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#1 2014-04-16 16:00:24

Tom Kalbfus
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Registered: 2006-08-16
Posts: 4,401

Martian Canal Highways

This idea came to me as I was driving down a highway. Imagine a paved highway on Mars made of asphalt. There are three lanes going one way and three lanes going the other, and a green space between the two directions on the highway just like on Earth, we also place an equal amount of green space on either side of the highway. So lets assume each lane is 10 feet wide (3 meters). There are three lanes going in one direction of the highway, that's 30 feet, plus we have breakdown lanes on either side, that's 10 feet wide on the inside and 10 feet wide on the outside for 50 feet in one direction, we have a 50-foot wide median and then another 50 feet for the 3 lanes and 2 breakdown lanes going the other direction, and we add 50 feet of green space on either side of the highway, for a total width of 250 feet, and we seal that in a plastic tube that is pressurized at a one-Earth atmosphere mixture of nitrogen and oxygen. to help hold all that air pressure in we place the plastic tunnel at the bottom of a Martian canal that we dig for this purpose, or perhaps we could use a natural river bed that may already exist on Mars for this purpose to save work. We put an outer plastic tube over this ancient river bed or canal and we pressurize to twice or three times the normal atmospheric pressure of Mars, this pressure is still to thin to allow breathing by a normal human, but it will allow liquid water to exist within a narrow temperature range. The atmospheric pressure of Mars is 0.087 psi, so lets triple this to 0.254 psi I think liquid water can exist under these conditions. The pressure within the highway tunnel will be 14.69 psi, same as Earth at sea level. A cubic meter of water weighs a ton under earth gravity and a ton is approximately 2200 pounds. On Mars this same amount of water would weigh 836 pounds. A meter cube of water is about 1600 square inches of a foot print, so divide what a cube of water weighs by the square inches of its foot print and we get 836/1600 = 0.5225 psi, we want to get to 14.69 psi so we divide 14.69 psi/0.5225 psi to get 28.11 meters of water on top of the highway tunnel, subtract half a meter of water to get 27.6 meters of water, the bottom of which equalizes with the air pressure of the highway tunnel. We also have 0.254 psi of compressed Martian atmosphere on top of the canal to allow for a liquid surface on top. So each cubic meter holds 1000 liters of water. Since the highway will be 250 feet wide with all the green space, each 10 feet translates to 3 meters. 25 * 3 = 75 meters, so a section of canal that was 75 meters wide by 75 meters which is 27.6 meters deep would contain 155250 cubic meters of water or 155,250,000 liters of water. Since we need to keep the interior of the highway tunnel habitable for humans, it needs to be heated, this would mean that some of the water above would be liquid but as we got closer to the surface in would be frozen most of the time, assuming we have some decent insulation of the tunnel walls. The plastic should be clear to let in sunlight and the 27.6 meters of water should also be clear to let in sunlight so it filters down into the highway tunnel below. Besides holding in the air pressure, 27 meters of water also makes great radiation shielding, in case of a solar flare. The Tunnels would contain highways that allow the passage of air breathing cars, perhaps hydrogen fuel cell vehicles. electrolysis plants crack the water into hydrogen and oxygen, and the hydrogen is sold in pressurized form at fuel stations placed inside the highway tunnels to refuel the cars inside at need, that way the cars don't need to be pressurized, only the tunnels do and since there is less leakage with less surface area per unit volume than individual cars, this would be a safer mode of transportation that traveling outside on the Martian surface in pressurized vehicles with airlocks.

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#2 2018-03-31 03:14:28

vemsemigma
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Registered: 2018-03-28
Posts: 10

Re: Martian Canal Highways

On a slight tangent, does anybody happen to know the ratio at which plants convert CO2 into oxygen?

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#3 2018-03-31 08:59:29

IanM
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From: Chicago
Registered: 2015-12-14
Posts: 276

Re: Martian Canal Highways

It's a bit complicated; even though the (simplified) equation for photosynthesis gives a 1:1 molar ratio for CO2 and O2, net oxygen production via photosynthesis is quite small per plant since most of it gets respired by the plant itself. (Respiration is just photosynthesis in reverse.)

Net Primary Productivity (technically the production of organic carbon, but duly converted since there's a 6:1 molar ratio between oxygen and organic carbon produced it works just as well) on land ranges from less than 48 mol O2/m^2 in the deserts up to more than 600 mol/m^2 in the tropical rainforests, with a typical value of ~360 mol/m^2 in the temperate parts of North America, Europe, and China according to http://www.globalcarbonproject.org/scie … IGURE6.htm. The concentration of CO2 in the atmosphere is currently around 400 ppm according to https://www.co2.earth/. Duly converted and spread across Earth's surface area, this gives around 1,960 mol/m^2 of CO2.

So assuming all of the CO2 is used by land plants this gives a ratio of 0.02-0.31 mol O2 ultimately produced by plants per mol CO2, or 0.18 for a temperate climate. On Earth the ultimate amount of O2 that is produced per CO2 is even lower since much of what's given by plants is respired by animals, fungi, or other organisms that don't make their own food(what are known as "heterotrophs"), but on Mars this could perhaps be controlled.


The Earth is the cradle of the mind, but one cannot live in a cradle forever. -Paraphrased from Tsiolkovsky

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#4 2018-03-31 11:25:51

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,744
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Re: Martian Canal Highways

This is a serious question? Ok.

IanM gave a good response. I'll give my take. Photosynthesis is a complicated process, I wrote a webpage about it. The page is a proposal to use invitro photosynthesis for life support.
http://canada.marssociety.org/winnipeg/chloroplast.html

The net reaction is:
6 H2O + 6 CO2 → 6 O2 + C6H12O6

That means 6 molecules of water + 6 molecules of carbon dioxide become 6 molecules of oxygen plus one molecule of sugar. Specifically a monosaccharide: simple sugars. Most common simple sugars are glucose, fructose, and galactose. These are all carbon rings: 6 carbon atoms in a ring. There are other sugars; pentose sugar has 5 carbon atoms in a ring. The most common pentose sugar is ribose, which is a component of DNA. These can be combined: a single hydrogen atom removed from one sugar, a hydroxyl group (one oxygen and one hydrogen) stripped off the other. Then the free bond of one simple sugar binds directly to the free bond of the other. This forms a disaccharide, which means 2 sugar. The "H" and "OH" bond together to form water. Examples of disaccharides: sucrose (white table sugar), lactose (milk sugar), and maltose (malt). Plants can also bond 6-carbon simple sugars into a long chain. Starch is a polysaccharide, meaning it's a lot of simple sugars linked together. Amylose is a long chain of monosaccharides, amylopectin is highly branched. Recent research shows amylose has a little bit of branching too; nature is messy. Starch is a combination of amylose and amylopectin. So the general formula for polysaccharides:
(C6H10O5)n·(H2O) where "n" is between 40 and 3000.

vemsemigma asked the "ratio at which plants convert CO2 into oxygen". By "oxygen", I assume he means O2. Notice combining simple sugars releases water, so the ratio of water to sugar changes a little depending whether it's a simple sugar or complex carbohydrate. However, the ratio of CO2 to O2 is always the same, it's always 1:1.

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#5 2018-03-31 17:19:33

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,122

Re: Martian Canal Highways

The other part of that question is which plants do the best exhale of o2 rate? As we would want to grow those that transform h20 and co2 into the sugars and air for man to breath at that highest of rates.

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#6 2020-08-23 08:03:26

tahanson43206
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Registered: 2018-04-27
Posts: 7,349

Re: Martian Canal Highways

This topic showed up when I asked FluxBB if anyone had discussed canals on Mars.

The topic itself is short, and as often happens in this forum, it spun off instantly into an entirely unrelated discussion of photosynthesis and production of useful molecules by plants.

I'm inspired by something GW Johnson said in the Mars Railroad topic recently.

GW Johnson was evaluating a proposal to use ice on Mars for transportation infrastructure, and he (quite rightly (of course)) pointed out that ice will sublimate rapidly in the cold dry atmosphere of Mars. 

This led me to think about countermeasures to prevent sublimation.

Along the way I thought of an ice canal, but that side concept does not address the issue of sublimation.

** Then ** I thought of laying a "thin" (ie, not deep) canal as a roadway, delivering enough water to the canal to let it form a durable substrate for a road (with automatic leveling a nice benefit of the procedure) and finally, top the surface with a thin but durable layer of a suitable road covering.

The costs (time, thought and energy) needed to build this roadway include:

1) Surface preparation using regolith moving tools
2) Securing water for the substrate
3) Heating the water to prepare it for "laying" the substrate
4) Laying the substrate
5) Waiting for the substrate to freeze
6) Making and delivering the road covering
7) Covering the surface with the durable material

This roadway would then be usable by wheeled or tracked vehicles.

Maintenance would include:
1) Inspection by vehicles traveling the road (carrying cameras as part of normal equipment)
2) Replacement of worn road covering as needed
3) Recycle the road covering

If touchup of the volume of the substrate is needed, that can be performed while the road covering is off.

Bringing this post back to the original topic ... this would be an "Ice Canal" with a durable cover to prevent sublimation.

Edit#1: Calliban's idea of basalt thread came to mind as a possible cover for an "Ice canal" roadway.  A covering of basalt thread might prove helpful on Earth, where asphalt is commonly laid to make road surfaces.  Asphalt (and its co-road-material concrete) is subject to damage by the combination of water, salt and stress caused by vehicular pounding and temperature change.

A mat made of basalt threads might be helpful in multiple respects:

This are all speculation because I have no experience with this material:

1) May provide a pothole prevention capability, similar to rip-stop fabric for parachutes and other critical applications
2) May provide protection of the underlying pavement from UV and plain solar radiation (could apply to ice as well as asphalt)

Related to this concept is the (relatively famous) steel mats used for temporary airfields in World War II

https://www.airspacemag.com/multimedia/ … 180951234/

A mat made of basalt thread could be woven on site by a robotic herd ? flight ? bevy ? of Calliban's Spiders (*)

Per Google, the generally accepted term for a group of robots working together is a "swarm"

The term would apply to a set of robots operating under control of a master program, or of a set of independently "intelligent" devices acting on a shared "program" to achieve an objective.  The latter concept is illustrated on Earth by bees and termites, and (no doubt) by many other insects, and perhaps even a few mammals.  A capitalist society of humans might even be viewed (with some skepticism no doubt) as comparable to a hive of bees or termites building a structure that provides for the collective need.

(*) The expression "Calliban's Spiders" was released for public use Calliban himself ... See NewMars.com/forums for details.

(th)

Last edited by tahanson43206 (2020-08-23 10:04:49)

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#7 2020-08-23 10:03:33

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,122

Re: Martian Canal Highways

The subliming of ice is part of the reason for enclosures of spaces where we would want water as it would evaporate even easier. The structures are dome like usually clear so as to use natural lighting. This is the argument for making a structure for a greenhouse. It would also be desirable for the covering over a water way Erie canal on mars for transport and other operations as we deem.
The formation of Ice-Crete is an attempt to slow sublimation of ice or water that is used to build structurally.
Basically a brick of materials that is coated with an epoxy, plastics, paints ect to make a barrier to the interior of the brick.

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#8 2020-08-23 12:23:39

tahanson43206
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Registered: 2018-04-27
Posts: 7,349

Re: Martian Canal Highways

For SpaceNut re #7

We are in Martian Canal Highways, which has a history of branching wildly off topic.

Your suggestion to think about Ice-crete works well, I think, if we assume the canal is frozen (which is reasonable for Mars)

Google came up with this citation (of several) https://en.wikipedia.org/wiki/Pykrete

The article includes the famous aircraft carrier idea proposed to Winston Churchill, with numerous details I had not seen before.

In any case, I ** really ** like your suggestion for the substrate on Mars.

The ** secret ** (to the extent there is one) is to (a) introduce fibers to strengthen the ice the way rebar strengthens concrete, and (b) to keep the material below the freezing point of water.

I ** like ** the suggestion because the compression capability of the material is significantly greater than plain ice, and that is helpful for a roadway application.

However, the need for a covering for a roadway of this type remains, because the material (called Pycrete in the article (after the inventor)) deteriorates when exposed to conditions that allow the water component to melt.

(th)

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#9 2020-10-24 13:52:56

jakeypoos
Banned
Registered: 2020-10-24
Posts: 8

Re: Martian Canal Highways

Your getting rid of the advantage of having a thin atmosphere to travel through. Better to Run pressurised cars on an open 2 lane road for short distances, taking advantage of Mars atmosphere's low resistance, and let hypoloop take care of longer distances.

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#10 2020-10-24 14:15:33

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,349

Re: Martian Canal Highways

For jakeypoos re #9 ...

First, welcome to the forum, and thanks for taking the leap to post here.

If you would like to learn about the culture of this forum, you would (most likely) find several members willing to help you design your posts to blend into the flow.

In this particular topic, if you read it from the top, the conversation has veered wildly away from the starting definition.

So, in a constant attempt to keep topics "on" topic, I'd like to remind you that this top[ic is NOT about how something might be better.

The topic is about making highways on Mars using canal concepts.

Your 2 lane road could most certainly be constructed as you have described it.  The properties of water and the properties of Mars intersect to permit construction of level roads using water as a construction material, provided it is covered with a material that separates the water (icecrete) below the surface from the atmosphere.

It could well turn out that merely grading the Mars regolith would provide a "dirt road" of sufficient quality to support extensive use by Mars settlers.

The proposition of ** this ** topic (as I understand it) is that water would provide a suitable material for construction of "improved" roads on Mars.

(th)

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#11 2020-10-24 16:27:15

jakeypoos
Banned
Registered: 2020-10-24
Posts: 8

Re: Martian Canal Highways

Thanks for your welcome. My comment is a constructive response in reply to the original post so is in no way off topic. I haven't read any other replies, just the original post and it prompted a thought. So I've posted it in reply.

I'm merely pointing out that if your filling a tube with air at earth pressure, your creating resistance. if you need pressurised vehicles to traverse the surface, then why not have a low pressure tube for those vehicles to travel in.

Last edited by jakeypoos (2020-10-24 16:33:04)

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#12 2020-10-24 16:36:16

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,349

Re: Martian Canal Highways

For jakeypoos re #11

Thanks for your reply ....

I admit to not having studied the original post by Tom Kalbus as closely as you did.

Are you interested in working on the original post, to see if anything can be salvaged?

The atmosphere of Mars is close to a vacuum already.

However, before we invest any more time in this particular topic, may I inquire about your interests?

This forum is very small, and it is possible your interests might catch on with one or more members here.

To make this work, take a look at the index level, and see if any of them match up with where you would like to make some progress.

PS ... I ** liked ** your opening post about Mars gravity!

The members of this forum are likely to agree with you, although the human race has ** Zero ** knowledge upon which to make a judgement.

I'll try to make a contribution to give your new topic a start.

(th)

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#13 2020-10-24 17:08:09

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,122

Re: Martian Canal Highways

Basically the underground vehicle transporter system for musk does remove the air in the tunnel as that is as you noted the resistance to motion even here on Earth. So by the virtue of mars low atmospheric pressure we are just about near that vacuum but with the need for air is the same for both place we do have the power issue for the means for motion that is the problem. On earth the vehicle sled has the power it where as we would need something simular for the mars system to work.

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