Author Topic: Can high-tech cavemen live on the Moon?  (Read 10854 times)

Offline Warren Platts

Re: Can high-tech cavemen live on the Moon?
« Reply #20 on: 01/23/2010 04:21 PM »
I don't think air leakage will be much of a problem. Some lavas may be porous, but porosity isn't what counts: permeability is what you have to worry about, and lava isn't permeable at all--unless of course there are extensive joints (cracks) and faults. Also the direction of the joints are important: horizontal joints won't leak nearly as bad as vertical joints.

But even extensive vertical jointing will not be a problem because the bedrock within which the lava tube is embedded will be overlain by a significant layer of lunar regolith (soil). The thing about regolith is that it is completely unweathered. That is, the grains are all sharp edged and unrounded. This speaks to permeability again: in the oil industry, the best reservoir rock formations are well rounded sandstones because they are not only highly porous, but also highly permeable. Lunar regolith, on the other hand, packs so tightly and has had literally billions of years to get settled in, the permeability is next to zero, and since it's a soil, it can't crack.

In fact I remember a Moon Miner's Manifesto article that once suggested using a "Chunnel"-type digging machine to dig tunnels through the regolith. They suggested that mere air pressure would keep the tunnel from collapsing, and that air leakage through the regolith would be negligible. Ah, here is the the link: Lunar Base Construction by Regolith Tunneling (SEI; Stafford) by David D. Graham

Therefore, if a regolith tunnel is impervious to air leakage, then it will work just as well as overburden for even a badly jointed lava tube cave.

And in any case, a small amount of leakage isn't a big deal anyway. You're always going to be leaking air. If nothing else, every time you open an air lock, some air will be lost to space. And if you're making ISRU rocket fuel, you'll be losing "air" to space by the ton every time you light off a rocket. So the problem is not leakage per se, it's the question of whether the leakage would be more than negligible compared to your oxygen manufacturing capability.

So there will be no need to worry about spray-on sealants or expensive inflatable tents (if you're going with an inflatable tent, then why even stick it inside of a lava tube: just put it on the surface; if you want radiation protection as well, then just pile on some regolith). The biggest technical hurdle as I see it, will be constructing the bulkheads.

But of course this entire scenario depends on actually returning to the Moon with boots on the ground....
« Last Edit: 01/23/2010 04:22 PM by Warren Platts »
"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."--Leonardo Da Vinci

Offline khallow

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Re: Can high-tech cavemen live on the Moon?
« Reply #21 on: 01/24/2010 02:12 AM »

So there will be no need to worry about spray-on sealants or expensive inflatable tents (if you're going with an inflatable tent, then why even stick it inside of a lava tube: just put it on the surface; if you want radiation protection as well, then just pile on some regolith). The biggest technical hurdle as I see it, will be constructing the bulkheads.

My view is that it is possible to get a lot better protection and thermal isolation in a lava tube than you can get by piling regolith on your tent and since you're not piling up regolith, it's less work as well. The problem is that lava tubes aren't everywhere. You need certain geological conditions (basalt flows and a certain downhill gradient) in order to get lava tubes. A lot of the interesting places (which often are interesting because they have geology far different from that which generates lava tubes) won't have lava tubes anywhere near them for this reason.

As an aside, a lava tube also has a good geometry for focused manufacture facilities. If you find a long lava tube, you can create one or more sections (by tunneling into the tube or exploiting any other openings) of protected machinery that take raw materials on one side and spit out finished products on the other side. I know of no manufacturing instance like this in modern times, but there were examples of this during the Second World War, particularly the abominable Mittelwerk factory where V-2 rockets were produced.

The reasoning is that simply, some sorts of manufacturing infrastructure will be sensitive to radiation or thermal heating and cooling. The environment inside a lava tube is relatively friendly to such equipment and it doesn't take a lot of work to excavate (aside from possibly making additional entrances to the tubes).
Karl Hallowell

Offline marciano77

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Re: Can high-tech cavemen live on the Moon?
« Reply #22 on: 01/25/2010 03:54 AM »
I would like to thank "khallow" for his interesting, sensitive, and coherent replies as well as the rest of the forum;Furthermore, I want to express my appreciation to all of those out there who tirelessly continue everyday thinking of different ways of exploring the outer space for the benefit of man kind. the following is one of NASA's interest and in which I'm involved with CSULB. Again I greatly appreciate everyone's comments.

RASC-AL
Revolutionary Aerospace Systems Concepts - Academic Linkage, is a
student design competition that is sponsored by NASA and managed
by the National Institute of Aerospace.
RASC-AL is open to undergraduate and graduate university-level
engineering students. RASC-AL projects allow students to incorporate their
coursework into real aerospace design concepts and work together in a team
environment. Project themes are announced in September, abstracts are due
February 5, 2010, and selected Teams and a faculty advisor are invited to provide a written
report and oral presentation at a competition, June 7-9, in Cocoa Beach, FL. Each Team
receives a generous stipend to cover travel expenses to the competition, and the winning
undergraduate and graduate Teams will be flown to a major aerospace conference to present their results.
For more information, visit www.NIAnet.org/rascal.

COMMON LUNAR SORTIE / NEAR-EARTH OBJECT (NEO) MISSION DESIGN
NASA is interested in architecture approaches that provide cost-effective Earth neighborhood exploration with minimal
infrastructure. One approach would be to perform sortie-class human missions to the lunar surface for 60 days at a
time to study particular sites of interest rather than being limited to a particular lunar outpost location. The lunar mission
of interest would be to transport a crew of 2 to 4 to the far side of the Aiken Basin region on the lunar surface for a 60
day mission. The Mission would require a minimum of 1,000 kg of usable cargo to be transported with the crew and at
least 10 mT of cargo to be transported without crew to pre-implace infrastructure to support the 60 day mission. This
same set (or subset) of hardware would also be used to support a 60~120 crewed mission to a Near Earth Object (NEO).
Assuming that commonality with currently planned Constellation architecture elements is not required, what low-cost
options are available to accomplish such a mission?

Offline Warren Platts

Re: Can high-tech cavemen live on the Moon?
« Reply #23 on: 01/25/2010 03:23 PM »
Quote
As an aside, a lava tube also has a good geometry for focused manufacture facilities. If you find a long lava tube, you can create one or more sections (by tunneling into the tube or exploiting any other openings) of protected machinery that take raw materials on one side and spit out finished products on the other side. I know of no manufacturing instance like this in modern times, but there were examples of this during the Second World War, particularly the abominable Mittelwerk factory where V-2 rockets were produced.

The reasoning is that simply, some sorts of manufacturing infrastructure will be sensitive to radiation or thermal heating and cooling. The environment inside a lava tube is relatively friendly to such equipment and it doesn't take a lot of work to excavate (aside from possibly making additional entrances to the tubes).
The Iridium satellite constellation was built by a crew of about 50 people using a similar assembly line process. It took 14 days to make one satellite, and they were pumping them out at the rate of about 4 per day. Also they were doing much of the fabrication of subsystems themselves, like printing their own circuit boards. A nice, large shirt sleeve environment provided by a lava tube would be ideal for such a satellite factory. Once it got going, it could capture the entire LEO to GEO satellite market because they could all be launched using reusable SSTO LVs from the Moon. There is no way an Earth-based launch system could compete.
"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."--Leonardo Da Vinci

Offline Rhyshaelkan

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Re: Can high-tech cavemen live on the Moon?
« Reply #24 on: 01/30/2010 11:28 PM »
Once it got going, it could capture the entire LEO to GEO satellite market because they could all be launched using reusable SSTO LVs from the Moon. There is no way an Earth-based launch system could compete.

And beyond. The industrial possibility of space is limitless from a human standpoint. Starting with Luna and NEO mining and fabrication shops. Fabrication, assembly, micro-g manufacturing at Terra-Luna Lpoints. Larger research facilities(yes the research done by NASA and other agencies at the various LEO locations was cool, but ultimately they have only scratched the surface for what marvelous applications out there).


As for the original post. Many people, myself included, live most their day inside a building. Whether that is a home or workplace. The thought that I would live in a "high-tech" cave is not unsettling. Ben Bova's book Welcome to Moonbase was a nice vision of the future colonization of Luna.

Using microwave emitters to heat and seal the Lunar rock is a possible plan for both lava tubes and excavated caverns.

Pat Rawlings vision here is one I hope to experience before I die.

We need to get 250 million to 1 billion sci-fi fanatics, space enthusiasts, dreamers to each donate $40-$100 USD each and we might have a go at bringing the future. SpaceX will hopefully succeed with their F9H launch vehicle. And with that we could land our tele-operated miners on the Lunar surface to start the infrastructure rolling.

But I am getting off topic. I just get excited by the possibility of space.
I am not a professional. Just a rational amateur dreaming of mankind exploiting the universe.

Offline Warren Platts

Re: Can high-tech cavemen live on the Moon?
« Reply #25 on: 02/01/2010 12:39 AM »
41st Lunar and Planetary Science Conference (2010):

IDENTIFICATION OF LUNAR VOLCANIC TUBES, A POTENTIAL SITE FOR HUMAN SETTLEMENT
USING 3D CHANDRYAAN 1 – TMC DATA . A.S. Arya1, R.P.Rajasekhar1, Ajai1 , A.S Kiran Kumar1, R.R. Navalgund1 , Space Applications Centre, Indian Space Research Organization, Ahmedabad–380 015 (India), [email protected]

http://www.lpi.usra.edu/meetings/lpsc2010/pdf/1484.pdf

Here is a real world example of a lava tube with a probable inside square footage of about 0.7 km^2. That's about 1/4 of a square mile or 160 acres.
« Last Edit: 02/01/2010 12:41 AM by Warren Platts »
"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."--Leonardo Da Vinci

Offline khallow

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Re: Can high-tech cavemen live on the Moon?
« Reply #26 on: 02/01/2010 02:50 PM »

Here is a real world example of a lava tube with a probable inside square footage of about 0.7 km^2. That's about 1/4 of a square mile or 160 acres.

Looks promising. It also looks like the floor of the rilles (collapsed lava tubes) are somewhere around 60 meters lower than the top of the roof.  That indicates some serious volume inside there. The usability of the tube will depend in part on how thick the roof is. A 360 meter wide roof that is 3 cm thick, isn't going to be even remotely safe, much less useful for human habitation.

On the plus side, the Moon seems to undergo a number of significant quakes (especially over the billions of years that this lava tube existed) so it's quite likely that the roof is very stable.

The other issue is whether either side of the lava tube grants easy access to the tube. Having to excavate tens of meters deep piles of rubble in order to enter the tube will be a lot more work than throwing some regolith over a modest sized habitat.

But this illustrates the potential of lava tubes. If we were to attempt to bury or tunnel 50 meter tall structures (especially 0.7 square kilometers of them!) deep underground, that would be a lot more work than using a lava tube of this size (with a solid roof). This may well be the site of a future lunar city.
Karl Hallowell

Offline Rhyshaelkan

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Re: Can high-tech cavemen live on the Moon?
« Reply #27 on: 02/02/2010 07:16 AM »
Go with easy first. Till infrastructure is built up. Then you can go for eccentricity  ;D

The blessing here is the light lunar gravity. Making any sort of structural proportionately less massive. I should not be a difficult matter to shore up the lava tube walls and ceiling. 

Edit: On further inspection of the .pdf 

Shore up and inhabit the uncollapsed section first. Then use the collapsed material to create an artificial roof over the smaller section then the larger section.

/Rhy drools
« Last Edit: 02/02/2010 07:27 AM by Rhyshaelkan »
I am not a professional. Just a rational amateur dreaming of mankind exploiting the universe.

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