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Hell yes!

Yes!

No.

Hell no.

[CaptainArchmage]

Alright Bay 12, this project aims to grow lettuce on Mars using CO2 from the Martian atmosphere. I've seen a couple of Mars-colony related links, what do you think? Here's the project page:
http://www.lettuceonmars.com/

The design uses an open system and grows an edible plant which has been subject to good deal of research. The lander is intended to go to Mars in 2018 and is funded by MarsOne, but the design should be valid on any landing Mars mission (example: NASA or ESA) that makes a soft landing. There happens to be a public vote on it, too; it is one of the ten finalists for the university payload, so if you want to see this happen, you need to vote for it now! Voting closes at midnight tonight. Voting instructions are on the project page.

Here's the project page on the mars one community website:
https://community.mars-one.com/proje...cro-greenhouse

An AMA about the experiment was also done on Reddit:
http://www.reddit.com/r/IAmA/comment...ow_lettuce_on/

Spoiler: For those who also play Kerbal Space Program as well as Dwarf Fortress (click to show/hide)

There's also a KSP mod I've done based on the designs. The Curse site is http://www.curse.com/ksp-mods/kerbal...-plant-science and on these forums at http://forum.kerbalspaceprogram.com/...n-resources%21 - plant or other life-oriented science in space is something we could do with in KSP as well!

Happy New Year to All!

[LordSlowpoke]

for the love of fuck why the hashtag

i mean i voted? but for what purpose

[CaptainArchmage]

for the love of fuck why the hashtag

i mean i voted? but for what purpose

Reason for hashtag: #twitter.

Why as to voting: because there's a public vote to select the university payload.

Why as to doing the mission: People will need to eat in space, and growing plants using at least some extra-terrestrial resources is very important.

[wierd]

Lettuce would probably do well with the reduced intensity of sunlight found on mars (it's hard to grow in the summer because heat and strong light make it produce stress mitigating compounds that make it unbearably bitter tasting). The issue would be concentrating the ambient atmosphere sufficiently, and sourcing local water.

Mars' atmosphere is about 1% that on earth. That means the marsONE experiment would have to concentrate the atmospheric gas over 100 times mars standard pressure. That's either one hell of a big pump, or a long wait between lettuce runs.

I suppose it makes sense to start with a food crop that is well suited to low light and low temperature. Personally, I would have selected a pseudo-cereal crop instead. Buckwheat can grow in the Himalayas, and is already adapted to arid, cold, low-light conditions. 

The real deal here is that mars' atmosphere, in addition to just having 1% pressure, is also over 90% carbon dioxide, with noteworthy deficiencies in nitrogen and other gasses essential to complex life. (You might not think that having molecular nitrogen around is that important as anything other than fire control, but you would be wrong. Fixation of molecular nitrogen by inorganic processes is dreadfully slow, and without fixating microbes in earth's soil actively converting it into fixed nitrogen compounds, large animal forms like we humans just wouldnt be possible. We couldnt source enough nitrogen for the protein mass of our bodies. Protein (any kind) contains significant quantities of nitrogen. Plants produce proteins, just as animal forms do, and they cannot survive without it.  It is true that many soil samples evaluated by the dozen or so rovers that have visited the red planet over the past 2 decades have detected perchlorates, there has only been a handful of not fully constrained spectrometer experiments indicating fixed nitrogen compounds in the soil.  This either means that the various space programs are not interested in nitrogen or nitrogenous compounds (Foolish, given their necessity for life) and have focused their instrumentation to look for other biomarkers, or that the surface soil is low in fixed nitrogen.

The hydrogen deficit can be overcome, since there is sufficient hydrogen bound up in the soil that clever colonists could balance the budget. I don't see that happening with the nitrogen deficit.

[CaptainArchmage]

Lettuce would probably do well with the reduced intensity of sunlight found on mars (it's hard to grow in the summer because heat and strong light make it produce stress mitigating compounds that make it unbearably bitter tasting). The issue would be concentrating the ambient atmosphere sufficiently, and sourcing local water.

Mars' atmosphere is about 1% that on earth. That means the marsONE experiment would have to concentrate the atmospheric gas over 100 times mars standard pressure. That's either one hell of a big pump, or a long wait between lettuce runs.

I suppose it makes sense to start with a food crop that is well suited to low light and low temperature. Personally, I would have selected a pseudo-cereal crop instead. Buckwheat can grow in the Himalayas, and is already adapted to arid, cold, low-light conditions. 

The real deal here is that mars' atmosphere, in addition to just having 1% pressure, is also over 90% carbon dioxide, with noteworthy deficiencies in nitrogen and other gasses essential to complex life. (You might not think that having molecular nitrogen around is that important as anything other than fire control, but you would be wrong. Fixation of molecular nitrogen by inorganic processes is dreadfully slow, and without fixating microbes in earth's soil actively converting it into fixed nitrogen compounds, large animal forms like we humans just wouldnt be possible. We couldnt source enough nitrogen for the protein mass of our bodies. Protein (any kind) contains significant quantities of nitrogen. Plants produce proteins, just as animal forms do, and they cannot survive without it.  It is true that many soil samples evaluated by the dozen or so rovers that have visited the red planet over the past 2 decades have detected perchlorates, there has only been a handful of not fully constrained spectrometer experiments indicating fixed nitrogen compounds in the soil.  This either means that the various space programs are not interested in nitrogen or nitrogenous compounds (Foolish, given their necessity for life) and have focused their instrumentation to look for other biomarkers, or that the surface soil is low in fixed nitrogen.

The hydrogen deficit can be overcome, since there is sufficient hydrogen bound up in the soil that clever colonists could balance the budget. I don't see that happening with the nitrogen deficit.

I think that's an excellent response! The pump can manage this pressure difference; nitrogen is either supplied from decomposition of nitrous oxide (which supplies oxygen to start germination), or by bumping the concentration of nitrogen in the greenhouse atmosphere by cycling the air through a membrane filter, which separates nitrogen from CO2 (and Oxygen). Also this was submitted for technical review and passed (the probe's contractors are Lockheed Martin and Surrey Satellites).

Actually the system is aeroponic, so there will be a nutrient solution. The experiment is intended to last a few weeks, or long enough to grow lettuce, but if the probe has the same experience as Phoenix or the Mars Exploration Rovers it could keep on functioning a lot longer.

Yes, water is supposed to be extracted from Martian soil by another experiment on the lander, but this design cuts down dependencies on those so water is brought along. The Mars atmosphere, by comparison, is freely available once you're on the surface. If it is possible to connect the water-extraction payload to the greenhouse something could be set up.

*Technically* venting the oxygen out of the greenhouse the project be contributing to the terraforming Mars too, albeit slowly. This is allowed under planetary protection as the HEPA filters stops almost all organic matter from getting in or out, but allows gasses through.

[penguinofhonor]

.

[wierd]

From the soil analyses I have read so far, water is probably the easiest thing to get on mars.  In the northern hemisphere, there are entire deserts made of gypsum powder/sand. 

Gypsum is hydrated calcium sulfate. Simply heating it above 300F will liberate significant quantities of water.  Heating it to over 5000F will thermally decompose the gypsum into calcium and sulfur oxides and will extract all possible water.  (300F is much easier to attain, and about 1/3 of the mass of the initial gypsum processed will be returned as potable water.)

Water, and therefor the hydrogen deficit, is therefore not a significant obstacle to colonization as long as dedicated mineral processing is in place.

Nitrogen on the other hand?

According to wikipedia:

Compared to Earth, the atmosphere of Mars is quite rarefied. Atmospheric pressure on the surface today ranges from a low of 30 Pa (0.030 kPa) on Olympus Mons to over 1,155 Pa (1.155 kPa) in Hellas Planitia, with a mean pressure at the surface level of 600 Pa (0.60 kPa).[129] The highest atmospheric density on Mars is equal to that found 35 km (22 mi)[130] above Earth's surface. The resulting mean surface pressure is only 0.6% of that of Earth (101.3 kPa).

...

The atmosphere of Mars consists of about 96% carbon dioxide, 1.93% argon and 1.89% nitrogen along with traces of oxygen and water.

What does this mean?  It means that even if you were to concentrate martian atmosphere to 1 bar pressure, only 1.89% of it would be nitrogen. You could separate this from the carbon dioxide (but not the argon) by reducing the temperature and allowing the CO2 to freeze into dry ice, then mechanically removing it.  The nitrogen however, will be approximately 50% diluted with argon.  This is just fine if you want it for habitat atmosphere filler: Almost 4% of the full gas canister is useful for that purpose (though your colonists may sound a little like mickey mouse).  But for horticulture, you need the nitrogen, not the genuinely inert noble gas.

That would require additional processing. Specifically, recompression to several hundred earth atmospheres (against the pressure gradient of mars' surface, this poses a significant material science hurdle. The pressure vessels would have tremendous stresses on them if they were open to the external environment. This processing would have to happen in pressurized environments to work at all.). This will cause the nitrogen to condense into liquid nitrogen, leaving free argon as the last remaining gas.

The knowhow and technology to accomplish the refining isn't the problem.

The problem is the absurd energy and process time it would take to get useful quantities of nitrogen from the martian atmosphere, and the absurd volume of martian atmosphere one would need to process.

Using a combined gas law calculator, I evaluated how much 1 liter of nitrogen gas on earth would equate at room temperature, given the differences in pressure.

1L on earth == 168.83L on mars. (Liters as measure of volume of gas)

A cubic meter is 1000 Liters. (again, measure of volume of gas)

So, to fill a habitat with the 70% nitrogen gas and 1 atm pressure needed for sustained agriculture on mars, which we will (for sake of easiness) say is 1000 cubic meters in volume, we would need 700 cubic meters of pure nitrogen gas at 1 atm.

This volume at mars pressure would be 118,181 cubic meters.

Again, only 2% of martian atmosphere is nitrogen.  So, we divide that absurd number by .02

5,909,050 cubic meters of martian atmosphere will have to be processed at 100% efficiency to produce the nitrogen necessary to fill the habitat.


It's just easier to take the nitrogen with you, and then be miserly conservative about it.

[wierd]

Bear in mind, the above is for nitrogen fixating microbes, not for plants. Many plant species can survive and thrive in upwards of 70% carbon dioxide environments, which is what I presume this experiment intends to test. Most plants are incapable of doing ANYTHING with molecular nitrogen, and instead either absorb it through their roots from the soil, or employ symbiotic microbes to process atmospheric molecular nitrogen into the fixed nitrogen they need.

However, an honest to goodness horticultural lab on mars would *NEED* to source fixated nitrogen from SOMEWHERE.  If fixating microbes are used to get it from atmospheric gas, then the above scary math hits home.

I am just pointing out the horrific math piled up against sourcing it from the atmosphere.  If there are nitrogen salts in the soil on mars already, then processing the dirt to get them is the way to go. Sadly, as I pointed out in the first post, there does not seem to be any suitable deposits of nitrate or nitrite or ammonium compounds in the regolith, making this unlikely.

Best bet would be to bring large canisters of anhydrous ammonia, and use it very carefully in tightly sealed agricultural units as a nutrient in the hydroponic mix. High density, high availability nitrogen can be taken to mars to meet minimum crew support requirements immediately this way.  Colony expansion would require sourcing additional nitrogen using either the atmospheric reprocessing approach (with all its warts), or extensive prospecting for nitrate salt flats.

[CaptainArchmage]

Bear in mind, the above is for nitrogen fixating microbes, not for plants. Many plant species can survive and thrive in upwards of 70% carbon dioxide environments, which is what I presume this experiment intends to test. Most plants are incapable of doing ANYTHING with molecular nitrogen, and instead either absorb it through their roots from the soil, or employ symbiotic microbes to process atmospheric molecular nitrogen into the fixed nitrogen they need.

However, an honest to goodness horticultural lab on mars would *NEED* to source fixated nitrogen from SOMEWHERE.  If fixating microbes are used to get it from atmospheric gas, then the above scary math hits home.

I am just pointing out the horrific math piled up against sourcing it from the atmosphere.  If there are nitrogen salts in the soil on mars already, then processing the dirt to get them is the way to go. Sadly, as I pointed out in the first post, there does not seem to be any suitable deposits of nitrate or nitrite or ammonium compounds in the regolith, making this unlikely.

The atmospheric processing is just one way to get nitrogen, the alternative and backup is to bring along and decompose nitrous oxide. The volume of the greenhouse actually isn't that big, as it is intended for a Mars lander, which makes the job of processing the air easier. As the growth system is aeroponic, the nutrients required will still be supplied in a nutrient solution; the experiment is expected to run for a few weeks, which is enough to grow lettuce.

[wierd]

Yup. Just wanted to point out that there is more to growing food on mars than just concentrating the atmosphere and pumping it straight in. 

MarsONE intends to send real live humans up there after automated support systems and habitats have been constructed using robots.

To support human colonists, there will need to be a supply of fixated nitrogen immediately available, and a means of appropriating more nitrogen.  Water isn't an issue, as I pointed out.  (You can get a 2 liter bottle of water out of a 5 gal bucket of gypsum sand. Easy.)  The nitrogen deficiency is. 

It is one of the things I *REALLY* hope curiosity or some future rover discovers, is a large nitrate salt desert similar to those found in south america. It would mean "mars colony == WAAAAAYYY easier".



Amusing thought:

As a consequence of the raw value of the nitrogen involved, mars colonists would not be able to afford the luxury of a casket burial. It would lock away several kilograms of fixated nitrogen. (Enough to grow an entire human's muscle and bone mass.) Rapid decomposition in a composter would be the most civically mindful solution.

i'd still eat the lettuce.

[Loud Whispers]

I WILL NEVER CONSUME #LETTUCE
ONLY LETTUCE

[wierd]

<joke>
But #LETTUCE is part HASH and part LETTUCE! It's a GMO of weed and salad! The ultimate diet food!
You aren't one of those hard-nosed drug hysteria types are you? Or worse, one of those anti GMO types right!?
</joke>

[Loud Whispers]

IF YOU MUST USE #<joke> #TO #JOKE #HUMANITY #IS #LOST #AND #MY #LETTUCE #IS #GONE #THANKS #OBAMA

[CaptainArchmage]

Yup. Just wanted to point out that there is more to growing food on mars than just concentrating the atmosphere and pumping it straight in. 

MarsONE intends to send real live humans up there after automated support systems and habitats have been constructed using robots.

To support human colonists, there will need to be a supply of fixated nitrogen immediately available, and a means of appropriating more nitrogen.  Water isn't an issue, as I pointed out.  (You can get a 2 liter bottle of water out of a 5 gal bucket of gypsum sand. Easy.)  The nitrogen deficiency is. 

It is one of the things I *REALLY* hope curiosity or some future rover discovers, is a large nitrate salt desert similar to those found in south america. It would mean "mars colony == WAAAAAYYY easier".



Amusing thought:

As a consequence of the raw value of the nitrogen involved, mars colonists would not be able to afford the luxury of a casket burial. It would lock away several kilograms of fixated nitrogen. (Enough to grow an entire human's muscle and bone mass.) Rapid decomposition in a composter would be the most civically mindful solution.

i'd still eat the lettuce.

I don't think it is really an issue, actually. In terms of volume, the Martian atmosphere is 2.7% nitrogen (this is different from the molar volume). With atmospheric pressure at 0.6% of Earth's, if you wanted a litre of pure nitrogen that would be found in 6172 litres of Mars air. This is feasible; to process the atmosphere, membrane gas separation is used, so compressors filter out the carbon dioxide. This is used on Earth for small scale scale uses, which is to say everything up to the large scale. Cryogenic separation is not used except for absolutely massive quantities of nitrogen.

The real question after you've pressurised is how much nitrogen will need to be added to the system per day to keep grow the plants. That isn't that near the amount required to fill the greenhouse growth chamber, or on the colony, fill the entire 1000 cubic meters, unless you are growing a very large amount of plants and are not re-using much. It will take some time to pressurise the chamber depending on your processing rate but without the nitrogen being consumed in that time it isn't so much of a problem.

I don't think the Mars colonists would want to be reprocessed into fertiliser, and given the above it isn't that necessary either. Technically the first stages of set-up of the colony are meant to be automated.

[wierd]

You arent thinking like a civil engineer.  The population of the colony will not be static, and the load on the seperator will not be static either.

As population goes up, local resource extraction will go up, number of horticultural labs will have to increase, and rate of nitrogen consumption will rise.

You have to plan for future capacity, not just immediate capacity. You also have to plan equipment service lifecycles, and other things in.