Author Topic: SpaceX's Martian Underground  (Read 19505 times)

Offline sanman

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SpaceX's Martian Underground
« on: 01/08/2017 07:47 AM »
I know people didn't like my thread on Elon's idea for a tunnel boring machine, feeling it wasn't SpaceX-related. But as I continue to read further about the idea, I was wondering if there's a possibility that a tunnel-boring machine could be the start of a path to more substantive ISRU on Mars (or Moon) than just making fuel by Sabatier, electrolysis, etc.

Could a tunnel-boring machine evolve into a mining machine? Could it eventually be turned into something very useful for ISRU?

http://www.fool.com/investing/2016/12/25/will-elon-musk-really-build-tunnel-boring-company.aspx

Quote

TUNNEL BORING MACHINES ARE MASSIVE PIECES OF EQUIPMENT -- TRAIN-SIZED MOBILE FACTORIES DESIGNED
TO DIG INTO THE EARTH. COINCIDENTALLY, THEY'RE ALMOST PERFECTLY SHAPED TO FIT ABOARD A ROCKET TO
MARS.


Musk knows ISRU is fundamental to the survival of any Mars colony, and obviously extraction of raw materials from the ground is a major challenge and necessity. What better way to gain experience in developing technology in this area than by going into the tunneling business? And perhaps as a way of not too overtly tipping his hand, "tunnel-boring" becomes the initial launch concept rather than "mining".

Let's also remember that Mars is very areologically stable - as a smaller planet farther out from the Sun, it has cooled faster and has a crust thickness comparable to Earth's despite its smaller size. Furthermore, the Martian interior could also serve as an additional source of power, via areothermal heating.

If reusable rockets, solar panels, and electric vehicles can each have their vital niche in enabling the Mars vision, can tunnel-boring technology prove to be another useful undertaking that would help sustain a Mars colonization effort?

Offline gospacex

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Re: SpaceX's Martian Underground
« Reply #1 on: 01/08/2017 10:36 AM »
Full-scale TBM is way too heavy for the initial colony. Even on Earth, TBMs make economic sense only if you need to bore multi-kilometer long tunnels.

I imagine much smaller machines will be used to build first Mars underground habitats. Perhaps these machines will be more versatile, not specialized only for tunneling work.

Offline Oersted

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Re: SpaceX's Martian Underground
« Reply #2 on: 01/08/2017 11:01 AM »
We are already discussing tunnelling in the Amazing Habitats thread. I think the contents of this thread fit very well in that one.

Offline sanman

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Re: SpaceX's Martian Underground
« Reply #3 on: 01/08/2017 11:58 AM »
Well, I was thinking there was the mining/ISRU aspect to this as well. Perhaps a tunneling machine would eventually evolve into a mining machine, which could extract ore and maybe even feed it into a smelter.


The article shows a large-sized machine as the current state of the art, but there's no reason that a smaller machine couldn't be used to bore large tunnels, if it had the right technology. I was thinking that microwave boring machine could be small enough and light-weight enough to be transportable to Mars, where it could be used to bore much larger cavities - although using the microwave approach for extracting ore might take some re-thinking (maybe with microwaves you could somehow bore and smelt at the same time?)


And at the same time, a microwave-based approach might offer the chance to disrupt the marketplace and take business from the higher-cost established players.

Offline guckyfan

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Re: SpaceX's Martian Underground
« Reply #4 on: 01/08/2017 12:13 PM »
Whatever he has in mind, I am sure it is significantly different to present day technology. Or else he would not get into it.

Offline meekGee

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Re: SpaceX's Martian Underground
« Reply #5 on: 01/08/2017 01:55 PM »
Full-scale TBM is way too heavy for the initial colony. Even on Earth, TBMs make economic sense only if you need to bore multi-kilometer long tunnels.

I imagine much smaller machines will be used to build first Mars underground habitats. Perhaps these machines will be more versatile, not specialized only for tunneling work.
And tunnels are not ideal living spaces.  You want to build an open space, so create a room and pillar space.

Road headers are more flexible, don't require the kind of support infrastructure that TBMs do, and you can have several of them working at once.

Even on Earth, operation and maintaining a TBM is tricky. A RH, OTOH, is just a simple tractor-like vehicle.
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Online llanitedave

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Re: SpaceX's Martian Underground
« Reply #6 on: 01/08/2017 05:05 PM »
Full-scale TBM is way too heavy for the initial colony. Even on Earth, TBMs make economic sense only if you need to bore multi-kilometer long tunnels.

I imagine much smaller machines will be used to build first Mars underground habitats. Perhaps these machines will be more versatile, not specialized only for tunneling work.

The cutting head alone is extremely massive.  A 4.5m cutterhead assembly can easily weigh 130 tons.

They also use huge amounts of power.  I don't think you gain much by trying to build a TBM on earth and transport it to Mars.  Wait until your Martian industrial capacity can support it, and build it there out of local materials.
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Offline Darkseraph

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Re: SpaceX's Martian Underground
« Reply #7 on: 01/08/2017 05:46 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. The hardware to do such a survey would individually be quite a lot lighter than a TBM.

Perhaps you would use aerial drones to photograph large swathes of the landscape in more detail than is possible with orbital satellites, to look for entracnes and sky lights on lava tubes and follow up candidates with a more detailed survey using rovers, ground penetrating radar, lidar and so on.

Eventually it may be desirable to use a TBM for construction on Mars but I don't expect this to be the case until there is an extensive human presense on the surface with tons of ISRU! Knowing what kind of rock you are boring into would be a very important step before using any such machine which will require a lot of surveying work to be done first.
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Offline Rocket Science

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Re: SpaceX's Martian Underground
« Reply #8 on: 01/08/2017 05:49 PM »
Drill and blast might work...
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Offline Patchouli

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Re: SpaceX's Martian Underground
« Reply #9 on: 01/08/2017 06:03 PM »
Something like a roadheader would be more ideal for use on Mars then a TBM since it's much simpler and lighter and you would have more flexibility in the shape of the chambers that can be created.
« Last Edit: 01/08/2017 06:04 PM by Patchouli »

Offline sanman

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Re: SpaceX's Martian Underground
« Reply #10 on: 01/09/2017 08:21 AM »
Something like a roadheader would be more ideal for use on Mars then a TBM since it's much simpler and lighter and you would have more flexibility in the shape of the chambers that can be created.

So that's interesting - could a roadheader like that one be used for mining purposes, for raw material extraction?
Can this thing be used for more than just tunneling?

Offline docmordrid

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Re: SpaceX's Martian Underground
« Reply #11 on: 01/12/2017 08:40 AM »
Something like a roadheader would be more ideal for use on Mars then a TBM since it's much simpler and lighter and you would have more flexibility in the shape of the chambers that can be created.

So that's interesting - could a roadheader like that one be used for mining purposes, for raw material extraction?
Can this thing be used for more than just tunneling?

Roadheaders were initially used for coal mining, so hell-yeah. Tunnels for the O-Train in Ottawa were done using three 135 ton roadheaders, and they were used for parts of the Big Dig..
« Last Edit: 01/12/2017 08:48 AM by docmordrid »
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Offline sanman

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Re: SpaceX's Martian Underground
« Reply #12 on: 01/12/2017 05:27 PM »
Roadheaders were initially used for coal mining, so hell-yeah. Tunnels for the O-Train in Ottawa were done using three 135 ton roadheaders, and they were used for parts of the Big Dig..

Wow, that's a lot of mass to send to the Moon or Mars.
I wonder if the thing could be redesigned to shave weight off it?

Additionally, making it all-electric power supply would also be required, as well as robotic/tele-operated/semi-autonomous.

And for the lunar environment, there's that pesky angular dust which always messes things up.

If you had something that big, and were using it all the time, you'd probably be able to expand your interior living space pretty rapidly from tunneling/burrowing.

I wonder what the ideal layout would be for a burrow?

Offline docmordrid

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Re: SpaceX's Martian Underground
« Reply #13 on: 01/12/2017 05:56 PM »
The cutter above is often used to cut an arched tunnel, like a quonset hut, but there are other heads used for profile cutting such as squaring off.  There are vertical versions for boring shafts.

The head motors are hydraulic, so power can be whatever you can run the pump with; electric, or an IC using ISRU methalox. Possibly alcohol + GOX using a different ISRU process.
« Last Edit: 01/12/2017 06:07 PM by docmordrid »
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Online TrueBlueWitt

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Re: SpaceX's Martian Underground
« Reply #14 on: 01/12/2017 06:13 PM »
The cutter above is often used to cut an arched tunnel, like a quonset hut, but there are other heads used for profile cutting such as squaring off.  There are vertical versions for boring shafts.

The head motors are hydraulic, so power can be whatever you can run the pump with; electric, or an IC using ISRU methalox. Possibly alcohol + GOX using a different ISRU process.

Cutters work well enough, as long as whatever you're boring through is solid enough to be self supporting..

Otherwise you may need a boring machine with shield and have to erect  support ribs/marscrete behind you.  At least not too much water to deal with.. depending on where you're going..

Offline Rocket Science

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Re: SpaceX's Martian Underground
« Reply #15 on: 01/12/2017 06:16 PM »
I like these cutters, even better if they can be made to work with existing vehicles with a PTO so that a dedicated vehicle need not to be sent the planet...
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Offline philw1776

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Re: SpaceX's Martian Underground
« Reply #16 on: 01/12/2017 07:17 PM »


Roadheaders were initially used for coal mining, so hell-yeah. Tunnels for the O-Train in Ottawa were done using three 135 ton roadheaders, and they were used for parts of the Big Dig..

So, now we know why Elon greatly upped the mass to LEO and landed on Mars from a paltry 100 tonnes
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Offline Robotbeat

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Re: SpaceX's Martian Underground
« Reply #17 on: 01/12/2017 07:53 PM »
Roadheaders were initially used for coal mining, so hell-yeah. Tunnels for the O-Train in Ottawa were done using three 135 ton roadheaders, and they were used for parts of the Big Dig..

Wow, that's a lot of mass to send to the Moon or Mars.
I wonder if the thing could be redesigned to shave weight off it?

Additionally, making it all-electric power supply would also be required, as well as robotic/tele-operated/semi-autonomous.

And for the lunar environment, there's that pesky angular dust which always messes things up.

If you had something that big, and were using it all the time, you'd probably be able to expand your interior living space pretty rapidly from tunneling/burrowing.

I wonder what the ideal layout would be for a burrow?
Usually underground mining equipment like that is already electric. They use a lot of power, and electricity is cheaper, but more importantly they don't require oxygen and don't have exhaust, which helps a LOT.

The first road header I saw on Google was electrically powered.
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Offline Robotbeat

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Re: SpaceX's Martian Underground
« Reply #18 on: 01/12/2017 07:56 PM »
The cutter above is often used to cut an arched tunnel, like a quonset hut, but there are other heads used for profile cutting such as squaring off.  There are vertical versions for boring shafts.

The head motors are hydraulic, so power can be whatever you can run the pump with; electric, or an IC using ISRU methalox. Possibly alcohol + GOX using a different ISRU process.
Gah, combustible fuels in an engine are just TERRIBLE if you're doing ISRU. They use about an order of magnitude more power (wasting like 90% of the energy) than electric, and since you have to bring along oxygen (and usually want to reclaim the water in the exhaust), usually don't even end up lighter even compared to battery power.

I wish that idea would just die.
« Last Edit: 01/12/2017 08:00 PM by Robotbeat »
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Offline docmordrid

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Re: SpaceX's Martian Underground
« Reply #19 on: 01/12/2017 08:04 PM »
Just stating the options. I agree with electric, unless you're boring some distance from high power generation. You're not going to carry a reactor or 200 m^2 of panels around. Solid oxide fuel cells maybe...
« Last Edit: 01/12/2017 08:06 PM by docmordrid »
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