In my World, a perfect storm of catastrophic size strikes earth and black-death levels of mortality ensue, cutting short the Great Space Race. The only problem is that there are over 10,000 people stuck on Mars, but with mortality in the billions, Earth nations (or whatever is left of them) can hardly concern themselves with a few thousand wayward souls.

Fortunately for the far-flung Martian colonies, a man by the name of Diego OfeAde unifies them with the generous support of ClF3, and is named Arbiter of Mars.

Now with the Martians only lacking a common residence, Diego decides that the future of Human Mars is at the Bottom of Valles Marineris. It has a few benefits; thicker atmosphere, aquifers, warmth during the day and night, protection from sand storms, etc. There is one little problem: a four-mile deep cliff between them and the valley floor.

Diego, however, has good faith in his friend Guoliang Guan to get their 250,000 tons of material down the chasm with their circa 2100~ technology and the industrial capacity of Atlanta.

My Question is:

How can the martians achieve the Herculean task of moving all quarter-of-a-million tons of (presumably fragile) material safely to the bottom of Valles Marineris?

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    $\begingroup$ Do they have any earth moving machinery? I'm assuming they'd have to have some $\endgroup$
    – AndyD273
    Commented Aug 31, 2017 at 14:35
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    $\begingroup$ Is there a particular reason why you used hard-science tag instead of science based? $\endgroup$
    – L.Dutch
    Commented Aug 31, 2017 at 14:40
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    $\begingroup$ Maybe this is a stupid question, but would it require anything more complicated than some careful driving? Valles Marineris is indeed deep as far as canyons go, but it's not a sheer cliff on both sides, for the entire length. A Martian colony in 2100 would probably have detailed topographical maps, and some capability to survey potential routes, so why not just find a place that's not too steep and drive down it? $\endgroup$
    – Phil Frost
    Commented Aug 31, 2017 at 18:22
  • 4
    $\begingroup$ @Phil Frost: The Grand Canyon is a lot steeper than the Mariner Valley, but you can get to the bottom just by walking. Probably could drive, too, if it weren't for the Park Rangers. $\endgroup$
    – jamesqf
    Commented Aug 31, 2017 at 18:46
  • 3
    $\begingroup$ I think more information is needed because as written I'm not sure what's stopping them from relocating in the most obvious ways. $\endgroup$
    – rek
    Commented Aug 31, 2017 at 20:45

7 Answers 7


Cut a road into the canyon walls.

In order to build stuff on Mars, they are going to need a lot of heavy earth moving equipment. Simply start digging/mining along the edge of the canyon, and make a very long ramp that the equipment can be hauled down. Then it's just a matter of driving down.

Soil on Mars

Marian soil is called regolith. It's basically a lot of rock, broken stones, and super fine dust, some of which is as small as 0.15 microns.
As others have noted the walls of the canyon are somewhat weathered, and a lot of the length would be considered very steep, versus sheer.

In other places you'll find basalt and other volcanic rock.

Valles Marineris is believed to be a tectonic fault where two plates separated while the planet was still cooling. If this is correct, then the bedrock would be very hard, but there is likely to be a lot of regolith piled up where the bedrock has weathered.

There may be places along the canyon where you could get away with a switchback road bulldozed through the surface. Other places may need to have the road cut into the rock more.

In regards to the regolith, you'd want a bulldozer or other large equipment to push boulders out of the way, and smooth/level the ground for the road.
You also would want something like a steamroller to compress the soil and keep it from crumbling away under the heavy loads.
You wouldn't want to go strait down hill with several ton load if the grade is too steep, and switchbacks might not be practical in all areas because the lower road can undercut the stability of the upper road, which would be bad, especially if the soil is loose.
Also, you wouldn't want a gradient of much more than 20%.
Gradient is calculated by dividing the vertical rise by the length of the run.
Working backward we get 20% = 7km(4mi) / 35km(21mi). So that means we need a road that is at least 35km long, which can either run parallel to the rim or switch back as the terrain allows.

  • 3
    $\begingroup$ I suspect you were downvoted on account of not having the "hardest" of science in your answer. I'm not sure, exactly, how you might improve that (maybe go into more detail on the tunnel-cutting process?) but at first glance that's my best guess. Regardless, you get a +1 from me for an elegant, tried-and-true solution. Cutting a roadway also allows for the addition of a railway later, in case movement of freight in and out of the valley becomes routine. $\endgroup$ Commented Aug 31, 2017 at 16:36
  • 6
    $\begingroup$ @MozerShmozer Yeah, I really don't know how to make that "harder". You take the tool and cut out the rock. People have been doing it since the beginning of recorded history. This isn't rocket surgery. :) $\endgroup$
    – AndyD273
    Commented Aug 31, 2017 at 18:43
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    $\begingroup$ @AndyD273 Actually it's Rock Surgery. :D Yeah ok I'll leave now... $\endgroup$ Commented Aug 31, 2017 at 18:46
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    $\begingroup$ Would you really call it earth moving equipment, or is it mars moving equipment? $\endgroup$ Commented Aug 31, 2017 at 19:09
  • 1
    $\begingroup$ @JeffLambert I think officially it's called Martian regolith, but earth is different than Earth, and so it kinda works both ways? Technically we were calling soil 'earth' a long time before we knew that there was such a thing as 'The Earth'. I say, if the machines were manufactured on Earth they are earth moving machines no matter where in the solar system they are. Plus it's less confusing for the sake of the question. What's a regolith mover after all? $\endgroup$
    – AndyD273
    Commented Aug 31, 2017 at 20:27

Drive up from the northern end of the valley, where there isn't a drop off; shown in the topographical map below:

enter image description here

Depending on where you start from this could be relatively easy or may involve constructing a ~4000 km road (the length of the valley). Assuming they have the infrastructure in place to travel long distance across the surface they could use existing land transports.

  • 9
    $\begingroup$ That would be one hell of a migration. Think of it: a lost people, led by a single powerful man, who trek across the wasteland seeking the Promised Land. There's some serious religious parallelism there (Israelites' 40 years in the Wilderness) that could make for an interesting story. $\endgroup$ Commented Aug 31, 2017 at 17:56

Just drive down it. Although the valley is large, it's not terribly steep. And like all valleys, some places are steeper than others.

Here's a cross-section from https://productforums.google.com/forum/#!topic/gec-mars/9kR0zzUGuRc:

enter image description here

Note the vertical scale is exaggerated 4 times, making the actual cross section more like this:

enter image description here

Moreover, as with any steep terrain, there are local features that are not as steep. Here's one approach that gets you into the valley without going down any of the steep slopes:

enter image description here

This is taken from a section near the middle:

enter image description here

With a detailed topographical map, some reconnaissance, planning, and care, getting to the bottom of the valley shouldn't be especially difficult. This is just one example. People do this sort of thing all the time on Earth, on much steeper terrain. The Grand Canyon is steeper but it's not difficult to drive down it.

We can assume since there are no roads on Mars, if the colony is mobile at all it has decent off-road capability. Even taking no effort to avoid the steep parts, and going straight down the canyon walls, the grade is only about 25%. While this would be a challenge to a typical Earth semi-trailer (Veil pass on I-70 is 6% grade), potential Mars vehicles would necessarily be more rugged.

The awe of Valles Marineris isn't the steepness: it's just the huge size of it. It's about as long as the United States are wide, and it's about as deep as Mt. Everest is tall.

Although, this does raise questions of why the valley would be any better. Indeed the atmosphere is thicker, but it's still very thin. According to this Mars atmospheric model by NASA, the pressure at altitudes below 7 km are

$$ p = 0.699 \cdot e^{-0.00009 h} $$

where $h$ is the altitude in meters. So at 0m, that's 0.699 kPa. At -5km, 1.09 kPa. Better I suppose, though compared to the 101 kPa on Earth at sea level, you'll still need pressurized suits. Even filling the suits with pure oxygen, you'll require a pressure of 32.4 kPa.

The valley is too wide to provide appreciable protection from wind storms. And wind storms on Mars are not all that bad. Peak winds are around 60 mph, while Earth storms can double that. And the atmosphere on Mars is so thin, the force imparted by a 60 mph wind is very much less. The problem with dust storms is really the deposition of dust on solar panels, but we can assume a colony has solved this problem with something as simple as a feather duster.

I can't find anything to indicate aquifers are more likely to be found in Valles Marineris. It's not known how the valley was formed, with erosion by water being only one possible explanation. And regardless, that there was water there in the past does not mean it's there now.

It is the case that only at the lowest elevations on Mars can liquid water exist (it would sublimate into vapor at higher altitudes due to the lower pressure), but if you just wanted to get to a lower elevation there are more easily reached places than Valles Marineris, such as Vastitas Borealis. Or you could aim for Hellas Planitia, which has lower elevations. While you're there, you can visit the crash site of the Mars 2 lander, the first man-made object on Mars.

If you're able to make use of subsurface water, they may be all over the planet. In fact if a colony were on Mars in the first place, it would probably already be situated over such an aquifer, with missions between now and 2100 having already surveyed the aquifers.

  • 5
    $\begingroup$ Don't forget: The Grand Canyon is steeper than Valles Marineris on a planet with higher gravity than Mars. $\endgroup$
    – Perkins
    Commented Sep 1, 2017 at 4:35
  • $\begingroup$ @Perkins I'm not sure the lower gravity is of too much benefit, since vehicles tip over just the same, and it reduces the friction between the wheels and the surface. $\endgroup$
    – Phil Frost
    Commented Sep 1, 2017 at 12:34
  • 1
    $\begingroup$ Gravity on Mars is about a third of what it is on Earth, which means that you can drop things much farther before they accelerate to dangerous velocities. The vertical acceleration from jumping off the edge would come out only slightly higher than jumping into the Grand Canyon if you picked a spot where it was only 6km deep. $\endgroup$
    – Perkins
    Commented Sep 1, 2017 at 19:07
  • $\begingroup$ Easily navigability should count for something $\endgroup$
    – user15036
    Commented Sep 2, 2017 at 4:53
  1. Construct sloped concrete tube down canyon wall.
  2. Use tube interior as elevator shaft to gently lower materiel and people to the bottom.
  3. Gravitational energy of descending elevator can be routed through turbine at top to generate power.
  4. After all are relocated to canyon bottom, use tube as solar updraft chimney to generate power for the colony.

1926 solar chimney diagrams

In 1926 Prof Engineer Bernard Dubos proposed to the FrenchAcademy of Sciences the construction of a SCPP to be located inNorth Africa with its solar chimney on the slope of a sufficiently high mountain as shown in Fig. 5 [53,,54]. from https://www.researchgate.net/publication/290788607_Historic_and_recent_progress_in_solar_chimney_power_plant_enhancing_technologies

I think that sweet painting looks exactly like the Martian version would.


Not sure exactly why everyone would have to leave their already perfectly good and functional shelters to live in the Valles Marineris (if 10,000 people are already living on Mars, they are not living in the equivalents of tents or temporary shelters), but since the objective is to move a lot of people and equipment a long distance (both vertically and horizontally), then the most sensible thing to do is move them by air.

Using airships sized for the Martian atmosphere (Martian atmosphere is roughly equivalent to the atmosphere on Earth at an altitude of @30km) provides a relatively quick way of reaching scattered settlements, picking up passengers or cargo, sling loading outsized loads and then simply flying directly to the new site and descending. The huge time and expense of building roads or tracks is eliminated, and transit time is reduced, limiting the time spent in the Martian environment.

To give you an idea of the scale and scope of this airships, here is the statistics of a propose scientific "superpressure" balloon for a scientific expedition to Mars:

The 1997 JPL Mars Geoscience AeroBot project, was aiming to launch a superpressure balloon on Mars.

Here some parameters:

Spherical Superpressure Balloon

Volume = 10,500 m3

Diameter = 27.17 m

Balloon mass = 55 kg

Gas Mass= 12kg

Payload = 15-30 kg

Float altitude = 6.5-12 km

Daytime AP = 240 Pa

Nighttime AP = 20 Pa

enter image description here

Proposed Superpressure Balloon on Mars

Another comparison might be to look at the Hindenburg airship on Mars:

The Hindenburg had a lifting volume of 200 000 m3 of hydrogen, which ideally would lift 237 tonnes at STP, and a structural mass of 118 tonnes. The atmospheric density on Mars is about 20 g/m3 (maximum I guess) and the density of hydrogen at 1 kPa and somewhat arbitrarily chosen 240 K is about 1 g/m3, giving 19 g/m3 of lift for a grand total of 3.8 tonnes.

enter image description here

A Martian Airship may be to the Hindenburg as the Hindenburg is to the Goodyear Blimp

So the airships will be huge compared to Earthly ones, but the advantages of using airlift are fairly obvious. As well, once the evacuation has finished, the airships can be useful in prospecting across the planet, going to the Martian poles to mine for water and frozen CO2 or retrieving items left behind in the initial evacuation (or heading back to the previous shelters, if people choose not to live in the Valles Mariners).

  • 2
    $\begingroup$ To meet the hard science requirement, I think you'd need to consider thrust as well. With an atmospheric density of 1% of what's found on Earth, propellers won't generate much thrust. Atmospheric drag drag would be proportionally less, but momentum works the same, so to have enough thrust to make this airship reasonable maneuverable is a challenge. I'd guess you'd need to burn rocket fuel. $\endgroup$
    – Phil Frost
    Commented Sep 1, 2017 at 12:44

If you are looking for funny and strange-looking answers you could come up wit really funny stuff.

Everything (as always) strongly depends on what is available, but:

  • It is likely large inflatable (low Martian pressure helps) balls are available.
  • It should be feasible either:
    • to surround a cargo parcel with inflated bags
    • suspend payload cargo approximately at center of a large inflated bag.
    • (something similar to Pathfinder landing gear)
  • throw them down the hill with good chance it survives the drop with little damage.
  • remember to add radio beacons to avoid loosing precios cargo

Nobody has mentioned the gondola lift yet (the bonus of being alliterative with Guoliang Guan).

Realistically, though, mass migrations don't happen because one person decides - they happen because of crisis. I have a hard time imagining crisis conditions outside the valley that weren't there when the settlers first emigrated.

I have a much easier time imagining an economic migration - because the temperatures and pressures outside the domes are greater in the valley (or the access to more layers of sedimentary deposit, or whatever), production rates in the valley far outstrip those above, and there are jobs that pay much higher than those on the upper surface. Such a migration would happen more slowly, and it's likely that outer settlements would continue to struggle along (much as rural America keeps on even though their economic output is dwarfed by that of America's cities).

A forced migration is also more believable, but Diego OfeAde would be more of a warlord in this case (Is that why you mentioned CIF3 - because of it's properties as a weapon rather than as rocket fuel?). Forced migration would quickly empty the upper surface of its inhabitants, and could ostensibly make Mars "more governable". It would, however, upset everybody who didn't really want to leave their homes and could cause a rebellion.

A forced migration for the purposes of military defense could be more popular, but it sounds like there are no enemies...

  • 1
    $\begingroup$ It is a forced migration. That's why I mentioned "with the generous support of CIF3" The compound will spontaneously combust the moment it touches Mars' oxygen rich sand, comsuming the land in a unextinguishable Hellflame and melting their habitats, burning​ them alive. That's why he's named Diego OfeAde, Diego is a Spanish name that means Supplanter, OfeAde is Yoruba for He desires the crown $\endgroup$
    – user15036
    Commented Aug 31, 2017 at 23:32
  • $\begingroup$ @TheoclesofSaturn: " unextinguishable" ? You just let it burn out. CIF3 is not a catalyst. It's consumed in the reaction. $\endgroup$
    – MSalters
    Commented Sep 1, 2017 at 10:20
  • $\begingroup$ @MSalters I believe he is referring to the fact that letting it burn it is all you can do. The stuff lights pretty much everything in fire, so you can't really extinguish it. It also has a tendency to leave dangerous byproducts behind as I understand it .ClF3 is really very nasty stuff. $\endgroup$ Commented Sep 1, 2017 at 12:17

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