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On mars with a limited greenhouse size we will feel like we are doing indoors farming in our rooms....
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Antius (or anyone), where did you get the values for CO2? I put the same values in at the NIST website and am getting a Cp of 761 J/kgK and Pr # of 0.78.
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I did a few heat transfer calculations to help answer this question.
I will calculate convective heat loss from a cylinder approximately at 30cm wide, 2m tall with a temperature of 36C in the Martian atmosphere. Wind speed = 10mph (4.5m/s). Density of Martian CO2 at -50°C and 0.81KPa is 0.44mol/m3 or 0.02kg/m3. Dynamic Viscosity is ~1x10-5pa.s. On this basis, the Reynolds number is:
Re=ρvL/μ
L is characteristic length, which is equal to 4 times cross-sectional area, divided by perimeter or 0.15m in this case. Reynolds is therefore 0.02x4.5x0.15/0.00001 = 1350.
Using the cylindrical cross-flow equation, Nusselt number can be calculated:
Nu = 0.193Re^0.618 x Pr^0.33
Prandtl, Pr=Cp.μ/k.
For CO2 under these conditions, k is 0.01W/m.K and Cp at 220K is 1960J/KgK. So Prandtl is 1.96. On this basis, Nusselt can be calculated to be 20.8.
The heat transfer coefficient, h= Nu.k/L. Which works out to be 1.4W/m2K.For a cyclindrical body with a surface area of ~1m2 and a temperature difference of 86K with the environment, heat loss rate can be calculated using Newton’s Law of Cooling:
Q=hA(T1-T2) = 1.4 x 1 x 86 = 120watts.
By contrast, radiation would lose 400watts of heat from the same body under the same conditions. So on the Martian surface, heat loss will be dominated by radiation and conduction. As a rough rule of thumb ‘the convection heat losses in the Martian atmosphere for any structure at room temperature, will be about 30% of the black body radiation heat loss rate’.
In a dust storm, with air velocity of 20m/s, the convective heat transfer coefficient increases roughly 2.5 times and thus reaches 75% of the black body radiation heat loss.
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This is how we combine greenhouse with housing for a colony to get a foothold on mars.
Simular Construction people below ground level with the cieling supporting the plants at a partial pressure while the habitat area could be higher.
This one shows how a house would possibly look inside but I would leave the above ground structure out of it until further along with colony building.
Of course the greenhouse door would have an airlock..
Possible harvest
We can dream or we can plan for what might be....
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Why have they put the solar panels inside? Clear glazing will still absorb some incoming radiation and reflect some more, reducing the incident radiation on the panels.
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Why have they put the solar panels inside? Clear glazing will still absorb some incoming radiation and reflect some more, reducing the incident radiation on the panels.
Very true. But no hail or snow. The high angle implies high latitude. At the equator you would pitch solar panels completely flat, 0° for maximum sunlight. At the pole you would pitch 90°, completely vertical to match latitude; base would have to rotate once per day to track the Sun. At high latitude you could cheat, produce more power in winter, less in summer. Set maximum to half-way between spring/autumnal equinox and winter solstice: latitude plus Earth's axial tilt / 2 = latitude + (23.4392811° / 2). These solar panels have a steep angle implying high latitude, so it should get snow in winter. Inside means no snow on solar panels, but you still need to brush snow off the dome.
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Looking closely at the upper right corner of the panels I can see that these are solar thermal hot water panels to which they are more protected by thermal cycle of freezing in the winter and might not need a heat exchanger as it would be water and not an antifreeze food grade in them.
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Given the topic of Indoor farming ...
As an unexpected reward for investigating various farm related topics on Google, I now receive a steady flow of farm related email advertising. Today's incoming included an item which seems (to me at least) to be potentially adaptable for Mars as either a sand shelter, or perhaps even a growing space, as shown on the company web site. In any case, I wrote the company inviting them to register in the forum for the purpose of collecting advice on how to adapt to Mars.
Begin Quotation:
Fabra Dome is a pioneer and a leader in the hoop barn industry. Fabra Dome is one of the oldest hoop barn providers in the United States.
End Quotation.
www.fabradome.com
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They look like big versions of what we call "polytunnels" in the UK.
The issue on Mars is pressurisation - which means the whole structure has to be able to withstand the pressure differential between inside (maybe not full Earth atmospheric pressure, but something close) and the outside which is 0.6% of Earth's atmospheric pressure .
Given the topic of Indoor farming ...
As an unexpected reward for investigating various farm related topics on Google, I now receive a steady flow of farm related email advertising. Today's incoming included an item which seems (to me at least) to be potentially adaptable for Mars as either a sand shelter, or perhaps even a growing space, as shown on the company web site. In any case, I wrote the company inviting them to register in the forum for the purpose of collecting advice on how to adapt to Mars.
Begin Quotation:
Fabra Dome is a pioneer and a leader in the hoop barn industry. Fabra Dome is one of the oldest hoop barn providers in the United States.
End Quotation.
www.fabradome.com
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Last edited by louis (2018-10-11 17:42:05)
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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There are a number of shelter builders in the US that make simular product out of a variety of materials for just as many different uses.
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Microbial manufacturing: Genetic engineering breakthrough for urban farming
They were exploring ways on microbial fermentation which create fertilizers, nutrients and non-synthetic pesticides for urban farms, in the form of small molecules.
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Here is an article about a gent in Hong Kong who is using shipping containers to grow crops. This model seems well suited for Mars. The dimensions are familiar to humans, and a complete package could be shipped to Mars in a collapsed form and reconstructed there.
https://www.yahoo.com/news/ap-photos-fo … 14267.html
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Here is an article about "regenerative farming" .... crop rotation is a concept known to humans for thousands of years.
It appears that with development of the scientific method, agricultural practice may have refined the concept. While the article at the link below is about outdoor farming on Earth, it should be adaptable to the indoor farming environment of Mars.
https://www.yahoo.com/huffpost/climate- … 00193.html
Over the past four years, Gentry has transformed two acres of trash-strewn dirt on Long Island’s southeast coast into a profitable organic farm by betting big on soil. Instead of pumping her crops with pesticides and petrochemical fertilizer, Gentry grows vetch, a hardy pea-like plant, and rye to cover the exposed soil between the rows of greens intended for harvest. She layers the soil with specially mined rock dust that replenishes minerals and pulls carbon from the air. And in the spring and summer, she uses a system of crop rotation ― shifting around where different crops are planted ― so that one plant’s nutrient needs don’t drain the soil. These practices are collectively known as regenerative farming.
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Here is another update to Louis' topic here ... on Mars, for the forseeable future, ** all ** farming will be indoor ...
Here is an ambitious effort on Earth that may provide insight into what is needed to reliably feed a population on Mars:
https://www.yahoo.com/news/massive-sust … 05253.html
Massive sustainable eco-farm harvests first crop
Thu, January 28, 2021 5:00 AM
This is a massive indoor eco-farm, and it has just harvested its first crop. These beefsteak tomatoes are chemical pesticide-free, non-GMO and grown with 100% rainwater. The 60-acre facility in Morehead, Kentucky is among the largest climate-controlled indoor farms in the U.S. Behind it is ag-tech startup AppHarvest and CEO Jonathan Webb. "It’s a totally different way of looking at agriculture.
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Orchids in orbit: Seeds tested in space
https://www.spacedaily.com/reports/Orch … e_999.html
Almost 30 grams of Nanjing orchid seeds were carried into space for breeding tests, accompanying three Chinese astronauts in China's Shenzhou XII manned spaceship, which was launched on Thursday. The seeds will be in space for three months.
A red orchid variety, Hongcao, features red buds and seedlings, a popular variant from Nanjing county of Fujian province.
It was selected and bred by the provincial testing center for forestry science and technology, which is affiliated with the Fujian Bureau of Forestry.
Since 2016, the center has been working with the flower research institute of the Academy of Agricultural Sciences of Yunnan province to carry out research on the breeding of Nanjing orchids in space.
About 100 grams of seeds were carried with the Tiangong II manned spacecraft via a Long March 5B large rocket and the Shenzhou XII, resulting in two sterile germinated strains.
Space breeding has been widely applied to innovations in the agricultural industry. Because of its higher probability of genetic variation, this method can cultivate new varieties of orchids with longer bloom cycles and better appearance and fragrance over ordinary ones.
For the experiment, researchers take advantage of the unique conditions of space, including cosmic radiation, the vacuum and microgravity to change the seeds' chromosome structure for laboratory tissue cultivation. Eventually the process generates new varieties.
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bump
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Renovated warehouse earmarked for large-scale vertical farm project
https://www.eadt.co.uk/news/business/on … et-8757704
Indoor vertical farm expanding to Muncie
https://www.wishtv.com/news/inside-indi … to-muncie/
A New Jersey start-up is using vertical farming to start selling fruit.
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Global Vertical Farming Market to Reach $5.8 Billion by 2026
https://finance.yahoo.com/news/global-v … 00644.html
Retro scifi is back?
Futuristic ‘automat’ dining thrived a century ago. Can covid revive it?
https://wapo.st/3jpzfUJ
Fungi could be used make soil from asteroids, as well as provide the structural backbone for homes built on Mars.
https://astronomy.com/news/2022/04/fung … es-on-mars
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In Sri Lanka, Organic Farming Went Catastrophically Wrong
https://news.slashdot.org/story/22/07/1 … ally-wrong
Faced with a deepening economic and humanitarian crisis, Sri Lanka called off an ill-conceived national experiment in organic agriculture this winter. From a report in March:
Sri Lankan President Gotabaya Rajapaksa promised in his 2019 election campaign to transition the country's farmers to organic agriculture over a period of 10 years. Last April, Rajapaksa's government made good on that promise, imposing a nationwide ban on the importation and use of synthetic fertilizers and pesticides and ordering the country's 2 million farmers to go organic.
The result was brutal and swift. Against claims that organic methods can produce comparable yields to conventional farming, domestic rice production fell 20 percent in just the first six months. Sri Lanka, long self-sufficient in rice production, has been forced to import $450 million worth of rice even as domestic prices for this staple of the national diet surged by around 50 percent. The ban also devastated the nation's tea crop, its primary export and source of foreign exchange.
By November 2021, with tea production falling, the government partially lifted its fertilizer ban on key export crops, including tea, rubber, and coconut. Faced with angry protests, soaring inflation, and the collapse of Sri Lanka's currency, the government finally suspended the policy for several key crops -- including tea, rubber, and coconut -- last month, although it continues for some others. The government is also offering $200 million to farmers as direct compensation and an additional $149 million in price subsidies to rice farmers who incurred losses. That hardly made up for the damage and suffering the ban produced. Farmers have widely criticized the payments for being massively insufficient and excluding many farmers, most notably tea producers, who offer one of the main sources of employment in rural Sri Lanka. The drop in tea production alone is estimated to result in economic losses of $425 million.
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This is an opportunity for thoughtful analysis of a leadership failure.
This is NOT a time for the kind of thoughtless emotional rants that so often show up in the NewMars forum.
It seems to me that the Mars enterprise requires a cooperative undertaking to build a viable, sustainable agriculture that does NOT depend upon imports.
It is not clear (to me for sure) why the Sri Lanka experiment failed, but it would seem there was a significant mismatch between the plan and the performance.
The education level of the work force has to have been a factor in the failure.
The communications required would seem to have been missing, but that is a detail I hope to see revealed in a thoughtful analysis.
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Who knew we were already thinking of a water poor condition that we will see for a time on Mars. These indoor farms can grow crops with 90% less water — and they’re transforming how we think about local produce
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This tiny flying robot could work as an artificial pollinator
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guide-to-solar-greenhouse-heaters from those that live off grid and mars is a long way away from a grid....
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Scientists Grow Plants in Lunar Soil
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Maybe the Robots will build your colony before humans get to Mars.
Will "Liquid CO2" Work you use it to drive electric generators Condense and you Boil, you can also use it hydroponics, your algae for your Aqua-Farm your Aquarium? Liquid CO2 the substance that can be found on Mars, both underground and on the surface. Perhaps set up your own Bio-domes and heat pumps and ecosystem within a Martian colony and part of a gravitational energy storage device.
'Liquid CO2 and Water'
https://www.youtube.com/watch?v=Rf7Ifg8fnRg
This Vertical Farm Gets the Price of Fresh Vegetables Down to $1 per Pound
https://vegnews.com/2023/8/vertical-far … bles-price
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South Pole Analogue Research
German Aerospace Center
https://www.youtube.com/watch?v=bZw0IPtCIeg
Testing vegetable cultivation for the Moon and Mars and 'DLR-Institut' research for the food production of the future in climatically unfavorable areas such as deserts and Arctic.
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