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#1 2017-11-08 05:47:09

louis
Member
From: UK
Registered: 2008-03-24
Posts: 7,208

Gorges, ravines...Earthsims for Mars.

I've mentioned before about the concept of finding a narrow gorge on Mars which can be blocked at both ends and then roofed, after which it can be pressurised and converted into an "earth-sim" on Mars. It would be a kind of blend of the natural and artificial...a little more artificial than your recreational park, but not much more. For a "starter gorge" earthsim we might be looking at perhaps something like 200 feet long, 15 feet wide and maybe 50 feet tall.

Some issues/points:

1.The roof could be made of thick glass. It could possibly be coloured pale blue for an added "earth-like" effect. The glass slabs here look about 20 feet long, so suitable for bridging a 15 feet gap.

https://www.google.co.uk/imgres?imgurl= … K..i&w=852

2.  Once the roof and openings are covered over, the gorge would be pressurised with earth-simulant air. I don't think anyone can say for sure how stable a pressurised environment would be in an earthsim.  I think it would depend on the nature of the rock and the regolith. Clearly if there is major leakage, we could look at cementing over the rock. However, I suspect that won't be necessary and that the gas flows from  depressurisation will gradually fill up cracks and crevices with microscopic dust that then limits loss.

3.  The floor of the gorge can be converted into rich soil for growth of vegetation. A rich compost like soil-base could be imported from a central soil manufacture facility and mixed with the existing regolith (assuming the surface material was suitable).  We could use quick growing trees, bushes and plants - like bamboo - to create a pleasant environment. 

4.  Narrow paths and anchor points for bushes could be created by gouging out the sides of the gorge walls (making use of any natural indentations.

5.  Lighting in the gorge would be supplemented by (a) use of reflectors on surrounding elevations to reflect light on to the gorge glass roof (b) light pipes being fed through to the top of the gorge and directed down and (c) electric lighting using the natural frequency range.

6. Heating would be provided by hot water pipes built into the rock walls and floor. Humidity would be controlled.

7. A climbing wall could be provided.  To maximise exercise potential and leisure interest, rope walkways could be suspended in the air, extending laterally and diagonally along the paths.

8. A water feature stream and pool could be added.

9.  The walls could be tunnelled into to create refreshment and leisure facilities. Also, a cycle path circuit could be created in the same way.

10.  We could of course create these gorges ourselves using conventional explosives (maybe tricky to use on Mars, but possible I would have thought) or heat-cracking/drilling techniques.

Any thoughts gratefully received.

Here are some nice narrow gorges and ravines on Earth:

https://www.google.co.uk/search?biw=160 … V8lWmkNxNM:

https://www.google.co.uk/imgres?imgurl= … Q..i&w=250

https://www.google.co.uk/search?q=ravin … ak5TYUPINM:

Last edited by louis (2017-11-08 06:20:41)


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#2 2017-11-08 08:38:45

elderflower
Member
Registered: 2016-06-19
Posts: 1,262

Re: Gorges, ravines...Earthsims for Mars.

Gorges and hillsides may exhibit slope stability issues which do not become apparent until the ice component of the regolith gets heated to melting point, due to its being protected by roof and walls. You have to heat your installation in order to grow things in the ground. Nothing grows in permafrost except for a few micro organisms, the only plant growth occurs in the thawed layer above the frost line.

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#3 2017-11-08 11:29:38

louis
Member
From: UK
Registered: 2008-03-24
Posts: 7,208

Re: Gorges, ravines...Earthsims for Mars.

I would have thought this was less of a problem with igneous rocks and I think they tend to be the type where you get gorges (i.e. they don't become broad valleys - like say a cut in sandstone - because they have a lot of inherent stability). However, I am not a geologist so am just guessing!

Yes, I think I did address the point about heating...building hot water pipes into the rock walls and the soil floor makes a lot of sense. Where soil was place in rock clefts to encourage plant growth, these would probably be quite shallow (as in mountains on Earth) and so influenced by the general internal air temperature.  The added insolation from reflectors should help keep the cavern warm, but ultimately this would be like heating a very large hall.

elderflower wrote:

Gorges and hillsides may exhibit slope stability issues which do not become apparent until the ice component of the regolith gets heated to melting point, due to its being protected by roof and walls. You have to heat your installation in order to grow things in the ground. Nothing grows in permafrost except for a few micro organisms, the only plant growth occurs in the thawed layer above the frost line.


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#4 2017-11-08 12:27:24

elderflower
Member
Registered: 2016-06-19
Posts: 1,262

Re: Gorges, ravines...Earthsims for Mars.

There are a lot of landslips in the Mariner valleys but there doesn't seem to be the amount of debris that you might expect. That leads me to suspect that the walls here, and maybe elsewhere on Mars, are partly composed of dirty ice. If this is so then when the collapses occur the ice can sublime and the dust can blow away, leaving a lot less rubble than might be expected.

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#5 2017-11-09 11:09:25

Antius
Member
From: Cumbria, UK
Registered: 2007-05-22
Posts: 1,003

Re: Gorges, ravines...Earthsims for Mars.

elderflower wrote:

There are a lot of landslips in the Mariner valleys but there doesn't seem to be the amount of debris that you might expect. That leads me to suspect that the walls here, and maybe elsewhere on Mars, are partly composed of dirty ice. If this is so then when the collapses occur the ice can sublime and the dust can blow away, leaving a lot less rubble than might be expected.

Interesting.  I can imagine this could be a real problem when it comes to siting structures on Mars.  Any significant heat flux into the ground could result in a build up of subsurface pressure that is then released explosively.  Even if pressure is released more gradually, the result could be subsidence.  A civil engineering nightmare, like building on tundra except worse.

On the other hand, in certain areas it may be possible to generate power by pumping heat into the ground and releasing the sublimed CO2 through a gas turbine.

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#6 2017-11-09 14:00:32

elderflower
Member
Registered: 2016-06-19
Posts: 1,262

Re: Gorges, ravines...Earthsims for Mars.

The requirements for building on permafrost have been established on earth. The main aim is to ensure that the ground stays frozen which means it keeps its stability. 
Sub surface CO2 reservoirs have been identified around Mars' South Pole so that will complicate exploration in that area, for sure.

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