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#1 2020-01-08 11:19:58

louis
Member
From: UK
Registered: 2008-03-24
Posts: 5,345

Food from electricity, air and water...

This looks interesting:

https://solarfoods.fi/#vision

A Finnish company claim to be able to make proteins using only electricity, air and water.

This could be an interesting technology for Mars, especially in the early stages when per capita expenditure is not a huge issue.

The cost I read elsewhere is reckoned to be about $5 per kg. If true, that is well within a Mars Mission budget.

Could be a useful emergency food supply if a crew get stranded on Mars after a launch failure...

Definitely worth keeping in mind.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#2 2020-01-08 12:43:34

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 230

Re: Food from electricity, air and water...

Interesting tech.  But we have already established that even producing molecules as simple as methane from water and CO2 is only about 5% efficient in its utilisation of electricity.  If the PV system is 20% efficient, then straight away we are down to a comparable efficiency to biomass fixation in plants - 1%.  The more complex the molecule, the more reaction steps and the lower the efficiency.  And proteins are a lot more complex than methane.

When one considers the complexity of many of the molecules synthesised by plants, it is remarkable that they are able to fix sunlight into biomass with efficiency of 1-2%.  Intermittent sunlight as well.  And they actually grow and reproduce while they do it, provided the correct environment exists.

Who knows?  Maybe synthetic protein will have an application if energy is really cheap on Mars.  I don't get why you would think that mass budget is less important for early missions.  The more mass that has to be poured into baseline systems, like power and food supply, the less available for actually useful equipment, that might allow the mission to yield scientific return.  There is only so much mass that can fit into a single heavy lift.  The more mass the more cost and the less available for other things.  Also, transit costs are likely to be lower later on, as scale economies and operational experience improve.  So if anything, inefficient options will be more tolerable later on.  But why would they be tolerable at all?  Just because someone finds them aesthetically pleasing?

Last edited by Calliban (2020-01-08 12:45:34)


Interested in space science, engineering and technology.

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#3 2020-01-08 13:25:36

louis
Member
From: UK
Registered: 2008-03-24
Posts: 5,345

Re: Food from electricity, air and water...

Well I said "early stages"...I guess thinking of a population up to 10,000 or so perhaps.

I would expect PV systems to be manufactured on Mars early on. Although PV manufacture is hi-tech it is reasonably straightforward and can be highly automated. We can import the manufacturing equipment to begin with. I would give this high priority after water mining and rocket fuel production.

I am not sure about the manufacturing equipment involved in the artificial protein manufacture but if that can be highly automated that will be a big gain for the Mars settlement since labour shortage will be the key resource deficiency.


Calliban wrote:

Interesting tech.  But we have already established that even producing molecules as simple as methane from water and CO2 is only about 5% efficient in its utilisation of electricity.  If the PV system is 20% efficient, then straight away we are down to a comparable efficiency to biomass fixation in plants - 1%.  The more complex the molecule, the more reaction steps and the lower the efficiency.  And proteins are a lot more complex than methane.

When one considers the complexity of many of the molecules synthesised by plants, it is remarkable that they are able to fix sunlight into biomass with efficiency of 1-2%.  Intermittent sunlight as well.  And they actually grow and reproduce while they do it, provided the correct environment exists.

Who knows?  Maybe synthetic protein will have an application if energy is really cheap on Mars.  I don't get why you would think that mass budget is less important for early missions.  The more mass that has to be poured into baseline systems, like power and food supply, the less available for actually useful equipment, that might allow the mission to yield scientific return.  There is only so much mass that can fit into a single heavy lift.  The more mass the more cost and the less available for other things.  Also, transit costs are likely to be lower later on, as scale economies and operational experience improve.  So if anything, inefficient options will be more tolerable later on.  But why would they be tolerable at all?  Just because someone finds them aesthetically pleasing?


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#4 2020-01-08 13:36:31

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 5,862
Website

Re: Food from electricity, air and water...

Exactly how do they do it? I would like to see details.

In 1999, I posted an idea on the original Mars Society forum. I later reposted here (Chloroplast life support). The idea was originally life support for a space station. Photosynthesis converts CO2 + H2O into O2 and sugar. Great! Let's use that. I came up with the basic idea in grade 7 when Skylab first launched. Of course university level biochemistry tells us it's more complicated than what I learned in grade 7. I tried to power it with electricity, but that proved too difficult. Photosynthesis requires chloroplasts; how do you distribute electricity to every tiny chloroplast? To be technical, the electricity would have to be delivered to thylakoids within chloroplasts. It's far more practical just to use light. And duplicating the natural process is so difficult, it would be easier to harvest intact chloroplasts from leaves of a plant. Keeping isolated chloroplasts functional is tricky; would require sterile water in a plastic bag. And the water would require elevated CO2 with O2 actively removed. So use a semipermeable membrane for the plastic bag, which lets O2 pass through but not CO2 or water. And an aquarium pump to circulate water inside the bag, moving water across the inside surface to stimulate O2 transfer.

The source of electricity in space is solar power, so why use photovoltaic panels to convert light into electricity just to use LED lights to convert it back? Instead use a mirror to reflect sunlight through a window onto the bags. A spectrally selective coating would block UV so the chloroplasts do not degrade.

I got a document from a professor for a university lab experiment to isolate chloroplasts. Turns out the easiest plant from which to harvest chloroplasts is pea. Chloroplasts will polymerize sugar to form complex carbohydrates; if they come from leaves of a pea plant, the carbohydrate will be pea starch.

Great! So using nothing but CO2, water, sunlight, and a little electricity to run pumps and fans, this recycles O2 and produces starch as a byproduct. Human metabolism breaks down carbohydrates such as starch with O2 we breathe to turn them into CO2 and water. Photosynthesis does exactly the reverse. Keeping the system sealed means no leakage into space. And you don't have to process feces into nutrients, which is a slow and complex process involving a lot of heavy equipment. This is simple and light-weight.

To make the starch palatable, you could grow bread yeast on water/starch solution. I bought a bag of pea starch and tried it. With beer yeast it tastes terrible! Wine yeast is also bad. But with bread yeast, cooked in a microwave oven, the result has the flavour and aroma of freshly baked bread. I played with concentration and cooking time until the result had the consistency of pudding. To give it flavour, you have to grow the bread yeast for 3 days. At room temperature.

Yeast requires additional nutrients. Protein and DNA require nitrogen, DNA requires phosphate. "Yeast nutrient" sold by stores for home-brew beer and wine is actually diammonium phosphate. My experiments worked with 500ml dry starch, 2 litres water, 1/4 teaspoon yeast nutrient, and 1/8 teaspoon traditional bread yeast. Cooked it produces 2 litres of "pudding". If done on a space station, a yeast "mother" could be maintained similar to sour dough bread. So 1/4 teaspoon of powder shipped up from Earth becomes 2 litres of food? Pretty good.

That "pudding" is mostly starch, but also has protein, lipids, and the complete vitamin B complex. Except B12; that requires specialized microbes. There are known strains of bacteria that can be grown like yeast and produce vitamin B12. That's a little beyond my home kitchen experiment.

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#5 2020-01-08 14:23:13

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 5,862
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Re: Food from electricity, air and water...

I should add, university undergrad experiments to isolate chloroplasts produce chloroplasts that remain viable for about 20 minutes. To be useful, a bag of chloroplasts should remain functional for 6 months. That's a transit from Earth to Mars. You can increase CO2 the same way soda pop is carbonated: add CO2 under pressure to clean water, keep it pressurized for a few hours. A relative operated a soda machine, found it carbonated after 8 hours. Then add soda water to the bag of chloroplasts. Water would have to be filtered with reverse osmosis to ensure no living bacteria get in to eat the chloroplasts.

However, that probably still isn't enough. This would require genetically engineering a pea. The plasmid for each chloroplast is copied from one chromosome in the nucleus of a leaf cell. Chloroplast DNA is about 85% the genes of cynaobacteria. The recycling system for photorespiration in plants requires steps by mitochondria and peroxisom. Cyanobacteria are a single cell organism, self-contained. They don't require any help. Furthermore, cyanobacteria have 3 pathways to recycle 2PG. The recycling system in plants is just one of those pathways. Adding genes from cyanobacteria could not only ensure the entire recycling pathway is done within the chloroplast, but the other two pathways as well. With chloroplasts able to recycle 2PG entirely themselves, chloroplasts harvested from said plants could be used for life support.

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#6 2020-01-08 14:40:05

louis
Member
From: UK
Registered: 2008-03-24
Posts: 5,345

Re: Food from electricity, air and water...

From their blurb:

"If “science is real magic”, then it’s time to meet the magic powder of science. Solein is a unique single-cell protein born from an equally extraordinary bioprocess of electricity and air. Its fully natural fermentation process is similar to the production of yeast, resulting in the purest and most sustainable protein in the world."

Well sounds like you are on the right lines with yeast...assuming they really have got a successful process there....

I must admit I thought they were chemically putting something together...excuse my ignorance.


RobertDyck wrote:

Exactly how do they do it? I would like to see details.

In 1999, I posted an idea on the original Mars Society forum. I later reposted here (Chloroplast life support). The idea was originally life support for a space station. Photosynthesis converts CO2 + H2O into O2 and sugar. Great! Let's use that. I came up with the basic idea in grade 7 when Skylab first launched. Of course university level biochemistry tells us it's more complicated than what I learned in grade 7. I tried to power it with electricity, but that proved too difficult. Photosynthesis requires chloroplasts; how do you distribute electricity to every tiny chloroplast? To be technical, the electricity would have to be delivered to thylakoids within chloroplasts. It's far more practical just to use light. And duplicating the natural process is so difficult, it would be easier to harvest intact chloroplasts from leaves of a plant. Keeping isolated chloroplasts functional is tricky; would require sterile water in a plastic bag. And the water would require elevated CO2 with O2 actively removed. So use a semipermeable membrane for the plastic bag, which lets O2 pass through but not CO2 or water. And an aquarium pump to circulate water inside the bag, moving water across the inside surface to stimulate O2 transfer.

The source of electricity in space is solar power, so why use photovoltaic panels to convert light into electricity just to use LED lights to convert it back? Instead use a mirror to reflect sunlight through a window onto the bags. A spectrally selective coating would block UV so the chloroplasts do not degrade.

I got a document from a professor for a university lab experiment to isolate chloroplasts. Turns out the easiest plant from which to harvest chloroplasts is pea. Chloroplasts will polymerize sugar to form complex carbohydrates; if they come from leaves of a pea plant, the carbohydrate will be pea starch.

Great! So using nothing but CO2, water, sunlight, and a little electricity to run pumps and fans, this recycles O2 and produces starch as a byproduct. Human metabolism breaks down carbohydrates such as starch with O2 we breathe to turn them into CO2 and water. Photosynthesis does exactly the reverse. Keeping the system sealed means no leakage into space. And you don't have to process feces into nutrients, which is a slow and complex process involving a lot of heavy equipment. This is simple and light-weight.

To make the starch palatable, you could grow bread yeast on water/starch solution. I bought a bag of pea starch and tried it. With beer yeast it tastes terrible! Wine yeast is also bad. But with bread yeast, cooked in a microwave oven, the result has the flavour and aroma of freshly baked bread. I played with concentration and cooking time until the result had the consistency of pudding. To give it flavour, you have to grow the bread yeast for 3 days. At room temperature.

Yeast requires additional nutrients. Protein and DNA require nitrogen, DNA requires phosphate. "Yeast nutrient" sold by stores for home-brew beer and wine is actually diammonium phosphate. My experiments worked with 500ml dry starch, 2 litres water, 1/4 teaspoon yeast nutrient, and 1/8 teaspoon traditional bread yeast. Cooked it produces 2 litres of "pudding". If done on a space station, a yeast "mother" could be maintained similar to sour dough bread. So 1/4 teaspoon of powder shipped up from Earth becomes 2 litres of food? Pretty good.

That "pudding" is mostly starch, but also has protein, lipids, and the complete vitamin B complex. Except B12; that requires specialized microbes. There are known strains of bacteria that can be grown like yeast and produce vitamin B12. That's a little beyond my home kitchen experiment.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#7 2020-01-08 17:02:28

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 5,862
Website

Re: Food from electricity, air and water...

louis wrote:

From their blurb:

"If “science is real magic”, then it’s time to meet the magic powder of science. Solein is a unique single-cell protein born from an equally extraordinary bioprocess of electricity and air. Its fully natural fermentation process is similar to the production of yeast, resulting in the purest and most sustainable protein in the world."

Well sounds like you are on the right lines with yeast...assuming they really have got a successful process there....

I must admit I thought they were chemically putting something together...excuse my ignorance.

Whenever some says "magic" or "magic powder" or "secret proprietary", my immediate response is bullshit! Be very careful of unsubstantiated claims.

Realize all plants use photosynthesis. Basic chemical process is:
6 CO2 + 6 H2O → 6 O2 + C6H12O6

Starch is polymerized by taking one hydrogen atom (H) from one molecule, and one hydroxyl (OH) from the other, and connecting the open bonds together. Sugar is a carbon ring, this links carbon rings together. The "H" and "OH" join together to form water.

Cellulose is also polymerization of sugar. The chemical formula is exactly the same; the only difference is which "H" or "OH" are removed to link sugars together. Human and other animals have enzymes in muscle cells and most cells to break apart starch back into individual sugar molecules. Sugar can then be used as an energy source, as food. But the way cellulose links it's sugars together, that enzyme doesn't work. Furthermore, because of the way sugars are bonded in starch, the starch molecule coils into a tight balls, and can branch. Cellulose is a straight molecule, doesn't branch and stiff. Cellulose is used as structural material for grass and other plants.

Lignin is formed by ripping open the carbon rings. It's also a polymer, but with carbon rings ripped open, the enzymes that animals use for digestion certainly won't work. And Lignin tends to cross-bond, so instead of a single chain, it's a far larger, more complicated structure. Lignin is the basis of wood. Trees are mostly made of cellulose and lignin.

The reason I'm going on about this: notice all starch, cellulose, and lignin are made from sugar. And all sugar is made of CO2 and water. That means the vast majority of all plants comes from air and water. There's a little bit of other substances in plants, but very little. For example, chlorphyll is the primary photodye used by plants to convert sunlight into electric charge that powers photosynthesis. Chlorophyll is a cage molecule made of carbon with 4 nitrogen atoms in the centre holding a single magnesium atom. It has a tail of carbon with methyll groups (CH3). I could go on but the point is it's mostly carbon, hydrogen, oxygen, and nitrogen (CHON), which comes from air. There's only a single magnesium atom per molecule; that magnesium comes from soil.

So when this guy claims they produce protein from air, realize he's talking about growing something. The description claims "fully natural fermentation process is similar to the production of yeast". Un huh. That's really sounding like he's growing algae. Is this Spirulina?

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#8 2020-01-08 17:27:42

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 17,402

Re: Food from electricity, air and water...

The nature of mars is an energy deficit before we ever start when compared to earth of at a minimum 600wm^2 dust storm or not and whether we enclose an area or go under ground. Its that setup that makes the food growth isolated and protected from mars that is a must. All the remaining is just what will it take to become efficient with growth of the food for the energy input.

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#9 2020-01-08 17:51:49

louis
Member
From: UK
Registered: 2008-03-24
Posts: 5,345

Re: Food from electricity, air and water...

You have to look at the number of people.

For the early missions, you only need one refuelled Starship to get people back to Earth - each one could take 50 people. So once you have your rocket fuel manufacturing operation facility up and running, it doesn't need to be expanded for several missions. Meanwhile every 2 years you could be bringing in hundreds of tons of PV generation equipment, as well as chemical batteries.

My point is that there will be plenty of excess electricity being generated if you want to use that for this sort of food production process. I think one reason you might wish to is that it looks like it could be highly automated. The final product would not need harvesting or processing in the way many crops and foodstuff would. It could then be mixed into protein shakes, flour or other types of food.

SpaceNut wrote:

The nature of mars is an energy deficit before we ever start when compared to earth of at a minimum 600wm^2 dust storm or not and whether we enclose an area or go under ground. Its that setup that makes the food growth isolated and protected from mars that is a must. All the remaining is just what will it take to become efficient with growth of the food for the energy input.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#10 2020-01-08 18:19:37

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 17,402

Re: Food from electricity, air and water...

Lots of good information in this Farming and the geography of nutrient production for human use: a transdisciplinary analysis

The variety of crops and of livestock as well as fish biomes but not how much land or energy for each are required. Lest we forget we have hugh biomes of forest and oceans with which we would not live with as well.

So data from FOOD, LAND, POPULATION and the U.S. ECONOMY

At least 1.2 acres per person is required in order to maintain current American plus Currently the 400 gallons of oil equivalents expended to feed each American ...

Its actually more when we include the other resources which make these other food possible along with the breathable air and materials we take for granted.

Lets call it 2 acres and that converts to 8093.71 m^2 for just 1 person....or 90 meters on a side...
https://www.metric-conversions.org/area … meters.htm

So now what is the energy that we need for solar light...

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#11 2020-01-08 19:57:14

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 5,862
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Re: Food from electricity, air and water...

SpaceNut wrote:

So now what is the energy that we need for solar light...

Hard to estimate. I have posted many times the need for ambient light greenhouses. It's the only way to recycle air and water in case of complete power failure. And this can greatly reduce energy consumption by using sunlight to produce food. Yes, we will need artificial light during dust storms. That energy can be used for industrial purposes normally, but all mining/refining/manufacturing will shut down during dust storms, power directed to greenhouses.

Most vegetables grow in partial shade on Earth. These can grow equally well in a Mars greenhouse. Mirrors can be used to enhance light for crops that require full sun. Full sun means 6 to 8 hours of direct light without blockage each day. A base built near the equator, such as the frozen pack ice at 5°N latitude, would get close to 12 hours per day, but at aphelion it will get 36% as much light at top of atmosphere. But Earth's surface gets 1050 W/m² while top of atmosphere gets 1361 W/m². Based on Mars semi-major axis, it gets 43% as much sun top-of-atmosphere, but that means Mars surface gets 55.83% as much sun. But again, at aphelion Mars surface gets 46.70%. Spectrally selective coating to block UV and control IR will pass 85% visible light, so that leaves vegetables with 57.69% at perihelion (closest to the sun), 47.46% at semi-major axis (middle of the year), and 39.7% at aphelion (furthest from the sun). So getting that 12 hours per day?

Carrots, radishes, beets and other root vegetables require at least half a day of sun to thrive, but again 12 hours per sol with 39.7% is fine. Perhaps some mirrors.

Tomatoes, cucumbers, peppers, peas, beans, corn, squash, and grain require full sun, so long-narrow greenhouses with mirrors along the side to double illumination.

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#12 2020-01-08 20:05:08

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 17,402

Re: Food from electricity, air and water...

For a well insulated for lose of thermal heat, well sealed from leaks of pressure and covered at night clear material it just meets the goal without enhancement from reflection if its stays warm enough inside.

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#13 2020-01-08 20:17:31

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 5,862
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Re: Food from electricity, air and water...

SpaceNut wrote:

For a well insulated for lose of thermal heat, well sealed from leaks of pressure and covered at night clear material it just meets the goal without enhancement from reflection if its stays warm enough inside.

One engineer friend in Canada, Janyce Wynter, was my age and went to the same high school. I don't remember her, but there were a lot of people in that school (website says 1,250), and she was one year older. Got to know her through the Mars Society. Unfortunately she passed away this August.

She told me there will be very little heat loss to atmosphere, because Mars atmosphere is so thin. Most heat loss will be to the ground, so we need to insulate the floor. I tried to calculate a heat flow spreadsheet, but didn't get it right.

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#14 2020-01-08 20:46:53

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 17,402

Re: Food from electricity, air and water...

Sorry to hear that...

Goggling mars greenhouse floor thermal insulation  for heat lose calculations reference materials
Will read more tomorrow for these links

https://www.greenhousemag.com/article/t … heat-loss/

Conductive heat loss = SA x U x TD
Infiltration heat loss = 0.02 x V x C x TD

http://www.marshome.org/files2/Hublitz2.pdf
ENGINEERING CONCEPTS FOR INFLATABLE MARS SURFACE GREENHOUSES

https://farm-energy.extension.org/wp-co … tation.pdf
Greenhouse Energy Efficiency (Heating)

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#15 2020-01-09 06:52:29

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 230

Re: Food from electricity, air and water...

RobertDyck wrote:
SpaceNut wrote:

For a well insulated for lose of thermal heat, well sealed from leaks of pressure and covered at night clear material it just meets the goal without enhancement from reflection if its stays warm enough inside.

One engineer friend in Canada, Janyce Wynter, was my age and went to the same high school. I don't remember her, but there were a lot of people in that school (website says 1,250), and she was one year older. Got to know her through the Mars Society. Unfortunately she passed away this August.

She told me there will be very little heat loss to atmosphere, because Mars atmosphere is so thin. Most heat loss will be to the ground, so we need to insulate the floor. I tried to calculate a heat flow spreadsheet, but didn't get it right.

Under high vacuum conditions, loose regolith is a much better insulator than any soil on Earth, about as good as Rockwool.  Take a look at Figures 1 and 2 in the link below.  I estimate a K of 0.025W/mK for lunar regolith at 300K.

https://ntrs.nasa.gov/archive/nasa/casi … 005262.pdf

This reference for Mars, gives a value of ~0.1W/mK.  Quite a good insulator.  And I bet that is applicable to soil containing moisture, ice and rocks, which all act as thermal bridges.

https://www.lpi.usra.edu/meetings/lpsc2009/pdf/1125.pdf

Mars is a dirty vacuum, but the compressibility of CO2 at Martian temperatures makes high vacuum less energy intensive on Mars than on Earth.  And thanks to low atmospheric pressure, vacuum is easy to contain and maintain on Mars.

Last edited by Calliban (2020-01-09 07:05:42)


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#16 2020-01-09 08:33:49

tahanson43206
Member
Registered: 2018-04-27
Posts: 1,645

Re: Food from electricity, air and water...

For SpaceNut re #14

Thanks for the MarsHome link.  This turned out to be a thesis by Inka Hublitz, carried out with support of NASA in (about) 1999/2000.

The paper is an example of what I've come to expect a PhD level thesis to look like.

The background material included in the paper is extensive and helpful to remind the reader of the conditions the deployment of inflatable greenhouse structures on Mars will have to contend with.

For Calliban re #15

It ** looks ** to me as though your presentation here might lead to an application of vacuum as a cost effective defense against heat loss?  Would you be willing to expand a bit upon that idea?  This is the first time I've run across that idea with respect to Mars.  The argument about the relative ease of making high vacuum on Mars certainly makes sense because the atmosphere is so close to a vacuum already.

For RobertDyck ... in posts elsewhere in the forum, I'm pretty sure I recall your pointing out the advantage of lifting living quarters (or other buildings) up on stilts in the arctic to reduce heat loss.  In thinking about Calliban's observations about vacuum and regolith, I'm wondering if anyone has already considered setting a Martian greenhouse on short stilts, and just allowing the already low air pressure to act as a heat shield?

Thinking back, I think the point you were making was about preventing transfer of heat from a building to permafrost to avoid melting leading to failure of the foundation, but if so, lifting a building above the regolith would (presumably) cut down on heat loss on Mars.

A skirt around the boundary of the structure would prevent flow of gases under the building, so convection losses would be reduced further.

As I understood Calliban's observation, the gas under the building could be mechanically reduced even further than the already low Martian pressure, to further reduce heat transfer by convection.

(th)

Last edited by tahanson43206 (2020-01-09 10:52:24)

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#17 2020-01-09 13:57:33

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 5,862
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Re: Food from electricity, air and water...

tahanson43206 wrote:

For RobertDyck ... in posts elsewhere in the forum, I'm pretty sure I recall your pointing out the advantage of lifting living quarters (or other buildings) up on stilts in the arctic to reduce heat loss.  In thinking about Calliban's observations about vacuum and regolith, I'm wondering if anyone has already considered setting a Martian greenhouse on short stilts, and just allowing the already low air pressure to act as a heat shield?

Thinking back, I think the point you were making was about preventing transfer of heat from a building to permafrost to avoid melting leading to failure of the foundation, but if so, lifting a building above the regolith would (presumably) cut down on heat loss on Mars.

The Mars Direct habitat is designed to do exactly that. However, habitats have been proposed that are dug into the ground so they can use regolith as radiation shielding. The mass of 2.4 metre thick regolith or more on the roof adds quite a structural load. That's more easily transferred to ground when the structure is built either on or in the ground. Furthermore, the sun is not always directly overhead. It's only overhead briefly at high noon on the spring or autumnal equinox at the equator. Any other time sunlight is at an angle, and solar radiation also comes from the Sun. Burying a habitat provides radiation shielding on all sides.

Besides, we don't know how wet permafrost is on Mars, or how deep. If the ice does not form any significant structural support, then melting the permafrost will cause the structure to sink or shift. If permafrost is composed of silt and ice with 50% ice, then melting will cause it to become liquid mud. If the ground is packed rocks and gravel with some ice between solid particles, then melting may not cause structural failure.

Here in southern Canada, we build houses with a full basement. The reason is to ensure the foundation is below the frost line. The frost line is the depth to which ground freezes. If wet ground freezes under your structure foundation, it could "heave", meaning lift the structure. When it does, it's always uneven. This causes the structure to twist and crack, breaking the structure. The solution is to dig so deep that the foundation is below any problem. In the arctic such as Nunavut or Alaska, the ground is frozen so deep that it's just not practical to dig below the frost line. If the frost line is hundreds of feet deep? However, if the permafrost is a thin layer and below that is bedrock, then you can dig down to bedrock. If the permafrost is thin and below that is packed rocks and gravel, then you could dig down to the rock/gravel layer.

If the ground looks like this, then be very careful. This is silt and ice, melting and slumping into the water body. Not sure where this is, but suspect it's the shore of Beaufort Sea.
ThawingPF_NPSCCresponse-303x202.jpg

If the ground looks like this, then you have a solid foundation. This is Devon Island in Canada's arctic, where FMARS is located. FMARS is in Haughton Crater, this is part of the coast.
d5e3f006-cf61-4387-8789-e5b210f2fc98.jpg

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#18 2020-01-09 14:44:36

tahanson43206
Member
Registered: 2018-04-27
Posts: 1,645

Re: Food from electricity, air and water...

For RobertDyck re #17 and topic in general

Thanks for this helpful review of insights for design of habitats in environments with potential (or actual) frost heaving problems.

The pictures you provided are particularly interesting.

Since this topic wandered into greenhouse heat loss, and Calliban suggested vacuum as a possible way to reduce it, I'm hoping you might be willing to consider that option.

I'm coming away from the discussion after your post, wondering if a "basement" under the greenhouse might be worth considering, whether it is evacuated entirely or just left with Mars ambient atmosphere, while the greenhouse itself would be partially pressurized.

Actually, (come to think of it) this topic has ** really ** drifted, because it started out with introduction of a potential new technology for creating useful protein directly from CO2 and H2O.

(th)

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#19 2020-01-09 15:04:32

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
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Re: Food from electricity, air and water...

tahanson43206 wrote:

Actually, (come to think of it) this topic has ** really ** drifted, because it started out with introduction of a potential new technology for creating useful protein directly from CO2 and H2O.

Would like to read how the company with the website from the Original Post proposes to do that. Are they just growing Spirulina? Need to answer that to get back on topic.

Or we could drift off into my chloroplast life support system. smile

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#20 2020-01-09 17:30:34

SpaceNut
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Posts: 17,402

Re: Food from electricity, air and water...

On earth the use of double pane windows are quite common to lower the energy lose through them and for those building an envelope home its a double shell built structure which has insulation in both inner and outer walls.

As RobertDyck indicated the levels of mars atmosphere is near a vaccum and as such the structure only loses the most of its internal energy through the foor contact to the ground.
In cold weather locations the basement can also be constructed as a double wall with thick insulation between them but when looking at Mars thats not all that easy as we are at a deficit before we start constucting for materials and for the energy that will be needed.

I think long before we will build we will bring and the simplest to bring is the vehicle for crew and cargo to convert to the chamber for food growth. If we want natural light we bring a top hatch lense unit to allow for the light to concentrate from its shape and then to spread out once on the inward side of the hatch lense assembly.
Once that is done then use a space foam insulation of a roll of good fiber insulation to wrap the capsule or cargo landers hull on the outside before burying it then connect to power, water supplies and plant the crop.
.

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#21 2020-01-09 17:49:49

RobertDyck
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From: Winnipeg, Canada
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Posts: 5,862
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Re: Food from electricity, air and water...

We can use PCTFE film for a greenhouse transported from Earth, such as part of a Mars Direct hab. But for a permanent settlement, we would use in-situ materials. The best greenhouse window material would be glass, made from white sand, soda, and lime. But it would be tempered to make it stronger and scratch resistant. Tempered glass is harder than sand grains of a dust storm, so won't craze. Greenhouse windows would be double pane, with each pane strong enough to hold in air pressure of the greenhouse. The gap would be pressurized more than Mars ambient, but less than greenhouse interior, so the gap could be monitored to detect a leak in either pane. The gap would be filled with argon gas to reduce heat loss. And the spectrally selective coating would be on the side of the glass inside the gap, so it won't scratch off from wear, either from outside or inside the greenhouse.

I've seen styrofoam placed under a basement floor. If the greenhouse has a concrete floor at grade level, you could place styrofoam beneath that. Could we use concrete? Can it be made pressure tight? Styrofoam can hold a lot of weight; limited, but with the weight of the floor spread out, it can survive. Foam bubbles at Mars ambient, because it's outside. So that's laboratory vacuum.

An inflated greenhouse for Mars Direct... would we use bubble wrap to insulate the floor? With firm plastic mesh flooring as a walking surface? Would we form the bubbles of the bubble wrap on-site on Mars using argon gas harvested from Mars atmosphere?

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