Untitled Story - Canyon Mars

(with thanks to metereology, geology, space exploration, & a nod to Larry Niven who described some interesting planets in his Known-Space series... Jinx, Plateau, & Canyon in particular; hope I am getting the names right, will need to go back & check that)

https://upload.wikimedia.org/wikipedia/commons/4/48/USGS-PlanetMars-TopographicalMap.png

canyon mars terraforming colonisation/colonization.  

to date, there have been few mars probe/rover/etc. landings in the southern hemisphere & few in lowest-altuitude (i.e.:  deepest) mars surface areas, which might be *the most * interesting, for water & potentially life (of our biochemical type/-s), etc.  

instead of transforming the whole planet, use, dig/deepen the existing lowest-areas (with preference to those nearer the equator), to create "havens" of higher atmospheric pressure + liquid water (& warmer temps).  combined with conventional mars-colony plans for pressurised structures, underground, etc.  

a deep hole holds the atmosphere in better, absent a strong-enough planetary magnetic field, can do a local ozone layer, etc. ? 

need to study - up on the orbital mechanics/characteristics of mars...  !  

water/lake/seas in the bottom (ice-melt from the surrounding ground? how much? would they need to add/channel water in, or pump it out/ depends on local conditions. how to do the sides/canyon walls? straight vertical , sloping, very gradual, or etc.? erosion problems? a lot depends on the type of material dirt soil sand gravel rock, etc.? heat-sear/melt the sides? uses way more power? cement/concrete? vegetation to brace/hold up the sides? ...?    ),  ozone to filtre/filter UV, the exccavated rock/dirt/sand/etc. banked around (far enough out, & arranged so as to NOT erode back in... !),  ice accumulations? (where? & natural, artificial, etc.?  uses of...?).  plants to make oxygen,  long slow conversion cycle to get fully-breathable air? airflow - O2 going up & out, CO2 down & in?  what plants/biology, cycles, etc....?  life-forms (mostly vegetation; plants, fungi, molds, microbes, etc.? hardened/tuned for uv & temp, etc. mars conditions (biology/ecology set-up) 

what about existing mars life, if any? (microbes? anything larger?  fossils, etc.?)  exported life forms from earth already there, whether ancient/natural, &/or from human acitivy/-ies ?  (invasive species problems/issues?) 

digging/excavation costs?  how? mining? robot, nanotech... ? nukes?  uses for the excavated materials? 

it could eventually end up something like the 'riverworld', with lots of canyons... ?

possible locations list:  

(lowest point on mars?  surface, caves, etc.?)

Hellas Planitia - under/near the Coronae Scopulus? - deepest but not that close to the equator... 30+ degrees south... 

various Chasma in the great canyon system near the equator? 

Hydraotes Chaos, Aureum Chaos, Aurorae Chaos - in the Margaritifer area? 

Various craters, preferably close to the equator. in particular Du Martheray & the little one north of it in the Isidis Planitia;  & those in the area of Masursky-Sagan to McLaughlin to Curie craters? 

Lyot, Stokes, Milankovic, etc. craters are way up north.  Hooke crater is way south.  - too far from the equator, too cold?, but interesting in later stages, maybe?  (is/does deeper = warmer? but the sunlight angles... check the data on mars-sun positioning during anual orbit, etc. cycles?)  

Utopia Planitia (of st:tng) gets quite deep, but also too far north...

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maybe start with a description of the location, in a terraformed mars-canyon that is either finished (& populated, etc.), or being created?   liquid water, atmosphere, orange-blue sky(?) plant life, sunlight, warmth, etc. ? caves, tunnels around it. the upper mars-terrain nearby, & so on... ? 

-start with the location before excavation starts? low point on mars; high pressure atmosphere, borderline for liquid water, temps? - cold, etc.

structure:  the idea is to go deep enough for the natural atmospheric pressure to get to earth-normal. so liquid water can exist, you can get solar warming, plantas, oxygen, etc. 

obviously, you have to start with the geography & terrain of the site-location that you choose, & work with that...   subuect to that starting-condition, the "ideal/in general" as follows?  

shallow-sloping vs steep (cliff) walls?  terraced?  - obviously shallow-sloping involves more moving/removal of dirt & rock.  

how about this?:  to optimise sunlight & solar-warming, shallow/gently sloping on the sides along the path of the track of the sun(light); so,  east, west, & equator-wards.  steeper on the pole-ward facing side?  so a long, shallow basin on 3 sides & a steeper cliff-wall on the 4th?

depending on the configuration & orientation, the east & west sides might be angled steeper pole-wards & shallower towards the equator (& the track of the sun)

use lots of black on the surfaces that get hit by the sunlight (like the pole-ward wall), to optimise solar heat-absorption? 

terraced levels/contouring/landscaping/etc. down to the water @t the bottom of the "hole"?  

climate basics:  the lighter oxygen goes up & out, heavier co2 flows in & down the sides.  the warmer air goes up & out (& cools as it rises?), cooler/cold air flow in down the sides?, these 2 effects work together? reinforcing?  how strong? will it need some kind of limits/controls on these effects?  wind baffles on the sides? (cliff or sloping?  & what weather patterns fo you get with that?  )   -- OK, so the walls on the sunward-sides should be more shallow-sloping, to optimise sunlight exposure in(to) the hole/canyon ?(should they?)?  what about the other walls? - does it matter? ...advantages of steep/versus/shallow? - terraced? high-low areas?  

how does the slope, etc. affect wind & weather?  higher banking/obstruction on the pole-ward side wall &/or behind/beyond it? to block/shape/control winds, cold?, etc.?  

oxygen levels would go up during the day (from/via photosynthesis), & co2 levels would go up @ night (no photosynthesis + heavier co2 coming down & in from the upper-main surface level of mars)

water flows down the sides from the permafrost level? how long/does it dry up eventually, permanent flow?  will there be too much or too little water in the bottom?  

warms, moist air rises from the bottom on the canyon? (plus the above airflow patterns) cools as it rises (plus in-canyon wind & weathger-patterns/microclimate) some of it precipitates out in-canyon (slopes or cliffs on the sides?) but some gets blown out over mars,  falls as snow?  does it melt/vapourise in the sunlight?  

how do the shadows work, in the canyon(s)? light, timing, climate effects, etc.  obviously, the shadows would be cooler than the sunlight...  

plants (animals?) biosphere/ecology stuff?  "green" recu *recycling, etc.  

mars colony stuff; tech, social, etc.?  

hill up the excavated dirt & rock to shape windflow on the mars surface  above the hole?  

how about "The Hole" as a name?  (for the 1st project-excavation?)   dante/inferno/divine comedy references?  

(^merge this with the stuff further up...!^ ) 

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a trip there? vacation/tourist/worker?  exploration/survey/beginning of the project?  

elon musk?  who/what other mars projects ?  americans, eu, russia, china? india ? etc....?  

at 

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STUFF:

* - "Mars spiders" (a real thing)  

-starting off extremely cold, non-breathable, barely habitable, etc.  getting warmer wetter milder etc. & more earth-like habitable as it gets deeper & more developed....    ?  

canyon walls steep-shallow?

solar (aside from photovoltaic & water thermal) ;  colours - dark - black for more warming, light for less warming, reflective to focus light/heat & cooling underneath, etc....?  use this/these (as) "passsive" effects; cANYON, ETC.?  (insulation/-ting?  retaining heat @night, etc.)  clouds fog etc....?  ?  - effects of environmental micro local climate etc.  ?  ?  

TODO:  sort, organise, & collate (etc.) the story notes! >__<!?