FECYT – Spanish Foundation for Science and Technology
The modules that the major space agencies plan to erect on the Moon could incorporate an element contributed by the human colonizers themselves: the urea in their pee. European researchers have found that it could be used as a plasticizer in the concrete of the structures.
NASA, the European Space Agency (ESA) and its Chinese counterpart plan to build moon bases in the coming decades, as part of a broader space exploration plan that will take humans to more distant destinations, such as Mars.
However, the colonization of the Moon poses problems such as high levels of radiation, extreme temperatures, meteorite bombardment and a logistical issue: how to get construction materials there, although it may not be necessary.
Transporting about 0.45 kg from the Earth to space costs about $10,000, which means that building a complete module on our satellite in this way would be very expensive. This is the reason why space agencies are thinking of using raw materials from the moon’s surface, or even those that astronauts themselves can provide, such as their urine.
Scientists from Norway, Spain, the Netherlands and Italy, in cooperation with ESA, have conducted several experiments to verify the potential of urine urea as a plasticizer, an additive that can be incorporated into concrete to soften the initial mixture and make it more pliable before it hardens. Details are published in the Journal of Cleaner Production.
“To make the geopolymer concrete that will be used on the moon, the idea is to use what is there: regolith (loose material from the moon’s surface) and the water from the ice present in some areas,” explains one of the authors, Ramón Pamies, a professor at the Polytechnic University of Cartagena (Murcia), where various analyses of the samples have been carried out using X-ray diffraction.
“But moreover,” he adds, “with this study we have seen that a waste product, such as the urine of the personnel who occupy the moon bases, could also be used. The two main components of this body fluid are water and urea, a molecule that allows the hydrogen bonds to be broken and, therefore, reduces the viscosities of many aqueous mixtures.”
Using a material developed by ESA, which is similar to moon regolith, together with urea and various plasticizers, the researchers, using a 3D printer, have manufactured various ‘mud’ cylinders and compared the results.
The experiments, carried out at Østfold University College (Norway), revealed that the samples carrying urea supported heavy weights and remained almost stable in shape. Once heated to 80°C, their resistance was also tested and even increased after eight freeze-thaw cycles like those on the Moon.
“We have not yet investigated how the urea would be extracted from the urine, as we are assessing whether this would really be necessary, because perhaps its other components could also be used to form the geopolymer concrete,” says one of the researchers from the Norwegian university, Anna-Lena Kjøniksen, who adds: “The actual water in the urine could be used for the mixture, together with that which can be obtained on the Moon, or a combination of both.”
The scientists stress the need for further testing to find the best building material for the moon bases, where it can be mass-produced using 3D printers.
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References:
Shima Pilehvar, Marlies Arnhof, Ramon Pamies, Luca Valentini, Anna-Lena Kjøniksen. “Utilization of urea as an accessible superplasticizer on the moon for lunar geopolymer mixtures”. Journal of Cleaner Production 247, 20 February 2020.
Than, they can’t recycle urine to water, what id better ?
If they use urea for building, they will have to find something else to fertilize the plants with.
Actually, the water may be recovered during “curing” via vacuum processes and make the concrete structure even stronger. Various methods of deposition construction (aka 3D-printing) have been proposed. It may even be useful to create a lunar regolith CMU (Concrete Masonry Unit aka cinder block) during water extraction/purification with the outputs being useful building blocks and potable water.
Surely you’re taking the p***?
It is also good for promoting initial breakdown of organic waste in the creation of compost.
The stable muck cleared out every day is used to create compost mostly because of the horse piss, which gets all the thermophilic bacteria going just beautifully….
How much will it cost to send up enough coffee and beer to get a useful amount of urine for making geopolymers? ;o)
Seriously though, how much urine would it take to get enough urea to make a structure of even modest size, say 3m x 3m?
In my opinion, they would be better off taking a tip from our ancestors and become cave dwellers; dig out underground shelters. Erecting structures requires materials. Digging just requires time.
Actually, urine was a major commodity in mediaeval economies. Used by tanners and dyers. Big manual collection process – sewers were hardly needed…
Around 9 grams urea per 24 grams of urine. A better use would be fertilizers. What one really need on the moon would be large amounts of energy. Plasma to make underground habitats. Actually, underground would seem to be easiest provided enough energy compared to any method/materials to build on the surface.
The more interesting issue is the purpose/benefit of Moon Base Human? Other than sci-fi writers.
“The more interesting issue is the purpose/benefit of Moon Base Human? Other than sci-fi writers.”
I would say a human Moonbase is one of the first steps in humans moving off the Earth permanently, which means it is one of the first steps in saving human civilization and the other creatures of the Earth from a catastophic end.
I think the common idea is to use it to stage for a large Mars mission. You could build a larger ship in Moon orbit and require a lot less energy to leave than trying to achieve Earth escape velocity, I suppose. That’s what I’ve seen thrown around anyway.
Will potatoes grow in it?
Use solar furnaces to melt the dust and form bricks.
As to the benefit, it costs a lot less to launch material from the moon compared to launching it from earth. Mine the moon and refine that materials to make the structural components for ships and orbiting structures. The high tech components will probably need to come from earth for awhile.
“….A better use would be fertilizers. What one really need on the moon would be large amounts of energy…..”
That would be for the urea – almost certainly the most important product from urine would be water.
Energy should be readily available from photo cells during the lunar day. Though nuclear is always going to win out for reliability…
There may be enough water at the lunar poles to support a sizeable human colony. Biological 3D printers could used to construct 1000’s of kidneys which could then produce the required urea.
Problem solved.
The main benefit of a manned moon base would be to galvanize public support for the space program. Unmanned probes and landers are cool toys, but few outside the scientific and science fiction communities care. Manned missions are what captures the world’s attention, especially if you can spin them to imply that someday anyone could go out there.
The main benefit of a manned moon base is, with proper equipment, any position on the moon (including back side) can at any time hit any point on planet earth with a laser strong enough to destroy an ICBM in boost phase.
Just make sure that you really, really, really trust those who are in control of the laser.
See The Moon Is a Harsh Mistress.
“In my opinion, they would be better off taking a tip from our ancestors and become cave dwellers; dig out underground shelters. Erecting structures requires materials. Digging just requires time.”
There are a lot of lava tubes on the Moon. Of course, structures would still be needed even in a lava tube. I guess they are going to build concrete blocks with 3-D printers and use those as structural materials.
Who will build the first structure on the Moon? I think we have a race going. 🙂
How are you going to build concrete blocks with 3D printers? They don’t print concrete, they print plastic. You’d need a LOT of 3D printer filament to make even one structural block of plastic.
Most of the current 3-D printers print plastic, however they have built 3-D printers that use titanium powder. They have also built ones that spray concrete. I read an article back in the 80’s where someone was trying to develop a 3-D printer that could be used to build houses.
I’m working on a 3-D printer that builds 3-D printers.
@Michael S. Kelly
That is the basic test of a 3D printer, one that can self replicate.
Wrong there are 3D printers that use Concrete. Buildings have been printed. Military has done it also.
There are also 3D printers for various other materials.
I just assumed they were going to create cement blocks the way they did in the quote below:
“Using a material developed by ESA, which is similar to moon regolith, together with urea and various plasticizers, the researchers, using a 3D printer, have manufactured various ‘mud’ cylinders and compared the results.”
I’m not an expert in 3-D printers, so I don’t know how practical this idea is. I would think if you have all the ingredients together on the Moon, that you could mix it up the old-fashioned way, and form it into blocks.
“old-fashioned way” Two guys with mortar hoes working mud in a box and dumping it in molds! That would certainly get the backing of brick mason’s union. 😉
I was watching one of those interesting TV shows on advanced construction designs and techniques and someone had developed a very large type of concrete 3D printer that could print an entire house in 48 hours with a crew of 4 around the clock. It wasn’t actually concrete but more like a sprayable Shotcrete with a plasticizer agent. The final result, including a structural roof that was part of the exterior and interior walls, was like an Adobe mud house, but made out of a high tech type cement.
They were using programmed robots for forming on the fly, and rebar placement including all conduit placement for electrical/utilities as they went. They would start at a level concrete base/pad and work around in a continuous build-up, all timed per section to be 3D printed in one continuous ‘pour’. It was actually quite an interesting concept that they were hoping to commercialize. I am a big fan of innovation and efficiency.
I saw something similar, in China, but rather than houses they printed out tower blocks of apartments which then had all the electrics and plumbing attached and simply locked together like Lego bricks.
https://www.cnet.com/news/worlds-first-3d-printed-apartment-building-constructed-in-china/
Seems the tactic is a version of “slip form” construction. This is taking opposing boards held level apart parallel at your desired wall thickness & putting into that horizontal chamber your wall material.
Then when the section cures you “slip” the boards up to run another course of wall & so on until achieve wall height you want. It is economic in terms of reusable construction framing material required to build up a wall.
There is however significant time involved fussing with the “slip” form, recreating it’s leveling & bracing once get above the foundation. I used slip form construction to make a thick thermal wall; large rocks collected nearby got put into the form chamber & batches of mixed cement were poured into the chamber atop those rock repeatedly.
Rammed earth walls can also be made using the slip form technique. Packing & tamping mud repeatedly into the form chamber by muscle power is physically too taxing for me though.
@ gringojay
This bridge was essentially “slip formed” over the river. The lanes were “printed” laterally in concrete (like an inkjet) and extended from both ends at once.
Amazing structural engineering.
https://www.figgbridge.com/i-91-brattleboro-bridge
They would likely not need to dig holes to live in. There is evidence of lava tube caves on a significant portion of the moon. These could be used to build shelters.
Don’t need to dig there are existing caves and lava tubes
That would be some stinky house they build. I say piss on this idea, not on the house.
Have they just discovered the secret ingredient in Roman concrete?
Which came first the piss or the house?
Chinese, every time I read/hear about anything chinese I get nervous…
And aromatic
Water is a valuable resource that would be better used in a continually recycled loop. To build structures maybe we should laser sinter moon dust.
In the process of collecting the urea other chemicals will be separated out. It would be a win/win.
Well, ain’t that a pisser.
Is that how they made the Chinese drywall that infected so many houses?
Give a whole new meaning to pi@@ing contest doesn’t it?
Colonists to the New World used pee to make gun powder and other items so this is just the next step!
Wine drinker’s urine was a valued commodity in France for gunpowder manufacture.
Human ingenuity, gotta love it!
Does any of this solve the #1 problem of radiation exposure?
Living deeper underground would limit radiation exposure, as well as provide excellent protection from micro meteorites which might be a larger problem due to no atmosphere to burn them out before reaching the surface. As others have noted, the lava tubes already exist and will just require some habitat construction deeper under the surface. Plus good insulation properties. If I get a chance, I would love to spend my final days in an old folks home on the Moon. Gravity on the good Earth is just getting a bit too much for me. 1/6 gravity sounds swell to me.