Designing a (Totally) self sufficient Mars colony

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Re: Designing a (Totally) self sufficient Mars colony

Postby Heisenberg » Wed Apr 24, 2013 8:11 pm UTC

A cave structure would be nice if we could seal and pressurize it. Barring that if we could at least find a nice cliff face we could shield off an area using regolith bricks or sandbags.

Question: Do we waste oxygen on greenhouses or can we make do with pressurized Martian atmosphere? And is it worth the hassle of gardening with breathing apparatus?

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Re: Designing a (Totally) self sufficient Mars colony

Postby Izawwlgood » Wed Apr 24, 2013 8:14 pm UTC

Heisenberg wrote:Question: Do we waste oxygen on greenhouses or can we make do with pressurized Martian atmosphere? And is it worth the hassle of gardening with breathing apparatus?

You need a bit of oxygen for plant respiration, but no, you basically just pressurize a greenhouse with pressurized (1/3rd-3/5ths ATM) Martian atmosphere and let it run. My sense is that you can then extract the oxygen and just keep pumping in more atmo, or something similar. I'm not positive, but I think if there's sufficient oxygen for respiration (which is as I understand it a very low requirement), most plants will convert all available CO2, eventually bottlenecking their growth on available atmospheric CO2. So, that's pretty rad.
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Re: Designing a (Totally) self sufficient Mars colony

Postby Ciber » Wed Apr 24, 2013 8:23 pm UTC

My plan has the greenhouses being separated from the main base with an airlock, they are also brick barrel vaults but with part of the roof replaced with windows. Which is much harder to seal so we only bother maintaining the minimum atmospheric requirements for the plants.

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Re: Designing a (Totally) self sufficient Mars colony

Postby Izawwlgood » Wed Apr 24, 2013 8:30 pm UTC

Truthfully, until you can do it reliably, having the greenhouse exposed to actual Martian sky isn't even that necessary; to maximize growth, you should use red and blue LEDs as grow lights which will be powered, naturally, by the bitchin' nuclear reactor that powers the base, and supplemented, naturally, with either solar generated electricity, or fiberoptic lighting pumping from paneling into the greenhouse itself. Much easier to clear out a cavern, set up some hydroponic tubing, and wire up some LEDs than dick around with window sealants.

Of course, if you're making your habitats out of strong, clearish plastic, you might not need bother with a window.
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Re: Designing a (Totally) self sufficient Mars colony

Postby Heisenberg » Wed Apr 24, 2013 9:38 pm UTC

I'm going to have to disagree. Putting a roof on a greenhouse, installing lights, and powering them with PV panels on top is something the laws of thermodynamics simply will not abide.

While I would not personally want to rely on a bubble enclosure for my own safety, couldn't we use multiple bubble enclosures for plants? If one pops, that sucks, but it's not the end of the world. Sunlight is one of the few resources on Mars we can count on. We should use it.

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Re: Designing a (Totally) self sufficient Mars colony

Postby Izawwlgood » Wed Apr 24, 2013 9:56 pm UTC

Heisenberg wrote:Putting a roof on a greenhouse, installing lights, and powering them with PV panels on top is something the laws of thermodynamics simply will not abide.
I didn't say power them solely with PV. But, for starters, red and blue LEDs are very effective and low power usage compared to what most people think of when they imagine greenhouse lights. Secondly, having a large enclosure with a glass canopy is problematic for the conditions of Mars, given that it's nearly vacuum outside (i.e., deadly to personnel and plants alike!), and that Mars is a dusty planet. Dust storm rolls in, and if you're relying on sunlight for your plants, they may be in trouble. Basically, if we're worried about dust covering our PVs, we should worry about it covering our greenhouse windows. Since windows aren't really necessary (we do, after all, have a pretty bitchin' nuclear generator), why bother?

Heisenberg wrote:Sunlight is one of the few resources on Mars we can count on. We should use it.
Agreed; which is why I said we could also pump whatever sunlight we feel like gathering in the form of fiberoptic cables, or cover the enclosure with PVs. Also, remember, we don't neccesarily need to have our greenhouse be long or wide; it can also be deep. We're going to have to start with hydroponics, so, there's no real requirement to have our garden be a plot of land that's a single level 50x50. It can be 20 levels that's 5x5x100. In some setups, having a clear window to allow sunlight to pump in is actually a hindrance.
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Re: Designing a (Totally) self sufficient Mars colony

Postby PM 2Ring » Thu Apr 25, 2013 6:18 am UTC

idobox wrote:Somebody talked about hydrogen fuel cells as a fuel source for ground vehicles. It could work, but I think it is needlessly complicated.


I mentioned using rechargeable batteries or fuel cells to power vehicles and other remote equipment. But I was assuming that we had access to enough water to make the fuel & oxygen for the cells.

Fuel cells can run on a variety of reactions. Hydrogen + oxygen is clean and gives lots of power, but hydrogen gas is pesky to handle. It's bulky in its gaseous state (i.e. it has a bad energy / mass volume ratio), under pressure it has a tendency to leak &/or react with the materials in the container, and it takes a lot of energy to liquify it. So there are good reasons to use methane (or other light hydrocarbon) instead of hydrogen. Oh course, hydrocarbon-based cells will produce CO2 as well as water, and if we wish to recycle the reaction products of our fuel cells, it's easier to store and reuse water than CO2.

Yes, fuel cells are more complicated than conventional batteries, and for best results you do need some rare metal catalysts in your fuel cell. But modern batteries use things like lithium, which may not be so easy to source locally on Mars.

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Re: Designing a (Totally) self sufficient Mars colony

Postby p1t1o » Thu Apr 25, 2013 9:18 am UTC

tomandlu wrote:Okay, with the current parameters, it's fairly clear that our landing vehicle is going to form a significant part of the colony. Assuming we want to reduce energy consumption, would inflatable bio-domes be an option? Could we go for big ones and make them habitable?


Since these are being considered for use as orbital habitats, I'm sure they would be suitable, the only problem I can think of being sandstorms, but I think the general consensus is that wind isn't a big problem.

At the very least you could use them for the storage of your bulk materials and things whilst you dig out your underground habs.

PM 2Ring wrote:but hydrogen gas is pesky to handle. It's bulky in its gaseous state (i.e. it has a bad energy / mass ratio)


You mean energy/volume ratio.



On another note - I would have thought that the hardest part of growing things on mars in a greenhouse is keeping it warm enough in there? It seems to me, if power generation is not a problem, that you might be better off supplying the plants with everything they need artificially, heat, light, atmosphere etc.

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Re: Designing a (Totally) self sufficient Mars colony

Postby idobox » Thu Apr 25, 2013 9:27 am UTC

PM 2Ring wrote:Yes, fuel cells are more complicated than conventional batteries, and for best results you do need some rare metal catalysts in your fuel cell. But modern batteries use things like lithium, which may not be so easy to source locally on Mars.

I think that's the kind of stuff we should bring from Earth.
The only use for fuel cells I'm aware of is in spacecrafts, because they already have a large supply of O2/H2. We have electric cars on Earth, and no fuel cell ones, even though they don't need to carry O2 or recycle water, because of price and infrastructure, but also because fuel cells are not that much better than batteries.
What's the energy density of liquid H2/O2 compared to modern batteries?

Heisenberg wrote:Question: Do we waste oxygen on greenhouses or can we make do with pressurized Martian atmosphere? And is it worth the hassle of gardening with breathing apparatus?

Why bother with greenhouses that take up a lot of space and are not that efficient when you could grow micro-algae? Photobioreactors are much more compact, and the algae don't waste precious energy building useless cellulite, resulting in a larger yield.
Sure, a diet of micro-algae pellets will be boring as hell, and maybe difficult to make balanced, but it is the best solution for the beginning, and should remain the main source of food, oxygen and hydrocarbons even when you start growing more conventional food.
In the context of biofuels, you can find people claiming algae are 10 to 300 more efficient per m² than conventional crops.

On another note - I would have thought that the hardest part of growing things on mars in a greenhouse is keeping it warm enough in there?

I'm not sure, the atmosphere is very thin, it shouldn't be a very efficient heat sink. Which poses a problem for power generation by the way.
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Re: Designing a (Totally) self sufficient Mars colony

Postby p1t1o » Thu Apr 25, 2013 10:03 am UTC

idobox wrote:I'm not sure, the atmosphere is very thin, it shouldn't be a very efficient heat sink. Which poses a problem for power generation by the way.


Yeah, that did come up during the initial discussion on nuclear reactors. IMO we couldnt go without one, I thought the best bet was to put it near on of the poles for access to water/dry ice for coolant. Not a complete solution sure, but it doesn't sound technically unfeasible.

idobox wrote:Why bother with greenhouses that take up a lot of space and are not that efficient when you could grow micro-algae? Photobioreactors are much more compact, and the algae don't waste precious energy building useless cellulite, resulting in a larger yield.
Sure, a diet of micro-algae pellets will be boring as hell, and maybe difficult to make balanced, but it is the best solution for the beginning, and should remain the main source of food, oxygen and hydrocarbons even when you start growing more conventional food.
In the context of biofuels, you can find people claiming algae are 10 to 300 more efficient per m² than conventional crops.


I like this idea, you can also do quorn as well, and you can at least make that into makeshift "meat" and other things, which s slightly more appealing than algae pills :) There s even a chinese takeaway near me that does quorn "crispy duck" pancakes...


So then that got me thinking - soylent green.

What would we do with the inevitable cadavers that will start to appear eventually. I'm not suggesting we spit roast them, but its an issue that will need to be dealt with.
Conventional burial is possible, but arguably less appropriate. And would we really be in a position to waste that much biomass/water/organics/inorganics?
Morbid sure, but "burial" in a bioreactor or a compostor is probably where all our dead stuff will have to go.

A buried corpse would still decompose at least a fair amount, due to the bacteria contained within. But would a corpse sterilise eventually? Or is it possible that the variety of bacteria, combined with the resources of a human body, would allow some bacteria to thrive and propagate?

A conventional graveyard could then become something of a "garden" whereby the presence of humanity on the planet, and the natural cycle of life and death gives way to the inoculation of a dead planet with new life? Might also be an important social resource for the colony.

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Re: Designing a (Totally) self sufficient Mars colony

Postby Ciber » Thu Apr 25, 2013 12:23 pm UTC

Cremation followed by dumping the ashes into a garden.

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Re: Designing a (Totally) self sufficient Mars colony

Postby idobox » Sat Apr 27, 2013 6:43 pm UTC

p1t1o wrote:I like this idea, you can also do quorn as well, and you can at least make that into makeshift "meat" and other things, which s slightly more appealing than algae pills :) There s even a chinese takeaway near me that does quorn "crispy duck" pancakes...

Quorn, or other high efficiency food conversion would be very useful for morale. Normal mushrooms could be grown on waste, and it might be possible to an equivalent to flour (mostly starch, fibers and gluten) from GM algae or other microorganisms.

p1t1o wrote:What would we do with the inevitable cadavers that will start to appear eventually. I'm not suggesting we spit roast them, but its an issue that will need to be dealt with.
Conventional burial is possible, but arguably less appropriate. And would we really be in a position to waste that much biomass/water/organics/inorganics?
Morbid sure, but "burial" in a bioreactor or a compostor is probably where all our dead stuff will have to go.

The corpse of a healthy marsonaut will be between 50 and 90kg, a large part of which is water and calcium carbonate, two things that are not especially rare or precious.
Recycling the body has a very strong emotional charge, conflicting with traditions and religious beliefs, and evoking strong taboos. I don't think it's worth it.
Cremation is a solution, typical burial is another one, and with a little care, bodies could be kept frozen, as a form of memento for the next generations. Just make sure nobody on board is zoroastrian or from a culture/religion with exotic funeral rites. You don't want to bring vultures on Mars.
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Re: Designing a (Totally) self sufficient Mars colony

Postby Izawwlgood » Sat Apr 27, 2013 8:48 pm UTC

idobox wrote:You don't want to bring vultures on Mars.
I just got an image of engineered vultures with 50 ft wingspans coasting on duststorms, spying for offered aeronauts, hibernating in canyons and building oxygen reserves from algae stored in their vacuum hardened feathers. . .
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Re: Designing a (Totally) self sufficient Mars colony

Postby eternauta3k » Sun Apr 28, 2013 6:03 pm UTC

It might pay off to make the habitat an extension of the ship the colonists have been living in for months.
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Re: Designing a (Totally) self sufficient Mars colony

Postby Copper Bezel » Sun Apr 28, 2013 10:16 pm UTC

Or at least the relevant parts. Landing any particular mass is not trivial, but it probably doesn't make sense to take two totally separate habitats with you and transfer from one to the other. That said, I guess it's also possible that the ship's habitat wouldn't be a meaningful contribution. I mean, if the initial Mars-base habitat is sent all folded up or deflated, it might be much larger than the habitat of the ship, and it's being sent ahead, right? Depending on what is sent ahead and how those modules work, I suppose that it really could go either way.
So much depends upon a red wheel barrow (>= XXII) but it is not going to be installed.

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Re: Designing a (Totally) self sufficient Mars colony

Postby tomandlu » Mon Apr 29, 2013 8:42 am UTC

Copper Bezel wrote:Or at least the relevant parts. Landing any particular mass is not trivial, but it probably doesn't make sense to take two totally separate habitats with you and transfer from one to the other. That said, I guess it's also possible that the ship's habitat wouldn't be a meaningful contribution. I mean, if the initial Mars-base habitat is sent all folded up or deflated, it might be much larger than the habitat of the ship, and it's being sent ahead, right? Depending on what is sent ahead and how those modules work, I suppose that it really could go either way.


What about using a space-shuttle-like craft as your main ship? Nice and big, but I've no idea whether the atmosphere on Mars would render it as aerodynamic as a brick or not... basically, I'd have thought that, having taken the trouble to get it there, your main ship ought to form a significant part of your colonisation plans.
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Re: Designing a (Totally) self sufficient Mars colony

Postby idobox » Mon Apr 29, 2013 10:58 am UTC

Your crew is going to spend some serious time in transit, and I'm not sure the habitat could be recycled.
I imagine the best habitat for the transit would be a bunch of cylinders assembled in LEO, a bit like ISS, with a thruster on one end, and a tank of water on the other end. Once the ship is launched, it would rotate toward the sun to use the water tank as a radiation shield. The ship will just be a giant tin can with food, oxygen and water reserves, and little else. You can use some parts of the ship on Mars, but it means the modules must be able to survive landing, making them heavier and smaller. Components like computers, beds, toilets, gas stabilizers, and such can probably be sent to the ground, but I would only use them as spare parts rather than count on them.

I think it makes more sense to have robots build an habitat on the ground before hand, have a ship built in LEO to go to Low Mars Orbit, and a simple lander to go down.
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Re: Designing a (Totally) self sufficient Mars colony

Postby Izawwlgood » Mon Apr 29, 2013 1:24 pm UTC

tomandlu wrote:What about using a space-shuttle-like craft as your main ship? Nice and big, but I've no idea whether the atmosphere on Mars would render it as aerodynamic as a brick or not... basically, I'd have thought that, having taken the trouble to get it there, your main ship ought to form a significant part of your colonisation plans.
Well, there is atmo, so aerodynamics matter. You can, afterall, aerobreak.

But that aside, yes, my sense is that using part of the ship or lander as the initial habitation module is reasonable, unless of course a habitation module was safely landed beforehand. At the very least, having some redundancy with where your first colonists live initially seems wise. But, their stay in the habitation module doesn't have to be very long; fairly simple construction machines/robots could easily dig out a reasonable underground habitat. To maximize safety, it might make most sense to use robots to build a small habitat remotely, and not even bother sending colonists until the thing was sealed and pressurized.
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Re: Designing a (Totally) self sufficient Mars colony

Postby Copper Bezel » Mon Apr 29, 2013 3:22 pm UTC

Yeah, that's the thing - if you're sending stuff ahead anyway, there's no reason not to give it exactly as much time as needed. There's still a question of whether some tasks would be better performed by humans in space suits than a variety of heavy, purpose-built robots, of course, but that depends mostly on the level of robotic technology available.
So much depends upon a red wheel barrow (>= XXII) but it is not going to be installed.

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Re: Designing a (Totally) self sufficient Mars colony

Postby Heisenberg » Mon Apr 29, 2013 8:35 pm UTC

Technically, there is a timing issue. The cheapest and fastest windows to Mars come by every 2 years or so. So you either have to spend more in fuel and transit time or design your hab / robots / air tanks to last a few years worth Martian dust storms. Neither are insurmountable, but it's not quite a "send it whenever you want" situation.

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Re: Designing a (Totally) self sufficient Mars colony

Postby Ciber » Tue Apr 30, 2013 4:30 am UTC

Would like to point out that those dust storms have a record of causing significantly less damage to man made objects than you are implying.
For the purpose of this exercise we are attempting to achieve self sufficiency withing 10 years, or 5 launch windows.
Self sufficiency is defined as the ability to support all colonists for a period of fifty years without resupply.

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Re: Designing a (Totally) self sufficient Mars colony

Postby Izawwlgood » Tue Apr 30, 2013 12:36 pm UTC

Don't forget though Ciber, you don't have to send your humans first. You can land humans on the planet at the 4th launch, have habitats, supplies, and fuel already created on site, and have the 5th launch be a general resupply/replacement mission.
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Re: Designing a (Totally) self sufficient Mars colony

Postby idobox » Tue Apr 30, 2013 9:29 pm UTC

Heisenberg wrote:Technically, there is a timing issue. The cheapest and fastest windows to Mars come by every 2 years or so. So you either have to spend more in fuel and transit time or design your hab / robots / air tanks to last a few years worth Martian dust storms. Neither are insurmountable, but it's not quite a "send it whenever you want" situation.

If you have builder robots in your first launch, you can build an unpressurised "hangar" very quickly to protect your most sensitive equipment before or very quickly after the beginning of dust storms.

In my opinion, the order of missions (more than one can be sent at the same time) should be:
Mason robots (concrete printer or brick layer, and some sort of excavator to dig shallow holes and make flat spaces)
Nuclear reactor (I'm assuming something too large or complex to be self contained and working upon landing)
Mining/smelting. The production of glass is actually more important in my opinion.
Fabrication of photo bioreactors.

I'm not sure the operation of the bioreactors can be done by telepresence, but it would be a good thing to have everything essential working before the humans arrive.
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Re: Designing a (Totally) self sufficient Mars colony

Postby Ciber » Wed May 01, 2013 3:19 am UTC

I do not believe that you have considered the complexity of such robots in great enough detail to address all their inherit problems.
In the most general sense, these robots will have to survive a variety of temperature changes and mechanical stresses before they even begin construction.
They will have to preform a variety of heavy and delicate construction work without any on hand mechanics to do basic maintenance such as dust removal and fixing minor breakdowns.
How will they be operated? Will it be entirely telepresence from earth in which case all actions will be undertaken far more slowly than they would be with on site operators, and in the event that something goes wrong the operator will be unable to do anything to salvage the situation until long after the problem has run its course.
The robots would require levels of sophistication, ruggedness, modularity, and lightness that I know for a fact has not yet been demonstrated.
Positing that they are run by on board AI implies breakthroughs of the type which are perpetually twenty years away.

As such I maintain that the most cost effective way to achieve the stated mission goals is to send our first wave of colonists as the second launch with the first having been a testbed launched in the previous launch window and the third being full of supplies and launched at the same time as the second but on a slower less energy intensive transfer.

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Re: Designing a (Totally) self sufficient Mars colony

Postby Copper Bezel » Wed May 01, 2013 6:03 am UTC

I still don't understand why test bed, supplies, colonists doesn't make sense. I agree that the robotics required to have a self-assembled Holiday Inn waiting for the first colonists to arrive are far beyond what we're capable of now. Realistically, the colonists are going to have to do some heavy lifting to get the bulk of the habitat functioning once they arrive.

But I can't fathom any reason to send the colonists on a track to arrive before the supply ship. I really don't know what good that does. Ideally, it'd be nice to send the supply ship ahead such that it lands and sets up shop before the colonists leave LEO, just in case something went wrong.

I tend to think that the point of sending the two missions at different times is precisely so that the supplies will be ready and waiting when the colonists arrive. Otherwise, you just set yourself up to have to take more of the survival necessities on the colonists' ship.
So much depends upon a red wheel barrow (>= XXII) but it is not going to be installed.

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Re: Designing a (Totally) self sufficient Mars colony

Postby Ciber » Wed May 01, 2013 11:45 am UTC

Well actually the first ship to arrive is the supplys, the third has all the construction equipment.

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Re: Designing a (Totally) self sufficient Mars colony

Postby Izawwlgood » Wed May 01, 2013 12:04 pm UTC

Ciber wrote:The robots would require levels of sophistication, ruggedness, modularity, and lightness that I know for a fact has not yet been demonstrated.
Yeah, it's not like we've placed atomic powered science tanks on Mars. More than once. That lasted significant lengths of time.

Ciber wrote:Well actually the first ship to arrive is the supplys, the third has all the construction equipment.
Man, throughout this thread you've had this weird habit of not really listening to other people in favor of insisting the colonization proceeds as you specify.
Copper Bezel wrote:I agree that the robotics required to have a self-assembled Holiday Inn waiting for the first colonists to arrive are far beyond what we're capable of now. Realistically, the colonists are going to have to do some heavy lifting to get the bulk of the habitat functioning once they arrive.
I don't think this is necessarily true. Humans are more versatile than robots, and potentially better at doing a number of things, but it seems silly to send humans to Mars to be what amounts to forklift operators.
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Re: Designing a (Totally) self sufficient Mars colony

Postby PM 2Ring » Wed May 01, 2013 1:13 pm UTC

Ciber wrote:As such I maintain that the most cost effective way to achieve the stated mission goals is to send our first wave of colonists as the second launch with the first having been a testbed launched in the previous launch window and the third being full of supplies and launched at the same time as the second but on a slower less energy intensive transfer.
[...]
Well actually the first ship to arrive is the supplys, the third has all the construction equipment.


What's the rush? We should use minimal energy transfers for all launches so as to maximize the payload mass relative to the energy cost. OTOH, I guess there is the issue that longer journeys mean a higher space radiation hazard for the personnel.

Izawwlgood wrote:Humans are more versatile than robots, and potentially better at doing a number of things, but it seems silly to send humans to Mars to be what amounts to forklift operators.

Indeed. Robots may not be (currently) able to do everything we'd like them to do in setting up the colony, but it makes sense (IMHO) to get as much of the job done as is practical before any humans arrive.

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Re: Designing a (Totally) self sufficient Mars colony

Postby tomandlu » Wed May 01, 2013 2:04 pm UTC

Okay, we send some slow-boats with supplies, then, when everything essential is verified as down and safe, we can send our colonists as fast as possible. I'm a bit sceptical about what these robots are going to accomplish, and I don't think they're necessary. We will have the colonists' landing-craft for an initial habitat, inflatable bio-spheres for habitats and hydroponics (shielded as necessary), and if we're building air-tight further habitation stuff out of local materials, I'm not sure how confident I'd be in the work of a robot. I'd rather use the cargo space for some other resource or human-usable tool or equipment.
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Re: Designing a (Totally) self sufficient Mars colony

Postby idobox » Wed May 01, 2013 3:17 pm UTC

tomandlu wrote:Okay, we send some slow-boats with supplies, then, when everything essential is verified as down and safe, we can send our colonists as fast as possible. I'm a bit sceptical about what these robots are going to accomplish, and I don't think they're necessary. We will have the colonists' landing-craft for an initial habitat, inflatable bio-spheres for habitats and hydroponics (shielded as necessary), and if we're building air-tight further habitation stuff out of local materials, I'm not sure how confident I'd be in the work of a robot. I'd rather use the cargo space for some other resource or human-usable tool or equipment.

That's the thing, your hydroponics or photobioreactors will need to be huge to support humans. I have found the number of 1.2acre of farmland to produce enough food for one human on Earth, which is roughly equal to 5000m², and it doesn't count all the forest and ocean needed to treat waste. Even with high yield and stuff, you will need a lot of space, which means large heavy infrastructure, and that's why I think it's crucial to have local glass production.

Copper Bezel wrote:I still don't understand why test bed, supplies, colonists doesn't make sense. I agree that the robotics required to have a self-assembled Holiday Inn waiting for the first colonists to arrive are far beyond what we're capable of now. Realistically, the colonists are going to have to do some heavy lifting to get the bulk of the habitat functioning once they arrive.

I'm talking of building the walls of the habitat, flattening areas to put machines shipped from Earth, that kind of things.
Collecting surface rocks is not that difficult, crushing and melting it is not exactly rocket science, even though it has never been done in these conditions.

If some steps are really delicate and need human control, the best solution would be to send humans in Mars orbit for a few months, and control the surface robots without delay.

Sustaining a human for more than a few weeks require massive infrastructure, and we need most of the less delicate stuff to be done before hand. To give an order of comparison, ISS receives 7 to 8 automated resupply missions a year, plus a few manned missions, and has a crew of 6. It gives you an idea of how much stuff we must carry for every month of human presence before the colony starts producing oxygen and food by itself. And if the guys have to build brick walls, they're going to need much more air and food than free floating scientists.
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Re: Designing a (Totally) self sufficient Mars colony

Postby Izawwlgood » Wed May 01, 2013 6:31 pm UTC

idobox wrote:I have found the number of 1.2acre of farmland to produce enough food for one human on Earth, which is roughly equal to 5000m², and it doesn't count all the forest and ocean needed to treat waste. Even with high yield and stuff, you will need a lot of space, which means large heavy infrastructure, and that's why I think it's crucial to have local glass production.
Quantity wise, this is for 'soil grown agriculture', and can be reduced at the very least a bit for hydroponics. Also, it assumes Earth growing conditions and crop choice; presumably, anything you're growing on Mars is going to be at least somewhat optimized for higher CO2, lower gravity, etc. But sure! It will take a lot of growing stuff to sustain colonists.
To that end, I suggest not bottlenecking your initial growing by the availability of sunlight. Instead of making a 10 square acre factory farm, why not make a single acre building with 10 layers of growing beds, and power it with LEDs, which draw power from solar paneling up top, and the colonies power source?

Additionally, you don't need glass to roof a greenhouse; plastics are probably more readily available, and potentially cheaper and more resilient. At the very least, doesn't require silica sources, and ethylene is the opposite of in short supply.

idobox wrote:If some steps are really delicate and need human control, the best solution would be to send humans in Mars orbit for a few months, and control the surface robots without delay.
Out of curiosity, what can a human do in LMO that they cannot do on Earth?

idobox wrote:Sustaining a human for more than a few weeks require massive infrastructure, and we need most of the less delicate stuff to be done before hand. To give an order of comparison, ISS receives 7 to 8 automated resupply missions a year, plus a few manned missions, and has a crew of 6. It gives you an idea of how much stuff we must carry for every month of human presence before the colony starts producing oxygen and food by itself. And if the guys have to build brick walls, they're going to need much more air and food than free floating scientists.
That's a great baseline comparison. The ISS is, however incapable of producing anything, which is something our colony will hopefully be able to do in short order, if not right off the bat.
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Re: Designing a (Totally) self sufficient Mars colony

Postby Heisenberg » Wed May 01, 2013 8:12 pm UTC

Sunlight is free! LEDs are expensive and heavy!

I don't see what you're gaining by building a 10 story building. Towns start with 1 and 2 story buildings because they're cheap and easy. People don't build 10-story buildings until land gets prohibitively expensive. Land on Mars is not expensive. We should build a bunch of one-story buildings.

If you're worried the sunlight won't be enough to grow crops then by all means bring along some LEDs, but light and space are both free on Mars, let's use them.

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Re: Designing a (Totally) self sufficient Mars colony

Postby Izawwlgood » Wed May 01, 2013 8:16 pm UTC

Heisenberg wrote:building a 10 story building
Izawwlgood wrote:10 layers of growing beds
Hombre, how big do you think crops are?
Heisenberg wrote:If you're worried the sunlight won't be enough to grow crops then by all means bring along some LEDs, but light and space are both free on Mars, let's use them.
I'm not sure why this point is so difficult to understand; if your BOTTLENECK is glass production, I'm suggesting not limiting yourself to how much surface area you can make transparent. That then sets up a bottleneck of light intensity; since you should supplement with LEDs anyway, why bother waiting for windows?
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Re: Designing a (Totally) self sufficient Mars colony

Postby Heisenberg » Wed May 01, 2013 8:28 pm UTC

Izawwlgood wrote:
Heisenberg wrote:building a 10 story building
Izawwlgood wrote:10 layers of growing beds
Hombre, how big do you think crops are?
I'm sorry. Are we sending a colony of dwarfs? Don't you want access to your crops?
Izawwlgood wrote:if your BOTTLENECK is glass production, I'm suggesting not limiting yourself to how much surface area you can make transparent. That then sets up a bottleneck of light intensity; since you should supplement with LEDs anyway, why bother waiting for windows?
Martian sun is just fine for growing crops. And if your bottleneck is glass, you should probably not use glass and use a better material, as you suggested in your last post.

When did we rule out transparent materials anyway? We can postulate about magic Holiday Inn-building Roombas but we can't make a wall you can see through?

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Re: Designing a (Totally) self sufficient Mars colony

Postby PossibleSloth » Wed May 01, 2013 9:07 pm UTC

Izawwlgood wrote:Out of curiosity, what can a human do in LMO that they cannot do on Earth?

I think he's saying they could directly control robots for jobs that require human control. It might be useful to have them go over the colony this way before actually landing.

Heisenberg wrote:I'm sorry. Are we sending a colony of dwarfs? Don't you want access to your crops?

We're not going to be growing corn or apple trees at the beginning. You could easily grow soybeans in hydroponic racks a few feet apart (assuming artificial illumination).

As far as the LED debate goes, chlorophyll has a pretty narrow absorption spectrum. Maybe it would be more efficient to use solar to power frequency specific LEDs (though probably not :P ). I'm guessing the best solution will be some combination of plastic bubbles and LEDs.

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Re: Designing a (Totally) self sufficient Mars colony

Postby Izawwlgood » Wed May 01, 2013 9:51 pm UTC

Heisenberg wrote:I'm sorry. Are we sending a colony of dwarfs? Don't you want access to your crops?
Yes, if only we had the technology to allow someone to reach something as high as 15 feet! With any luck, by the time we put humans on Mars, science will have found an answer!

My issue with a single layer agricultural program is that A ) it maximizes the potential risk from biome sealant failure instead of minimizes it, and B ) it maximizes the distance pumps must pump liquid (from one end of the greenhouse to the other, and all the grow beds need to be terraced, meaning at a great enough distance, your plants may be at roof level anyway). I see a multistacked hydroponics setup as superior in this regard because it allows you to minimize sealant failures, maximizes the efficiency of pumps, and doesn't result in wasted spectra falling on plants
Heisenberg wrote:When did we rule out transparent materials anyway?
We didn't; I've on a couple of occasions now mentioned plastics.
PossibleSloth wrote:We're not going to be growing corn or apple trees at the beginning. You could easily grow soybeans in hydroponic racks a few feet apart (assuming artificial illumination).

As far as the LED debate goes, chlorophyll has a pretty narrow absorption spectrum. Maybe it would be more efficient to use solar to power frequency specific LEDs (though probably not :P ). I'm guessing the best solution will be some combination of plastic bubbles and LEDs.
Basically this. Also, I think it's probably quite efficient to use solar power to supplement LEDs. At the very least, LEDs are much less energy intensive than people seem to think, and they'll probably be needed anyway for plant growth.
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Re: Designing a (Totally) self sufficient Mars colony

Postby Ciber » Wed May 01, 2013 11:56 pm UTC

Talking about using plastic for windows directly contradicts an earlier posters statement that carbon is rare on mars.
Talking like silica is rare directly contradicts the fact that mars is covered in sand. Though glass made from it may be red tinted.

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Re: Designing a (Totally) self sufficient Mars colony

Postby Izawwlgood » Thu May 02, 2013 2:29 am UTC

Ciber wrote:Talking about using plastic for windows directly contradicts an earlier posters statement that carbon is rare on mars.
From Page 1;
Izawwlgood wrote:Most of the atmosphere is comprised of CO2; pressurize it and inflate some greenhouses. React it with Hydrogen, bam, CH4 + Oxygen. You can also convert it to C2H2, bam, plastics industry.
We've been talking about making plastic on Mars since then. Ethylene is the precursor to... a lot... of plastic polymers.
Ciber wrote:Talking like silica is rare directly contradicts the fact that mars is covered in sand. Though glass made from it may be red tinted.
From page 3;
Silica is not in short supply on Mars. As for why you think it would be red tinted; I imagine if you're smelting regolith, you can extract the iron, magnesium, or manganese impurities that may tint your product red.
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Re: Designing a (Totally) self sufficient Mars colony

Postby PM 2Ring » Thu May 02, 2013 11:23 am UTC

Izawwlgood wrote:
idobox wrote:If some steps are really delicate and need human control, the best solution would be to send humans in Mars orbit for a few months, and control the surface robots without delay.
Out of curiosity, what can a human do in LMO that they cannot do on Earth?

The Earth-Mars distance varies between about 3.2 light-minutes to over 22 light-minutes; that delay makes it very tricky to do delicate remote-control stuff, even at the small end of the range. At the large end, there's the additional complication that the Sun is in between Earth & Mars, which tends to interfere with communications.


Heisenberg wrote:Sunlight is free! LEDs are expensive and heavy!

By the time it gets to Mars, everything is expensive. Using current technology, it costs around $5000US to put a kg of stuff into space, and that's just near Earth orbit. So if you're paying $5000/kg for your potatoes, I reckon a kilo or two of LEDs could be a good investment. :)

Heisenberg wrote:Towns start with 1 and 2 story buildings because they're cheap and easy. People don't build 10-story buildings until land gets prohibitively expensive. Land on Mars is not expensive. We should build a bunch of one-story buildings.


I thought our habitats were mostly underground, to provide radiation shielding. Of course, a greenhouse needs to be exposed to the sunlight, but it will probably need some form of radiation shielding that is transparent in the visible spectrum. Fortunately, water fits the bill, if you have enough of it. But using LEDs may end up being the better option.

Even though our habitats are mostly underground, it still makes sense to pay heed to the square-cube law and make our excavations roughly spherical to maximize the volume / surface area ratio. The bigger the surface area, the more sealant you need to make the habitat air & water-tight, and the more area you have to lose heat through.

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Re: Designing a (Totally) self sufficient Mars colony

Postby idobox » Thu May 02, 2013 2:47 pm UTC

Izawwlgood wrote:
idobox wrote:I have found the number of 1.2acre of farmland to produce enough food for one human on Earth, which is roughly equal to 5000m², and it doesn't count all the forest and ocean needed to treat waste. Even with high yield and stuff, you will need a lot of space, which means large heavy infrastructure, and that's why I think it's crucial to have local glass production.
Quantity wise, this is for 'soil grown agriculture', and can be reduced at the very least a bit for hydroponics. Also, it assumes Earth growing conditions and crop choice; presumably, anything you're growing on Mars is going to be at least somewhat optimized for higher CO2, lower gravity, etc. But sure! It will take a lot of growing stuff to sustain colonists.
To that end, I suggest not bottlenecking your initial growing by the availability of sunlight. Instead of making a 10 square acre factory farm, why not make a single acre building with 10 layers of growing beds, and power it with LEDs, which draw power from solar paneling up top, and the colonies power source?

I used the only number I found, I expect hydroponics and bioreactors to be much more compact, but we have to be aware a 1m3 bioreactor cannot sustain a human.

Additionally, you don't need glass to roof a greenhouse; plastics are probably more readily available, and potentially cheaper and more resilient. At the very least, doesn't require silica sources, and ethylene is the opposite of in short supply.

Talking about using plastic for windows directly contradicts an earlier posters statement that carbon is rare on mars.

Ethylene will not be in short supply once you have greenhouses, but if you want ethylene to build greenhouses, you have a problm. To produce glass, you just need silica and heat, so it appears to be easier to produce in a first time.
Carbon is not especially rare, but it takes energy to turn it to a useful form. So we have two options, and we have to take into account energy and machine complexity to choose the best one. Glass breaks, needs purified sand, and is very energy intensive ; ethylene requires compressing the atmosphere, and feeding it to photosynthetic organisms, a process that is not very efficient, the transformation of ethylene requires more complex machinery, and plastic chemistry often requires additives.
Out of curiosity, what can a human do in LMO that they cannot do on Earth?

Control robots in real time. Which might be useful to speed up some sensitive operations like plumbing, starting the nuclear reactor or assembling bioreactors.
It also allows a rather low deltaV budget to come back when supplies run out.

idobox wrote:Sustaining a human for more than a few weeks require massive infrastructure, and we need most of the less delicate stuff to be done before hand. To give an order of comparison, ISS receives 7 to 8 automated resupply missions a year, plus a few manned missions, and has a crew of 6. It gives you an idea of how much stuff we must carry for every month of human presence before the colony starts producing oxygen and food by itself. And if the guys have to build brick walls, they're going to need much more air and food than free floating scientists.
That's a great baseline comparison. The ISS is, however incapable of producing anything, which is something our colony will hopefully be able to do in short order, if not right off the bat.

That's my point, we need the colony to be able to produce air and food very quickly once the crew is here. We can't send humans to pile up bricks, because we will then need years worth of food and oxygen.

PM 2Ring wrote: thought our habitats were mostly underground, to provide radiation shielding. Of course, a greenhouse needs to be exposed to the sunlight, but it will probably need some form of radiation shielding that is transparent in the visible spectrum. Fortunately, water fits the bill, if you have enough of it. But using LEDs may end up being the better option.

I'm a big fan of photobioreactors and LEDs. Algae culture in a closed environment is rather easy, compared to growing more common crops (cf biosphere), and more efficient. Also, the local sun power is rather low (30% or so of what we have on Earth), especially if we go to the pole to access water and CO2 ice deposits, and we will have nuclear power available. If you really want, you can put them on the surface to a get more light.

Even though our habitats are mostly underground, it still makes sense to pay heed to the square-cube law and make our excavations roughly spherical to maximize the volume / surface area ratio. The bigger the surface area, the more sealant you need to make the habitat air & water-tight, and the more area you have to lose heat through.

Heat dissipation might be a problem actually. It's cold on Mars, but the atmosphere is a poor heat sink, and we'll have a bunch of stuff producing heat (power generator, photosynthesis, humans running around, eventual production of materials like metal, glass or plastics, etc...).
Compact shapes are still a good idea to save sealant and reduce leak risks.
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