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Tom Kalbfus

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Registered: 2006-08-16

Posts: 4,401

Carving Lunar homes out of bedrock

This church gives me an idea of how we might build homes on the Moon. What if we built it out of the Moon itself. First we get some bulldozers and remove all the regolith down the bedrock, and then we carve a building by excavating voids, and the stuff left behind is the structure of the building. So instead of making lunar concrete, we just remove everything but the shape of the building we want, like the way this Ethiopian Church was made!

RobertDyck

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Re: Carving Lunar homes out of bedrock

There have been several proposals for Lunar habitats. One was a nuclear explosion to excavate a large cavern, then build in the cavern. The problem with that is the explosion fractures rock around it, leaving no structural strength. The cavern is prone to cave-in, and in most cases will collapse as soon as it's formed. And a nuclear explosion will leave a lot of radioactivity; do you really want to live in the centre of a radioactive hot-spot?

Another idea was to build a pressure dome on the Moon, and bury it with loose regolith. The regolith provides protection from micrometeors and meteorites. Since the Moon has no atmosphere, do we use the term "meteor" or "meteorite" or "meteoroid"? Anyway, it's the same piece of rock hitting you no matter what you call it. The regolith also provides radiation protection. Since the Moon has no atmosphere, it has much more radiation than Mars.

Another design called for a flat platform raised above an ISS-like habitat module, with regolith piled on the flat platform. Another design would use a soft inflatable with hollow tubes, like Michelin-Man. The hollow tubes would not be filled with air, but Lunar regolith. Considering how sharp Lunar sand and fines proved to be, I don't think that one was plausible. Lunar regolith is rock pulverized by multiple meteor and micrometeor impacts. It's freshly broken rock that never weathered. Another proposal called for digging an underground base using mining techniques, building pressurized modules within those mined spaces.

All these sound more practical than carving a geometric shape out of solid bedrock. Why carve solid bedrock when you can just use a front-end loader to move loose regolith that has the constency of mixed sand, fines, and gravel?
Lunar Regolith - NASA

The lunar surface is covered by a layer of unconsolidated debris called the lunar regolith (fig. 53). The thickness of the regolith varies from about 5 m on mare surfaces to about 10 m on highland surfaces. The bulk of the regolith is a fine gray soil with a density of about 1.5 g/cm3, but the regolith also includes breccia and rock fragments from the local bedrock (reviews by Heiken et al. 1974 and Papike et al. 1982). About half the weight of a lunar soil is less than 60 to 80 microns in size. The grain size distribution is given in figure 55.
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Figure 55 - Grain size distribution of mature lunar soil (75081) and orange soil (74220). About 10 percent of a lunar soil is greater than 1 mm, 50 percent is greater than 100 microns, and 90 percent is greater than 10 microns (from Heiken et al. 1974).

RobS

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Re: Carving Lunar homes out of bedrock

It is not clear the moon has much unfractured bedrock because there has been so much "impact gardening." The outer several kilometers of the moon is all fractured. But the presence of lava tubes--some of which may be several hundred meters across and many kilometers long!--show there is real bedrock and once you go down a few dozen meters, it isn't broken up top much. The lava tubes have real potential for settlement.

Tom Kalbfus

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Registered: 2006-08-16

Posts: 4,401

Re: Carving Lunar homes out of bedrock

The Earth probably has been impacted more times than the Moon because of its greater gravity would attract more asteroids and comets, also it is a bigger target to hit. Another problem is the Earth has plate tectonics and the Moon doesn't. The Ethiopians still managed to build their church. What I'm saying is why not build structures out of the Moon's bedrock itself instead of worrying about making cement in a vacuum. There has been talk of carving asteroids to make space habitats, why not make one out of the Moon itself?

RobertDyck

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From: Winnipeg, Canada

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Re: Carving Lunar homes out of bedrock

Here is a proposal from ESA. It does not use any form of concrete, just loose Lunar regolith piled on top. They are far from the first to propose this, but this is one design using current technology...

Void

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Registered: 2011-12-29

Posts: 7,082

Re: Carving Lunar homes out of bedrock

Its all good.  Frankly I am getting ready for a hibernation.  Getting tired of the P**** Fencing.  However here we go Jeff Bezos has a plan.  I really should just stop reading, but here it is...

http://www.space.com/35913-bezos-blue-o … ivery.html

Don't get me wrong, I love anyone who will handle reality like an adult (Better than me), but I confess I am getting tired.  But love the guy

Quote:

Bezos and Blue Origin Reportedly Pitch 'Amazon-like' Delivery for the

0  0 MORE

Blue Origin founder Jeff Bezos poses in front of his rocket.
Credit: Blue Origin
Jeff Bezos' space company, Blue Origin, reportedly pitched the new administration on setting up an "Amazon-like" delivery service for the moon.
In a January white paper circulated within NASA and the Trump transition team, Blue Origin proposed developing a cargo lander called Blue Moon that could support a future lunar base at the south pole, where there are both deposits of water ice and regions in almost constant sunlight.

Ya, I am ready for a hibernation, but wow!  Just what I wanted (sort of).  It will do quite well...

Nite Nite....

Last edited by Void (2017-03-04 19:26:06)

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Done.

SpaceNut

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From: New Hampshire

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Posts: 28,838

Re: Carving Lunar homes out of bedrock

Sorry for the absence from discusions but that is what happens when you need to fix up another clunker computer to be able to keep live to the net.

All versions of a lunar habitat start with the funding issue and then with the options of how the mass limitation and then finally with the limitations of power to make it all work to which when we add the human element in makes it go much slower and at a higher level funds required.

Tom Kalbfus

Banned

Registered: 2006-08-16

Posts: 4,401

Re: Carving Lunar homes out of bedrock

We can build stuff on the Moon before we send humans there, using teleoperated robots. Robot time is not as expensive as human time on the Moon. On Mars this is harder to do as we don't have near real time teleoperation as we do on the Moon. So all we have to do is send the machines to the Moon to carve habitats out of bedrock, before we send an actual human to live there. I'm pretty sure the machines would weigh less than the actual bedrock they would be carving. We would probably need to seal up the cracks with some resin so air doesn't leak out. And of course the airlock doors would probably have to be brought from Earth.

Void

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Registered: 2011-12-29

Posts: 7,082

Re: Carving Lunar homes out of bedrock

That's true Tom.

RobS in post #3 mentioned lava tubes, which naturally could be included with your ideas Tom

https://sservi.nasa.gov/articles/lava-tube-lunar-base/

Natural caverns occur on the moon in the form of ‘lava tubes’, which are the drained conduits of underground lava rivers. The inside dimensions of these tubes measure tens to hundreds of meters, and their roofs are expected to be thicker than 10 meters. Consequently, lava tube interiors offer an environment that is naturally protected from the hazards of radiation and meteorite impact.
The interiors of lava tubes could protect human explorers from different aspects of the lunar environment, including cosmic rays, meteorite impacts, and the extreme temperature differences between the lunar day and night. Just like caves on the Earth, lunar caves, including lava tubes, have benign temperatures that are constant. These are extremely favorable environmental conditions for human activities and industrial operations. Significant operational, technological, and economical benefits might result if a lunar base were constructed inside a lava tube.
One possible example is the Marius Hills pit, which was discovered in images from the Japanese SELENE/Kaguya Terrain Camera and Multiband Imager, and reported in Geophysical Research Letters. The SELENE/Kaguya Terrain Camera team made a fly-over movie of the hole, which is available here. The hole is nearly circular, 65 m in diameter, and located in a sinuous rille at the Marius Hills region, a volcanic province on the lunar nearside. The hole was estimated to be 80 to 88 m deep. The area around the hole is covered by a thin (20 to 25 m) lava sheet, which may help protect the lava tube from collapse due to meteorite bombardment. Because the Marius Hills pit is in the middle of a sinuous rille, it likely represents a collapse in the roof of a lava tube. The pit itself may have been caused by an impact that punched through the lava tube roof.

Enlarged image of the Marius Hills pit showing a small crater on the northwestern edge and small boulders on the southern lip of the hole. NAC M114328462R [NASA/GSFC/Arizona State University].
It appears such a lava tube could house a lunar base on the Moon. The thickness of the roof would provide safe long-term shelter against radiation and meteorite collisions. Creation of similarly shielded environments would be a significant cost to manufacture for any lunar base on the lunar surface. Lava tubes could be used merely as receptacles for prefabricated, modular habitats, either imported from Earth or fabricated from lunar resources. Penetrative cracks in the roof may exist, which would make it extremely difficult to render the enclosed volume airtight, but the lava tube could act as a receptacle for self-enclosed habitats.
The primary advantage of housing a lunar base in a lava tube is the potential to use extremely lightweight construction materials. None of the components would have to support any shielding mass whatsoever. The habitat shell would not have to support much of its own weight because it could be supported from the walls and ceilings of the lava tube. Habitats could even be inflatable, similar to Bigalow’s Sundancer space hotel, or supported entirely by air pressure.
Also, current designs for lunar equipment must function properly over a wide range of temperatures. While tools are severely limited and degrade rapidly on the lunar surface, the more benign and constant temperatures inside a lava tube would allow the use of existing tools and commonly used materials. Inside a lava tube all equipment would be well shielded from IR and UV radiation, and heavy machinery could be solidly anchored to firm bedrock—a rarity on the lunar surface.
Other advantages, such as dust mitigation, could be realized from a lava tube base. While loose dust may be a nuisance for a large number of operations on the surface, the lava tube could be kept relatively dust-free. Lightweight, highly flexible space suits could be made for crews venturing outside of man-rated habitats but remaining inside the lava tube.

Last edited by Void (2017-03-05 12:19:15)

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Done.

SpaceNut

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From: New Hampshire

Registered: 2004-07-22

Posts: 28,838

Re: Carving Lunar homes out of bedrock

Drop a boring tunnel machine on the surface and have it down angle the hole until we are x distance below the surface and then have it carve out the chamber for man to live in going back out to dig another until the unit dies. Bring a lander to the opening capable to create a air lock door system for the atmosphere to be trapped inside for man to live once we fill it with all the goodies that we would want and need.