Author Topic: Intact lava tube found on Moon  (Read 2964 times)

Offline anonymous

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Intact lava tube found on Moon
« on: 10/19/2017 01:33 PM »
A paper from researchers at JAXA claims to have found at least one intact lava tube in the Marius Hills on the Moon using data from Kaguya/SELENE's radar sounder and GRAIL's gravity sensor. The cavity must be at least several kilometres long and at least a kilometre wide and tall. The entry would be through the Marius Hills Skylight, which is on Marius Hills Sinuous Rille A. I haven't read the paper (behind a paywall), but here are some other articles about it as well:

http://onlinelibrary.wiley.com/doi/10.1002/2017GL074998/full

http://www.purdue.edu/newsroom/releases/2017/Q4/potential-human-habitat-located-on-the-moon.html

https://www.sciencealert.com/the-perfect-real-estate-for-a-moon-base-has-just-been-confirmed

http://www.newsweek.com/colonizing-moon-scientists-lava-tubes-underground-city-688292

https://www.theguardian.com/science/2017/oct/19/lunar-cave-discovery-raises-hopes-for-human-colonisation-of-moon

Does this make Marius Hills the best location for a Moon base, as Science Alert claims? It offers radiation protection that you don't get at the poles and probably protection from the lunar dust, but you only need a five metres of regolith over your base to get virtually complete radiation protection and you can't use solar power in a cave. The Guardian claims that the cavern may contain ice, although the other articles I've read don't say that and I don't know if it's a real possibility. If it did contain ice, it would be probably be more conveniently located than the ice at the bottom of deep craters at the poles. If it doesn't, lack of access to ice would be a disadvantage compared to the poles.

What do you think about this discovery and its implications?

Offline TrevorMonty

Re: Intact lava tube found on Moon
« Reply #1 on: 10/19/2017 05:10 PM »
Lava caves provide shelter from radiation, metorites and stable temperature (-20C ?). These factors simplify habitat construction as light inflatable dome is all that is need. May also be low or nearly free of lunar dust.


The down sides are surface access, something for Elon Boring machine to solve. Power as surface solar poanels have to deal with 14days of darkness. Water for consumption and rocket fuel may have to come from poles, few 100kms overland and or 1.5km/s hop.
« Last Edit: 10/19/2017 05:12 PM by TrevorMonty »

Offline anonymous

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Re: Intact lava tube found on Moon
« Reply #2 on: 10/19/2017 06:28 PM »
The Marius Hills are 14 degrees North, so they're about 2300 km from the north pole. Since -20C isn't enough to keep ice from sublimating, access to water would be the main problem.

Offline Ludus

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Re: Intact lava tube found on Moon
« Reply #3 on: 10/20/2017 01:28 AM »
What would be the best way to seal a 100m wide lava tube end to maintain atmosphere? The settlement might expand down the tube leaving the different air tight compartments in place, adding new ones as needed so only the last one was still up against vacuum.

Offline nacnud

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Re: Intact lava tube found on Moon
« Reply #4 on: 10/20/2017 01:33 AM »
Probably something like a bigelow expandable module. There is no way of knowing the structural integrity of the tubes without going there.

Online Space Ghost 1962

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Re: Intact lava tube found on Moon
« Reply #5 on: 10/20/2017 03:09 AM »
Lava tubes are dangerous and often contain hidden surprises, some of them chemical in nature. (There are a few on Hawaii you can visit if you'd like to try it out for yourself - one I'd particularly recommend is at South Point, not far from the road to the Green Sands beach.)

Consider the requirements for assessing even a small segment of one with a pressure suit. There would likely be falls, suit punctures, corrosives, hazardous situations, roof climbs, partial collapses, rock falls.

It might be less risky to land/operate a tunneling machine. Where you could expose/inspect/seal/encase as a continuous process. Doesn't need to be many meters in diameter.

Offline woods170

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Re: Intact lava tube found on Moon
« Reply #6 on: 10/20/2017 09:12 AM »
Lava tubes are dangerous and often contain hidden surprises, some of them chemical in nature. (There are a few on Hawaii you can visit if you'd like to try it out for yourself - one I'd particularly recommend is at South Point, not far from the road to the Green Sands beach.)

Consider the requirements for assessing even a small segment of one with a pressure suit. There would likely be falls, suit punctures, corrosives, hazardous situations, roof climbs, partial collapses, rock falls.

It might be less risky to land/operate a tunneling machine. Where you could expose/inspect/seal/encase as a continuous process. Doesn't need to be many meters in diameter.
Hence why Elon has established The Boring Company. It's not just for avoiding LA traffic jams and facilitating Hyperloop.

Offline IRobot

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Re: Intact lava tube found on Moon
« Reply #7 on: 10/20/2017 10:49 AM »
I find this development quite exciting to the point that for the first time since 1970's we have a valid reason to return to the Moon!

Offline KelvinZero

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Re: Intact lava tube found on Moon
« Reply #8 on: 10/20/2017 11:24 AM »
I find this development quite exciting to the point that for the first time since 1970's we have a valid reason to return to the Moon!
Erhmm.... that would be the confirmation of water in permanently shadowed polar craters right next to peaks of eternal light, on November 13, 2009.

But this would make a nice touristy sort of attraction.. I spose..

Offline Apollo-phill

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Re: Intact lava tube found on Moon
« Reply #9 on: 10/20/2017 11:43 AM »
Having been inside a lava tube , I agree with what SpaceGhost wrote.

The one I went in had a wide entrance ( walk-in )  but soon narrowed and after a few metres, needed be on hands/feet crawling.

Being of magmatic/lava origin the tube was very hazardous and required stout footwear, sturdy gloves and thick clothing.
Still managed get a couple of rips in trousers and one glove.

It was of a " glassy, slippy "  nature due to glass- like silica particles in the various minerals with all sizes of ridges and humps to negotiate . Certainly not smooth inside ! Once past entrance by a few metres, extremely dark, damp and cold.

The lunar tubes will probably be the same ( minus damp ) and would, I think , need walls/floors " smoothing out" before any construction ( inflatable or not ) took place .

Stout surface structures able to withstand a thick layer of lunar regolith over the top might be easier to construct ?


Phill







Offline redliox

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Re: Intact lava tube found on Moon
« Reply #10 on: 10/21/2017 02:10 PM »
I believe the lava tubes, like at Marius Hills, definitely should be investigated.

How could a probe explore a skylight like one of these?
"Let the trails lead where they may, I will follow."
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Offline Bob Shaw

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Re: Intact lava tube found on Moon
« Reply #11 on: 10/21/2017 02:23 PM »
Why not roof over a crater or a rille? Easy access, and none of that scary stuff!

Offline redliox

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"Let the trails lead where they may, I will follow."
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Offline Archibald

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Re: Intact lava tube found on Moon
« Reply #13 on: 10/21/2017 04:25 PM »
there was an Apollo mission that landed at the Marius Hills (was it Apollo 15 ?)

Do we know how far is the hole from the Apollo landing site ?

Edit - forget it, it was only the backup site.
https://en.wikipedia.org/wiki/Marius_Hills
https://www.hq.nasa.gov/pao/History/SP-4214/ch12-5.html
« Last Edit: 10/21/2017 04:32 PM by Archibald »

Offline oldAtlas_Eguy

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Re: Intact lava tube found on Moon
« Reply #14 on: 10/21/2017 05:34 PM »
Just to give some scale to this. If the probable lava tube of possible length of 310 miles by 100 meters diameter was excavated out for the full length to that diameter then the volume that would represent is 3.9Billion cubic meters. If you assigned a person 1000m^3 that would be space for 3.9million people. It would be more space than most urban dwellers have on Earth.

Online sanman

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Re: Intact lava tube found on Moon
« Reply #15 on: 10/21/2017 11:07 PM »
Just to give some scale to this. If the probable lava tube of possible length of 310 miles by 100 meters diameter was excavated out for the full length to that diameter then the volume that would represent is 3.9Billion cubic meters. If you assigned a person 1000m^3 that would be space for 3.9million people. It would be more space than most urban dwellers have on Earth.

So that would require almost 4.8million metric tonnes of air to pressurize such a huge volume. Lots of ISRU required for that. Is there even any nitrogen on the Moon in any form?

Even ISRO found a lava tube on the Moon some time back:

http://archive.indianexpress.com/news/isro-finds-safe-cave-on-moon/754312/

https://economictimes.indiatimes.com/isro-finds-cave-on-moon-can-be-used-as-an-outpost/articleshow/7562900.cms
« Last Edit: 10/21/2017 11:12 PM by sanman »

Offline nacnud

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Re: Intact lava tube found on Moon
« Reply #16 on: 10/21/2017 11:12 PM »
Not that I can find with a quick google search, I think more geological information is needed.

Online sanman

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Re: Intact lava tube found on Moon
« Reply #17 on: 10/21/2017 11:17 PM »
Instead of a big huge lava tube, perhaps what's needed in the early period is a reasonable-sized cave. What would be the ideal volume for an early underground lunar station? Probably no more than several thousand cubic meters at most?

Besides the lava tubes, are there any other processes on the Moon that could have created caves - perhaps smaller ones?

Here's a good article by Paul Spudis:

https://www.airspacemag.com/daily-planet/cave-living-moon-180961494/

Quote
But lava tubes are found only in the maria, which are mostly concentrated near the equator and at low latitudes. One of the biggest drawbacks to cave living on the Moon is that we don’t have any near the poles. At the poles there is near-constant sunlight, along with deposits of water ice—valuable resources essential for human habitation. Yet enjoying the advantages of underground living doesn’t require caves. It is possible to place a habitat at the bottom of a deep crater, lay out an airlock, access tunnels, electrical cables and cooling lines, and then backfill (cover over) the crater with lunar regolith (soil) using a bulldozer. This simple construction technique provides all the thermal and protection advantages of cave dwelling, without restricting the outpost location to a less than optimum locality.

The advantages of cave life seem so attractive that every time a new lunar lava tube discovery is made, there is a call to use them to live on the Moon or other planets (most recently shown in the current “Mars” television mini-series). But people live where they can make their livelihoods and on the Moon, that “pay dirt” is at the poles, in the form of water and electrical power. The Willie Sutton principle still prevails.
« Last Edit: 10/21/2017 11:27 PM by sanman »

Offline TomH

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Re: Intact lava tube found on Moon
« Reply #18 on: 10/22/2017 07:56 AM »
WaPo Article: https://www.washingtonpost.com/news/speaking-of-science/wp/2017/10/21/a-newly-discovered-moon-tunnel-could-be-the-perfect-place-for-a-colony-scientists-say/?hpid=hp_hp-more-top-stories-2_moontunnel-847pm%3Ahomepage%2Fstory&utm_term=.8c462aabd598

While lava tubes do have certain dangers, perhaps an inflatable hab could be inserted and then inflated, the tunnel ceiling geologically inspected and reinforce/plastered possibly. This would avoid excavation of regolith and provide radiation shielding, possibly thermal insulation during the lunar night.

Offline KelvinZero

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Re: Intact lava tube found on Moon
« Reply #19 on: 10/23/2017 06:40 AM »
I believe the lava tubes, like at Marius Hills, definitely should be investigated.

How could a probe explore a skylight like one of these?
Google found this:
https://www.nasa.gov/pdf/637136main_Whittaker_Presentation.pdf

The rappel example is how I imagined it.

Random thought: I wonder if the ice at the poles could also create caves or at least overhangs. I think the lunar poles have moved over time so you could imagine a situation of different layers with different amounts of ice. Or perhaps an impact within or at the edge of a crater laying magma over icy ground that disappears out from under the much stronger roof.

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