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#151 2020-01-31 15:29:23

Yggdrasil
Member
Registered: 2020-01-10
Posts: 4

Re: Construction technology for Mars?

louis wrote:

I am sure the content of the book's great but the graphics!!! We need to move away from the 80s red dust vibe! It's horrible!!

Let's use more real colour. Let's picture people more as they would be on Mars ie in pressurised environments, indoors or in vehicles, not undertaking hazardous EVAs.

My feelings exactly... That's actually one of the reasons I'm taking part in this discussion.

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#152 2020-01-31 18:12:29

louis
Member
From: UK
Registered: 2008-03-24
Posts: 5,854

Re: Construction technology for Mars?

One reason I made that comment was that a couple of years ago we had an unusal weather event - happens about once very 20 years where we get a load of orangey Saharan dust dumped over the UK. Going outside, it reminded me of how Mars was supposed to be - everything looking so orangey...but here's the thing: after 10 minutes you can sense your eyes and brain are making a conscious effort to readjust and pick out the real colours and you begin to see more and more the full range of colour. I am sure if I had experienced that orange-dust environment for several days, eventually I would have retuned by colour perception almost entirely and been able to discern the full colour range - in other words I would be ignoring (as far as conscious perception went) the "orange filter". 

That's why I feel over-orange representation of human experience on Mars are misleading. 

Yggdrasil wrote:
louis wrote:

I am sure the content of the book's great but the graphics!!! We need to move away from the 80s red dust vibe! It's horrible!!

Let's use more real colour. Let's picture people more as they would be on Mars ie in pressurised environments, indoors or in vehicles, not undertaking hazardous EVAs.

My feelings exactly... That's actually one of the reasons I'm taking part in this discussion.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#153 2020-01-31 19:25:08

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,199

Re: Construction technology for Mars?

Metals that are moving and are struck will ring or vibrate like a bell and that is one of the mechanisms which are taking place in the metal when cold.
The plastic are a situation of unprotected via uv protecant films will degrade with time as well.

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#154 2020-02-10 15:26:28

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 478

Re: Construction technology for Mars?

I am impressed by Casey Handmer's work.

https://caseyhandmer.wordpress.com/2019 … ver-rated/

His idea of a ETFE blanket, anchored to the ground with cables, is a very good one.

https://caseyhandmer.files.wordpress.co … 213244.png

I ran a few calcs to look into what sort of material requirements this would entail.  I assume that tensile cables will be made from basalt fibre, which is 20 times more energy efficient than steel on a MJ/MPa.m basis.  I assume that the pressure in the habitat in 0.4bar and that the ceiling height in 30m.  The tensile strength of basalt fibre is 3GPa and I assume a working stress of 1GPa.  There would be one cable for every 10m2 of roof.  The internal pressure must be balasted by 10t/m2 of soil and rock to balance internal pressure.  So each cable must be anchored to at least 100t of rock.  So it will need to be tied to an anchor at least 10m beneath the surface.  The density of basalt is 2.7t/m3.  For each m2 of land, some 1.6litres of fibre must be used, weighing 4.32kg.  Each kg of basalt fibre requires 5kWh of electricity.  So, each m2 of land requires 21.6kWh of electricity to render it habitable.

How much land could we produce each year, if our basalt fibre plant is powered by a 1GWe nuclear reactor?  The reactor will produce 7.89billion kWh per year, assuming 90% capacity factor.  So that's 365km2, or 141 square miles.  Of course, the ETFE manufacture will consume a lot of power too.  But if basalt fibre can be used to reinforce it, only a very thin layer will be needed.

So assuming we can scale basalt fibre and ETFE manufacture quickly; a Mars colony could paraterraform country size areas of the Martian surface within a few decades, using a standard size nuclear power reactor.

Last edited by Calliban (2020-02-10 15:34:14)


Interested in space science, engineering and technology.

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#155 2020-02-10 17:59:07

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,199

Re: Construction technology for Mars?

Basalt processing walking machine:

SpaceNut wrote:

You know just a single word can trigger a memory and I seem to recall a mobile habitat thaty walks on earth and its in use already in Antartica.
Lets alter its use but make use of its size to assist in making a mobile self contained mining to end woven plant for use on Mars or the asteriods keeping in mind that we need to be able to land the mass for mars as it will be by and far easier on the asteriod. As indicated before self automated with telerobotic control supplied by nuclear power in the 10 kw where we obsorb the radiated enegey for other pocesses in the mining processing area of the units design.
If the mass needs to be distributed to several modules we can link them together to form a train like movement.
https://cdn.archpaper.com/wp-content/uploads/2013/02/antarctica_03.jpg

This will be part of the Mars My Hacienda topic plot concepts of roving and mining business concepts as part of the Teohold plot 0003 post #19. It is also part of the mobile roving plot 0008 registry as well to process materials to make temporary habitats for each plot to make use of. The habitats might be able to make use of a 3D weaving process which is being used on the Adept heatshield. We will need to see where it fits into the other open registries as a business and for how many might be needed to make all of the product types from chairs to rebar....

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#156 2020-02-11 11:59:38

elderflower
Member
Registered: 2016-06-19
Posts: 1,260

Re: Construction technology for Mars?

ECTFE and similar polymers require a supply of Fluorine containing rocks to be located, mined and processed. I assume there will not be much difficulty getting Chlorine from the regolith, even if there are no massive salt deposits to hand.
The availability of Fluorine came up in the discussion on terraforming using greenhouse gasses.

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#157 2020-02-11 16:01:26

louis
Member
From: UK
Registered: 2008-03-24
Posts: 5,854

Re: Construction technology for Mars?

He's good, isn't he? Thanks for the interesting calculations supplementing his proposal.

I had an idea a while back about something similar - a huge plastic tent that would be held up by air pressure aided by fairly lightweight poles to a height of about ten feet at intervals of several feet. The edge of the tent would be held down by thousands of tons of regolith.

Don't know if you are able to answer this, Calliban, but at what point would the pressure inside the "big tent" become a risk to the structural integrity of the plastic, assuming the ground is theoretically sealed?  Is it less than 0.1 bar, or more ?  Do you have a guesstimate?

I suppose I'm thinking along these lines: if the limit was say 0.1 bar , maybe with a mix of oxygen at 30% of the air inside the tent,
if people could wear a pumping mechanism to concentrate the atmosphere by a factor of 6, perhaps they could move around in MCP suits, breathing this atmosphere through the equivalent of an aqualung , quite happily. If the limit is higher than 0.2 bar, the pumping requirement is correspondingly reduced.  It might be less satisfying than Handmer's suggestion, but it might be a lot less resource intensive that putting in place high tension cables.  You don't give an estimate for the amount of energy required to actually install the structure for Handmer's proposal...wouldn't that be what really eats up the energy - digging down ten metres and attaching cables to rock masses...then everything having to be inspected, probably by humans close up. On your figures, you've got to install 1,000 cable attachments for every 100 x 100 metre area of structure. That's a lot when you think about it - a cable every 3.3 metres in every direction.

If the big tent idea works, you could connect these tents with tunnels (with air locks for catastrophic failure control)  and the area they cover could be essentially limitless. Heat loss would be an issue, presumably, but there are theoretical solutions including additional heating, hot water storage, and thermogenic plants (that release heat at night).

Calliban wrote:

I am impressed by Casey Handmer's work.

https://caseyhandmer.wordpress.com/2019 … ver-rated/

His idea of a ETFE blanket, anchored to the ground with cables, is a very good one.

https://caseyhandmer.files.wordpress.co … 213244.png

I ran a few calcs to look into what sort of material requirements this would entail.  I assume that tensile cables will be made from basalt fibre, which is 20 times more energy efficient than steel on a MJ/MPa.m basis.  I assume that the pressure in the habitat in 0.4bar and that the ceiling height in 30m.  The tensile strength of basalt fibre is 3GPa and I assume a working stress of 1GPa.  There would be one cable for every 10m2 of roof.  The internal pressure must be balasted by 10t/m2 of soil and rock to balance internal pressure.  So each cable must be anchored to at least 100t of rock.  So it will need to be tied to an anchor at least 10m beneath the surface.  The density of basalt is 2.7t/m3.  For each m2 of land, some 1.6litres of fibre must be used, weighing 4.32kg.  Each kg of basalt fibre requires 5kWh of electricity.  So, each m2 of land requires 21.6kWh of electricity to render it habitable.

How much land could we produce each year, if our basalt fibre plant is powered by a 1GWe nuclear reactor?  The reactor will produce 7.89billion kWh per year, assuming 90% capacity factor.  So that's 365km2, or 141 square miles.  Of course, the ETFE manufacture will consume a lot of power too.  But if basalt fibre can be used to reinforce it, only a very thin layer will be needed.

So assuming we can scale basalt fibre and ETFE manufacture quickly; a Mars colony could paraterraform country size areas of the Martian surface within a few decades, using a standard size nuclear power reactor.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#158 2020-02-11 16:23:21

Terraformer
Member
From: Lancashire
Registered: 2007-08-27
Posts: 3,294
Website

Re: Construction technology for Mars?

I don't like the idea of putting all the purposes of a building on a single layer.

If I were laying out a Martian town, I'd use the tent idea, but at a lower pressure, maybe 50mb. This would be a CO2 dominated atmosphere that would be used to grow adapted plants, producing food, fibre, and oxygen for the town. Within that would be the pressurised complex of buildings that is the town proper, with covered arcades for streets and shielded buildings to cut down on radiation, and including of course some parks, maybe in domes.

One thing that could be good for building pressurised environments is a hexagonal platting system. I have thought of this for Luna. They tessellate, which domes don't, and a circular pressure vessel can fit inside them. With the addition of another hexagon built inside that, you will get thick walls for radiation shielding. Streets would run between the hexagonal blocks. With standardised blocks, they could be used for many purposes - hospitals, hotels, townhouse developments around a square, parks... of course some blocks would need to reserve right of way for more direct routes for any railway added later. When you need more space, build another hexagon and top off the new street. As the city grows, the older parts could be redeveloped, maybe growing a forest of taller buildings from them that would reach above the pressurised streets.


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#159 2020-02-11 17:47:25

louis
Member
From: UK
Registered: 2008-03-24
Posts: 5,854

Re: Construction technology for Mars?

Can you grow plants at 0.05 bar even with a 100% CO2 atmosphere? I thought - from memory -  it had to be closer to 0.2 bar

Terraformer wrote:

I don't like the idea of putting all the purposes of a building on a single layer.

If I were laying out a Martian town, I'd use the tent idea, but at a lower pressure, maybe 50mb. This would be a CO2 dominated atmosphere that would be used to grow adapted plants, producing food, fibre, and oxygen for the town. Within that would be the pressurised complex of buildings that is the town proper, with covered arcades for streets and shielded buildings to cut down on radiation, and including of course some parks, maybe in domes.

One thing that could be good for building pressurised environments is a hexagonal platting system. I have thought of this for Luna. They tessellate, which domes don't, and a circular pressure vessel can fit inside them. With the addition of another hexagon built inside that, you will get thick walls for radiation shielding. Streets would run between the hexagonal blocks. With standardised blocks, they could be used for many purposes - hospitals, hotels, townhouse developments around a square, parks... of course some blocks would need to reserve right of way for more direct routes for any railway added later. When you need more space, build another hexagon and top off the new street. As the city grows, the older parts could be redeveloped, maybe growing a forest of taller buildings from them that would reach above the pressurised streets.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#160 2020-02-11 18:03:58

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,199

Re: Construction technology for Mars?

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#161 2020-02-11 18:14:40

louis
Member
From: UK
Registered: 2008-03-24
Posts: 5,854

Re: Construction technology for Mars?

And what is the answer?  Can you summarise?

SpaceNut wrote:

Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#162 2020-02-11 21:15:51

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 478

Re: Construction technology for Mars?

Louis, re the tent idea and your question about structural integrity.  The thin-walled pressure vessel equations will help.
https://www.mathalino.com/reviewer/mech … re-vessels

The answer to your question will depend upon the strength and thickness of the polymer.  ETFE has a breaking strength of 40MPa.


Interested in space science, engineering and technology.

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#163 2020-02-11 21:37:47

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 478

Re: Construction technology for Mars?

One option for tent material, assuming that abundant basalt fibre is used for structural reinforcement; is high density polyethylene.  This is easier to make than ETFE.  UV resistance could be provided by a thin layer of zinc oxide applied to the exposed surfaces.


Interested in space science, engineering and technology.

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#164 2020-07-13 21:36:08

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,199

Re: Construction technology for Mars?

Sustainable engineers Kenoteq are reinventing the brick

Bricks are made from clay -- a type of soil found all over the world. Clay mining strips the land's fertile topsoil, inhibiting plant growth.

In conventional brick production, the clay is shaped and baked in kilns at temperatures up to 1,250°C (2,280°F). The majority of brick kilns are heated by fossil fuels, which contribute to climate change.

There are places that we have found to have clay so we can do it the old fashion way.

BB16FAHY.img?h=416&w=799&m=6&q=60&u=t&o=f&l=f&x=612&y=284

Of course for earth its about recycling materials.

K-Briq. To make it, construction and demolition waste including bricks, gravel, sand and plasterboard is crushed and mixed with water and a binder. The bricks are then pressed in customized molds. Tinted with recycled pigments, they can be made in any color.

In the UK, around 2.5 billion new bricks are used in construction every year -- and about the same number of old bricks are demolished. A seemingly simple solution to the brick production problem would be to re-use old bricks.

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#165 2020-07-30 22:11:36

ssorthiya58
Member
Registered: 2020-07-30
Posts: 1

Re: Construction technology for Mars?

We will need to use what we have on mars when it comes to materials to manufacture from.
These three words are about the same in cement, concrete, and mortar for what we use on earth.

I have heard of Granite chips and dust being used with cement or as a cement, which means its possible to use basalt as a filler material as well.

classification of aggregates
<a href="https://www.engineeringbrother.com/2020/07/classification-of-aggregates-used-in.html">classification of aggregates</a>

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#166 2020-07-31 16:49:29

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,199

Re: Construction technology for Mars?

Welcome to NewMars, ssorthiya58.
Thanks for the link in htlm code structure but we us the BBCode formats in the PhP forum coding.
See link lower left corner of the quick reply box above the submit button..

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#167 2020-08-01 08:13:40

SeaDragon
Member
From: Merry Old England
Registered: 2020-07-25
Posts: 16

Re: Construction technology for Mars?

louis,

Casey Handmer is amazing but I'd like to add a technical fix to that fluorine access problem for ETFE.

The call for ETFE is based on the impression that UV damage would destroy other types of plastic which is not necessarily true - it's mostly the production of oxygen based free radicals that causes the issue (for quick reading: https://en.wikipedia.org/wiki/UV_degradation ). If you can stop oxygen from inside diffusing into the plastic then UV degradation is greatly reduced and the inclusion of hindered amine light stabilisers (HALS) as copolymers, even making up as little as 0.25% of the total plastic, this can be greatly reduced yet further.

So:
- With a thin layer of something like poly(ethyl vinyl alcohol), usually written EVOH, the majority of oxygen transmission into a plastic habitat skin can be stopped
- A small amount of HALS copolymers stops initial free radical compounds made just after UV absorption in the plastic from propagating and leads to spectacular decreases in corrosion rates before any oxygen that does get through can make things worse.

With these fixes we can just use PET or a similarly cheap and easily produced plastic with no crazy elements like fluorine needed at all.
If we reinforce with basalt fibre (very nearly as good as Keflar but far far cheaper than Keflar) instead of Keflar or equivalent we'd be able to build this sort of thing at an industrial scale using only the resources we have on hand + a few low mass imported extras like HALS copolymers, accounting for perhaps 400 tonnes of plastic per 1 tonne of HALS or something.

Last edited by SeaDragon (2020-08-01 08:14:35)

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#168 2020-08-01 08:39:45

tahanson43206
Member
Registered: 2018-04-27
Posts: 3,074

Re: Construction technology for Mars?

2020/08/01 The thought behind this post is to provide an index to thoughtful posts in this topic:

SearchTerm:BrickPressureLoading http://newmars.com/forums/viewtopic.php … 28#p144728

This post by IanM was part of a discussion on building brick structures to take pressure on Mars.

I'd like to invite others to look over the topic and add links to particularly interesting or valuable posts.

***
For SpaceNut ... down the road, it might be possible to interest a few (admittedly unusual) members to support creation of an index to content of the forum.

An index topic could be constructed in the Meta New Mars top level index.

The snippet above is an example of what might be added to such a topic. 

A couple new members have joined the fray recently, and they cannot possibly find anything worth their time using the simple FluxBB search tool, except by blind luck. 

Edit#1: Also for SpaceNut ... you are welcome to add links to ** this ** post, if you run across items that relate directly to the search argument.


(th)

Last edited by tahanson43206 (2020-08-01 08:46:41)

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#169 2020-08-01 11:05:28

Void
Member
Registered: 2011-12-29
Posts: 3,474

Re: Construction technology for Mars?

SeaDragon,

I was happy to see your post #167.  Would adding a coating of sunscreen be useful and compatible?  Titanium Dioxide.

Done


I like people who criticize angels dancing on a pinhead.  I also like it when angels dance on my pinhead.

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