You are not logged in.
So you haven't read my recent post. Read Post #169 in "Greenhouse - hydroponics vs soil". Not the initial post from 4 1/2 years ago.
Again, the paper you cling to uses a mission in interplanetary space 400 out of 900 days. That's 4/9 of the time. A greenhouse on Mars is on Mars all the time. So that paper is not relevant.
Offline
Apples to Apples
So you haven't read my recent post.
Did, sure, and your (working) links.
"In the very near future, 2001 Mars Odyssey will be collecting the first Martian radiation environment data."
Kinda dusty, don't you think?
But why focus on these rather dated studies of human equivalent dose, instead of relevant crop irradiation studies, in a crop thread? Plants don't have human organs, you know. You mentioned that you lack a journal subscription, but many studies are available outside the paywall.
You should start by noting the actual Curiosity measurements of ionizing radiation; i.e., the paper I gave you, which you were fishing about for. It's "the only thing I would consider more authoritative than the papers I published [sic]." Read that and you'll have a reference point for evaluation of LEO crop irradiation studies.
Grays per day: it's the way to compare irradiated apples to apples.
Last edited by Lake Matthew Team - Cole (2017-01-18 20:03:25)
Offline
Studies by Guelph University show plants continue to grow in a hypobaric chamber down to 10 kPa pressure. Below that pressure the plants wilt, stop growing. The catch is they transpire water faster through their leaves, the lower the pressure the faster they transpire water. But in a sealed greenhouse, or their sealed hypobaric chamber, water transpired just condenses on walls and drips back into soil. So they don't need more water. They did one experiment where they dropped the pressure to Mars ambinent, held it for an hour, then restored pressure. The spinach wilted, but as soon as pressure was restored it perked back up and continued growing. This simulated a pressure failure on Mars. The researcher said he didn't have the courage to hold it at Mars ambient more than an hour.
Other tests by Guelph University show plants can handle much more radiation than humans. The issue is not plant exposure to radiation, but radiation exposure to workers in the greenhouse.
When I created this thread, it was intended to discuss which plants to grow, and how big the greenhouse has to be. Burying the greenhouse defeats the point. As I've said many times, an ambient light greenhouse is the only life support that works in complete power failure. On a space station in Earth orbit, if life support fails you can evacuate back to Earth in 20 minutes. On the Moon, you can evacuate back to Earth in 3 days. On Mars you can't evacuate, you have to wait for the planets to align then it's 6 month transit back. So bugging-out (to use a US military term) is not an option. If life support fails, you fix it or die. I have argued for multiple life support systems, with components that can be mixed-and-matched for a great number of options. But all life support has a single point of failure: power. An ambient light greenhouse is the only life support system that works in complete power loss. Not only do plants recycle oxygen, but water transpired through leaves condenses on cold windows to drip into collection troughs. So grey water from sewage processing is provided to plant roots, becoming potable water in collection troughs.
Last edited by RobertDyck (2017-01-10 15:24:59)
Offline
Other tests by Guelph University show plants can handle much more radiation than humans.
You could link the paper, or at least identify it. You could also acknowledge the findings of other relevant crop irradiation papers mentioned here; especially those good papers that happen to contradict your repeated assertions about ionizing radiation.
As you put it:
"If they're too long... skip to the last page."
Last edited by Lake Matthew Team - Cole (2017-01-10 22:05:51)
Offline
From Light to Dairy
Perfect Day
Lake Matthew Team - Cole wrote:I didn't attempt a Perfect Day / Thrive synthetic dairy plant in that scheme, because I can't quantify the plant's yield. I imagine it could boost calorie production significantly.
Perfect Day has kindly responded. With current tech, a 1,000-liter tank can produce ~300 liters of milk a week. Improvements are certainly possible, but that's about 15 million dairy calories per Mars year, right there. (Net calorie gain depending on the mix of crop/alternate sugars used in fermentation.)
One interesting alternate source of fermentation sugar is the Proterro photosynthetic sugar manufacturing system.
Requirements: The bioreactor uses a salt solution to maximize photosynthetic sugar production, and NaCl is of course a major ZLD end-product. Nutrients would come from ZLD and/or other fertilizer production facilities considered here and elsewhere. CO2 is abundant on Mars of course.
Production: Commercial yield target is 30x sugar cane yield, so a very compact reactor should be feasible. Envisioning direct integration of Proterro bioreactor onto Perfect Day fermenter, we can see a high-efficiency greenhouse path "from light to dairy". Conceivably all greenhouse sugar production might be transferred to the reactors, improving space utilization significantly.
Last edited by Lake Matthew Team - Cole (2017-01-14 12:09:56)
Offline
Lake Matthew Team - Cole.
I am going to directly borrow from your presented materials here, to Crops, Unconventional. I do like photolysis, but then again, biological photosynthesis, and fermentation, are used, and usable. I don't have a personal bias, I like whatever works best.
End
Offline
Offline
RobertDyck wrote:Other tests by Guelph University show plants can handle much more radiation than humans.
You could link the paper, or at least identify it.
You could also acknowledge the findings of other relevant crop irradiation papers mentioned here; especially those good papers that happen to contradict your repeated assertions about ionizing radiation.
As you put it:
"If they're too long... skip to the last page."
Incidentally, ongoing Guelph crop studies in the CESRF test against Mars environmental conditions, but not against ionizing radiation.
CES director Mike Dixon contributed to 2014 recommendations for the MELISSA higher plant compartment. The paper compares radiation environments on Mars and in LEO, on ISS:
"On the Moon and Mars, the radiation levels are high, especially due to heavy ions from galactic cosmic rays (GCR) and energetic protons from large solar particles events (SPE)... The accumulated dose on the Mars surface is 77 cGy per year for GCRs and 35 cGy per event for large SPEs... The International Space Station (ISS) is located at low Earth orbit: here the radiation consists of GCRs and SPEs, and protons and electrons when passing through the South Atlantic Anomaly (SAA) of the radiation belt. The radiation dose at the ISS can vary but has been measured to be on average 15 cGy per year for GCRs, 4.6 cGy per year for SAA and up to 10 cGy within a few days during an intense SPE [25]."
So by those averages Mars irradiation is roughly 4x ISS.
Last edited by Lake Matthew Team - Cole (2017-01-18 14:32:52)
Offline
I'm on break at work right now. It's a temporary job, ends at the end of this week.
In Greenhouse - hydroponics vs soil on January 3rd I quoted one of my own posts. Here it is again, these are the papers I cached on the local chapter website. This paper says on Elysium Planetia at low lying areas radiation is 22 cSv per year. That's half of ISS for the same year. Because solar radiation changes form solar minimum to solar maximum, you do have to compare on the same year.
I have a set of papers published by the team for the MARIE instrument on Mars Odyessey. I saved a copy on the local chapter website.
Radiation Climate Map
Mars Flux Paper
FC-Nara-Paper
PS-Nara-PaperThe first two papers have the same charts at the end. The charts give numbers. With total radiation in the range of 20 - 24 REM/year for any place we would want to go, results of 0.5 REM/year neutron is relatively small. US nuclear reactor workers are allowed 5 REM/year, and radiation from a reactor will be almost exclusively neutron.
There is a paper from Curiosity, but I don't have a current subscription to the journal Science.
Mars’ Surface Radiation Environment Measured with the Mars Science Laboratory’s Curiosity Rover
Offline
No, use Grays, not Sieverts. Crop thread.
And where are those Guelph plant irradiation tests you mentioned? You didn't identify the paper.
Last edited by Lake Matthew Team - Cole (2017-01-18 14:27:11)
Offline
All reported radiation is either in REM or Sieverts, not Grays. Apples and Oranges.
I got my information from Guelph at a workshop where a scientist from Guelph made a presentation. So directly from the primary investigator. It was the 5th Canadian Space Exploration Workshop, at Canadian Space Agency headquarters. I'll look for papers. For now there's this fluffy newspaper article...
Guelph scientist learning to grow crops on Mars
Offline
All reported radiation is either in REM or Sieverts, not Grays.
No, human studies use Sieverts because of weighting factors for human tissues. N/A in crop thread.
...there's this fluffy newspaper article...
No, that's a reprint of the news article I just gave you -- which notes that they don't test for radiation there.
I'll look for papers.
Look before posting assertions, and you'll save yourself some trouble.
Last edited by Lake Matthew Team - Cole (2017-01-18 20:06:01)
Offline
Look before posting assertions, and you'll save yourself some trouble.
Did you read the 4 papers from the MARIE team? That's the radiation instrument on the Mars Odyssey orbiter, the team worked at the Johnson Space Center, NASA.
I've said before, the paper you keep quoting refers to radiation in deep space, not the surface of Mars.
Offline
...the paper you keep quoting refers to radiation in deep space, not the surface of Mars.
No, you've just confused yourself there. It's the paper you wanted:
Mars' Surface Radiation Environment Measured with the Mars Science Laboratory's Curiosity Rover
Last edited by Lake Matthew Team - Cole (2017-01-18 21:30:19)
Offline
Hopefully this forums link will get us back on track with Farming, Gardening & Homesteading Country lifestyle, homesteading, blacksmithing and living off the grid
Now depending on farming techniques we now can start to formulate how large a garden needs to be to sustain a crew from as simple as a single person all the way to a colony of 100 or much much more....
Offline
Again a fantasy answer to the topic. From the Case of Mars' recipe, carbon monoxide and hydrogen can be converted to ethene. Ethene with supercritical carbon dioxide produces acrylic acid. Enantiopure hydration of acrylic acid makes enantiopure lactic acid. Can enantiopure calcium, sodium or potassium lactate be converted endergonically by grown micro-organisms in imitating animal gluconeogenesis to glucose? Can the energy source be ATP from ATP synthase?
Then the light dependent reactions of photosynthesis can be deployed and the produced ATPs are used for making glucose from lactate. No need for the micro-organisms to breathe Martian atmospheric carbon dioxide.
Last edited by knightdepaix (2017-03-04 09:32:46)
Offline
http://www.fao.org/docrep/018/ar117e/ar117e.pdf A Publication on Soil and Plant Testing as a basis for Fertilizer
Recommendations, prepared by Dr. A. Cottenie, as a result of this Expert Consultation, is printed as FAO Soils Bulletin 38/2.
Offline
Yes. We have some very productive cold ocean areas where Arctic cod are fished. This sounds like a good idea.
Question:
Why build an enclosure over these aquaculture pools? Why not just build them deep, let them freeze over, and cover the ice with perhaps a meter of bulldozed regolith to stop sublimation?
In the liquid pools underneath, the water pressure under the ice-plus-regolith should be high enough to scuba-dive safely on pure oxygen in an ordinary wet suit. Just rig some underwater sunlamps with some UV content, and grow all manner of aquatic crop plants and aquatic/water-breathing animals. Do some pools as fresh water, others salty. There is plenty of both (water-as-ice and evaporite salts) on Mars.
These aquaculture habitats would be a complement to some sort of pressure-dome buildings on the surface, where one could grow a variety of dry-land crops and raise dry-land animals (and live). I think a glassed-in mushroom shape is the best way to maximize local materials in construction, while providing a reliable pressure vessel to contain the atmosphere inside. These could be quite large, actually.
I have articles discussing engineering materials, requirements, and approaches for design analyses for both kinds of such habitats, plus some structural requirements derived for the classic clear domes of science fiction, all posted over at "exrocketman". Shorten your scroll-down search by using the keyword "Mars", and then you'll see those pretty quickly.
GW
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
Offline
When a month long, or even a year long dust storm hits, how much does it affect the surface temperature on Mars?
If the surface temperature drops too much for too long the greenhouse temperature will drop and it would trick any fruit trees into going dormant.
Offline
Obviously we need backups of some sort. I have argued for ambient light greenhouses. The reason is it's the only life support that does not require power. I could list several life support systems, and I argue we need them all. And ensure we can mix-and-match components to create an even greater number of combinations. We don't want the Apollo problem that the lithium hydroxide canister to scrub CO2 from cabin air was incompatible: round in the Command Module, square in the Lunar Module. A more modern example: the current system on ISS is based on electrolysis of water. It uses a regenerable sorbent to scrub CO2 from cabin air, and Sabatier reactor to combine all the hydrogen from electrolysis with half the CO2 from cabin air to produce water and methane. Water is recycled, methane dumped in space. Great! Wonderful! But currently the other half of CO2 is dumped in space. I want to add to that a direct CO2 electrolysis system (MOXIE) to remove oxygen from the CO2 currently dumped in space. That would recycle oxygen more tightly, and an alternate source of O2 means water electrolysis can be dialed down a bit, so that improves water recycling as well. The "mix-and-match" thing on Mars is that MOXIE can be used to produce oxygen from CO2 extracted from Mars atmosphere. It requires energy to extract CO2 from Mars atmosphere, but this is a useful backup mode.
The problem with all that is every life support system has a single point of failure: power. If power goes, you're dead. Recent research has shown a greenhouse large enough to produce all food that Mars settlers will need has a unique problem: it produces too much oxygen. But on Mars that's a good thing. Too much oxygen the system has surplus, that can be stored in case of emergency. And Mars has atmosphere, so you can always get more CO2. And plants can be watered with grey water from sewage processing. They transpire water through their leaves, that humidity will condense on cold windows dripping into collection troughs along the bottom of windows. That water tastes better than the best water filtration system NASA has ever made. So a greenhouse may not be stable indefinitely, but can provide both oxygen and water for several months at a time with absolutely no power.
A few individuals have pointed out a Mars dust storms. Obviously plants will require artificial light in a dust storm. But an ambient light greenhouse also means the greenhouse does not require power during normal operation. All power can be reserved for mining, refining, manufacturing. But during a dust storm, power will have to go to artificial light. And today LED lighting has been commercialized. Last time I bought light bulbs, I couldn't find compact florescent. The light beside my front door has 2 "chandelier" bulbs. Incondescent bulbs consume 40 watts each, the light fixture requires 2 bulbs. Compact florescent consumes 9 watts, but the new LED bulbs take 4.5 watts each. Very energy efficient. Sufficient light for the greenhouses will mean reduced power for mining, refining, manufacturing. In fact you would halt all mining and refining during the dust storm.
NASA JPL: NASA Mars Orbiters Reveal Seasonal Dust Storm Pattern
Dust lofted by Martian winds links directly to atmospheric temperature: The dust absorbs sunlight, so the sun heats dusty air more than clear air. In some cases, this can be dramatic, with a difference of more than 63 Fahrenheit degrees (35 Celsius degrees) between dusty air and clear air. This heating also affects the global wind distribution, which can produce downward motion that warms the air outside the dust-heated regions. Thus, temperature observations capture both direct and indirect effects of the dust storms on the atmosphere.
Offline
Research showed that a greenhouse large enough to produce all the food that Mars settlers will need produced too much oxygen?
What was the size of the greenhouse? What plants were used?
Offline
Are we chatting about photosynthesis?
https://www.ncbi.nlm.nih.gov/books/NBK22383/
That article summarizes that plant and bacteria can grow with acetate. On the other hand glyoxylate can be inputted into the glyoxylate cycle. So the tipping points are acetate/acetic acid and glyoxylate/glyoxylic acid.
The all chemical pathways to acetic acid and glyoxylic acid are already known or in industrial use for years. With reference to Martian conditions
a1) from the Case of Mars or other sources
2 moles of carbon dioxide + 4 hydrogen ---(empirical only) ---> 1 ethylene + 2 water
a2) https://en.wikipedia.org/wiki/Acetic_acid#Production
chemical company Showa Denko, which opened an ethylene oxidation plant in Ōita, Japan, in 1997, commercialised a cheaper single-stage conversion of ethylene to acetic acid.[36] The process is catalyzed by a palladium metal catalyst supported on a heteropoly acid such as silicotungstic acid. Similar process use the same metal catalyst on silicotungstic acid and silica:[37]
C2H4 + O2 ---(empirical only) ---> CH3CO2H
It is thought to be competitive with methanol carbonylation for smaller plants (100–250 kt/a), depending on the local price of ethylene. The approach will be based on utilizing a novel selective photocatalytic oxidation technology for the selective oxidation of ethylene and ethane to acetic acid. Unlike traditional oxidation catalysts, the selective oxidation process will use UV light to produce acetic acid at ambient temperatures and pressure.
b1) http://science.sciencemag.org/content/327/5963/313
Electrocatalysis by a copper complex helps reduce carbon dioxide to oxalic acid;[17] this conversion uses carbon dioxide as a feedstock to generate oxalic acid.
2 moles of carbon dioxide + 1 mole of hydrogen ---(empirical only) ---> 1 mole oxalic acid
b2) Historically glyoxylic acid was prepared from oxalic acid electrosynthetically:[6][7]
https://en.wikipedia.org/wiki/Glyoxylic … eparations
This synthesis has been documented in a chemistry textbook that was published in 1920. The original article was in 1904.
http://onlinelibrary.wiley.com/doi/10.1 … 5E7.f04t04
1 mole oxalic acid + 1 mole hydrogen ---(empirical only) ---> glyoxylic acid.
Offline
Natural light covers all the color spectrum but LED's not so but with the selected color ratios of Red to blue some plants do grow quite well.
Significant reduction in energy for plant-growth lighting in space using targeted LED lighting and spectral manipulation LED red:blue ratio of 95:5 allowed leaf lettuce seedlings to grow normally.
Lettuce stands were grown hydroponically in a growth chamber controlling temperature, relative humidity, and CO2 level. Several red:blue ratios were tested for growth rate during the lag phase of lettuce growth. In addition, start of the exponential growth phase was evaluated. Following establishment of a 95% red + 5% blue spectral balance giving the best growth response, the energy efficiency of a targeted lighting system was compared with that of two total coverage (untargeted) LED lighting systems throughout a crop-production cycle, one using the same proportion of red and blue LEDs and the other using white LEDs. At the end of each cropping cycle, whole-plant fresh and dry mass and leaf area were measured and correlated with the amount of electrical energy (kWh) consumed for crop lighting. Lettuce crops grown with targeted red + blue LED lighting used 50% less energy per unit dry biomass accumulated, and the total coverage white LEDs used 32% less energy per unit dry biomass accumulated than did the total coverage red + blue LEDs. An energy-conversion efficiency of less than 1 kWh/g dry biomass is possible using targeted close-canopy LED lighting with spectral optimization
Offline
I'm not sure if this has been mentioned yet, but cotton will very likely be the fabric of choice for the clothes of early Martians, as it is made from plant matter as opposed to such fabrics as wool or silk. Even suits can be made from it, such as seersucker suits (of course, such suits would remain rather informal, but it's unlikely that formality would be the early Martians' main concern). The capabilities of one bale of cotton are given by https://www.cotton.org/pubs/cottoncount … u-make.cfm.
Assuming a colony of 100, and assuming that each person would want 7 pairs of (men's, for the sake of defensive pessimism) briefs, 2 (men's, ditto) dress shirts, 10 T-shirts, 5 pairs of Jeans, 2 pillowcases, 7 pairs of socks, and 2 bedsheets, that would be:
-700 pairs of briefs
-200 dress shirts
-1,000 T-shirts
-500 pairs of Jeans
-200 pillowcases
-700 pairs of socks
-200 bedsheets
Which would all combined need around 5 bales of cotton, or per the same source 2,400 lb. According to http://www.cotton.org/econ/cropinfo/cos … ns/usa.cfm, 1 acre of cotton yields ~700 lb, so a colony of 100 would need around 3.5 acres of cotton fields to satisfy it. According to that same source, cotton costs around $0.61 a pound, so the total cost of the cotton items (assuming no inflation between now and this settlement) would be around $1,464, or around $15 per person, though import costs might drive this up a bit.
The Earth is the cradle of the mind, but one cannot live in a cradle forever. -Paraphrased from Tsiolkovsky
Offline
Cotton is not likely to be competitive with polyester, polypropylene, polyethylene and the like because of the labour input required to convert plant based fibres into cloth and ropes. Perhaps, when the colony is much larger, cotton (or flax or bamboo or sisal etc.) might be grown as a source of luxury fibres. You would need a large acreage to allow deployment of automated equipment.
Offline