Author Topic: SpaceX's Martian Underground  (Read 18562 times)

Offline pobermanns

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Re: SpaceX's Martian Underground
« Reply #40 on: 01/25/2017 08:15 PM »
It might be better to rely on a cheaper prexisting Tunnel Boring Machine, The Universe, that has already created tunnels on Mars for us!

Caves and Lavatubes likely already exist on the surface and a survey of these and their extent with human and robotic assets would be a better starting off goal. Most of these lava tubes are probably not ideal for habitation or not close to useful resources but a few probably are and with an extensive enough survey, these could be discovered.

I recently visited a lava tube, on Lanzarote Island (part of the Canary Islands). I'm not a geologist, so this was all-new for me. In case y'all have never seen one, here's my report on that.

The tunnel starts from near sea level on the east side of the island, and goes uphill about 7 KM toward the summit of "La Corona". Our tour only went a about half a KM into it, starting at "Cueva de los Verdes", but I've seen a cross-section map that shows that it's continuous for most of the way. As shown on the JPG, another attraction, "Jameos del Agua", was a non-continuous but additional section, right on the Atlantic.

The graphics that I've seen some members here post, about having multiple, half-cylinder pressure habitats within a lava tube, wouldn't have worked in the one that I visited. It wasn't wide or high enough. I didn't take any measurements, but I'd estimate that the widest point that I saw was 50-60 feet, and the highest about 40 feet. And at that widest point, the ceiling was only 20 feet. Many sections were much tighter, including places where we had to stoop to pass thru, although I'm sure that with explosives or other equipment these could have been expanded. There was one section where there were actually two levels, so perhaps such an area could have supported a structure of 100 foot in height. Some areas had strangely smooth walls, but most of the ceilings were very jagged. In many places the floor was relatively flat, but still with fist-sized or bowling-ball-sized rocks all over. Rock in-falls were common, but again, I'm sure that these could be cleared with time and effort. I would estimate that we were about 100 feet underground for most of the tour.

Again, I'm no expert on this, so I defer to any of you who are.

« Last Edit: 01/25/2017 08:32 PM by pobermanns »

Offline Darkseraph

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Re: SpaceX's Martian Underground
« Reply #41 on: 01/25/2017 08:30 PM »
I couldn't claim to be an expert on this, but from what I've heard, it's expected that much larger lava tubes are possible on the Moon and Mars due to lower gravity. And that due to lack of seismic activity or significant weather, these structures are likely to be reasonably stable.  That could turn out to be wrong, that there are no suitable sized accessible caves or that those that exist are dangerous for habitation. We'd have to do an extensive geographic survey to find out first. Japan is aiming to land a robot (SLIM )in or near such a lava tube in 2019 and I'm looking forward to what is discovered.

https://en.wikipedia.org/wiki/Smart_Lander_for_Investigating_Moon
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Online Robotbeat

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Re: SpaceX's Martian Underground
« Reply #42 on: 01/25/2017 08:40 PM »
Mars has significant weather.

It sucks that lava tubes tend to be at high altitude where the air is thinner (harder EDL, greater temperature extremes, worse surface radiation, etc etc) and there's less water.
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Offline pobermanns

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Re: SpaceX's Martian Underground
« Reply #43 on: 01/25/2017 08:40 PM »
Personally, I'd doubt that the Moon has any lava tubes. From the theory of Late Heavy Bombardment which I've heard, the "Mare" areas are all due to impact heating and lava flooding, and not due to volcanic activity.

However, your suggestion about the lower gravity on Mars might make the necessary difference. Frankly, I can't see how even expert volcanologists can predict this one. Any rock-hounds out there?

Offline pobermanns

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Re: SpaceX's Martian Underground
« Reply #44 on: 01/25/2017 08:43 PM »
Mars has significant weather.

It sucks that lava tubes tend to be at high altitude where the air is thinner (harder EDL, greater temperature extremes, worse surface radiation, etc etc) and there's less water.

Agree with most of the disadvantages, but why is worse surface radiation a problem if you're under 100' of rock?

Online Robotbeat

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Re: SpaceX's Martian Underground
« Reply #45 on: 01/25/2017 08:52 PM »
Mars has significant weather.

It sucks that lava tubes tend to be at high altitude where the air is thinner (harder EDL, greater temperature extremes, worse surface radiation, etc etc) and there's less water.

Agree with most of the disadvantages, but why is worse surface radiation a problem if you're under 100' of rock?
Because you're not always inside and not always under the rock. It'd be nice to see the surface, and practically, people will need to venture outside in vehicles and spacesuits.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline rsdavis9

Re: SpaceX's Martian Underground
« Reply #46 on: 01/25/2017 08:52 PM »
You got to go out and clean your solar panels, unload delivery rockets, etc.
bob

Online Robotbeat

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Re: SpaceX's Martian Underground
« Reply #47 on: 01/25/2017 08:53 PM »
What if... Radiation just ends up not being a big issue? Then there's not as much reason to be in a lava tube.
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Offline Phil Stooke

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Re: SpaceX's Martian Underground
« Reply #48 on: 01/25/2017 08:59 PM »
"Personally, I'd doubt that the Moon has any lava tubes. From the theory of Late Heavy Bombardment which I've heard, the "Mare" areas are all due to impact heating and lava flooding, and not due to volcanic activity."

I'm sorry but this is completely false.  The idea that the maria were caused by impact heating was promoted by Harold Urey in the 1950s and 1960s, and even he accepted the alternative view promoted by Gene Shoemaker and confirmed by Apollo samples, that the maria are true volcanic lavas.  Dating mare basalts shows that volcanism extended at least a billion years after the large basins were formed, and Shoemaker's observation of post-basin but pre-mare craters (Sinus Iridum, Archimedes, Cassini etc.) showed a substantial time gap between impact and lava.  Check out Don Wilhelms' book 'To a Rocky Moon' for details.

Offline pobermanns

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Re: SpaceX's Martian Underground
« Reply #49 on: 01/25/2017 09:12 PM »
"Personally, I'd doubt that the Moon has any lava tubes. From the theory of Late Heavy Bombardment which I've heard, the "Mare" areas are all due to impact heating and lava flooding, and not due to volcanic activity."

I'm sorry but this is completely false.  The idea that the maria were caused by impact heating was promoted by Harold Urey in the 1950s and 1960s, and even he accepted the alternative view promoted by Gene Shoemaker and confirmed by Apollo samples, that the maria are true volcanic lavas.  Dating mare basalts shows that volcanism extended at least a billion years after the large basins were formed, and Shoemaker's observation of post-basin but pre-mare craters (Sinus Iridum, Archimedes, Cassini etc.) showed a substantial time gap between impact and lava.  Check out Don Wilhelms' book 'To a Rocky Moon' for details.

Well, if that's all true, then I tip my hat to an expert - which I personally ain't.

Offline Darkseraph

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Re: SpaceX's Martian Underground
« Reply #50 on: 01/25/2017 09:22 PM »
What if... Radiation just ends up not being a big issue? Then there's not as much reason to be in a lava tube.

On in the Moon in particular, to avoid some of the downsides of huge temperature swings. That effects Mars too, but much less.
"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." R.P.Feynman

Online Robotbeat

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Re: SpaceX's Martian Underground
« Reply #51 on: 01/25/2017 09:47 PM »
Agreed. If you had a lava tube handy, it'd be utilized.
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Offline jimvela

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Re: SpaceX's Martian Underground
« Reply #52 on: 01/25/2017 11:29 PM »
Personally, I'd doubt that the Moon has any lava tubes. From the theory of Late Heavy Bombardment which I've heard, the "Mare" areas are all due to impact heating and lava flooding, and not due to volcanic activity.

Take a look at this:

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

or if you prefer

http://phenomena.nationalgeographic.com/2016/03/25/scientists-may-have-spotted-buried-lava-tubes-on-the-moon/

That sure looks like a good candidate for a lava tube to me...

Offline pobermanns

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Re: SpaceX's Martian Underground
« Reply #53 on: 01/25/2017 11:45 PM »
Personally, I'd doubt that the Moon has any lava tubes. From the theory of Late Heavy Bombardment which I've heard, the "Mare" areas are all due to impact heating and lava flooding, and not due to volcanic activity.

That sure looks like a good candidate for a lava tube to me...

"That sure looks like a good candidate for a lava tube to me..."

Not to me. Seems like wishful thinking. And while I hope that GPR will help in guiding us to clear understanding of the presence or absence of subterranean cavities, I'm afraid that on-site exploration by humans or human-operated-robots will be needed to resolve this question. I'd really like for this to be true, but not being in a vacuum, I won't hold my breath.
« Last Edit: 01/25/2017 11:48 PM by pobermanns »

Offline Torbjorn Larsson, OM

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Re: SpaceX's Martian Underground
« Reply #54 on: 01/26/2017 01:31 AM »
Personally, I'd doubt that the Moon has any lava tubes. From the theory of Late Heavy Bombardment which I've heard, the "Mare" areas are all due to impact heating and lava flooding, and not due to volcanic activity.

However, your suggestion about the lower gravity on Mars might make the necessary difference. Frankly, I can't see how even expert volcanologists can predict this one. Any rock-hounds out there?

We know there lava tubes on Mars [ https://en.wikipedia.org/wiki/Martian_lava_tube ] but that is due to indigenous volcanism [ https://en.wikipedia.org/wiki/Tharsis_Montes ].

Frankly, I would not put too much credence into suggestions of a late bombardment* seeing how the idea is caused by a statistical error [ http://www.pnas.org/content/113/39/10802 ], and further is not consistent with basic planetary physics and especially chemistry of the Tellus-Theia collision [ ]. And not surprisingly then it just doesn't fit with our biological record [ibid]. An extraordinary hypothesis needs extraordinary evidence, and in retrospect this hypothesis lacks that. (It would not be the first time... ::)

* If you want to satisfy the generic Nice model there are many observations that place the equivalent mechanisms in the natural early bombardment. Which planetary orbit changes is consistent with what we see in other systems.

Offline pobermanns

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Re: SpaceX's Martian Underground
« Reply #55 on: 01/26/2017 09:52 AM »
Frankly, I would not put too much credence into suggestions of a late bombardment* seeing how the idea is caused by a statistical error [ http://www.pnas.org/content/113/39/10802 ], and further is not consistent with basic planetary physics and especially chemistry of the Tellus-Theia collision

So, are you saying that the LHB theory is incorrect? If so, is this now the prevailing opinion among planetary scientists?

And not surprisingly then it just doesn't fit with our biological record [ibid]. An extraordinary hypothesis needs extraordinary evidence, and in retrospect this hypothesis lacks that. (It would not be the first time... ::)

* If you want to satisfy the generic Nice model there are many observations that place the equivalent mechanisms in the natural early bombardment. Which planetary orbit changes is consistent with what we see in other systems.

Agree that "An extraordinary hypothesis needs extraordinary evidence", but I really don't understand what you're saying here. Maybe translate it for a non-scientist?
« Last Edit: 01/26/2017 09:52 AM by pobermanns »

Offline sghill

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Re: SpaceX's Martian Underground
« Reply #56 on: 01/26/2017 01:17 PM »
On Mars, you don't want a mechanical TBM.  Too many parts to break down.  The logical path is to utilize things you will be able to make on site up there- power and fuel.

That means a TBM that uses a flame drill or heated subterrene, which have no rotating drill head to contact with tunnel surfaces.  They melt their way through- thus eliminating wear parts a 33 million miles from a supply store.  Hook them up to the colony's power supply and light the burner with methane you're already making up there.

You want a glassified tunnel surface to prevent zillions of small air leaks and act as its own pressure vessel.  Glass forced into cracks also acts as anchors to provide mechanical support for the walls and ceilings

This:

http://www.freepatentsonline.com/4073351.html

And This:
http://forum.nasaspaceflight.com/index.php?topic=34667.msg1362562#msg1362562
Bring the thunder Elon!

Online Robotbeat

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Re: SpaceX's Martian Underground
« Reply #57 on: 01/26/2017 01:20 PM »
WAYYYY too energy-intensive.
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Online Robotbeat

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Re: SpaceX's Martian Underground
« Reply #58 on: 01/26/2017 03:10 PM »
Yeah, it matters. Repairing stuff on-site is lower mass than the Gigawatt of power this would reaquire. That energy production equipment has to come all the way from Earth, too.
« Last Edit: 01/26/2017 03:18 PM by Robotbeat »
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Offline llanitedave

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Re: SpaceX's Martian Underground
« Reply #59 on: 01/26/2017 07:16 PM »
"Personally, I'd doubt that the Moon has any lava tubes. From the theory of Late Heavy Bombardment which I've heard, the "Mare" areas are all due to impact heating and lava flooding, and not due to volcanic activity."

I'm sorry but this is completely false.  The idea that the maria were caused by impact heating was promoted by Harold Urey in the 1950s and 1960s, and even he accepted the alternative view promoted by Gene Shoemaker and confirmed by Apollo samples, that the maria are true volcanic lavas.  Dating mare basalts shows that volcanism extended at least a billion years after the large basins were formed, and Shoemaker's observation of post-basin but pre-mare craters (Sinus Iridum, Archimedes, Cassini etc.) showed a substantial time gap between impact and lava.  Check out Don Wilhelms' book 'To a Rocky Moon' for details.

Well, if that's all true, then I tip my hat to an expert - which I personally ain't.


It's true.  But don't tip your hat, toss it.
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