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NASA Designs 'Ice Dome' For Astronauts On Mars (phys.org)
An anonymous reader quotes a report from Phys.Org: The "Mars Ice Home" is a large inflatable dome that is surrounded by a shell of water ice. NASA said the design is just one of many potential concepts for creating a sustainable home for future Martian explorers. The idea came from a team at NASA's Langley Research Center that started with the concept of using resources on Mars to help build a habitat that could effectively protect humans from the elements on the Red Planet's surface, including high-energy radiation. The advantages of the Mars Ice Home is that the shell is lightweight and can be transported and deployed with simple robotics, then filled with water before the crew arrives. The ice will protect astronauts from radiation and will provide a safe place to call home, NASA says. But the structure also serves as a storage tank for water, to be used either by the explorers or it could potentially be converted to rocket fuel for the proposed Mars Ascent Vehicle. Then the structure could be refilled for the next crew. Other concepts had astronauts living in caves, or underground, or in dark, heavily shielded habitats. The team said the Ice Home concept balances the need to provide protection from radiation, without the drawbacks of an underground habitat. The design maximizes the thickness of ice above the crew quarters to reduce radiation exposure while also still allowing light to pass through ice and surrounding materials.
I still think they need to look into solar sintering based glass fiber production. Sinterable dust is all over on mars, and already loaded with melt temp reducing salts. The median bulk composition of Martian dust needs to be released for materials research, to see if viable glasses can be produced this way. (You just need a bead of glass and a centrifuge to spin off glass fiber. Even with the lower light levels, this should be doable on Mars. That gives the raw material for sandbag based habitat construction.)
So far though, I have yet to see a good bulk mineral assay of martian dust, only formulations for simulants that simulate texture for landings. That is not useful for evaluating glass quality for fiber production.
The martian water tends to be 2 kinds:
So saline that it will literally burn your skin off on contact (because it is basically bleach).
Frozen, and buried under a lot of overburden.
The first kind avoids sublimation and freezing due to its high salinity. It is useless for astronaut/colonist use. Would require extensive reprocessing to be made useful. Not cheap.
The second kind avoids sublimation due to the pressure exerted by the overburden, and the frigid deep soil temperatures of Mars. Mining it requires removal of the overburden (strip mining), which is not cheap. Once exposed, it will begin sublimating immediately. A great deal will be lost to this form of evaporation, and the mine strip will be geologically unstable, due to the volatility of the ice. Not cheap.
Putting dirt into sandbags? Potentially very cheap.
... I do have to admit, this one seems the best thought out (it's been covered here on Slashdot before). The level of detail that they went into on their work was impressive, on every front. Some of the unique concepts are rather interesting, such as having the outer ice shell shaped as a fresnel lens, thus concentrating sunlight to higher levels in the interior. I also like the nested aspects of it - providing a large uninsulated (but pressurized) staging yard (quite useful, particularly once you start ramping up ISRU and need room for lots of industrial systems and feedstock/output stockpiles), and an insulated greenhouse/courtyard around the primary shelter (nice thought toward human factors, as well as small scale agriculture). Having the primary shelter be constructed on Earth and simply landed (with its interior space initially filled up with the hardware needed to make the outer radiation protection / pressure shell) hits all the right buttons as well. Having the "printer" slide along grooves in the shell it sprays out is also a lot more elegant of a design than many other potential alternatives.
Still, there's a massive amount of engineering and testing that would be needed to make such a thing. And a lot of in-situ demo missions as well for each aspect of the technology, especially the (no hardware design given) vaporization-based water recovery system, but up to and including a small scale inflate-and-print testbed.
For the love of Crom, am I the only one here who wants to keep the U.S. technologically competitive?
The idea I had in mind is more akin to a high temp version of a cotton candy machine.
A central vessel at the spin axis is under the focal point of a Fresnel lens. A small shaker chute dispenses more dust to this crucible as material is removed. The crucible has two or three small holes through which material may be expelled, and it rotates at several hundred rpm. The mechanical stretching needed for glass fiber comes from the fiber hitting the side of the hopper, while the axis continues to rotate. This should produce a cotton wool like glass fiber, which should be workable into simple construction forms.
Due to the aridity, even water soluble glasses may end up being useful, if nothing else but for creating dust collection filters for atmospheric concentrators.
Have you seen any basalt fiber production process that actually works like that? I haven't. I would hesitate to say that it "should", because if it did, I'd expect people to use it.
As for the heating: it's hard enough to melt things like zinc with sunlight. Hot enough to melt basalt with just sunlight? On Mars? Now that's a very tall order.
Again, you keep saying "glass". Mars is basaltic, not rhyolitic. You're talking basalt fiber. And the main mechanical properties you need for most applications are tensile/yield strength and young's modulus, as well as creep and flexural behavior. And getting the desired properties means using an appropriate source material.
And I'm still not sure for what purpose you brought this up in relation to building habitats. Basalt fiber reinforced concrete is very much a real thing (I'm actually getting ready to build a basalt fiber reinforced house), but again, it'd be much simpler/cheaper/more reliable just to import your fiber from Earth, at least while one is just getting a colony established.
For the love of Crom, am I the only one here who wants to keep the U.S. technologically competitive?
When I say "glass", it is not necessarily "amorphous silicon dioxide". It is more " amorphous phase metal oxide". It need not be silicon oxide.
"glass" refers to its structure, not composition.
glass thus does not require silicon to be created. an example is oxide glass, made from 90% alumina.
there ARE clay formations and claystone formations on mars, which would produce viable glasses.
As for solar only based sintering (on mars), I still think it is doable, and could be simulated on earth with appropriate feedstocks, and occultation of the Fresnel lens to model the 60% or so reduction of solar intensity.
A Fresnel lens from a big screen rear projection TV produces a focal point suitable for this purpose on earth. (It can melt pure silicon oxide without a flux, which has a vitreous transition temp of 1475k) We would need a significantly larger one on mars, but still within the realm of being sent there rolled up in a shipping tube.
I don't doubt that it's possible; it's the rate that's the issue. Not knowing what your goal is (aka, what the fibers are for), it's hard to get a sense of how rapidly you'd need to melt it, and thus how big of a system you'd have to have.
For the love of Crom, am I the only one here who wants to keep the U.S. technologically competitive?