Colonising Mars and a meme I found

[Cassel]

16 hours ago, DerekL1963 said:

The mobile need not be theoretically perpetuum - the rate it runs down is directly proportional to the rate energy and raw materials are extracted from the system. 
 

I do not think we understand each other. Physics claims that it is impossible to create a machine that produces more energy than it has received in the form of fuel. Biology is also physics only it is physics of living organisms and so this experiment with the biosphere failed, because scientists expected that a closed system would generate more energy than it receives.

Imagine that you have a water pump, which pumps water circulating in a circle. Even if you connect the turbine to this water stream, which will drive the generator and give energy to the pump, this system will not work anyway. Closed system like that can not work and, for example, power up your laptop on which you will research something.

You need solar panels or a coal mine to power your laptop and water pump.

From a self-sufficient base on Mars (or any another planet) you expect something like above. A closed system, which is supposed to provide energy in the form of food, for example to supply your heart so that it can pump blood over and over again in circle. The fact that your heart does some work does not return anything to this closed system. From closed system perspective this is a waste of energy, a leak or whatever you call it.

Another problem with growing food are the elements, minerals, material from which the plant builds its cells. This also has to be delivered to this system, no matter if it is hydroponics or not, you need this in huge amounts. I suspect that even the Earth does not create a perfect closed system, only the fact that it is huge and many processes occur at the same time does not allow us to examine it.

Each plant is made up of about 50 elements, how on Mars do you plan to find and mine them in quantities suitable for the production of for example 45 kg of rice a day?
@magnemoe wrote that the problem on Mars will be copper needed for some tech, and what about those 50 elements required for the production of plants? This will not be a problem?

[Green Baron]

Who brought that self propelling machine up ? I would say we all here are aware that a greenhouse needs energy from outside as well as a constant supply of nutrients or an initial charge that lasts so far or a connection to a machinery that recycles the waste that was produced in the the process of digestion of its products or, most probably, a combination of those.

Or aren't we ;-) ?

Edit: oh, i see. There is a misinterpretation here:

@DerekL1963 wrote: "The ability to be self sufficient in manufacturing underlies the solution to all problems."

That means, if i am not mistaken, that for a colony to function independently from earth, it must be able to produce and maintain everything it needs on its own. Of course (unnecessary to mention) in the given physical limits.

Hope i am not too impertinent with pointing that out, and ready to be corrected if i misunderstood.

Edited October 4, 2018 by Green Baron

[tater]

49 minutes ago, Green Baron said:

@DerekL1963 wrote: "The ability to be self sufficient in manufacturing underlies the solution to all problems."

That means, if i am not mistaken, that for a colony to function independently from earth, it must be able to produce and maintain everything it needs on its own. Of course (unnecessary to mention) in the given physical limits.

This is exactly right (Derek, and your take on the meaning).

You can have colonies on Earth that might depend on trade for a certain level of lifestyle (say the American Colonies importing metals, tea, etc for a long time), but on Earth, the worst case situation is that the colonists continue to live, but are forced to live as the indigenous peoples do. On Mars (or anywhere else in space), such a failure of capability literally kills everyone. They don't miss having some luxury, they die. This is why any analogy to colonialism on Earth is patent nonsense.

A Mars colony, from its inception needs to be able to survive at least 1, or perhaps some multiple number of synods with zero resupply. That's just to be a decently safe outpost. To be a final "backup" for humanity, it needs the appropriate genetic diversity, AND they must be able to function indefinitely with no input from home.

[DAL59]

1 hour ago, Cassel said:

growing food are the elements, minerals, material from which the plant builds its cells. This also has to be delivered to this system, no matter if it is hydroponics or not, you need this in huge amounts. I suspect that even the Earth does not create a perfect closed system, only the fact that it is huge and many processes occur at the same time does not allow us to examine it.

Each plant is made up of about 50 elements, how on Mars do you plan to find and mine them in quantities suitable for the production of for example 45 kg of rice a day?
@magnemoe wrote that the problem on Mars will be copper needed for some tech, and what about those 50 elements required for the production of plants? This will not be a problem?

There are some chemicals on Mars, and there is plenty of metal in Mars' moons.

[KSK]

2 hours ago, DAL59 said:

There are some chemicals on Mars, and there is plenty of metal in Mars' moons.

Okay, I’m pulling these figures and other information from Wikipedia. I’m assuming that planetary geology and plant nutrition aren’t particularly emotive subjects, so this information is unlikely to be maliciously wrong or subject to edit wars. With that said, if anyone cares to provide alternative sources, then please do.

Plants require nine macronutrients (carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, sulphur, calcium and magnesium) and at least another eight micronutrients (iron, boron, chlorine, manganese, zinc, copper, molybdenum and nickel).

Plants are over 95% carbon, hydrogen, nitrogen and oxygen by mass. Micronutrients are present at around 0.02% or lower. So 45kg of rice would contain roughly 9g of the most prevalent micronutrients, assuming that my mental arithmetic isn’t letting me down. Some micronutrients are present at 1000x lower levels (0.1ppm vs 200ppm), so around 0.009g in 45kg of rice.

There is water on Mars. That takes care of our hydrogen requirements. Mars’ atmosphere contains carbon dioxide, so carbon and oxygen are available too. Martian soil contains, amongst other elements: magnesium, phosphorus, sulphur, chlorine, potassium, calcium, manganese, iron, nickel and zinc. All are available in reasonable quantities, that is the relevant minerals are present at around 1-10% by weight.

Soil in this context refers to unconsolidated particles below 10cm in size, including material that is fine enough to be transported by wind. In other words, stuff you can go and dig up relatively easily. Inasmuch as anything is ‘easy’ on Mars of course.

Where does that leave us? The most  obvious nutrient we still need to supply is nitrogen. Then we need to find some boron, copper and molybdenum to complete our set of micronutrients. We may need some other elements too but presumably only at micronutrient levels or lower.

Curiosity has found veins of boron containing minerals on Mars. Molybdenum and copper have been found in Martian meteorites.

Mars’s atmosphere contains about 1.5% nitrogen. That’s not going to be easy to exploit but it is there. Perhaps more usefully, Curiosity has found evidence for biologically useful nitrogen) that is, nitrates) on Mars.

TL: DR.  Most of the nutrients needed to support plants are available in Martian soil or air. Molybdenum and copper may be harder to find but both are apparently present. Both are also extremely useful industrial metals, so one might expect some effort being made to find workable sources of them for a Mars colony. Nitrogen may be a bottleneck depending on the quantities of nitrates that can be found, although it is also present in the Martian atmosphere.

Edit. I completely agree that food production is only one aspect of getting a Mars colony going. Having a working industrial base capable of supporting all other activities (including food production) will be the cornerstone of a self-sufficient Martian colony, assuming such a thing is possible. However, I personally find Martian agriculture to be an interesting concept and one that I’ve done a little reading around as research for my KSP fiction (in which my Kerbals have an extremely pressing need to be able to grow plants on Duna). 

Edited October 4, 2018 by KSK

[Cassel]

37 minutes ago, KSK said:

Okay, I’m pulling these figures and other information from Wikipedia. I’m assuming that planetary geology and plant nutrition aren’t particularly emotive subjects, so this information is unlikely to be maliciously wrong or subject to edit wars. With that said, if anyone cares to provide alternative sources, then please do.

Plants require nine macronutrients (carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, sulphur, calcium and magnesium) and at least another eight micronutrients (iron, boron, chlorine, manganese, zinc, copper, molybdenum and nickel).

 

The problem with the phrase "essential for plants" is that it is positioned by Google and it is difficult to find how many of elements is in plant cells.
I once read that there are about 50 elements, and that farmers are only using 16 for cultivation, 16 is enough to grow few generations, but in long run this may be causing slow degradation of subsequent generations of the plant. If you are talking about a self-sufficient colony on another planet, you can not count on someone sending new seeds of healthy plants?

And you forgot about selenium, it is also considered essential in some publications.

[DerekL1963]

4 hours ago, Cassel said:

I do not think we understand each other. Physics claims that it is impossible to create a machine that produces more energy than it has received in the form of fuel. Biology is also physics only it is physics of living organisms and so this experiment with the biosphere failed, because scientists expected that a closed system would generate more energy than it receives.

No, to be honest, the problem isn't that we don't understand each other.  The problem is that you're using scientific concepts with... let's be gentle and just say a less than complete understanding of the concepts.

What physics says about a machine is completely and utterly irrelevant.  Earth itself by your measure is a closed system - one that has functioned as a biosphere for aeons and has supported  agricultural societies for millennia.  It serves as existence proof that you have no idea what you're talking about.

And no, Biosphere 2 did not fail because they expected it to generate more energy than it receives.
 

39 minutes ago, KSK said:

TL: DR.  Most of the nutrients needed to support plants are available in Martian soil or air. Molybdenum and copper may be harder to find but both are apparently present. Both are also extremely useful industrial metals, so one might expect some effort being made to find workable sources of them for a Mars colony.

The elements are present - but it's an open question as to whether they are present in economically useful quantities in concentrations that are economically recoverable.  Creating a self sufficient colony is as much an economic (allocation of capacity) problem as it is a technological one.

[Cassel]

2 minutes ago, DerekL1963 said:

No, to be honest, the problem isn't that we don't understand each other.  The problem is that you're using scientific concepts with... let's be gentle and just say a less than complete understanding of the concepts.

What physics says about a machine is completely and utterly irrelevant.  Earth itself by your measure is a closed system - one that has functioned as a biosphere for aeons and has supported  agricultural societies for millennia.  It serves as existence proof that you have no idea what you're talking about.

As far as I know, there were several "great extinctions", so it was the reset of this biosphere.

After every extinction for a time there were more minerals and energy available than the living organisms used. Therefore, after great extinction, there is such a revival of vegetation, which gives access to development for animals, and after some time another reset is killing organisms and releasing minerals trapped in their bodies. Or I missed something? If you would implement great extinction in biosphere it would work a lot longer :-)

 

[Green Baron]

28 minutes ago, Cassel said:

As far as I know, there were several "great extinctions", so it was the reset of this biosphere.

The biosphere in itself is in constant exchange with cryo, atmo, hydro, lithosphere and energy from the sun (space). In modeling, for the sake of simplicity, some of the numerous processes can be regarded as being closed (adiabatic), but irl they are of course not.

Extinction events are simply abrupt changes in the rate of interaction between biosphere and the other spheres. Processes are disrupted or reconfigured by external or internal series of events and evolution needs some time to adapt. But that does not change the principle that energy and nutrients are needed for the biosphere to keep going.

The biosphere is not a closed system. Switch it off from cosmic energy supply and it freezes stiff.

Stop plate tectonics and the carbon cycle will be disrupted. Once all the carbon has been bound by corals and other skeletal organisms and these have died it'll become different to keep up the complexity. And the atmosphere will probably cool down to freezing temps as well (has been the case in earth history when strong weathering of mountain ranges bound much carbon).

And these are only two quick examples that went through my head. There are many many others, in all scales.

 

All not that easy to grasp, but understandable :-)

Edited October 4, 2018 by Green Baron
oops

[KSK]

1 hour ago, DerekL1963 said:

The elements are present - but it's an open question as to whether they are present in economically useful quantities in concentrations that are economically recoverable.  Creating a self sufficient colony is as much an economic (allocation of capacity) problem as it is a technological one.

Agreed. However I am encouraged by the quantities of minerals that seem to be there and that some of them are reported as being present in forms that I think are bioavailable. Hence Martian soil may not need a lot of processing and so be economically useful for agriculture. Whether Mars has industrially economic sources of those elements is a whole other question though, yes.

1 hour ago, Cassel said:

The problem with the phrase "essential for plants" is that it is positioned by Google and it is difficult to find how many of elements is in plant cells.
I once read that there are about 50 elements, and that farmers are only using 16 for cultivation, 16 is enough to grow few generations, but in long run this may be causing slow degradation of subsequent generations of the plant. If you are talking about a self-sufficient colony on another planet, you can not count on someone sending new seeds of healthy plants?

And you forgot about selenium, it is also considered essential in some publications.

Good point about selenium. I really don't know much about this other than what I've read, which is why I can be a bit pedantic about sources, and fessing up to the fact that I'm normally relying on a single source.

From a quick search though it seems that selenium is found as a trace element at Gale crater. Then again, so is lead. I don't know how that would affect a growing plant or, more importantly whether it would be sequestered in that plant and so get into the colony food chain.

Speaking as a chemist, 50 essential elements seems like quite a lot given that there are only 92 naturally ocurring elements and that quite a few of those are toxic, radioactive or chemically unreactive. But - like I said, I don't know much about this  - if you could find a reference for that longer list of plant nutrients, I'd be interested in reading it. From a bit of searching it seems that selenium can be beneficial to plants but there's a debate as to whether its essential. It does seem clear that there's quite a fine line between a beneficial Se concentration and.a toxic one for plants.

Speculatively, I'm wondering if some of the other 50 elements on your list are also 'beneficial but may not be essential'.

[kerbiloid]

7 hours ago, KSK said:

However I am encouraged by the quantities of minerals that seem to be there and that some of them are reported as being present in forms that I think are bioavailable. Hence Martian soil may not need a lot of processing and so be economically useful for agriculture.

The Martian "soil" (and they would better call it "weathering rind") is a sand&gravel full of toxins, with no humus (as there were no plants), with traces of useful minerals here and there.

It's absolutely useless for agriculture at least because:

• hydroponics doesn't require the sand (you should better make glass for the hydroponics from that sand);
• one should clean out all toxins (just to get the useless sand);
• the humus should be created from scratch from fast-growing plants (see algae), in a planetary scale.
• you should build a whole agricultural machines industry for you plowland, while you should anyway start from hydroponics which doesn't require them
• those tiny amounts of useful microelements can be much easier delivered from Earth unless the Earth became Venus, or you terraform the whole Mars.

7 hours ago, KSK said:

Whether Mars has industrially economic sources of those elements is a whole other question though, yes.

The question is even not about economics.
If you need 1000 t of equipment to produce 2000 t of product, it's easier to import 2000 t of product.

7 hours ago, KSK said:

selenium is found as a trace element at Gale crater

So, they should have 1000 t of equipment there, 1000 t of equipment here, a whole plant in every crater to dig out such traces.
Like on Earth, but on Earth such local plants are just minor tentacles of the whole existing industry having an infinite pool of air and water, under normal pressure, in comfortable temperature, and with no cosmic radiation.

***

Biosphere-2 failed because a stable biosphere couldn't be scaled down such easily.
Exact technical reasons do not play a great role here, because Earth geological and climatic conditions have changed many times while the life exists.
So, that "biosphere" was not enough complex to withstand the changes and neutralize them by changing itself.
It was designed as a static system, while a stable biosphere is by definition dynamic.

Edited October 5, 2018 by kerbiloid

[YNM]

10 hours ago, Cassel said:

If you would implement great extinction in biosphere it would work a lot longer :-)

who to say the cycle in a biosphere has to be short ? we even arise only after a long time.

 

 

 

Anyway, all this cycle aside, yes in general we need a lot of stuff to be continuously sent there for a long, long time. But the idea of living stably on Mars, that's not a bad idea.

Not as bad as killing half the population so the other half can live a bit longer. (though it depends on how desperate you are)

[DerekL1963]

1 hour ago, kerbiloid said:

If you need 1000 t of equipment to produce 2000 t of product, it's easier to import 2000 t of product.

Only if you completely use up the 1000t of equipment in the process - which would be pretty weird and...  and well pretty much impossible to do other than intentionally.
 

1 hour ago, kerbiloid said:

Biosphere-2 failed because a stable biosphere couldn't be scaled down such easily.

Biosphere-2 failed for any number of reasons, none of which have anything to do with scaling.  Because of flaws in the concept, design, and implementation it never functioned to the point where it could serve as a test of scalability.

[KSK]

@kerbiloid. 

I am clearly wasting my time here.

I try to have a constructive discussion based on available facts, an acknowledgement of where I'm getting those facts from and an acknowledgement of potential problems and/or questions to which I don't have an answer.

In return I receive a dismissive reply based on exaggeration, numbers presented without justification and which is apparently ignoring the points I've made. For example, I describe a soil (with a definition of what I mean by soil) in which a large number of agriculturally relevant elements are present at anywhere between 1 and 10% by weight. You respond by describing it as a 'sand / gravel with traces of useful minerals here and there'. Those two descriptions are not consistent.

It's possible that I'm not explaining myself very well. It's also possible that I'm not fully understanding your reply. However, given the hostile and dismissive tone of that reply, I have no further interest in taking the time to contribute to this discussion.

Good day. I can't honestly say that this has been a pleasure, so I feel no need to thank you for our 'discussion.'

[Cassel]

11 hours ago, KSK said:

Plants are over 95% carbon, hydrogen, nitrogen and oxygen by mass. Micronutrients are present at around 0.02% or lower. So 45kg of rice would contain roughly 9g of the most prevalent micronutrients, assuming that my mental arithmetic isn’t letting me down. Some micronutrients are present at 1000x lower levels (0.1ppm vs 200ppm), so around 0.009g in 45kg of rice.

Now I have looked more closely at your calculations and you count only for 45kg of grain, what is intended for human consumption, but to grow 45kg of rice you must provide raw materials to build the whole plant.
Entire plant weights about 80g of which about 8g is grain, so you must have about 450kg of "green waste" to produce 45kg of grain.

If there is any animal that can eat the green part of the plant, we have a source of food for meat farming :-)

But 45kg is a daily requirement. One rice ripening cycle is optimistic 60 days (pessimistically 90 days, without hydroponics 120 days).
One 60 day cycle is 2700 kg of grains needed, which gives about 27t of plant weight every 60 days.
This means that every 60 days you need 540kg of micronutrients and 26.5t of carbon, hydrogen, oxygen and nitrogen.

[James Kerman]

I admire your research, @Cassel but I think rice is not the best crop due to the high water and volume requirements.

I have been reading about NASA's Controlled Ecological Life Support System (CELSS) and ESA's Micro-Ecological Life Support System Alternative (MELiSSA) and I think that Spirulina is a more attractive candidate as a food base.  Of course you need to augment this with food stuffs high in B12 and Omega 3 and the most likely candidates seem to be certain crickets, grasshoppers and grubs.  Any waste products can be converted into growth medium or even used as cellular feedstock for additive manufacturing.  Some plants can also be used to generate oxygen and as effective carbon scrubbers.

I agree with other members that food is one of a long line of products that would be required for a colonization effort but I feel it is the most urgent and persistent requirement for a colony or long term mission.

Edited October 5, 2018 by James Kerman

[DerekL1963]

50 minutes ago, Cassel said:

This means that every 60 days you need 540kg of micronutrients and 26.5t of carbon, hydrogen, oxygen and nitrogen.

It's almost as if you've never heard of composting.  Much of that "green waste" can be recovered and recycled.

[Cassel]

And that's not all. If we are talking about the very beginning of building a base for 100 people, then you would have to send a micronutrient supply for about 2 years. So 6.5t microelements and probably some carbon, oxygen, nitrogen ... 27t for one cycle, in 2 years we need about 12 cycles, so 328.5t.

Of course, sending such a quantity of raw materials does not make sense rather, we would send about 33t of rice.
But you still need a warehouse on Mars that will store these 6.5t microelements and almost 330t of other raw materials in case the machines that gather those resources on Mars will malfunction, to level that repairing them on the planet would be impossible. Of course, this magazine should be shielded from radiation, right?

9 minutes ago, DerekL1963 said:

It's almost as if you've never heard of composting.  Much of that "green waste" can be recovered and recycled.

In 60 days? I think that instead of composting better would be feeding animals for meat production.
 

17 minutes ago, James Kerman said:

I admire your research, @Cassel but I think rice is not the best crop due to the high water and volume requirements.

 

I started with rice because of @YNMgave some numbers I could make calculations. Regardless of what the plants will be, I would suggest on a solution that will give you the opportunity to grow a few species of plants, then you will need a tons of micronutrients and other raw materials necessary to produce plant cells.

Edited October 5, 2018 by Cassel

[James Kerman]

From Wikipedia:
 

Quote

Spirulina thrives at a pH around 8.5 and above, which will get more alkaline, and a temperature around 30 °C (86 °F). They are autotrophic, meaning that they are able to make their own food, and do not need a living energy or organic carbon source.

 

[Cassel]

42 minutes ago, James Kerman said:

From Wikipedia:
 

 

No thank you https://en.wikipedia.org/wiki/Spirulina_(dietary_supplement)#Quality-related_safety_and_toxicology

edit:
@DerekL1963

I found that White-tailed deer, Mallards and Common carp can feed on rice fields, so they could be better than composting, since compost also requires pressurized space.

Edited October 5, 2018 by Cassel

[kerbiloid]

3 hours ago, DerekL1963 said:

Only if you completely use up the 1000t of equipment in the process - which would be pretty weird and...  and well pretty much impossible to do other than intentionally.

Either a mineral deposit contains 10 t of resource, or 100 t, you anyway have to carry a full set of equipment. And it doesn't weight like a feather.

3 hours ago, DerekL1963 said:

Biosphere-2 failed for any number of reasons, none of which have anything to do with scaling.  Because of flaws in the concept, design, and implementation it never functioned to the point where it could serve as a test of scalability.

You can't build enough complex biosphere to stay adaptable to the external conditions changes keeping it below some reasonable size.
Because any creature has finite size, and any self-reproducing population has finite amount of units.
Those concrete and so on problems were just the particular case which killed that particular biosphere.

So, this was exactly a scalability problem.
It should be more complex and contain much bigger and numerous populations. Then it would neutralize any particular problems.

The only self-sustaining biosphere we know is planet-sized, btw. Why one should expect that a compatible one should fit just a building.

3 hours ago, KSK said:

I am clearly wasting my time here.

That's exactly what all of us have gathered here for, but I really can't remember when I had become your student.

Earlier (in other threads) I had brought the numbers at least twice, and was going to do this third time.
But I got ashamed and demotivated by more experienced Martian terraformers even before started doing this.
I'm always open to a constructive discussion with numbers, but I'm not a student and you're not a (my) professor. 
So, next time.

3 hours ago, Cassel said:

Entire plant weights about 80g of which about 8g is grain, so you must have about 450kg of "green waste" to produce 45kg of grain.

While a unicellular cell is a 100% grain itself.
And it grows much faster than a whole plant, so its productivity is incompatible.

3 hours ago, Cassel said:

f there is any animal that can eat the green part of the plant, we have a source of food for meat farming :-)

For bones and hair growing. Steak parts are just a small part of an animal body.

Though, of course the furs look great on spacesuits.

2 hours ago, DerekL1963 said:

It's almost as if you've never heard of composting. 

As you can see, I'd suggested the fast-growing algae for composting almost from the very beginning.

2 hours ago, DerekL1963 said:

Much of that "green waste" can be recovered and recycled.

All of that green algae waste can be recycled just from vat without waiting for their leaves and stems growing.

2 hours ago, Cassel said:

So 6.5t microelements and probably some carbon, oxygen, nitrogen ... 27t for one cycle, in 2 years we need about 12 cycles, so 328.5t.

Is this for open-air farming or for a colony inside a glass dome?
If the latter - how should 300 t of metals and semi-metals just disappear? And if they are in a heap, why not recycle them?

2 hours ago, Cassel said:

In 60 days?

You are right, that's too long. A compost could be prepared faster.

2 hours ago, Cassel said:

I think that instead of composting better would be feeding animals for meat production.

Not everything green can be fed to the animals. And anyway compost is better.

2 hours ago, Cassel said:

White-tailed deer, Mallards and Common carp can feed on rice fields

Don't forget about piranhas, they can utilize the inedible animal parts.

2 hours ago, Cassel said:

No thank you https://en.wikipedia.org/wiki/Spirulina_(dietary_supplement)#Quality-related_safety_and_toxicology

(Missed this).
That's exactly why I suggest the fast-growing algae just as a source of compost.

Edited October 5, 2018 by kerbiloid

[Green Baron]

Earth's biosphere is NOT "self-sustained".

And a certain organism called human must use up resources like land, water, raw materials, ... in order to make a limited living.

A greenhouse can NOT be run by just pooping into it or adding algae. Depending on what is being grown (tomatoes, peppers, cucumbers, ...), specialized nutrients must be added, lighting calibrated, waste disposed, gases mixed and added, others drawn out, constant water flown and moisture controlled, contamination by malevolent bacteria, fungi, etc. removed, etc. pp. And after some time one may have a fraction of what humans need to survive for a certain time.

Everyone (including me) could just start to read the publications, studies and data sets provided as links here and elsewhere on the danger of getting answers to at least some of the questions.

Running in circles, flinging numbers and formulae at each other, does not lead to new insights ;-)

Edited October 5, 2018 by Green Baron

[Cassel]

59 minutes ago, kerbiloid said:

While a unicellular cell is a 100% grain itself.
And it grows much faster than a whole plant, so its productivity is incompatible.

Is an experiment in which human for at least a year was fed ONLY such organisms?

Quote

For bones and hair growing. Steak parts are just a small part of an animal body.

Though, of course the furs look great on spacesuits.

Addiction to technology probably took people's mind. We learned how to use of practically every part of the animal to meet different needs centuries ago.
Not only steaks are edible. Bones can also be used, bone marrow is also a food from which you can prepare a soup https://en.wikipedia.org/wiki/Bone_marrow_(food)

You can use skins as clothes inside the base, unless it's a nudist base. Leather shoes and clothes are quite expensive on Earth and they are used all the time, so I do not see a problem to use them on Mars. Fur can be used as fur bedding, pretty expensive on Earth? Or used as private room decoration.
 

Quote

Not everything green can be fed to the animals. And anyway compost is better.

You are right, that's too long. A compost could be prepared faster.

Those parts of plants that can not be given to animals can be used for composting.
 

Quote

Is this for open-air farming or for a colony inside a glass doom?
If the latter - how should 300 t of metals and semi-metals just disappear? And if they are in a heap, why not recycle them?

We are talking about hydroponics farm.
 

 

Edited October 5, 2018 by Cassel

[kerbiloid]

20 minutes ago, Green Baron said:

Earth's biosphere is NOT "self-sustained".

Exactly. But it's the thing which we have closest to that. Any closed dome biospheres are just funny toys like those glass spheres with toys and snow inside.

20 minutes ago, Green Baron said:

A greenhouse can NOT be run by just pooping into it or adding algae. Depending on what is being grown, specialized nutrients must be added, lighting calibrated, waste disposed, gases mixed and added, others drawn out, constant water flown and moisture controlled, contamination by malevolent bacteria, fungi, etc. removed, etc. pp. And in the the you may have a fraction of what humans need to survive for a certain time.

And that's why trying to create a local biosphere looks a poor idea.
The greenhouses should be just an add-on to the industrial food production.

16 minutes ago, Cassel said:

Is an experiment in which human for at least a year was fed ONLY such organisms?

Is an experiment of rice, deer, and carps living in a glass dome at least for year?
The algae are just a compost. The protein cells are just animal or plant cells which you eat from the dead animal bodies. A cell of chicken not grown into a chicken, a unicellular chicken.

16 minutes ago, Cassel said:

Addiction to technology probably took people's mind. We learned how to use of practically every part of the animal to meet different needs centuries ago.

You definitely can't do anything on Mars without technology first.
Centuries ago (like now) we had soil, air, and water for free. Mars doesn't.

16 minutes ago, Cassel said:

Bones can also be used

Bones are apatite mixed with a horn-like protein. No need to grow such structures, and unlikely you can would eat them.

16 minutes ago, Cassel said:

You can use skins as clothes inside the base, unless it's a nudist base. Leather shoes and clothes are quite expensive on Earth and they are used all the time, so I do not see a problem to use them on Mars.

Why wear furs and leather in a glass dome?
And you need chemicals to process the skins.

Edited October 5, 2018 by kerbiloid

[Cassel]

1 hour ago, kerbiloid said:

Is an experiment of rice, deer, and carps living in a glass dome at least for year?

There is an experiment in which such animals and plant species lived side by side for thousands of years.
We have thousands of years of experience in animal husbandry, so on Mars we could also deal with deer breeding.
 

Quote

The algae are just a compost. The protein cells are just animal or plant cells which you eat from the dead animal bodies. A cell of chicken not grown into a chicken, a unicellular chicken.

Has anyone eaten it?

Quote

You definitely can't do anything on Mars without technology first.
Centuries ago (like now) we had soil, air, and water for free. Mars doesn't.

That is why we need to get back to what it was and learn to use organic products again as well as our ancestors did.

Quote

Bones are apatite mixed with a horn-like protein. No need to grow such structures, and unlikely you can would eat them.

But I would eat a soup that is made of bone marrow.
Heart, kidneys, liver, stomach, brain, even the intestines can be used.
The production of gelatin starts with the boiling of bones, skins, and hides.
What part of the animal would be wasted in your opinion?

It is not only about nutritional values, but also about the psyche of people who would live in such a base. Sometimes a change is needed and you have to eat something other than rice. At last, this is to be a home, not a labor camp or a prison.

Quote

Why wear furs and leather in a glass dome?
And you need chemicals to process the skins.

This is a good moment so you would give an alternative to these leather (ecological) shoes and clothes. How do you want to make them without using chemistry on Mars?

 

Edited October 5, 2018 by Cassel