Engineers Investigate a Simple, No-Bake Recipe to Make Bricks from Martian Soil | Hacker News Reader

Engineers Investigate a Simple, No-Bake Recipe to Make Bricks from Martian Soil

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107 pointsjameslk59 comments

It would be really tempting to go settle Mars. Just... Leave everything behind, and go.

I don't know why. Long-term survival seems unlikely for the first batch of colonists. It's almost inevitable that there will be some sort of disaster. And even if not, you'd have to live underground to avoid the radiation. Ever want to go for a walk? Not so easy on mars. Surely you'd start to feel caged after just a few weeks. Because you are.

And yet I can't get it out of my head how tempting it would be. Why? Is it genetic? I've heard that one reason neanderthals died out is they would migrate until running into an obstacle, like the ocean, and then settle there on their perfectly-good land. The net result was that neanderthals stopped expanding. Whereas we did things that didn't make sense: launch ourselves into the sea, for example. And now we want to launch ourselves into the vast nothingness of literally-nothing, to go live as moles in a confined area, possibly without most of the amenities we take for granted.

Yet I think I would. I just wish I could figure out why.

Part of it is a longing for community. Life sometimes seems so pre-packaged. It's an awesome life, to be sure, and in the society you're reading this comment in, you probably have a lot of power to affect your life. You could get rich. Or you could move to a new country, or decide what career you want. But it's all been done before. And I think Mars is an escape hatch from that. There, the frontier exists. Even if it's the life of a mole in a cage, it's a cage nobody has ever dared to build before. And that's exciting.

I'm glad to find out I'm not the only one - every since I read Red Mars I've loved the idea of colonising Mars even though I'm completely aware that rationally it is a completely daft idea.

"“Maybe it’s a little early… Maybe the time is not quite yet… But those other worlds – promising untold opportunities – beckon. Silently, they orbit the sun, waiting…”

Right - I'm off to watch Wanderers a few times...

> the idea of colonising Mars even though I'm completely aware that rationally it is a completely daft idea.

Here's some rational reasons for why it's a good idea:

* It would be a challenge, and (as there is lots of historical evidence for) innovation comes from people working on hard problems. So it would lead to innovations

* It would inspire a generation to be more interested in areas like science and technology

* The fresh start of a new planet would provide the opportunity for people to try out new forms of social structure. The founding of the USA is a historical example of this. Broken systems and structures is a big problem on earth right now.

* Ultimately if humanity only exist on a single planet, then it's at great risk of being wiped out by some catastrophe. Getting off earth is important for our future existence.

(A long time ago, I read Robert Zubrin's "The Case for Mars" and I think a lot of these ideas came from that. https://www.amazon.com/Case-Mars-Plan-Settle-Planet/dp/14516...)

It might be a sense of contributing to development of your society. Every brick you make is a significant visible improvement for everyone there. But on Earth, a lifetime's work is nothing compared to the whole world's output. You can't see if you're improving things, making things worse, or having no effect at all. If you do simple things like make bricks on Earth, they probably have negative value - somebody will have to do more work to break or discard them soon enough.

It will be a new frontier. The frontier's role is to strip us down to the essentials of life and survival, leaving behind layers of social mores so that individual, productive energy can flow without any other impediments than nature and what our mind can make of it.

From "The Frontier in American History" (1921) [1] written by historian Frederick J. Turner. The first chapter was an essay published in 1893.

> "The stubborn American environment is there with its imperious summons to accept its conditions; the inherited ways of doing things are also there; and yet, in spite of environment, and in spite of custom, each frontier did indeed furnish a new field of opportunity, a gate of escape from the bondage of the past; and freshness, and confidence, and scorn of older society, impatience of its restraints and its ideas, and indifference to its lessons, have accompanied the frontier. What the Mediterranean Sea was to the Greeks, breaking the bond of custom, offering new experiences, calling out new institutions and activities, that, and more, the ever retreating frontier has been to the United States directly, and to the nations of Europe more remotely."

[1] http://www.gutenberg.org/ebooks/22994

I know the feeling, although I think I might be (almost) as happy to be one of the folks here on earth helping to facilitate others' travel to mars.

I believe the importance of truly new frontiers like Mars is much higher than most think. They give a productive outlet to the most daring and restless, supply inspiration and drive for countless people, and generally help to move everything in a more positive direction. Factoring that in, the return on investment for such endeavors is unbeatable.

I find the whole proposition absurd mostly for reasons described in the post above. But humans are an absurd species, I guess I think more the way that Neanderthals did.

From your genes' perspective, successfully reproducing on Mars would be one the best things you could possibly do. The population of another planet would have a hell of a founder effect.

Only if the whole party doesn't die, which would almost certainly happen because Mars has the small problem of not supporting life. Also, family trees grow by merging, and ain't nobody on mars.

I think it's part of our nature to want to explore the unexplored and conquer the unconquered. It seems to be a recurring theme throughout our history that the latest fascination is always what lies just beyond the edge of civilisation. Whether it's the Orient from the perspective of European traders, the depths of the ocean or the hidden mysteries of the Amazon jungle to a Victorian adventurer, or any number of other intrigues from different cultural perspectives.

I agree that the main reason that Mars is so appealing is because modern life is so predictable. We've explored nearly everything on Earth and have set ourselves up to live a consistent, pre-planned life. Mars (and more broadly, space) represents a return to the mysteries of the past. Why live a normal, standardised life in commoditised modernity when we can live and die on the last remaining frontier?

Moden life is predictable because we've taken a massive energy debt out against the future with serious consequences for the biosphere to pay for it, big entropy is about to happen re climate change and soon you might find yourself in mad max.

I don't disagree with you though, we've made things temporarily boring for ourselves by indulging in far too much convenience and luxury.

I'm not sure that climate change is going to have that sort of effect within our lifetimes. Maybe in 100 or 200 years, which is why we're trying to avert it now - if worldwide disaster were due within 50 years I'm not sure there'd be any point to trying to scale down our greenhouse gas production.

This guy seems to think we've got that much time before all hell breaks loose due to runaway clathrate gun methane buildup and dramatic ocean level rise from both temperature expansion and glacial melt. I don't really like to think about it... https://guymcpherson.com/

So it's not really that predictable

You're a Human. Terminal wanderlust is a hereditary condition.

https://vimeo.com/108650530

The grass is redder on the other side?

I know why I would go, although realistically speaking there's no chance of that happening. Chasing new ventures makes me feel alive. That's the one thing I particularly enjoy about our industry, we get to try new things constantly. The Internet is like the ideal testing grounds. You have an idea, you create something on the spot. And there's no bigger adventure than colonizing Mars. Sure, going there means that you'll probably never see Earth again or even worse your relatives and friends. But you know, it doesn't matter that much. After all, we're all alone. Once you come in terms with that you become free.

We are, by nature, gluttons and that gluttony is insatiable in whatever infinite forms it takes (expansion, desire, fame, being the first, etc...) Explains pretty much our entire history.

Maybe it's just DRD4-7r gene.

Could also be the toxoplasma talking.

If we wait a bit longer, we can send robots instead.

Also, I don't think we are compatible with a different gravitational constant.

Gravitational constant is the same everywhere. The hint is in the name, "constant".

Just like "spring constant," which is the same for all springs.

He meant https://en.wikipedia.org/wiki/Standard_gravity

Reading articles like this, the first thing I think is "What about all the challenges that make just getting someone there seem like a pipe dream". Let's figure those out before we start to architect your Martian dream home.

Wet blanket? Its a false dichotomy - don't have to actually do one thing before another; can do them all at once. You can be sure folks are working hard on the problem of transporting humans across space.

Maybe I've missed the articles where people have really good ideas on how to protect travelers from solar radiation for the duration of the voyage, or maybe I've been misinformed on how big of a problem that is. I suppose I'd just like to hear that there is progress on these fronts, as well as playing with Martian mud. It feels like pandering to Sheldon's who dream of fleeing Earth.

Probably the latter, it's not that big a deal.

http://www.mars-one.com/faq/health-and-ethics/how-much-radia...

The article is obviously a little biased, but still seems reasonable.

But on top of all this, to me at least, is the question of how much should be expected of the pioneers. Should they be as safe as someone who buys an airline ticket? Or should they suffer increased cancer risk, an inability to return, limited living space, and so on?

I think that it wouldn't be unreasonable to even triple the radiation dose allowed modern NASA astronauts, who are expected to retire and live long healthy lives.

I find this surprising. I recall watching/reading accounts (from sources that were definitely on-board with the venture) claiming that unanticipated solar flares add a lot of complication.

But even disregarding the perils of such a trip, there's so much to contend with that makes it not just a exciting hot-spot for pioneer types. The static buildup due to soil up to 50 times as fine as dust on Earth (soil full of toxic perchlorate salts too), living for the rest of your life in 38% the gravity human bodies have evolved in, zero nature or anything else we evolved in, and of course living in a bio-dome without Pauly Shore.

I wish they'd teleport us there with better, and better, VR equipment. So everyone on Earth could experience Mars first hand.

Well, you could always go with the second wave.

NASA has already sent a number of robots there, starting with Viking in the 1970s. I'm confused as to why you say "if we wait a bit longer" unless you mean something with artificial intelligence.

We operate over a range of gravitational pulls today. Unfortunately its only 1% (from equator to pole). But that's something.

The regolith is always redder on the planet next door.

Some surprising materials have this property, including aspirin which can be formed into tablets with no other ingredients.

Sounds similar to rammed earth construction? https://en.wikipedia.org/wiki/Rammed_earth

Yes, this is rammed earth. Styling it as a discovery seems strange. Also strange:

> Researchers also investigated the bricks’ strengths and found that even without rebar, they are stronger than steel-reinforced concrete.

That's under compression, I'm sure.

No! Flexural strength of 50MPa!!! And rammed earth only has a compressive strength of 4.3MPa! Concrete has a flexural strength of around 30MPa, and I don't know math so I don't know what the reinforced concrete is like, but this is still stronger than even cooked bricks.

Here's the source publication: https://www.nature.com/articles/s41598-017-01157-w

It looks like because of the composition of the martian soil they figured this would never work without a bonding agent and that it would require heating, and then somebody tried it anyway, and it worked. But here's the neat takeaway: The method they used to form it, along with particle size, and whacking it versus slowly loading it, significantly strengthened the resulting bricks. Nobody expected these things to happen, it seems.

From article:

"Loading rates were either quasi-static [..] or impact [..]. The lateral boundary condition of compaction loading was either rigid (confined by a steel wall), free, or flexible (confined by an elastomeric wall)"

"Compacted Mars-1a solids were cut into beams and subjected to three-point bending tests"

"It is remarkable that the lateral boundary condition of compaction loading significantly influences the strength and the shape of the compacted solid, specifically, the thickness-to-diameter ratio. Compared with the boundary condition, the effect of loading rate is secondary."

"With the rigid boundary condition, the compacted Mars-1a samples are structurally integral but the flexural strength is relatively low, comparable with ordinary clay bricks. When the lateral boundary is free or flexible, R is nearly 3 times higher than that of rigid boundary condition.

Between the free and flexible boundary conditions, the flexible boundary condition reached high R at much lower Pmax and the resultant solid thickness was only slightly smaller than that of the rigid boundary condition, much larger than that of the free boundary condition. The strength-wise efficacy of forming inside a flexible boundary is ~150–200% greater than the free boundary for R ~30 MPa, taking into consideration the flexible boundary’s larger sample sizes."

Concrete alone has a shitty tensile strength, compared to its compressive strength. If you add steel cables to the concrete, the hybrid material's tensile strength increases.

Similarly, Cod is what you get when you add natural fibers and other material to rammed earth. Its tensile strength is also significantly higher due to the addition of the fibers.

So then my next question is: could they bring along some cheap fibers (like mylar?) to strengthen these Mars-1a bricks even more? Maybe the way the materials are forming now, they don't need added tensile strength, or the fibers could interrupt the formation somehow. But it's worth trying...

Impressive! Thanks for the paper link. The impact of flexible/free boundary condition is very interesting. It points to a key role for shear during compaction. Maybe grains rolling and locking?

For fibers, I wonder if asbestos would be available. Maybe too hazardous.

Edit: From the paper:

> With the flexible boundary condition, the particle motion is localized. Clearly, during compaction it is critical to allow rotation and transverse motion of Mars-1a particles, so as to maximize the effective contact area and to promote bond formation. Excessive particle motion, however, may introduce defects, which explains why the free boundary compensates with higher pressure to achieve similar R as the flexible boundary.

This is very cool. Martian regolith seems ideal for rammed earth construction.

I wonder how uniform Martian soil is. We have explored only a tiny fraction of the surface with actual robots. On Earth there is a huge variation between different regions. I would expect it to be similar on Mars.

Martian regolith is believed to be fairly uniform across the planet, and this is backed by analysis at several widely-scattered locations. The dust is definitely well-mixed, but coarser parts are mostly of local origin and can vary, but because of the lack of biological elements are much less varied than on Earth.

This is making me wonder if it might be a viable/useful construction technique on Earth, depending on how hard it is to make the Martian soil simulant.

It's been done:

> The Auroville red soil got its colour from iron oxides, which give excellent properties and make remarkable building materials.

http://www.earth-auroville.com/earth_in_auroville_introducti...

https://en.wikipedia.org/wiki/Adobe (mudbrick with straw as structural reinforcement) it already is, it was also similarly used for reinforcing statue casts (with hairs iirc)

If I've understood this correctly, Martian compressed soil is supposedly much better than Adobe due to its iron nanoparticles?

yeah was more a general answer to the innovative process of mixing texture with the mud

>Historically, additives such as lime or animal blood were used to stabilize it, while modern construction adds lime, cement, or asphalt emulsions.

Curious to know what filler material is practical on Mars. I suspect animal blood is out of the question, unless of course, we consider the human settlers. I can see some potential for an amusing modern-day Modest Proposal with the problem of colonizing Mars.

"The amount of pressure needed for a small sample is roughly the equivalent of someone dropping 10-lb hammer from a height of one meter, Qiao said." On Earth or with Mars's gravity?

I initially thought that too but realized it was a meaningless concern.

Even if you knew g, it wouldn't help because the pressure also depends on the thickness of soil it's landing on, as well as its mechanical properties - like how much it's already been compressed. A hammer dropped onto concrete exerts more pressure than it does dropped onto sand.

Also, what's the shape of the footprint of the hammer? Error in that will be more than the difference between Earth and Mars gravity.

See comments below for the link to their paper in Nature. Most relevant test case is "Impact test, Flexible boundary condition", where they give all the data on their test methodology.

If you load Supplementary Data, Figure S9[1], it shows 400MPa at 1ms. It also shows (for the above test) around 9mm displacement at what looks like 365MPa? I suck at math so I'll let someone else figure out the force.

[1] https://static-content.springer.com/esm/art%3A10.1038%2Fs415...

Wouldn't they just use a hand operated mechanical press though? Add hydraulics if you need more pressure.

Something like this thing: https://www.youtube.com/watch?v=v7rgjxHP-yA with whatever adjustments for the mold and needed pressure.

And are those metric lbs or imperial meters? That sentence is quite the example of unit confusion!

If they can make them into interlocking Lego-style blocks, creating cut & cover tunnels is pretty easy.

https://www.youtube.com/watch?v=LoRIztYmWjY

You can do this on earth, with more pressure.

https://en.wikipedia.org/wiki/Compressed_earth_block

http://www.dirtcheapbuilder.com/Home_Building/Earth_Block_Co...

Neat! But fwiw, the Martian bricks are up to 50 times stronger :3

Here's what The Onion, ahem, American voices have to say about it: http://www.theonion.com/americanvoices/scientists-constructi...

This seems like one of those things that you'd really want as a plan A but absolutely require sensible plan B as a backup.

Plan A would be to send some robots to try building using this technique.

If it doesn't work, you're only out a few robots (who may be able to be repurposed).

If it does work, leave them to it building a habitat which can be fitted out by further waves of robots later. By time that's all done the hard part of sending humans there will be more possible, and they'll have a base ready to move into.

Wall-e unit for compressing blocks and leaving a heap.

> Digitally reconstructed brick

Huh?

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