New Mars Forums

Official discussion forum of The Mars Society and MarsNews.com

You are not logged in.

Announcement

Announcement: As a reader of NewMars forum, we have opportunities for you to assist with technical discussions in several initiatives underway. NewMars needs volunteers with appropriate education, skills, talent, motivation and generosity of spirit as a highly valued member. Write to newmarsmember * gmail.com to tell us about your ability's to help contribute to NewMars and become a registered member.

#26 2020-01-09 18:28:52

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,122

Re: Greenhouse Architecture

RobertDyck wrote:

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?

Of course these are things which will make up the Mars first crew greenhouse in which we will use the Greenhouse as life support and food trying to see if Agriculture Study Mars Pure CO2 Greenhouse

Offline

#27 2020-06-26 20:14:28

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,122

Re: Greenhouse Architecture

mars-pyrimid-render-preview-featured_resize_md.jpg

Offline

#28 2020-07-06 12:19:00

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,154

Re: Greenhouse Architecture

Interesting article describing how the Soviets developed a citrus industry, eventually growing plants is areas where temperatures dropped as low as -30C.
https://www.lowtechmagazine.com/2020/04 … tures.html

Citrus trees are very sensitive to frost - a single frost can kill them.  The Soviets grew them in trenches and protected them from frost by covering the trenches with wooden boards and cloth during cold weather.

On Mars, of course, all greenhouses would need to be pressurised to at least 100mbar for human access, probably a bit more.  But the concept of a covered trench remains a good one from a heat management point of view.  Most plants can tolerate exposure to low temperature so long as they don't freeze.

Last edited by Calliban (2020-07-06 12:19:29)


Interested in space science, engineering and technology.

Offline

#29 2020-07-06 17:30:55

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,349

Re: Greenhouse Architecture

For Calliban re #28 ... thank you for this interesting report on Soviet success in growing citrus crops! 

The article (and the comments following) made the point that this method of cultivation was (and would be) very labor intensive.

However, what was done by Soviet citizens in times of stress could be done by robots on Mars.  The selected varieties (short with fruit just off the ground) seem (to me at least) attractive for the conditions on Mars. 

Of particular interest to Mars settlers ** might ** be the notion of a trench for a single (or perhaps a double) row of plants, in contrast to the more familiar concept for a green house of a half-cylinder of transparent material set at ground level.

(th)

Online

#30 2020-07-06 17:51:31

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,744
Website

Re: Greenhouse Architecture

Calliban wrote:

On Mars, of course, all greenhouses would need to be pressurised to at least 100mbar for human access, probably a bit more.

Based on data from Air Force experiments, posted by a Mars Society member on the original Mars Society forum in 1999, minimum pressure is 2.5 psi pure oxygen. Test subjects were test pilots, so men in their prime, healthy and strong. And after they went through high altitude training. This was before cockpit pressurization. Pilots could breath 2.0 psi pure oxygen, under ideal conditions they could remain conscious up to 30 minutes, but eventually even the strongest pilots would black out. Pilots could breathe 2.0 psi partial pressure oxygen if total pressure was higher, and remain conscious indefinitely. But to answer the question of minimum pressure for a human: 2.5 psi = 172 mbar.

Offline

#31 2020-07-06 17:58:00

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,744
Website

Re: Greenhouse Architecture

Carbon Dioxide In Greenhouses

For the majority of greenhouse crops, net photosynthesis increases as CO2 levels increase from 340–1,000 ppm (parts per million). Most crops show that for any given level of photosynthetically active radiation (PAR), increasing the CO2 level to 1,000 ppm will increase the photosynthesis by about 50% over ambient CO2 levels.

Note: 1,000 ppm at 1 atmosphere pressure (1,013.25 mbar) = 1,000 / 1,000,000 * 1,013.25 = 1.01325 mbar partial pressure.

Humans get a headache if exposed to CO2 at 2% for 1 hour or more. At 1 atmosphere, 2% = 20,000 ppm.

Offline

#32 2020-07-06 18:02:01

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,349

Re: Greenhouse Architecture

For RobertDyck re #30, and Calliban re #29

Is there a hybrid solution available here?   If the humans are wearing air mixture supply equipment that is working at the pressure they need for breathing, could the greenhouse be pressurized to a lower level?  I recall from earlier topics in this forum, research has established fairly definitively what pressure plants need. 

It might turn out (if someone can find the earlier work) that the minimum pressure needed by plants is greater than 100mbar. 

So, I think there are at least two questions to be answered ... the first is already given.  The second is what is the minimum pressure needed for plants on Mars? My recollection is that the study was sponsored by NASA and carried out by a university, using equipment designed to simulate the Mars atmosphere in an outer chamber, while the proposed (test) greenhouse was set up inside.

(th)

Online

#33 2020-07-06 18:23:13

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,122

Re: Greenhouse Architecture

You are possibly thinking of the support that some need for copd that is oxygenation for the blood to rise as they require an oxygen concentrator. It can be portable battery operated for inside a greenhouse structure. Use a partial helmet to satisfy the pressure needs for the individual person.

Speaking of greenhouse I made a post for the Mu Hacienda with regards to it lack but plenty of conversation has take place.
we have many topics that can ad are mentioned in the first page for the registry to continue with and why not add in this one.

Offline

#34 2020-07-06 18:29:20

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,744
Website

Re: Greenhouse Architecture

The figure of 2.5 psi has 2 significant figures, so the metric conversion has to be rounded to 170 mbar. That's already with breathing apparatus with 100% oxygen, and after the human has gone through high altitude training. At 3.0 psi pure oxygen (206.84 mbar, round to 200 mbar) with breathing apparatus with 100% oxygen, no high altitude training required.

Guelph University found spinach could grow as low as 10 kPa (100 mbar) without affecting plant growth. The catch was lower pressure required more water. However, in a sealed greenhouse, the water would transpire through leaves to become humidity, which would condense on walls, drip down into collection trough to be channelled back into soil. So lower pressure caused water flow through the plant to speed up, but no net consumption.

So plants need at least 100 mbar. You could use robots or "Waldo" arms to work with plants, but human access requires at least 170 mbar, ideal 200 mbar. Or a pressure suit.
fcf907b8de6fa408eed6a661d9cf7fe4.gif

That's still a lot better than what NASA uses right now for their EMU suits. Because Shuttle and ISS operate at 1 atmosphere pressure, suits require higher pressure to reduce oxygen pre-breathe time before going through decompression. EMU uses 4.3 psi = 296.47 mbar, round to 300 mbar.

Offline

#35 2020-07-12 04:47:57

elderflower
Member
Registered: 2016-06-19
Posts: 1,262

Re: Greenhouse Architecture

Without buffer gas (on earth that is Nitrogen, on Mars it might be Nitrogen and Argon mixture) fire is a huge problem. Things burn in pure Oxygen very vigorously and are exceedingly difficult to extinguish.

Offline

#36 2020-12-15 23:04:28

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,122

Offline

#37 2020-12-16 16:08:37

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,154

Re: Greenhouse Architecture

Good find Spacenut.  Here is another article on the same topic.

https://www.lowtechmagazine.com/2015/12 … house.html

A slight variant on the concept would be to construct an array of pits, with simple, repeatable glass panel frame dome structures forming a transparent cap on top of the pit.  The cap would be anchored by cast basalt ropes to stakes driven into the walls and floor of the pit.  The walls would be planted with food plants, with light loving plants at the top and shade tolerant plants towards the bottom.  The pits would be connected by tunnels at depths of at least 5m.

Last edited by Calliban (2020-12-16 16:14:49)


Interested in space science, engineering and technology.

Offline

#38 2020-12-19 14:50:56

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,122

Re: Greenhouse Architecture

NASA guest scientist set to spend a year at DLR's EDEN ISS Antarctic greenhouse for the first time

https://www.dlr.de/content/en/articles/ … ogies.html

The EDEN ISS project is subjecting a futuristic model greenhouse of this kind to long-term testing in extreme Antarctic conditions. In the first extensive overwinter research campaign, the greenhouse produced a total of 268 kilograms of food in an area of just 12.5 square metres over the course of nine and a half months. This included 67 kilograms of cucumbers, 117 kilograms of lettuce and 50 kilograms of tomatoes. An initial greenhouse concept for future space missions has been developed using the results of this research.

https://www.awi.de/en/

https://www.dlr.de/content/en/institute … stems.html

Offline

#39 2021-01-21 04:51:34

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,154

Re: Greenhouse Architecture

Similar to previous suggestions for algae farming; how about growing plants in small floating barges, rather like floating plant pots, in transparent brine filled plastic pipes?  The pipe would weave across a patch of ground and would be connected at both ends to an underground facility.  At the beginning of each day, the pipe would be flooded with brine and the barges would be floated into the pipes with the assistance of brine flowing into the pipes from a header tank.  As sun down approaches, a sluice is opened at the other end of the pipe and the barges then reenter the underground facility, which will remain warm overnight.  The remaining brine will be drained out of the pipes to prevent freezing overnight.

All gardening and harvesting of the plants takes place in the underground facility over night, which is fully pressurised, shielded and insulated from cold by a thick layer of regolith.  The plants housed in their barges only enter the external pipe network when temperature sensors indicate that temperature within the pipe has risen above freezing.  Note: if large amounts of nuclear waste heat are available to be pumped through the pipe, then the barges could remain in the pipe for as long as photosynthetically available light was present - I.e. sunrise to sunset.

My initial thoughts are that the pipe would be ETFE or polyethylene, with steel or cast basalt fibre ribbing to provide tensile strength against internal pressure.  The floating plant pots would probably be polyethylene.

There would be two brine tanks within the underground facility.  One header tank that feeds the pipe and carries the barges back into the pipe; and a sump tank, into which the brine drains at the end of each day.  An electric pump is used to pump water from the sump tank into the header tank.  If the tanks are large enough, then this can make use of direct solar electric power during the day, or any excess power from the Mars base.  In this way, farms can absorb intermittent electrical energy, as the header tank acts as a gravity store.

An added benefit to growing plants in floating capsule pipelines, is the potential for water purification.  The brine in the pipes will experience substantial evapouration during peak sunlight hours.  By maintaining a steady air flow through the pipe, moist air can be extracted from the pipe and water drawn off by passing it over a cold surface.  The plants themselves do not come into direct contact with the water in the pipe.  So it can be waste water or hypersaturated brine.  The production of fresh water could be an important side benefit of pipeline farming.

Other significant benefits are that humans work exclusively underground and do not need to take cosmic ray dose by venturing into a greenhouse.  Watering the plants is probably unnecessary, as condensation on the top of the pipe woukd drip feed the barges with a steady supply of water.  The pipe is also far more compact than a greenhouse that requires human access - my initial thoughts are that it would be about 1' (30cm) in diameter, with the floating barges being perhaps 28cm in diameter.  The actual amount of brine needed to floating the barges would therefore be a small fraction of the total volume of the pipe.  By storing the barges underground over night, we do not need to worry about heating a greenhouse overnight.

Possible complications of a trailing pipe: (1) The radius of curvature cannot be too high, or the barges will jam within the pipe; (2) A leak could occur anywhere along a long pipe- single point failure.  The resulting pressure drop may well freeze the pipe; (3) If the pipe freezes with water in it, the resulting expansion would probably destroy the pipe; (4) Abrasion between the pipe and barges is a problem that needs to be accounted for in design; (5) If the pipe gets dirty of experiences algae growth on its inner surfaces, then we need some way of cleaning it; (6) As we are storing the barges in a pond in the underground facility overnight, the area of the underground pond would need to be substantial.  Also, the daily movement of the barges from underground facility, to pipeline and then back again, implies a substantial amount of handling.  The operation would need to be designed to minimise human labour input.

Last edited by Calliban (2021-01-21 05:32:47)


Interested in space science, engineering and technology.

Offline

#40 2021-01-21 07:35:20

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,349

Re: Greenhouse Architecture

For Calliban re #39

Bravo!
Tour de Force! 

SearchTerm:Pipe Greenhouse concept Calliban http://newmars.com/forums/viewtopic.php … 80#p176080
SearchTerm:Greenhouse Pipe variation

(th)

Online

#42 2021-01-22 03:25:16

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,154

Re: Greenhouse Architecture

Yes.  A slightly different proposal is being made here.  Whereas microalgae could be grown in thin 3D printed panels, other crops require more space and soil to grow.  The problem is that pressurised greenhouses are likely to be expensive to build and farming them requires that humans take substantial surface dose from cosmic rays.  They are also likely to require heating to prevent freezing during the Martian night.  The solution is to grow plants in floating tubs which float in transparent pipes on the Martian surface.  The tubes can be quite compact compared to any greenhouse, as human attendance is not required. 

I am prepared to make a prediction about Mars agriculture.  If it turns out that microalgae are cheap to grow in 3d printed panels, then the first application will probably be animal fodder.  Meat may end up being cheap on Mars.  Wheat and other grain crops will be expensive, as they will be difficult to grow on Mars.  Microalgae will be cheap and Martians will find all sorts of novel ways of combining and incorporating them into processed foods.  Long live the Mars Congressional Republic!

Last edited by Calliban (2021-01-22 03:28:14)


Interested in space science, engineering and technology.

Offline

#43 2021-01-22 06:59:26

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,349

Re: Greenhouse Architecture

For Calliban re #42

Thanks for expanding upon your vision ... Would you pressurize the tubes at all, or would they be operated at Mars ambient pressure?

RobertDyck has proposed a pressure of 1/2 Earth Sea Level (rounding for simplicity) and a mixture of gases such that Oxygen is maintained at 2.7 psi.

The greenhouse overnight docking pond would therefore (perhaps?) be operated at that pressure?  It doesn't have to be, of course.  Automation could handle interaction with the floating rafts if any is needed.

If you mentioned that aspect of your design, I missed it.

(th)

Online

#44 2021-01-22 17:42:44

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,744
Website

Re: Greenhouse Architecture

We could get more precise. For reasons previously explained: 2.7 psi oxygen + 3.5 psi nitrogen. Then add some argon. Easy to harvest is the same ratio of N2:Ar as Mars atmosphere, because then you don't have to separate argon from nitrogen. Viking 2 measured atmosphere in 1977; at that time it was 2.7% nitrogen, 1.6% argon. Each lander or rover sent in the 21st century has a similar but slightly different result. Let's use the Viking 2 result.
3.5 psi N2 x (1.6% ÷ 2.7%) = 2.074 psi argon.
So total 2.7 psi O2 + 3.5 psi N2 + 2.074 psi Argon = 8.274 psi total.
Human breath will convert some of that oxygen to CO2, but total pressure will remain the same. There will be some water vapour. But CO2 is measured in parts per million. On Earth outdoors CO2 is roughly 400 ppm = 0.04%. At sea level that's 0.587838 psi, round to 2 significant figures so 0.59 psi. Should we increase total pressure by that amount? Does it make any difference?

That's 56.3% Earth atmospheric pressure at sea level. Does that make any difference?

Offline

#45 2021-01-22 18:46:21

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,349

Re: Greenhouse Architecture

For RobertDyck ... thanks for adding the specific recommendations for human habitat on Mars to this topic.

Your post did not include a response to Calliban's recent suggestion.  May I inquire what you think of it (as you understand it in its current early form)?

With feedback, Calliban may be able to fine tune his concept, or perhaps enhance it with new insights.

At this point, the concept of moving plants (in this case algae) into the sunlight and back indoors at night seems reasonable. 

A variation on the theme would be to provide dwelling tunnels on either side of a valley so that the plant pods float to one destination in one of Calliban's light tunnels, while a similar set of plants are floating toward the other indoors facility.

This system would be taking advantage of natural sunlight without the complexity of mirrors to route sunlight into underground chambers.

(th)

Online

#46 2021-01-22 20:54:55

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,744
Website

Re: Greenhouse Architecture

A lot of options are possible. I'm sure Mars will have a lot of different configurations. The design proposed by Calliban would work. A couple details...

Instead of ETFE or polyethylene, I would recommend PCTFE. It can handle cold better; embrittlement temperature for PCTFE is 100°C colder than the south pole of Mars in winter. And PCTFE is the most impermeable to water or moisture. There are some polymers more impermeable to oxygen, but they all become brittle at -60°C or warmer. Mars night gets down to -80°C in summer. And PCTFE is highly resistant to UV degradation. ETFE is the premier polymer film for greenhouses on Earth, but it doesn't have to be pressurized, and doesn't have to withstand extremes of Mars. Besides, if you have the resources to make ETFE, then you can make PCTFE instead.

Atmosphere of Mars is so thin that any greenhouse or habitat will have very little heat loss to atmosphere. Most heat loss will be to the ground.

The pipes will require some sort of spectrally selective coating. NASA uses such a coating on windows for spacecraft and stations since Apollo. Mercury didn't have it, and astronauts developed cataracts later in life. The problem is UV in space. Earth's ozone layer completely blocks all UV-C and most UV-B. These are the higher frequency / higher energy forms of UV. A spectrally selective coating can block 98% of UV-C and B. This can be improved with UV absorbine dye, but that can also block some visible light. When applied to glass, the glass blocks some so it blocks 99% of UV-C and B.

It can also block about 40% of IR. This controls radiant heat loss. This can be tailored to reflect more long-wave IR from warm things like the floor and furniture, while allowing through more short-wave IR from extremely hot things like the surface of the Sun. Reflecting 10% to 20% of short-wave IR and 40% to 45% of long-wave IR has a net warming effect (traps heat in). Here's a chart that shows various window coatings. #5 is spectrally selective low-e glazing, developed from NASA's coating.
spectrally_selective.jpg
UV-C is 100-280 nm wavelength. UV-B is 280-315. UV-A is 315-400. This chart is in micrometers, so 0.3 to 0.4μm = 300 to 400nm.
Near IR is 0.75-1.4μm @ 3,591–1,797°C, short-wave IR is 1.4–3μm @ 1,797–693°C, mid-wave IR is 3–8μm @ 693–89°C, long-wave IR is 8–15μm @ 89 – −80°C.

Compare this to the solar spectrum. This chart shows yellow, which is light from Sun. Red is sunlight that reaches the surface of Earth, after absorption by Earth's atmosphere. Mars obviously doesn't have Earth's atmosphere, so compare yellow to the spectrally selective chart above. (click solar spectrum image for larger view)
220px-Solar_spectrum_en.svg.png

I also read an idea from one of the "Case for Mars" papers, from before the founding of the Mars Society. The idea was aluminized mylar curtain drawn across the ceiling of the greenhouse at night to trap in all radiant heat. Obviously opened during daylight. Some people have questioned whether that curtain is needed if we have the low-e coating. A detailed numerical heat flow analysis would answer that. Unfortunately I haven't learned how to do that.

My greenhouse design remains on the surface. Most heat loss will be to the ground, so that needs to be dealt with. A couple options: one is to build the structure on stilts or piles/piers, like houses in the arctic. The reason they do that in the arctic is to avoid heating the ground where there's permafrost. Melting the permafrost causes the house to sink into the ground. I doubt that's a concern on Mars, but would prevent direct contact with the cold ground. Another option is some sort of insulation under the floor: argon filled bubble wrap, styrofoam board, or other. Another option is a "basement", perhaps just a crawl space. The crawl space could be allowed to get cold, with insulation on the under side of the floor. Or some sort of styrofoam board skirt buried in the ground at the perimeter of the building. So ground directly under the building is separated from the rest of Mars. Allow dirt directly under the building to get warm, but separating that ground from the rest of Mars so it doesn't leak heat.

Or there's his idea of floating barges in pipes. Unique. Ok.

Offline

#47 2021-01-23 09:13:08

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,349

Re: Greenhouse Architecture

For RobertDyck and Calliban ....

It is encouraging (to me for sure) to see the two of you engaged in renewing this topic, and chipping away at the iceberg of unknowns that must be removed in time for Mars settlers to enjoy a reasonable chance of survival, let alone a rewarding and enjoyable life.

The question I'd like to toss out today arises from the circumstances of the Earth's plodding circuit of the Sun, and it's specific impact upon the region from which this post originates.  We "enjoyed" a 20 degree Fahrenheit morning here.  A few birds and a hardy squirrel were out for the morning ration of peanuts and raisins. In looking at the hibernating yard and garden plot, I reflected that these conditions are going to be normal on Mars.  Not much is growing here, that I can see.  The greenhouse structures each of you are designing need to provide thermal conditions which the plant life you've chosen to support will find encouraging. 

RobertDyck, you have specifically mentioned temperature (and control of temperature through passive techniques such as stilts and skirts).  Your ideas have the distinct advantage of a solid historical base of experience on Earth, from which their application on Mars seems (to me at least) a reasonable stretch.

For Calliban, I like your idea of moving plant pods and would like to see your ideas continue to evolve.  Those ideas are approaching Void's level of boldness, but of course with your steady hand on the reins, they have a good chance of proving themselves in practice.

(th)

Online

#48 2021-01-23 11:07:31

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,744
Website

Re: Greenhouse Architecture

Oops. I just noticed the "spectrally selective, low-e glazing" in the chart is not what I described. The chart shows transmittance, not reflectance. That means transmittance is lowest for near-IR and short-wave IR, more for long-wave IR. So this will have the effect of net cooling. That would be used for buildings built in southern American states, like southern California, Texas, or Florida. The idea is to reduce air conditioning rather than winter heating. Well, you understand the principles. Just choose a coating for Mars that favours heating, not cooling.

Offline

#49 2021-01-24 07:10:03

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,154

Re: Greenhouse Architecture

RobertDyck wrote:

I also read an idea from one of the "Case for Mars" papers, from before the founding of the Mars Society. The idea was aluminized mylar curtain drawn across the ceiling of the greenhouse at night to trap in all radiant heat. Obviously opened during daylight. Some people have questioned whether that curtain is needed if we have the low-e coating. A detailed numerical heat flow analysis would answer that. Unfortunately I haven't learned how to do that.

I have some background with heat transfer calculations.  I will put together a spreadsheet sometime this week.


Interested in space science, engineering and technology.

Offline

#50 2021-01-25 04:47:36

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,154

Re: Greenhouse Architecture

This link provides estimates of thermal conductivity and specific heat of Martian surface regolith.
https://www.lpi.usra.edu/meetings/lpsc2009/pdf/1125.pdf

Specific heat is fairly typical for dry rock.  The thermal conductivity is quite low, presumably because the surface regolith is dry, loose and under near vacuum conditions.  It is therefore quite a good insulator by Earth standards.

I am going to start work on the spreadsheet today.  I am going to look at different scenarios in terms of insolation and insulation.  But early indications suggest that loose, dry regolith is a good insulator in itself.

Last edited by Calliban (2021-01-25 04:49:46)


Interested in space science, engineering and technology.

Offline

Board footer

Powered by FluxBB