Author Topic: Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD  (Read 296329 times)

Offline Lumina

Changing the subject:

From what we have learned from IAC speech, we can probably safely assume that:

(a) ITS won't be carrying ready-made tuna can habitats to Mars (there is no pod-dropping)
(b) There is no need to carry ready-made habs (wedge, or any other shape) because the ITS itself can serve as a temporary hab on Mars
(c) Habitat components will be delivered flat-packed for assembly on Mars (like all other cargo)

These assumptions lead to the conclusion that the very first humans on Mars (on a long-stay mission) will be building habitats. Agree / disagree with this conclusion?

What kind of amazing, spacious habitats can we envision? What selection of habitat building components would you want in your flat-packed containers?
« Last Edit: 10/11/2016 02:02 AM by Lumina »

Offline docmordrid

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Re: Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD
« Reply #1141 on: 10/11/2016 02:13 AM »
I would think the ideal starter structures would be quonsets of some variety; either inflated with high density brominated expanding foam, or internally braced metal. Cover either with regolith/sulfur "Mars cement."

Or...a Mars version of this

« Last Edit: 10/11/2016 02:22 AM by docmordrid »
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Offline lamontagne

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Re: Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD
« Reply #1142 on: 10/11/2016 04:21 AM »
Changing the subject:

From what we have learned from IAC speech, we can probably safely assume that:

(a) ITS won't be carrying ready-made tuna can habitats to Mars (there is no pod-dropping)
(b) There is no need to carry ready-made habs (wedge, or any other shape) because the ITS itself can serve as a temporary hab on Mars
(c) Habitat components will be delivered flat-packed for assembly on Mars (like all other cargo)

These assumptions lead to the conclusion that the very first humans on Mars (on a long-stay mission) will be building habitats. Agree / disagree with this conclusion?

What kind of amazing, spacious habitats can we envision? What selection of habitat building components would you want in your flat-packed containers?

You could have large arched buildings.  In the present illustration 10m x 20m x 5m high,  a house with 2m covering of sand and rock.  Built from carbon fiber panels, these would be under tension from the atmospheric pressure, despite the thickness of covering, but probably not by much.  Sealing the panel joints needs some clever design.

The large window is recessed for radiation.  However you can stand before it safely for a few hours a day, I expect.

The suits are back access.  Light pipes bring in the light to the back.   Since there is no wind, and the sand provides thermal insulation, these might be quite cheap to design and build, except for the pressure on the luxurious window.  From the ITS Spaceship design, clearly, large windows are part of the plan!

These houses could be packed fairly close together, saving on the work for covering.  Tunnels between buildings need some thought though.

For an In situ equivalent, panels made from basalt fibers could perhaps be used, although I don't know what could serve as filler between the fibers?
« Last Edit: 10/11/2016 04:30 AM by lamontagne »

Offline Impaler

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Re: Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD
« Reply #1143 on: 10/11/2016 05:31 AM »
What is the structure made of that supports the weight of the regolith cover.  I can't see a giant window like that being remotely practical, it can't be transported or installed without some huge equipment and how it can be sealed effectively is a huge issue.

Offline vapour_nudge

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Re: Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD
« Reply #1144 on: 10/11/2016 08:40 AM »
Imagine living in a tent like that for two years on Mars. Not exactly exciting, pretty boring really, even the restaurant and night club tents would still have no real atmosphere.

Offline uhuznaa

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Re: Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD
« Reply #1145 on: 10/11/2016 12:42 PM »
Changing the subject:

From what we have learned from IAC speech, we can probably safely assume that:

(a) ITS won't be carrying ready-made tuna can habitats to Mars (there is no pod-dropping)
(b) There is no need to carry ready-made habs (wedge, or any other shape) because the ITS itself can serve as a temporary hab on Mars
(c) Habitat components will be delivered flat-packed for assembly on Mars (like all other cargo)

These assumptions lead to the conclusion that the very first humans on Mars (on a long-stay mission) will be building habitats. Agree / disagree with this conclusion?

What kind of amazing, spacious habitats can we envision? What selection of habitat building components would you want in your flat-packed containers?

Hmm. You will build your habitat only where you can find lots of easily accessible water. Like a glacier with thick ice you can drill, heat and pump. And if you do that anyway, melting caverns and tunnels into the ice would be the easiest way to build habitats from Mars resources. There are glaciers with ice up to half a mile thick and stretching for tens of miles, this would give you not only lots of propellants but also lots of room to live in. You'd need insulation to keep the warmth in and the ice from melting but this is much easier than building pressure vessels. Gives perfect radiation shielding too.

Actually building your habitat on the surface isn't going to scale very well. You will only be able to build quite small habitats, interconnected with lots of airlocks just to make sure that a single leak doesn't seal your fate. Makes lots and lots of stuff you will have to bring along and to maintain and to care for.

Glaciers will be structurally sound, so you have much more freedom in fitting them out and using them long-term. And once the machinery is in place you can continue to expand your habitats for a long time and use your cargo capacities to bring more useful stuff than pressure vessels (or components of pressure vessels).




Offline rsdavis9


Hmm. You will build your habitat only where you can find lots of easily accessible water. Like a glacier with thick ice you can drill, heat and pump. And if you do that anyway, melting caverns and tunnels into the ice would be the easiest way to build habitats from Mars resources. There are glaciers with ice up to half a mile thick and stretching for tens of miles, this would give you not only lots of propellants but also lots of room to live in. You'd need insulation to keep the warmth in and the ice from melting but this is much easier than building pressure vessels. Gives perfect radiation shielding too.

Actually building your habitat on the surface isn't going to scale very well. You will only be able to build quite small habitats, interconnected with lots of airlocks just to make sure that a single leak doesn't seal your fate. Makes lots and lots of stuff you will have to bring along and to maintain and to care for.

Glaciers will be structurally sound, so you have much more freedom in fitting them out and using them long-term. And once the machinery is in place you can continue to expand your habitats for a long time and use your cargo capacities to bring more useful stuff than pressure vessels (or components of pressure vessels).

I like it.
I think drilling and application of hot water is the way to go. Very much like mining of sulfur on earth. They drill a hole and pump down hot water which melts the sulfur and brings it to the surface in a pipe. Also like you said gives you excavating tools for building underground caves.

added link of sulfur mining:

https://en.wikipedia.org/wiki/Frasch_process


« Last Edit: 10/11/2016 01:09 PM by rsdavis9 »
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Offline lamontagne

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Re: Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD
« Reply #1147 on: 10/11/2016 01:08 PM »
What is the structure made of that supports the weight of the regolith cover.  I can't see a giant window like that being remotely practical, it can't be transported or installed without some huge equipment and how it can be sealed effectively is a huge issue.

The structure is made from panels that are strong in tension.
The weight of 2 m of regolith is about 2 tonnes per m2 on Mars, the internal pressure of the habitat is 100 000 kPa, or just about 10 tonnes per m2.  So the building is not crushable.  It rather tends to explode!

The window is built as a group of panes, exactly like the main window of the ITS Spaceship.  Whatever works for it will work for the house.
The whole thing is shipped flat, and assembled Ikea fashion at Mars.
It could be assembled on site and should keep its shape, rather like a geodesic dome.  Then an airtight membrane is added to the inside, like rolls of vapor barrier here on Earth.  Pressure is added to the minimum breathable and the whole think is leak tested.  Then you can add a first layer of regolith on top.
Pressure is increased to full Earth normal, and the rest of the regolith is added.
The building is always under tension, never under compression.

Here is a more detailed version.  I've decided to do without the awning for this one.  Kids are just warned not to play all day beside the big window :-)

At 5 kg/m2 it would weigh about 3 tonnes, including the floor.

The main limit to how big this design can be is the angle of repose of the regolith (ends up looking like a pyramid pretty fast as it gets taller) and the safe tension loading of the structure.  Using light pipes, you can extend it lengthwise pretty much forever, but there probably is an optimum size for a volume on Mars versus the risk of catastrophic failure.

I wonder about the behavior over time?  Tension structures are fragile in some ways and creep may be an issue?  The water and oxygen will take their toll as well.

The regolith might be tailing from the water mines?  Depends if the water can be found in clean sheets or if ot is bounded with other materials, I expect

« Last Edit: 10/11/2016 01:26 PM by lamontagne »

Offline JasonAW3

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Re: Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD
« Reply #1148 on: 10/11/2016 02:15 PM »
What is the structure made of that supports the weight of the regolith cover.  I can't see a giant window like that being remotely practical, it can't be transported or installed without some huge equipment and how it can be sealed effectively is a huge issue.

The structure is made from panels that are strong in tension.
The weight of 2 m of regolith is about 2 tonnes per m2 on Mars, the internal pressure of the habitat is 100 000 kPa, or just about 10 tonnes per m2.  So the building is not crushable.  It rather tends to explode!

The window is built as a group of panes, exactly like the main window of the ITS Spaceship.  Whatever works for it will work for the house.
The whole thing is shipped flat, and assembled Ikea fashion at Mars.
It could be assembled on site and should keep its shape, rather like a geodesic dome.  Then an airtight membrane is added to the inside, like rolls of vapor barrier here on Earth.  Pressure is added to the minimum breathable and the whole think is leak tested.  Then you can add a first layer of regolith on top.
Pressure is increased to full Earth normal, and the rest of the regolith is added.
The building is always under tension, never under compression.

Here is a more detailed version.  I've decided to do without the awning for this one.  Kids are just warned not to play all day beside the big window :-)

At 5 kg/m2 it would weigh about 3 tonnes, including the floor.

The main limit to how big this design can be is the angle of repose of the regolith (ends up looking like a pyramid pretty fast as it gets taller) and the safe tension loading of the structure.  Using light pipes, you can extend it lengthwise pretty much forever, but there probably is an optimum size for a volume on Mars versus the risk of catastrophic failure.

I wonder about the behavior over time?  Tension structures are fragile in some ways and creep may be an issue?  The water and oxygen will take their toll as well.

The regolith might be tailing from the water mines?  Depends if the water can be found in clean sheets or if ot is bounded with other materials, I expect

A couple of minor points that may be good for consideration;

     1.  Build the actual structural framework inside of the pressure envelope.  This would make the whole operation simpler, and could use lower pressure to do the leak checking.

     2.  Use Bigelow style pressure envelopes.  The wall thickness will minimize puncture potential, add additional radiation protection, and minimize envelope creep.

     3.  The windows could be reinforced with clear Plexiglas panes, between panes of the aluminum glass.  Pressure could then be reduced more gradually between the inner panes and outer panes, thus dissipating the pressure stress between the inner and outer window surfaces.  The Plexiglas would also help reduce radiation coming in from outside.  (On a side note; the space between panes could also be filled with a O2 and CO2 sensitive polymer gel that would be clear, but harden if exposed to either O2 or CO2.  this could prevent pressure leaks through the windows).
My God!  It's full of universes!

Offline lamontagne

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Re: Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD
« Reply #1149 on: 10/11/2016 03:43 PM »
What is the structure made of that supports the weight of the regolith cover.  I can't see a giant window like that being remotely practical, it can't be transported or installed without some huge equipment and how it can be sealed effectively is a huge issue.

The structure is made from panels that are strong in tension.
The weight of 2 m of regolith is about 2 tonnes per m2 on Mars, the internal pressure of the habitat is 100 000 kPa, or just about 10 tonnes per m2.  So the building is not crushable.  It rather tends to explode!

The window is built as a group of panes, exactly like the main window of the ITS Spaceship.  Whatever works for it will work for the house.
The whole thing is shipped flat, and assembled Ikea fashion at Mars.
It could be assembled on site and should keep its shape, rather like a geodesic dome.  Then an airtight membrane is added to the inside, like rolls of vapor barrier here on Earth.  Pressure is added to the minimum breathable and the whole think is leak tested.  Then you can add a first layer of regolith on top.
Pressure is increased to full Earth normal, and the rest of the regolith is added.
The building is always under tension, never under compression.

Here is a more detailed version.  I've decided to do without the awning for this one.  Kids are just warned not to play all day beside the big window :-)

At 5 kg/m2 it would weigh about 3 tonnes, including the floor.

The main limit to how big this design can be is the angle of repose of the regolith (ends up looking like a pyramid pretty fast as it gets taller) and the safe tension loading of the structure.  Using light pipes, you can extend it lengthwise pretty much forever, but there probably is an optimum size for a volume on Mars versus the risk of catastrophic failure.

I wonder about the behavior over time?  Tension structures are fragile in some ways and creep may be an issue?  The water and oxygen will take their toll as well.

The regolith might be tailing from the water mines?  Depends if the water can be found in clean sheets or if ot is bounded with other materials, I expect

A couple of minor points that may be good for consideration;

     1.  Build the actual structural framework inside of the pressure envelope.  This would make the whole operation simpler, and could use lower pressure to do the leak checking.

     2.  Use Bigelow style pressure envelopes.  The wall thickness will minimize puncture potential, add additional radiation protection, and minimize envelope creep.

     3.  The windows could be reinforced with clear Plexiglas panes, between panes of the aluminum glass.  Pressure could then be reduced more gradually between the inner panes and outer panes, thus dissipating the pressure stress between the inner and outer window surfaces.  The Plexiglas would also help reduce radiation coming in from outside.  (On a side note; the space between panes could also be filled with a O2 and CO2 sensitive polymer gel that would be clear, but harden if exposed to either O2 or CO2.  this could prevent pressure leaks through the windows).
1,2-There is no framework, it's a series of flat panels, that are under tension and therfore structural.  We do not really need the protection that Bigelowe provides since we are covering it with tonnes of regolith.  The panels might indeed be replaced by flexible fabric, except perhaps around the windows. Good idea.
The Bigelowe modules are quite heavy, the BA3100, about the same size as this, is about 70 tonnes.
3- Reinforcing with plexiglass is a good idea.  However, I like the idea of saying : we use the same method as for the ITS Spaceship, it simplifies design at this very conceptual stage! 
You need a pretty big hole to create a catastrophe with these volumes.
 


Offline rsdavis9

1. Hollow out hole in glacier.
2. Spray urethane foam to insulate and air tight seal.
3. Install door and window.

Done
With ELV best efficiency was the paradigm. The new paradigm is reusable, good enough, and commonality of design.
Same engines. Design once. Same vehicle. Design once. Reusable. Build once.

Offline cro-magnon gramps

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Re: Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD
« Reply #1151 on: 10/11/2016 04:48 PM »
1. Hollow out hole in glacier.
2. Spray urethane foam to insulate and air tight seal.
3. Install door and window.

Done

Do glaciers not move, even on Mars??? what I mean, here on Earth Glaciers do creep.. slowly, so there might be a problem with structural integrity.

edit for clarification...
« Last Edit: 10/11/2016 04:50 PM by cro-magnon gramps »
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Offline lamontagne

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Re: Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD
« Reply #1152 on: 10/11/2016 05:59 PM »
1. Hollow out hole in glacier.
2. Spray urethane foam to insulate and air tight seal.
3. Install door and window.

Done

Do glaciers not move, even on Mars??? what I mean, here on Earth Glaciers do creep.. slowly, so there might be a problem with structural integrity.

edit for clarification...
Indeed. See Wikipedia camp century and project iceworm.
3 km of tunnels, lasted only a few years.

Offline rsdavis9

Hmmm doesn't sound too good.
" By mid-1962 the ceiling of the reactor room within Camp Century had dropped and had to be lifted 5 feet (1.5 m)"

Maybe smaller holes wont distort as much?
How about flexible wall coatinga?

Also glaciers move because of inflow(snow) and outflow(ocean/melt). On mars covered with dirt I would expect inflow and outflow to be minimal/non-existant?
« Last Edit: 10/11/2016 06:43 PM by rsdavis9 »
With ELV best efficiency was the paradigm. The new paradigm is reusable, good enough, and commonality of design.
Same engines. Design once. Same vehicle. Design once. Reusable. Build once.

Offline eriblo

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Re: Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD
« Reply #1154 on: 10/11/2016 08:54 PM »
According to Wikipedia you need about 50 m of ice on Earth before the pressure becomes great enough for it to start deforming. As you noted there is likely not much flow on Mars which combined with the lower gravity and the much lower average temperature means that it will should be fine if you do not dig to deep - you will have to go below 29 m before the pressure even overcomes 1 atm of hab pressurization.
« Last Edit: 10/11/2016 08:55 PM by eriblo »

Offline RoboGoofers

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Re: Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD
« Reply #1155 on: 10/11/2016 09:29 PM »
... it will should be fine if you do not dig to deep - you will have to go below 29 m before the pressure even overcomes 1 atm of hab pressurization.

Also that's where the Balrogs live.

Offline uhuznaa

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Re: Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD
« Reply #1156 on: 10/11/2016 09:50 PM »
According to Wikipedia you need about 50 m of ice on Earth before the pressure becomes great enough for it to start deforming. As you noted there is likely not much flow on Mars which combined with the lower gravity and the much lower average temperature means that it will should be fine if you do not dig to deep - you will have to go below 29 m before the pressure even overcomes 1 atm of hab pressurization.

This, and also the glaciers on Mars seem to be millions of years old which seems to indicate only very slow flows. There's also nothing added on top of them in the short term. Would be wise to check this though, if you're mining water from them drill deep and check if the holes deform over time. If they don't a big glacier should be good to build a base in.

Or find a nice cliff with soft stone and dig in there. Would be harder than melting ice (or cutting it with hot water/steam) but at least the stone is already there and there's no shortage of it... Just another way of using in situ resources and I think you would have to use all you can.

People often underestimate the effort you have to put into safe pressure vessels. One atm is ten tons of pressure per square meter and one small crack can cause it to fail catastrophically. There's little reason to assume you could build them with less mass than those Bigelow modules.

Offline zodiacchris

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Re: Elon Musk IAC Mars Speech - Sept. 27, 2016 - DISCUSSION THREAD
« Reply #1157 on: 10/11/2016 09:53 PM »
Yes, the glaciers on Mars (with the exceptions of the ones at the poles) are artefacts that have been stationary and covered with rock and soil for eons. Apart from sublimation, they should be stable, and are also very cold due to the low surrounding ambient temperature. Provided you don't dig to deep and exceed the creep limit where the ice starts to plastically deform, the construction of tunnels and caverns with a steam lance should be straightforward and produce vital water as a byproduct. I would think that setting up a first base on top of a glacier, dig through the overlying rubble and melt out a system of storage and habitat caverns (ala ants nest) would be the most straightforward way of creating habitat space and water, if you bring airlocks and insulation. But then I am biased, as a geologist I'm always prone to digging down and I like mines...
« Last Edit: 10/11/2016 09:57 PM by zodiacchris »

Online Chris Bergin

Wouldn't it be best to take what is clearly a splinter topic of habs into its own thread (surprised we don't already have one), but that'd be a good idea, as it's a 57 page thread and a lot of people will have missed the start of the Hab discussion (or missed it).

So if we don't already have one, start the thread and link it in here.

Offline Lumina

(EDIT: Mods - per Chris's request above, a new topic was started at http://forum.nasaspaceflight.com/index.php?topic=41427.msg1597894#msg1597894, is it possible to move the habitat posts & discussion on this page over there?)

Here's my vision for amazing habitats on Mars. I imagine networks of cliffside cities with many panoramic windows dug out from mesas, natural canyon walls or even Tatooine-style dugouts, featuring:
 
- multiple levels,
- dozens of windows and dome-covered verandas with panoramic views,
- excellent protection from radiation,
- robustly stable indoor temperatures, so one less thing that can go wrong,
- shirtsleeve access via tunnels to surface facilities above or nearby (e.g. power generation, greenhouses, landing pads),
- redundant protection from decompression with segments protected by automatic airlocks,
- grand and inspiring elaborate carved entrances with inspiration from all ancient cultures on Earth,
- direct shirtsleeve access (via tunnels / airlocks) to mines for resource extraction

Besides excavation equipment and the usual internal equipment needed for habitats, the following will be needed:

- a scalable and flexible solution for a flooring and false ceiling system that can eventually use in situ resources,
- a scalable solution for sealing excavated tunnel surfaces that can also eventually use in situ resources (some kind of epoxy?),
- automatic airlocks and door systems to separate segments for safety,
- a modular system to create windows or external domes to cover "verandas", also evolvable to use in situ resources for the future.
« Last Edit: 10/12/2016 03:27 AM by Lumina »

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