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Moon Earth

For Moon Missions, Researchers Test a 3D-Printable, Waterless Concrete (technologyreview.com) 31

"If NASA establishes a permanent presence on the moon, its astronauts' homes could be made of a new 3D-printable, waterless concrete," writes MIT Technology Review. "Someday, so might yours.

"By accelerating the curing process for more rapid construction, this sulfur-based compound could become just as applicable on our home terrain as it is on lunar soil..." Building a home base on the moon will demand a steep supply of moon-based infrastructure: launch pads, shelter, and radiation blockers. But shipping Earth-based concrete to the lunar surface bears a hefty price tag. Sending just 1 kilogram (2.2 pounds) of material to the moon costs roughly $1.2 million, says Ali Kazemian, a robotic construction researcher at Louisiana State University (LSU). Instead, NASA hopes to create new materials from lunar soil and eventually adapt the same techniques for building on Mars.

Traditional concrete requires large amounts of water, a commodity that will be in short supply on the moon and critically important for life support or scientific research, according to the American Society of Civil Engineers. While prior NASA projects have tested compounds that could be used to make "lunarcrete," they're still working to craft the right waterless material.

So LSU researchers are refining the formula, developing a new cement based on sulfur, which they heat until it's molten to bind material without the need for water. In recent work, the team mixed their waterless cement with simulated lunar and Martian soil to create a 3D-printable concrete, which they used to assemble walls and beams. "We need automated construction, and NASA thinks 3D printing is one of the few viable technologies for building lunar infrastructure," says Kazemian.

Beyond circumventing the need for water, the cement can handle wider temperature extremes and cures faster than traditional methods. The group used a pre-made powder for their experiments, but on the moon and Mars, astronauts might extract sulfur from surface soil.

Kazemian and his colleagues recently transferred the technology to NASA's Marshall Space Flight Center for further testing...

For Moon Missions, Researchers Test a 3D-Printable, Waterless Concrete

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  • To extract sulphur from lunar rock?

    • by wierd_w ( 1375923 ) on Monday December 02, 2024 @05:05AM (#64984625)

      I dont see how it is even necessary.

      If it were me, I would not consider sulfur at all. I would have 3 machines there:

      1) mobile glass pot furnace
      2) rock crusher
      3) laser based sintering system to do the 3d printing.

      The minerology of the moon is significantly composed of silicon oxides and aluminum/magnesium oxides. This means it can be turned *DIRECTLY* into mullite glass.

      It is rather energy expensive (and thus bad for the laser) to do this directly with just the printer robot. However, once glass is made, it has a SIGNIFICANTLY lower melting point than the initial crystallized minerals used to make it. Melting it in an induction pot furnace, cooling it, then smashing it into smalt mix powder, would provide ample binder for use with the laser sintering robot. It could be mixed with the raw regolith as a bulk filler, same as with the sulfur based concrete idea.

      • Even simpler, use solar power. Plenty of it there. Use mirror furnaces, like they use at Odeillo in France. 3000 degrees not enough? And free power, once you get your mirrors built. Even the mirror structures can be made slimmer, only 1/6th gravity to worry about. I can't see a downside.
        • Yes, the sunlight on the moon is extremely intense and unfiltered by any atmosphere. You wouldn't even have to completely melt the lunar dust, just sinter it.

  • On the moon. Just a barren dust
    • by Z80a ( 971949 )

      It's more like a bunch of micro knifes that scratch and cut like hell rather than regular earth dust.
      But on the other hand, there's low gravity and Helium-3 there, which are pretty useful.

      • Even though there is more He3 on the moon than on earth it is still in very low amounts and would be very challenging to harvest.

    • On the moon. Just a barren dust

      The term used in the scientific literature is "regolith", basically meaning pulverized rock.

      "Lunar soil" is the popular term, not the scientific one. Basically the word has problems because "soil" means different things to different groups of people.

  • by wierd_w ( 1375923 ) on Monday December 02, 2024 @04:57AM (#64984619)

    Lunar regolith is composed of a significant fraction of alumium oxide and silicate mineral, meaning it can be thermally fused into mullite glass.

    https://www.lpi.usra.edu/publi... [usra.edu]

    https://www.nature.com/article... [nature.com]

    If they are heating that shit up with a thermal source anyway, why carry the sulfur up there in the first place?

    Martian regolith is more... varied... in its composition. I can see the need to consider bringing a binder up with the mission to get started...

    But the moon?

    Just laser sinter that shit in-situ.

    • by McLoud ( 92118 )

      Lunar regolith is composed of a significant fraction of alumium oxide and silicate mineral, meaning it can be thermally fused into mullite glass.

      https://www.lpi.usra.edu/publi... [usra.edu]

      https://www.nature.com/article... [nature.com]

      If they are heating that shit up with a thermal source anyway, why carry the sulfur up there in the first place?

      Martian regolith is more... varied... in its composition. I can see the need to consider bringing a binder up with the mission to get started...

      But the moon?

      Just laser sinter that shit in-situ.

      Given the amount of Iron on Mars, couldn't we use it instead?

      • Given the amount of Iron on Mars, couldn't we use it instead?

        The amount of iron in Mars' surface rocks is not significantly different to that on Earth. What makes the (modest) difference in colour is that the surface iron is more oxidised than most other planets, so there is a higher proportion of Fe3+ : Fe2+ ; meanwhile on Earth, you rarely see the colour of the rocks for the organic matter coating it.

        But ... take a Mg-mineral ; substitute Fe for the Mg ; more often than not the melting point goes up. Bec

    • Just need a big mirror to melt the regolith. No need to make electricity and then a laser, if all you want is heat.
    • Lunar regolith is composed of a significant fraction of alumium oxide and silicate mineral, meaning it can be thermally fused into mullite glass.

      Aluminosilicate glasses are extremely high melt-temperature materials, with typical melt temperature of about ~1900 C. The thermal problems here are immense. And if you're accepting process temperatures this high, just simply melt the regolith directly-- lunar regolith should melt about 1320 C, which is still pretty hot.

      On the other hand, sulfur melts at 115 C. Your choice.

    • Don't even need lasers, just make mirror furnaces with the intense, unfiltered solar energy.

  • Made from faux Martian and lunar soil, a new sulfur-based compound could also lead to faster construction on Earth.

    I find it unlikely that anything based on sulfur is going to work on Earth. I'm not a chemist so I can't say for sure but I have the sneaking suspicion that it may smell of sulfur as it breaks down.

    It could benefit construction on Earth, too. Kazemian sees the new material as a potential alternative for traditional concrete, especially in areas with water scarcity or a surplus of sulfur. Parts of the Middle East, for example, have abundant sulfur as a result of oil and gas production.

    Well there's a great idea, just encourage the production of oil and gas. /s -_-

    • It's not so much encouragement of oil / gas production, as a use for a waste stream coming from existing oil / gas production.

      That's not necessarily a terrible thing, depending on what that sulfur is used for currently - if they're just putting it in a big hole in the ground, this is better.

  • But a few questions:
    1) this lunarcrete uses molten sulfur as a binder; but S melts at 235F/112C. The surface temp of the moon in day can hit 121C. Um....?
    2) while energy on the moon (in the right places) is abundant and effectively limitless, going for a molten product seems...overengineered? The moon's gravity is only 1/6 of Earth's, it would seem to me that compression-blocks (just sifted and maybe doped) of lunar soil would be absolutely adequate for a majority of general-use roles? Particularly when

    • The moon's gravity is only 1/6 of Earth's, it would seem to me that compression-blocks (just sifted and maybe doped) of lunar soil would be absolutely adequate for a majority of general-use roles?

      Because of meteorites, I suspect that the vast majority of living and working spaces would have to be pretty far below the surface anyway. And the moon DOES have seismic activity, so something stronger than compression blocks might be needed. OTOH, maybe the inherent "give" in them might be an advantage in that situation.

      • OTOH, maybe the inherent "give" in them might be an advantage in that situation.

        That's going to make keeping an atmosphere inside the structure so much easier.

        Alternatively, you build your pressure vessels inside (and not connected to the walls of) structures made of your "Lunacrete" or whatever, with sufficient overengineering that you're confident the roof isn't going to come in on the pressure vessel.

  • The group used a pre-made powder for their experiments, but on the moon and Mars, astronauts might extract sulfur from surface soil.

    Does anyone have a handy link for an analysis of lunar regolith? Does it contain 0.1% of S (so, 1000 tonnes processed per tonne of sulphur produced)? Or 0.01% S (so 10,000 tonnes processed/ tonne sulphur produced)?

I'd rather just believe that it's done by little elves running around.

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