New Mars Forums

I'll have to put together a list myself, as I'll be sharing the work with someone else. 

Ironically, upon reading up on the subject, one of the recommended plants for a terrarium is _Coffea arabica_.   :0  I'll check the local coffee companies (There are four in my town, along with ten coffee shops -- God bless Louisiana.    )  and see if they can supply me with unroasted viable beans.  I'll do more research to see if I can take it to seed inside a terrarium. 

I may be premature in my earlier assessment.  Arabica might turn out to be the little bean that could.

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Regarding the use of appetite suppressants and restricting dietary calories, I would be extremely hesitant to do this because people doing hard physical work need more food than sedate ones.  Also, food and the variety thereof can be very important to the morale of isolated outposts. 

I still have my worries about tea and coffee, because these are both insect pollinated plants.  So is chicory.  Tea and chicory may still prove useful at a Mars outpost because the leaves are consumed, giving a much higher return on the effort of hand pollination.  Compare this to all the beans required for just a single cup of coffee, every one of which must be hand pollinated by Jose Jiminez.

I am not gravely concerned with the effect of air pressure on food preparation.  If you let someone else make the coffee every morning, that?s someone else?s problem.  

However, epinasty is a major concern in any Martian greenhouse that gets exposed to outside air.  It can be even more drastic at low pressures.  Epinasty is caused by exposing the plants to a bad gas mix, such as too much carbon dioxide, too little oxygen, or anything more than traces of oxidizers.  Although they get a kick out of a little extra CO2, anything more than 100mbars or so C02 partial pressure is bad for their health.  People start suffocating at around 30mbar partial pressure CO2, so the plants really can?t take over about three times more than the crew.  Plants can get by happily with less than 1% of that.  Their need for oxygen also means that the carbon monoxide in the Martian atmosphere is almost as toxic to plants as it is to us.

You cannot simply compress the native Martian air and feed it to the crops.  It must be filtered through a heated platinum catalyst bed (an automobile catalytic converter would do nicely) to reduce the carbon monoxide first, and even so, it?s bound to take a few passes.  It would still be very much worth our while to treat the air and use it, since it can be added to air from the habitat to make a good mix for the plants.  However, we should grow the plants with hab air to get the most efficient use of the oxygen they produce and just trickle in some extra CO2 at a rate both plants and crew are comfortable with. 

And yes, in case you were wondering, IMHO, all those visions of greenhouses with the ?special mix? atmosphere tended by farmers in oxygen masks are a bunch of baloney.

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Oh dear. 

A horrible realization has just occured to me: with the exception of chicory, all major agricultural sources of caffeine are from tropical plants, which will be very hard to grow on Mars (it being at best equivalent to the terrestrial northern/mountain growing regions here on Earth). 

The scarcity of this vital nutritional component may well place great hardship on the Martian civilization. 

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Hello All.  I have some more notes on food production.

There are other methods of plant propagation than the ones I mentioned earlier: propagation from tubers (potatoes), from rhizomes (yams & mint), from runners (strawberries), from cuttings (sugar cane), and pollination by water (seaweeds, mosses).  Most plants that can be propagated by these methods can also be started from seed, which makes the shipping weight for the first crops very light.  Saving seeds is going to be very important for a greenhouse where the nearest hardware store is six months away, which means that hybrids will NOT be a particularly useful thing (especially annuals).  Hybrids do not breed true.  Older varieties of plants, such as the so-called "heritage" varieties which are no longer in fashion, are probably the best place to look for plants that can be adapted to use on the Martian surface.

Also, it turns out that plants are far more tolerant of exposure to vacuum than animals.  A crop raised in a pressurized terrarium could be harvested by opening the terrarium to the outside air.  The crop would not be damaged by exposure to outside air and the seeds would still be viable.  The plants we harvest it from may still be viable as well if the exposure does not also involve exposure to cold temperatures associated with the climate and decompression.

Instead of great big greenhouses, we may be able to get by with a bunch of little hotboxes.  Our first crops on Mars may be grown in terrariums.

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OK, I know I?m not as invested in the discussion of probes vs. people as I should be, or I?d be making my wise*ss cracks in the appropriate forum, but it?s time to get serious.   OK? I?m not here to come down on the side of those who think robotic probes are unnecessary any more than I agree with those who think that people are.  Robotic probes, for all their failings, are utterly devoid of the single greatest failing of human beings.   If a robotic probe screws up, nobody dies.  (I almost died when we lost a probe because the programmers couldn?t convert from English to Metric, but it?s not the same thing.)  We should use robotic probes before a Mars mission, during a Mars mission, and forever after during the entire history of Martian civilization.  We must also send people to get the job done right, and I tire of all the either/or debates.

Power to the People!  Energy to the Probes!

But I ask you, who is going to publish a good book on this debate?  Or a ?Great Book of Zubrin?, for that matter?  (Hey, don?t knock it.  I understand that ?Bimbos of the Death Sun? did quite well.)

Has there been anything occurring at New Mars that needs writing about?  I see all sorts of good ideas come through here.

Hmm?

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Oh, well, if you mean the humans would actually have to GET there... 

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Excellent idea, Shaun.  Polyurethane foams are great for composite construction, as is styrofoam and similar plastics.  With the addition of layers of fiberglass or other plastics, they can be made remarkably strong. You can find how-to directions in books on auto repair, fiberglass, and aircraft composite construction.

Regarding Josh's fear of the plastics freezing, I suspect it would be practical to heat slow cure plastics.  As for most thermoset plastics (like two-part epoxy, polyesters, etc.), these produce their own heat through chemical reactions that take place within the setting plastic.

The polyurethane foam fillers that are sold in cans have relatively high compressive strength, which makes a layer of it quite strong when layers of cloth are epoxied to either side.  (To break it, one must crush the foam and/or rip the cloth ? not an easy task with fiberglass & kevlar.)  Your question about the affect of air pressure is important, though.  The vapor pressure limit affects the solvent, not the plastic left behind.  But it?s important to note that the ?triple expanding? formulas for polyurethane foams are not as strong as the regular variety because the gas pockets get larger before the foam sets.  I suspect that you couldn?t take a can of polyurethane off of the shelf at Lowes? and expect it to work on Mars, because it would expand too much to retain its strength. 

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A PS for backyard tinkerers:  The polyurethane sealer formula sold at hardware stores (the paint, not the foam)  is not ideally suited for structural composites because it?s quite rubbery compared to epoxies when it dries.  However, it is ideal for rubberizing cloth.  For instance, one could apply it to nylon to make an inflatable, air-tight structure.

Pity.  It was a good point.  Physical impossibility makes an excellent impetus for social change.

For example, some forms of traditional burial are likely to prove as impossible on Mars as they are in the Arctic during the winter here on Earth.  There are places in the far north where it is customary to store bodies in the community morgue until spring thaw, because burying them earlier requires digging through the rocky ice frozen above the permafrost.  On Mars, the permafrost never melts, so unless grave diggers bring their ice saws and air hammers, subterranean burial may be out in many places on Mars.  (Early explorers are likely to go where the ground is hardest.  That's where the water is.)

The traditional 6 feet under may be as physically impossible on Mars as travelling back to Earth for All Saints Day.

Cremation, on the other hand, is not so hard.  If you freeze dry the body first (easy to do on Mars -- all you have to do is expose it to the outside air for a few weeks), it will burn on its own.  Just add oxidizer.

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LOL!  Go 'Long!  NASA does that to you, too?   

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I am inclined to agree, as there is no such thing as the ghost police. 

Indeed, the state determines how a body is legally disposed of in _all_ cases in the United States.  Exceptions have to be cleared through government agencies.  Have you ever been to a funeral where the family's customs required them -- not grave diggers -- to bury the body?  Here in the States, the grave diggers still have to stick around, because if the family does a slipshod job and nobody fixes it, the grave diggers are charged with a crime.  The situation is similar with other disposal methods.

The state has a lot to say about the dead, and is, in fact, one of the places you can go to inquire about going through the pockets for loose change.   

But I must ask: Are there any examples of societies where it is customary _not_ to allow the friends/family of the deceased any say in the fate of the body?  I'm not referring to anecdotes of deviants violating some taboo, but rather societal traditions.  One could imagine a society, for example, where tradition forbids anyone who knew the deceased to even touch the body and it is taken from them immediately.  But there would have to be people willing to do that, an entire social institution requiring organization and resources.  Who would want to mess with that bunch of smelly old meat, if not the family? 

The state does indeed often control how this is done, and in fact will see to it if necessary.  But that is not the path of least resistance for a society to take.  If there is a something to be done, it makes sense to allow the people who want the job to take over.  Grave diggers cost resources, as does any disposal method that doesn't involve leaving them to rot where they lay.  If there's no reason to do differently, the state will do whatever's cheapest.

I suspect that the main reason societies usually prefer families to deal with their own dead is more than shoulder shrugging.  It's expediency. 

I predict that the martians will generally allow the families of the dead to deal with their own bodies, just as every other society with any sense has done.

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Well, if rights are the big issue...

Whose right is it to see to the disposition of "their" dead? 

If I understand Clark correctly, I should not expect the dead guy to rise up and do it.

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PS: Also, a related question: "Who can give me permission to go through the pockets and look for loose change?"  If you can answer that, you know where the real rights are.

It might be a good idea for items launched to Mars, the Moon, or into space in general, to be recyclable. 

Hmm...

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