question whether trying to build and sustain an infrastructure for meat production and consumption would be advisable for an off-world settlement as a practical matter. Particularly at the outset.
To me, it’s a matter of necessity, efficiency, and sustainability.
As for necessity, combining a legume (such as lentils) with a grain (such as rice, wheat or millet) provides a complete protein with all of the essential amino acids. Just like meat, but without all the loaded up fat and cholesterol. When I’ve been on a training diet based on legumes, grains, and fresh vegetables, I’ve put on muscle mass with no difficulty at – all while dropping fat as a bonus.
Yes, B12 is an issue for a strictly vegetarian diet. But B12 either can be synthesized onsite from bacteria – just like on Earth – and/or imported in supplement form with perhaps far less effort and expense than that required to establish the comparatively extensive infrastructure necessary to grow and maintain livestock.
And, while our stomachs are not cow or rabbit stomachs, that’s really in truth beside the point. There’s absolutely nothing in our anatomy or physiology that requires that we eat meat rather than a vegan diet with B12 supplementation.
So, I question the necessity of building an off-world infrastructure for raising animals for meat consumption.
As for efficiency, it seems that it would be more efficient to grow plant feedstock for just one population, humans, rather than trying to also grow feedstock for multiple other populations of animals, too. It will be hard enough to grow plant feedstock for humans as it is without taking on the burden of growing plant feedstock for a multitude of animals as well. That is, a settlement can grow plant feedstock sufficient for human nutritional needs simply and directly without also having to grow yet additional plant feedstock to try and sustain a multitude of animals as well. A simple grow, store and eat versus grow, feed, maintain, slaughter, salt and/or freeze meat, etc., etc.
I understand that animals can consume plant parts that the humans do not eat. But that biomass also can be put to use in a number of other ways (e.g., compost, energy production) that are arguably more efficient than trying to sustain multiple animal populations.
So, I question the efficiency of building an off-world infrastructure for raising animals for meat consumption.
As for sustainability, I would think that there would be a horde of possible things that could go wrong trying to raise multiple Terran animal populations on another world. For example, we don’t know yet what long term reduced gravity will do to humans, much less chickens, pigs and cattle. While plant populations also face risks such as disease, an off-world settlement arguably would be increasing the number of things that potentially could go wrong several times over by trying to raise both plants and animals. Inviting the application of Murphy’s Law with a vengeance.
So, I question the sustainability of building an off-world infrastructure for raising animals for meat consumption – especially early on.
Perhaps a long, long way down the road, an off-world settlement could try and build and sustain the infrastructure for meat production. But it doesn’t seem to be either necessary or advisable in the beginning years or even decades as the settlement is trying to claw its way to just basic sustainability and self-sufficiency.
Sort of a Martian by choice, vegan by necessity type thing.
Now, they are going to have coffee, aren’t they?
: ^ )
PS. Eating vegan doesn’t mean a life of unappetizing yeast cakes and algae crackers, far from it.
As for methane, Joe G, that’s an issue that can be ameliorated to a large degree by the way in which the legumes are prepared (soaked and slow cooked helps a good bit). Also, intestines that are constantly switching back and forth between meat and legumes/grains produce more gas than intestines that have made the adjustment instead to eating primarily legumes and grains.
But, if all else fails, it looks like they will have a Martian orbiter already in place to track the phenomenon, lol:
http://exploration.esa.int/mars/46124-mission-overview/
George, Good points all… You mentioned the fact that animals can eat plant parts that aren’t edible for humans… That is why historically speaking, some human cultures kept herds of grazing animals, especially in marginal environments, because the cows, goats, sheep, reindeer could convert indigestible plant material into digestible meat, as well as useful by products like leather, bone, horn, wool.
It was mentioned earlier that light levels on mars are comparable to overcast conditions in north… I can tell you from many years of gardening that at such a low light intensity plants will shut down… Ironically about the only thing that would continue to grow would be grasses… But its obvious that we’d either need light collectors or artificial light powered by , probably something like a nuclear power plant.
Now, I wouldn’t recommend bringing cows to mars… You’d never be able to grow enough grass for them… However, there is a type of Tilapia that is able to eat free floating algae, sort of a filter feeder arrangement… I cant vouch for how they taste. Usually algae imparts a horrible swamp-like taste to a fish… Down south they farm catfish in these muddy ponds… The practice is to put them in clean water for a while to clean their systems out before selling them.
Not to get lost in minutia, we might want to consider converting some of that algae into seafood.
The question about raising meat is what level of population and complexity are we talking about. Fish is relatively easy to keep a large and genetically diverse population. If we are talking about bovines we will need a herd of at least 50 animals which is quite a commitment. However when we have tens of thousands of people on Mars, it is not much of a commitment at all. There is a limit to have much we can use plant food practically. After we have 6000 calories a day of food, two years of supply reserves and sufficient compost for all our needs it makes no sense to throw away food, we can feed it to the animals for concentrated food later. When the Polynesians engaged in the exploration and colonization of the Pacific Islands they would carry on their large catamarans tubers but also pigs and chickens. Let us not forget that Polynesians were a stone age civilization. We can carry animals on our space catamarans to Mars, they are eventually a part of our colonization kit. But this indeed is a question for the future
You do not need 50 animals, I think. A single cow and a freezer full of embryos gives you all the genetic diversity you might ever want, certainly more then your average herd of Holsteins. After arrival, you breed the herd to the size you want, all the while drawing on the supply of embryos. “Natural” breeding can, of course, also be done, but it is optional.
Much more serious, in my view, is the issue of space. Grazing is not really an option, so you have to keep them in house, and feed them plant leftovers from the greenhouse. I imagine rabbits or chickens would be more effective than cattle. It would be good to have milk, though.
Fish, I am not so sure. They require a lot of water, which comes at a premium on Mars.
I never had given much thought prior to this article to how challenging basic food production would be as spread out into the Solar System.
It appears that providing this most basic of necessities presents every bit as much of a challenge to settling the Solar System as do such high profile issues as propulsion, radiation protection, and biomedical issues attending long term micro- or low-gravity.
Particularly if the food is going to be grown underground (to reduce the need for constructing freestanding pressure vessels and to limit radiation exposure), we really should be using a lunar base as a test bed for off-world agriculture. Having the Earth only a three-day ride away in case (i.e., when) something goes wrong seems preferable to trying this out for the first time on a world over thirty million miles away at its closest approach.
Biospheres and labs are great. But nothing is going to tell you whether you can reliably produce settlement-sustaining amounts of food from an artificial Earth ecosystem on another world quite like fully cutting the cord and trying it on another world, from scratch. And I’d rather work out the inevitable kinks in that with Earth three days away rather than thirty million or more miles away.
The private sector groups with “go fever” to not just explore but instead also settle Mars now within the next decade or so perhaps are leaving out “a few” incremental steps. Steps that are fundamental prerequisites to the success of any long term settlement on another world.
“Particularly if the food is going to be grown underground (to reduce the need for constructing freestanding pressure vessels and to limit radiation exposure), we really should be using a lunar base as a test bed for off-world agriculture. Having the Earth only a three-day ride away in case (i.e., when) something goes wrong seems preferable to trying this out for the first time on a world over thirty million miles away at its closest approach.
Biospheres and labs are great. But nothing is going to tell you whether you can reliably produce settlement-sustaining amounts of food from an artificial Earth ecosystem on another world quite like fully cutting the cord and trying it on another world, from scratch. And I’d rather work out the inevitable kinks in that with Earth three days away rather than thirty million or more miles away.”
Very good point and this should be quite obvious , the road to Mars and beyond passes by the Moon. Every body here knows the famous Tsiolkovsky’s quote : “The Earth is the cradle of humanity, but mankind cannot stay in the cradle forever”. It does not mean than just out of the cradle Man can jump and run everywhere he wants ,he must learn to walk and alot of other things too.
I am totally in favor of human colonization of the Moon. We can and will try what works there, though we will need to deal with the carbon issue too which is easier to solve on Mars. As mentioned though the Moon is indeed only a week away from Earth. Mars is where we can realistically cut the cord. Colonizing new lands was never easy on Earth, new powers survived due to superior kit and cruelty which are so obvious when reading the history of European colonization. However on Earth we have an advantage that is not obvious to non specialists: ecosystem services. Colonization of the US would have been far harder if the pioneers had to create soil and fertilizer and the whole ecosystem in general. This is why Antarctica is still limited to research stations 200 years after its discovery while the Western Hemisphere or Australia support large populations. Also growing food on a planet or moon is far easier than on a spaceship or starship. How closed do stellar colonization systems need to be? Do we pack everything on Earth, or should we start at some faraway station to the stars such as V774104? Let’s solve the easier problem of food on a planet before we reach the stars
” You are not going to find a lot of volunteers that are willing to go on a multi year mission, after you tell them , “oh by the way, we built a state of the art, 100 billion dollar facility, but you’re going to have to eat yeast cakes, algae crackers and mealworms for the next 4 years” ….
…Not true . Thousands of people have already declared willingness to go for a mars mission without even much of a chance to get back to earth . If the diet is declared healthy enough by specialists , there will no lack of qualified volunteers just because of sensitive stomacks and noses . …..Anyhow , as anybody who ever tried to eat Thai food will know , if you add enough spices , nobody will feel the diferece between cow-burger and worm-burger ….
In order to survive on mars or the moon , the best strategy will be to have at least two separate and completely different systems , each of which can supply a survival-diet in a crisis , so we need both underground hothouses AND an alternative system using sunlight for growing algae in transparent plastic tubes . Without this double solution , the underground hothouses wil have to 100% secure against plant deseases , which is not possible at all with todays technology . At present nobody has sucseeded to make a completly closed-loop agricultural system for more than few weeks , while monoculture algae can been grown in sealed containers for as long as it pays to operate a certain unit .
When you say that there is no one species that can supply all nutrients that humans require, I think you’ve overlooked the POTATO…..!
Even on Ireland before the blight they did not eat just potatoes. Also, what happens when Phytophthora infestans reaches Mars?
Re: Vitamin B12.
It seems to me that engineering crop plants to produce B12 might be the best way to solve this problem for sustainability. This gets around the importation of bulk B12 from Earth.
Re: Productivity.
Crops waving in the breezes of a pressurized greenhouse under pink Martian skies seems to be an image in many minds. In that scenario, animals are best used to consume the unconsumed parts of crops, ie the bulk in many cases. [ Ecosystems are quite effective at recycling, unlike human systems.]
Single celled algae are very efficient sunlight converters with very high productivity, which is why they are the basis for a number of biofuel experiments. However, they are hard to harvest and it makes sense to have animal intermediaries. Fish are perhaps ideal, either Tilapia or a species of carp. We probably cannot eat a diet of zooplankton. During WWII, experiments on rats to do so by a very hungry England showed that a diet of more than 30% zooplankton was problematic, IIRC.
The subject of farming leads naturally to the issue of what is needed for an enclosed biosphere, and Bisophere II notwithstanding, we really need to know what terrestrial organisms we need to bring along, wittingly or otherwise. The idea of super healthy, sterile Spacers from Asimov’s robot stories is no longer tenable.
Well, sure. The point of mentioning B12 isn’t to suggest that animal husbandry is a necessary or even efficient way of providing that vitamin. 3 micrograms a day. Each colonist could bring with them a lifetime supply, and never notice the space it took up in their pocket.
It’s just to refute the idea that humans aren’t natural omnivores.
Obviously it would make sense to engineer our intestinal flora to provide all needed vitamins. They already provide sone of them. One less worry.
But people like eating meat. Including it in the diet would be a morale booster. A milestone for the colonists to work towards.
A successful Mars colony will eventually produce its own meat, unless moral scolds were given dictatorial power. It would be a luxury good, and the local production of it a sign of success.
This is an amazing discussion !
I want to add two points:
. About Perchlorates ,I think they can be found only on the surface because that where very probably they are produced.They can also accumulate in holes or be blown away by winds. But I am pretty sure that basement rocks don’t contain them. And you can crush them to make the soils you need.
Bringing the light : This can be done with the optical fiber which can carry the sun light from the surface of Mars into the subterranean greenhouses.
Mars or Moon, I would go underground, for the most part. Laser boring robots could work 24/7 creating huge caverns in reduced gravity. You could have fields, forests, and even lakes in them. You could have insects, rodents, lizards, birds, squirrels, fish and whatnot living in those ecosystems. I mean, just think about entering Forest Seven (a cavern of couple of square kilometers), strolling about, and listening to birds sing? I wonder how bird flight would look like in Mars’ gravity…
I would definitely try to bring animals along. Not really for eating them (except occasionally), but rather for eggs, milk and as pets! Besides, having animals (and dirt/germs in general) around is good for the immune system, so there’s that, too.
I suppose there could be transparent surface domes in case you want to see the actual Sun without donning your space suit, but I don’t think all that radiation is good for you (or the plants?) in the long term.
Biosphere 2 is the largest experiment ever conducted to create an enclosed complex ecosystem and it is generally considered a failure. Trophic links even on remote islands are pretty complex. Simplified managed ecosystems a.k.a. agriculture will be the norm at first, botanical gardens will take time
A number of posters have suggested raising fish.
Over and above commercial fish farms themselves, the number of successful large aquaria around the world reflects that establishing working indoor fish habitats is the maturest technology of the three (plant, livestock & marine). Maturest in terms of being able to successfully replicate a working stand-alone habitat in a remote location – like having a working large aquarium out here in the middle of the desert in Las Vegas.
Can’t see any reason why that same habitat technology could not be readily applied to a subterranean water reservoir on another world, with concentrated natural light piped in or artificially recreated. Not even sure that marine life would miss a beat in reduced gravity, so long as they could adjust their natural buoyancy level to compensate. They perhaps might have the easiest transition of all the species from Earth’s 1g to reduced gravity.
What would be fun (don’t tell the PETA people) would be to stock a large salt water subterranean reservoir/habitat with a variety of game fish, like red snapper, lemon fish and grouper. Settlers then could go spearfishing with scuba gear like we would do off the offshore platforms in the Gulf Coast oil patch. Sport, exercise, and fresh fish all in one habitat (without having to keep an eye out for sharks and barracuda). Martian red snapper caught fresh that day, now that could make the place seem downright habitable.
Aquifers are more likely to be rocks with millimeter level porosity rather than underground lakes. No features on Mars yet have been identified as Karstic, and I would be very surprised if Karst is present there
Was thinking more of man-made subterranean reservoirs as opposed to being able to exploit preexisting naturally occurring underground water reservoirs.
Unless they come up with a way to protect against radiation, underground may well be the way to go for all food production — whether crops, livestock or fish.
If the following Wikipedia summary is correct, they don’t quite have the surface radiation licked just yet for longer term exposures:
“The Mars Odyssey spacecraft . . . found that radiation levels in orbit above Mars are 2.5 times higher than at the International Space Station. Average doses were about 22 millirads per day (220 micrograys per day or 0.08 grays per year.)[26] A three-year exposure to such levels would be close to the safety limits currently adopted by NASA.[citation needed] Levels at the Martian surface would be somewhat lower and might vary significantly at different locations depending on altitude and local magnetic fields. Building living quarters underground (possibly in lava tubes that are already present) would significantly lower the colonists’ exposure to radiation. Occasional solar proton events (SPEs) produce much higher doses.”
. . . . [R]esults from a 2006 study indicated that protons from cosmic radiation may cause twice as much serious damage to DNA as previously expected, exposing astronauts to greater risk of cancer and other diseases. As a result of the higher radiation in the Martian environment, the summary report of the Review of U.S. Human Space Flight Plans Committee released in 2009 reported that ‘Mars is not an easy place to visit with existing technology and without a substantial investment of resources.'”
https://en.wikipedia.org/wiki/Colonization_of_Mars#Radiation (footnotes omitted).
So, if you gotta’ dig a hole (or two or . . . ), thought it would be fun to replicate a salt water habitat with one, along the way to augmenting and diversifying the settlers’ food supply.
Curiosity found that surface radiation conditions on Mars is similar to that of the ISS. I don’t know how much the polymer of the greenhouse skin would protect, but even very little will be more than just plain Martian air. These are conditions where plants can grow. For animals long term results are TBD
Great article!
One thing I think that is implied in these scenarios that people have overlooked is that the lifestyle of the early settlers is essentially going to be that of high tech peasants. I.e a life style/culture where agriculture is a way of life to provide your own needs rather than a business.
I think animals will be part of the system, but as part of the ecological system, consuming inedible parts of plants, wastes etc., rather than primarily for meat production. Like in peasant societies animals would only be slaughtered when they are no longer productive, which probably means slow cooked goat/chicken/rabbit stews & curries rather than beef steaks, and only on special occasions.
The other reason to keep animals, particularly mammals is as research subjects on reproduction and the raising of young. I’d be a lot more confident about having children off Earth if we at least had experimental evidence of several generations of goats or rabbits in hand.
Aside from necessities, there are also luxuries to consider, it might be that on the “Resupply Day” feast everyone gets a small piece of freeze dried steak and the rest of the time has to make do with flavourings, like refined “essence of steak” or dried lamb flakes (similar to bonito flakes in Japanese cuisine) to flavor your tofu burger. It sounds like the Spice Trade just got re-established!
Spice Melange?… oops, wrong desert planet ;)
We can actually do a lot things with the plant remains before we need to feed them to animals but I agree, before we unleash full scale colonization it is better is we test the physiology with animal models. Then again I am not in favor eating mouse, which after all is the main mammal model. In Ancient Greece the only time the poor ate meat was during the religious festival, when the state would slaughter 100 ox to whatever god and then pass meat to its citizens. I expect a similar ceremony to arise during resupply day
Those mighty Russian rockets are doing good work.
And speaking of rockets, I’ve written several books on the subject of relativistic rockets.
My newest title to be available in a few days is:
Call Of The Cosmic Wild: Relativistic Rockets For The New Millennium. 3rd Expanded Edition.
The book is electronic to be available on numerous platforms.
The publisher is X-libris.
Regardless, it is nice to see chemical rockets enable our probes to ply the depths of our solar system. We will eventually need nuclear fission and/or fusion powered systems. Antimatter rockets would be ideal and I believe will be possible at some point. Currently, the quantity of antimatter produced in our accelerators per year is on the scale of one nanogram which has the yield of a hand grenade when mixed with normal matter. So, we will need to ramp up production to enable matter-antimatter rockets: – a really large caveat!
Regarding space-based agriculture, that is a must for long duration space ark missions as well as extremely relativistic spacecraft capable of travel to other galaxies and taking advantage of large Lorentz factors for time dilation.
There is the hybrid fusion/fission/antimatter drive, very small amounts of AM are needed to start a good explosion, it will be easier to control than a AM-M drive that’s for sure.
Many people advocate raising mammals and birds because there will be a ready supply of plant waste such as stems and leaves. If I were homesteading on Mars, I would rather use this material as a medium for 3D printing.
Thank you all for your kind words. I have read all of your comments. I will keep on answering questions if you have them but, just as most space agriculture plans, there are still too many unknowns to be decided.
The problem with surface greenhouses and mirrors is that they will need a lot of cleaning to remove accumulating dust. This may prove inconvenient depending on the size and shape of the greenhouse. PV panels in contrast can be orientated to be easily accessible and even self cleaning.
We could have a hollow bar with nozzle jets at the bottom of the mirrors and during the cold night CO2 is compressed to a liquid (heat goes into green house or underground). Then the liquid is sublimed by solar heat during the day to jet blast the mirrors.
Wouldn’t this just add complexity and something else to fail and maintain? Maybe to sop up the unemployed (although this would be the broken window fallacy)?
It need only be used infrequently, say once every couple of days and then used for something else say maintaining pressure in the habitat or moving other liquids.
Cleaning will likely be done by robots, imagine a type of Roomba able to climb or suspended from the top of the greenhouse/panel by wires. Any advantage of better accessibility for PV panels is going to be negated by there being 5 times as much area to clean.
While I agree that the underground grow chamber is workable and solves a lot of problems, I’m not willing to give up just yet on a surface greenhouse! Being able to work on growing the crops and just casually look out to the surface is going to be a huge psychological / morale booster that I think will be a very important human factor in such an utterly remote alien outpost.
A surface greenhouse could be shielded from radiation using superconducting magnetic shields. You’d want to shield the whole base anyway just to keep everyone from getting cancer. Sure beats living underground.
Regarding dust accumulation on the transparent PVC , perhaps some jets could be arranged to blast compressed atmospheric CO2 across the exterior surface at periodic intervals. Heat can be provided by circulating RTG coolant in a closed underground loop up and through the greenhouse. Actually you may wish to heat the entire Mars base this way. Yes, the Mars colony had best be nuclear powered.
Could a geothermal (areothermal?) heat pump do the heating trick as well? We bury pipes here on earth and circulate fluid through them to leverage (sink or source) the earth’s interior heat. Does Mars have significant interior heat (magma) or is it as cold as a stone?
Don’t forget that 3D printers can print concrete (perhaps made from regolith) structures and also GLASS!
This has got to be one of the most exciting and interesting topics on Centauri dreams ever. And that bar is set very high indeed.
For plants our radiation requirements are not as strict as for animals, let alone humans. If some radiation level is likely to cause cancer to a person at age 80, it is unacceptable. Farm animals do not generally reach middle age, let alone old age. For plants it is enough that they produce their crop, if they are genetically damaged in the process that is not that important: we often do not use them as seed anyway for genetic reasons. The F1 generation which is what are most cultivated hybrids has higher yield than any of its parents, but its output the F2 generation has lower yield than F1. It is easier to keep a seeding nursery that to try to create viable seeds, edible food is sufficient.
There is significant research on reducing radiation but so far nothing practical has emerged. As for dust, I see the astronauts going out to clean the surface of the greenhouse just as they clean the surface of the solar panels. A geothermal pump could do the trick if we drill deep enough that the planet is warm. We will also need water as the heat medium to be injected in the hot rocks and pulled back up to warm the greenhouse. It is much easier to use a solar water heater, of the kind that you find on rooftops in Greece.
The best solutions are often limited only by the scope of our imagination and the laws of physics.
Mars is likely frozen to many kilometers, solar is the most reliable of the heat sources then next nuclear.
This would give you a wholesale shift in co2 and possibly methane. What other species would you shed to balance the shift? I think we take a lot of our patterns for granted because our biosphere is elastic due to its scale. At a small enclosed scale removing or adding a person or large mammal by choice or by accident or age is non trivial?25million salmon dead of blu green algae would not be just a loss of protein it would be a wholesale shift in processing of gas and water, in Chile this means dumping at sea, in space if you dump into space you have lost all of the resource asset if you dump into the void. Perhaps allowing it to freeze and processing dead fish in batches would be an option. Then you have to have a strategy for the algae too, and separate water to restart a healthy system. Monolithic harvests are likely to be more risky than staged and overlapped harvests?
We need to know what simplified compost looks like if that is the case.
What is the minimum healthy complexity that will return all nutrients to the system.
If ther eis an anolmaly do you have the complexity to rebalance constructively to virii or bacteria? We do simplified agriculture on earth because we externalise all the excess from monoculture, nitrates flow into aquifers, toxins into bees, etc
on the moon the scale of the planet means that balancing or avoiding changes in mass means that trade deficit would be measured in mass and impact on orbit.? dealing with geological time matters if we want to keep seasons and tides on earth.
Reading this:
http://www.lpi.usra.edu/meetings/geomars2001/pdf/7044.pdf
It says ~ 10K /km, so around the equator you’d likely have to get down to perhaps 8-10 km depth to get even moderately useful geothermal heat for a greenhouse. OTOH, under Martian gravity, that’s not a challenging depth in terms of rock pressure. I think, though, some kind of molten salt solar heat system would be a better choice.
Speaking of molten salt… Ionic liquids are a new class of chemical with extraordinary properties. Imagine a liquid with a freezing point of -100c, transparent, and no vapor pressure to speak of. Just the thing to hose down a dusty greenhouse on Mars. Well, not hose, we’re still talking pretty viscous at those temps. But a film of it flowing down the sides would certainly deal with dust, and deny it the chance to cause abrasion during a dust storm. Might even be feasible to make Martian solar ponds with the stuff. I’m going to have to look into it.
In the dry, dusty environment of Mars, a simple brush should be superior to an ionic liquid (or any liquid, really), by far. Given the advances in robotics and the added complications of EVA I do not see humans bother with the cleaning. A crew of Roomba-like sweepers will take care of it.
All this talk of “printed meat” is starting to make yeast cakes and dried algae chips sound down right appetizing… I cant help but think the massive factory infrastructure (synthesizing complex chemistry) to support flesh printers would, by far , cost more than simple low tech farming techniques… Weve been doing this for thousands of years after all… We do have alot of experience in this area… Im not making light of the difficulties of doing this inside what is in effect a huge terrarium… Worst comes to worst… Grow the vegetables there and parachute in massive deliveries of spam… (Just make sure they include the teriyaki flavored spam…)
I tried to keep the article towards tried and proven methods of agriculture. I am pretty sure people have great ideas on how to revolutionize agriculture which due to the law of unforeseen consequences fail. The European populations have rejected GMOs because they came into the market right in the middle of the third Mad Cow crisis. I’ve seen GMO proponents failing to understand the vehement rejection thinking it is lack of familiarity rather than fear of long term consequences. Hydroponics has now been around for over 50 years. CAFOs possibly longer. Their issues are known, CAFOs can indeed make workers sick, though being exposed to a variety of germs before the general population is not necessarily bad, you might have already been exposed in the past so you could be more likely to survive. Carniculture is at best in the prototype stage and for all we know it could be the next thaliomide. Creating a colony is a balance between the need to minimize the spatial footprint, minimize local infrastructure and minimize resupply requirements from Earth. These three requirements are often contradictory. When creating something that you intend to last it is better to use systems of long heritage than the bleeding edge, which could turn out problematic in a few years.
I general I agree. But we should bear in mind that unlike Earth, Mars is a totally new environment with almost none of the environmental services that allow agriculture on Earth to be easily spread. What I would like to see is low cost experiments that simulate Mars so that we can test what works and what doesn’t. Apart from gravity, this could be done on Earth. We really do need to know what will work robustly so that Martian ag gets going without some disastrous failures.
I’ve heard commentary to the effect that they rejected GMO’s because it was a plausible excuse to impose protectionist measures against American agricultural products, which they were otherwise prohibited by treaty from doing. But that doesn’t really effect your point.
Hydroponics is probably the most advanced food production technique I’d want a colony to depend on, for exactly the reasons you give.
Alex Tolley wrote: “What I would like to see is low cost experiments that simulate Mars so that we can test what works and what doesn’t. Apart from gravity, this could be done on Earth.”
Alex I completely agree with that idea. Lets get started with the tests we can do here on Earth and can afford to do. There are a lot of unknowns, so the soon we can start the better.
I think there are other factors than gravity however. Mars has a different radiation environment and the temperature is different than Earth. We will have to learn about all of those before we can succeed in settling Mars. If we want to grow in the Mars regolith we will have to learn to deal with the percolates and other soil differences.
There is much to learn.
Of course, many martian greenhouse simulations have been run on Earth. Most recently:
Wageningen University and Research Centre. “First tomatoes, peas harvested on Mars, moon soil simulant.” ScienceDaily. ScienceDaily, 8 March 2016. .
The Mars Society has had a greenhouse at the Mars Desert Research Station in Utah for many years (recently rebuilt after a fire).
Micky, none of the Martian greenhouse simulations I have heard of were adequate. The greenhouse at the Mars Desert Research Station is very short term. The one at Wageningen University is better, but still does not address what we need to learn. I am glad they are all being done, but we need more.
We need to feed a few people completely from the greenhouse and we need to do that from a closed environment. The conditions need to mimic Mars as much as possible. I think there is a long way to go. Still it is a long journey, so it is good that they have started.
Matt, Antarctica has a greenhouse, isolated but not enclosed. The only large-scale, enclosed project was Biosphere II. It was only partially successful. No one since has put that kind of money into a fully enclosed system.
I think we could simulate Martian regolith, but you are right that radiation from cosmic rays wouldn’t be possible to simulate, only easily handled alpha and beta particles to simulate solar radiation, as well as full spectrum sunlight. To me that is another argument in favor of building underground, it removes another variable, and therefore uncertainty from a Mars food production cycle.
Ioannis suggestion that we use modern farming practices that will require shipping seed to the colony makes little sense to me. A colony will need to use traditional farming methods and reserve seed for future harvests. Yes the yields may be lower, but they are sustainable.
My criteria would not be about minimums. It would be about resilience and ‘comfort’ in an ecological sense.what is a comfortable bank of o2 to have if a leak happens. What is the right cycle of mammals to plants to sustain a comfortable level of co2 and o2 in balance over time and to allow for any unforseen disease, crop failure, surprise multiple births, human visitors, ways to subset the group for offshoot camps. Ways to have internal quarantine for failover. Think of it like an internet with nutrient routing, atmosphere failover, data and seed backups, distributed agency so that different teams can assess critique and modify from a default working configuration for adapting to the needs of niche purposes or just to understand the full dimensions of comfort, identify and avoid single points of failure.
Ecology and compost life and death are cyclical and we take a lot of the alchemy of decay for granted on earth because it is large and has its own way of generating equilibrium or we have had enough space to ignore the damage where the ecology has been tilted out of whack towards dead zones.This means most of us and most of our agriculture are not sensitive to the nose of a fine compost, or the perfect recipe for resilient and adaptive circulation. I think we will find that we will need more species than we anticipate in order to provide living infrastructure for the species we find tasty or useful. Something like avoiding ecological vertigo from the ‘top’ of the food chain acrobatic troupe. =)
No one has mentioned an important player in space colonization: mouse/rat. In Asia, field mice are food for many people, probably Westerners find this kinda gross probably because they are somehow associated with NY mutant rats from some people point of views. But I think they coexist with us almost everywhere for several thousand years hence bringing them to Mars or on multi-generation starships is just matter of time, besides these little animals will give us free tunnels if we’re on Mars.
‘…besides these little animals will give us free tunnels if we’re on Mars.’
and a lot of gnawed wiring looms, just what you need in a dangerous environment.
hmmm… radiation…. rats… all we need is some char sui sauce… hang them up in the green house windows to cook a little… sort of radiation roasted…
If people are going to be carrying cows to Mars, then why not moose, caribou, and deer? Is life really worthwile without the ocassional moose steak? Just kidding. Or maybe not. Is it?
But at some point we must look at what is feasible, and what is redundant. Once Mars’ peopulation reaches a million or so people, then maybe large animals will be invited along on the trip. Until then insects, and shellfish, can supply all the vit B12 we need. Either that or we import it. 2 micro grams a person, a day isn’t that much. It’s 500,000 doses in a single kilogram, and 500,000,000 in a single ton.
As well, we won’t be going to Mars, let-a-lone establishing any sort of base there in the next 30 years, by which time I would expect bio-engineering to make some leaps forward. How about algae that tastes like strawberries?
And I would expect algae to make up the base of any diet of those furture martians. Why? be cause of the redundancy. They can grow several times what they need to eat, and if things fail it allows time to clean out the vats and restart before anyone starves. Heck, so long as they got good and water, they could retry growing algae several times before anyone starves to death. Now, if soil somehow gets contaiminated it might or might not be possible to restart their agriculture.
To add variety hydroponics could be used to grow a variety of side dishes to supplement the algae and crickets. Of course I would expect that to be redundant – after all, if we can send people to mars surely we can find a variety of ways to make algae taste good using hundreds of possible recipes.
I wonder if there’s a way to make algae taste like chocolate. Can we live without chocolate? Now that’s a definite no. No chocolate, then no mars anything, except mars bars.