Lunar Lava Tubes

[Jonfliesgoats]

This is a fluff piece, but it seems there may be large caverns in the moon.

https://www.sciencenews.org/article/moon’s-lava-tubes-could-be-colossal?tgt=nr

[kerbiloid]

Yes, Wells wrote about this.

 

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Also there should be a sea. And mushrooms.

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Of course! The moon must be enormously cavernous, with an atmosphere within, and at the centre of its caverns a sea.

"One knew that the moon had a lower specific gravity than the earth, one knew that it had little air or water outside, one knew, too, that it was sister planet to the earth, and that it was unaccountable that it should be different in composition. The inference that it was hollowed out was as clear as day. And yet one never saw it as a fact. Kepler, of course -"

 

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Maybe even worse better.

 

[lajoswinkler]

It's not exactly a new thing. We've even took high resolution photos of their entrances. Lots of them.

[VikingStormtrooper]

If large enough, and structurally stable as well, the lunar lava tubes would be a lot better than the surface in order to host colonists. Just a few tens of meters below ground level are enough to have a completely natural quasi-uniform temperature - on the surface, instead, the difference in temperature between night and day, and the long duration of the day-night transition, would make it extremely expensive to actively maintain a uniform temperature. Moreover, a layer of lunar rock would be an excellent shelter in terms of radiations and small meteorites, very good news for long-term stay. Apart from solar panels and spaceports, the human presence on the Moon is then more reasonable underground.

[kerbiloid]

One who plays Minecraft, knows: a mountain is not a monolith, it's a heap: rock here, gravel there.
While nothing shakes this lunar roof, it doesn't slough. But would be incautious to build a home under it..
A dug pit, covered with a concrete dome is good, is nice, is predictable.
One would better avoid such tubes, they are not bro.

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Also, we can never be sure about lunar graboids' holes.

 

 

[VikingStormtrooper]

8 minutes ago, kerbiloid said:

One who plays Minecraft, knows: a mountain is not a monolith, it's a heap: rock here, gravel there.
While nothing shakes this lunar roof, it doesn't slough. But would be incautious to build a home under it..
A dug pit, covered with a concrete dome is good, is nice, is predictable.
One would better avoid such tubes, they are not bro.

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Also, we can never be sure about lunar graboids' holes.

 

 

True, but AFAIK no one wants to use the tubes as they are in order to get a shelter; they would be a sort of natural container, but the inside should be covered with concrete obtained from the lunar dust. This would increase structural integrity! In addition, pillars and columns may be useful to further increase it.

In any case, there should be some kind of pressurized module in order to grant breathable air at the right pressure; this is another reason not to use the inside of the tubes as they are. Leakages have to be avoided!

Edited December 31, 2016 by VikingStormtrooper

[Scotius]

Leakage can also be prevented by covering cave walls with a plastic sheets, or a layer sprayed like a paint. Kinda like Bigelow's inflatable module placed underground. Caves could also be used as natural fuel tanks. Several meters of ground and rock acting as a radiation\meteorite shield is nothing to sneeze at.

[YNM]

So... We've been overlooking it ? Caveman on the Moon anyone ?

[kerbiloid]

Flintstone Base.

Edited December 31, 2016 by kerbiloid

[Jonfliesgoats]

Yeah, it's interesting.  I knew about some lava tubes on the moon, but I did not know they were this big or plentiful.  Some nation will exploit these for habitation, etc.  We just need a reason (economic, military or ideological) to establish a presence on the moon for now.

[cubinator]

I would love to see exploration of these vast cave systems. As long as we can keep the exogorths away the caverns can be of great use.

[Kombat engineer]

  

HIVE CONFIRMED.

[StrandedonEarth]

Hopefully they won't run into any morlocks...

[Kombat engineer]

or kitans

[cubinator]

2 hours ago, StrandedonEarth said:

Hopefully they won't run into any morlocks...

I think they're more likely to run into really soft insect-people...although they do have a social "hierarchy" similar to the Morlocks/Eloi.

[kerbiloid]

The only thing with these tubes practical usage still to be clarified:
why anybody would need to keep something beneath a several meters thick, randomly baked, regolith crust — rather than just to bulk this into a pit and cover with foil?
Somebody can steal this? Or it will be flooded by rain?

About radiation.

According to  http://www.space.com/24731-mars-radiation-curiosity-rover.html

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over the 180-day journey. It is approximately 300 mSv, ... an explorer would be exposed to more than 15 times an annual radiation limit for a worker in a nuclear power plant.

So, the open space radiation level between Earth and Mars orbits is 30 times higher than could be allowed,
To weaken it down to the Earth sanitary standard, it should be weaken for 30 times.
So, you need lb(30) ~= 5 half-value layers between the inside and the outside.

Presuming that the radiation is mostly Roentgen and gamma rays, and also that this is the most penetrative part of the radiation, you need 5 half-layers of concrete.
According to https://en.wikipedia.org/wiki/Half-value_layer, the concrete-vs-gamma half-layer thickness = 4.5 cm. So, 23 cm will make you fill like at home _{of course if you work in a nuclear power plant}.

As the nuke team limit usually is 10 times higher than for civilians, you need lb(10) = 3.3 half-layers more.
Total: (5 + 3.3) * 4.5 = 37 cm.
So, a 0.5..1 meter thick concrete roof above head will force you to suffer from radiation absence.

These tubes roof unlikely can be so thin, as it couldn't carry such area weight, especially without columns. It's not a real concrete, it's a random crust.
So, it must be several meters thick.
This means that trying to enforce this tube roof you would build columns and ceilings capable to carry 5 meters of ground instead of 0.5 meter of the concrete.
So, you get 1-storey underground house by the price of 10-storey concrete building.
Also, you gain the unpredictably spread caverns beneath your dungeon, which makes it very romantic but highly unstable.

So, these tubes are nice to study and maybe sometimes visit, but they are bad from practical point of view.

Also, 1 meter of concrete protects you from meteorites and fallen stars.

***

This is your bro.

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Also bro:

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Not bro:

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Edited January 2, 2017 by kerbiloid