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update: Water at the poles has some more recent news:

I just wrote a comment that includes the following sentence:

I think the J. P. Morgan of Mars will get rich shipping water from the ice near the poles to the people near the equator where it's sunny.

But I was being whimsical and not thinking it through.

While there is oxygen everywhere in the atmosphere (in the form of CO2) water for drinking and growing food (carbohydrates!) and for hydrogen for fuel (and perhaps other uses) on Mars might really need to come from water ice near the poles.

If regolith near the poles is say 20x more hydrated than near the equator where it's "warm and sunny" (also important for growing food), is there any even remotely, potentially economical way to move the water from the poles to the people?

Canali? Pipes? Trains? Hydrogen balloons? ATVs? Anything?

"Economical" I suppose would mean that it takes 20x times less excavation and processing resources per kg of water, but more resources to move it to where it's needed. Even more because it may be nonlinearly more difficult to extract any water from nearly dry 2% rock than from a nice juicy vein or layer of polar ice.

below: Here's an upload to Wikimedia; click for full size.

enter image description here

Cornelis
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uhoh
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  • Comments are not for extended discussion; this conversation has been moved to chat. – called2voyage Jun 14 '18 at 12:44
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    Is this not a Worldbuilding SE question ? Is there any reason why you'd prefer to ask here rather than there ? – Cornelis Aug 05 '18 at 13:00
  • @Conelisinspace here I'm asking about building a pipeline or other common Earth-based structure that is well understood today based on information we already have about Mars today. There you are asking about planetary-scale modification of both Mars' surface and of it's atmosphere. – uhoh Aug 05 '18 at 13:11
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    You're asking about an imaginary Martian transporting system, and that's exactly what Worldbuilding SE is about, constructing imaginary worlds and settings. – Cornelis Aug 05 '18 at 20:52
  • @Conelisinspace I see that you are trying to start a 2nd argument here as well. This is not the right way to use Stack Exchange. If you keep this up I might consider flagging you. Use a chat room for discussion, not parallel streams of comments on two unrelated posts simultaneously – uhoh Aug 05 '18 at 21:10
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    Will answers to this question not tend to be almost entirely based on opinions, rather then facts ? Have you seen any economical calculations in the answers which justify the opinions that are put there ? – Cornelis Aug 05 '18 at 21:26

8 Answers8

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You don't care about transporting H₂O. You want to transport hydrogen and oxygen atoms, and if that includes a few other atoms as baggage, that's no big deal. One easily available atom is carbon, as it can be extracted from CO₂.

So you need two pipelines. Hydrogen has the nasty property of escaping pipelines, so you need to bind it to carbon to produce CH₄. (Methane). It freezes only below 90K, which is not going to happen even on the poles. Oxygen can be transported as just O₂. It won't freeze either.

So, you need H₂O, CO₂ and a lot of energy to produce the CH₄. That's where you need nuclear energy; solar power isn't a good option near the poles. On the plus side, at your base you get a CH₄+O₂ stream that you can pour straight into a fuel cell. This recovers the H₂O and CO₂. You also get electricity and heat, which are also valuable, without having a nuclear reactor near your base.

Note that CH₄ and O₂ are also incredibly useful for a lot of other chemical processes. There will be a need to produce plastics, and CH4 is a reasonable source material for that.

Cyclic3
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MSalters
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    Carbon has an atomic weight of 12 and Hydrogen of 1. So you would need 3 tons of carbon for each ton of hydrogen. What could serve as a source of that much carbon at the pole? Or alternatively, how do you get the carbon back to the pole after you split the methane? – Philipp Jun 11 '18 at 15:26
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    @Philipp: There's plenty of CO2 at the poles (as well as H2O). No need to get it back, turn it into carbon fiber or other useful stuff at your equatorial base. The biggest problem is actually the energy you need, the formation of CH4 and O2 is energy-negative. On the plus side, you can get some of the energy back at the base by reforming the H2O and CO2 in a fuel cell. So drop a nuclear reactor at the pole, at a very safe distance, and get heat+power+H2O in your base. – MSalters Jun 11 '18 at 15:45
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    Please beware that in your setting, the nuclear reactor at the pole may be "at a very safe distance" from people but not from your water supply. – Pere Jun 11 '18 at 19:10
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    It seems like it would be more economical to transport ice chunks in a conveyor-belt / pipeline combo, rather than using electrolysis to separate the molecules. You'd have to deal with the liquid, solid, and gaseous forms simultaneously, but that could likely be handled mechanically, within a single enclosure ("pipe"). – jpaugh Jun 11 '18 at 19:14
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    If you have nuclear energy, just colonize the poles. If your agriculture in space requires sunlight because you don't have a reactor, you can count me out. – Mazura Jun 12 '18 at 02:53
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    Seems to me that you could save yourself a whole lot of energy by just transporting it as water. Water is stupid-dense (1 metric ton per meter cubed), far more so than liquid methane (0.42 t/m3). Elemental oxygen is also highly corrosive and dangerous stuff, whereas water is practically inert. Long and short, don't waste your time cracking water, and just transport it in well insulated, slightly warmed pipes. – UIDAlexD Jun 14 '18 at 14:25
  • @UIDAlexD: You'd be looking at between 1W and 10W/m2, I think. For a 3 m diameter, 5000 km pipe that's 100.000.000 m2 surface area so up to a GW in heat loss. – MSalters Jun 14 '18 at 19:16
  • @MSalters A 3m pipe can carry a huge amount of water, though. I put that into an online calculator and, at a speed of 5 m/s ( a good speed for residential pipes), that's delivering 120,000 tons of water per hour. At 50 m/s (I'm not sure about the kind of speed-regimes pipelines operate in) that'd be 1,200,000 tons per hour. From what I've been able to find, practical electrolysis requires about 140 MJ per KG, so a gigawatt of power would afford you ~7 kg of hydrogen per second, or 25 tons per hour. With those numbers, I'd rather spend a gigawatt on heating. – UIDAlexD Jun 15 '18 at 13:54
  • @UIDAlexD: It seemed reasonable in comparison to e.g. the Alaska pipeline, which is 1.2 meter diameter and only caries oil. You might be a bit optimistic about the flow speed. Geometrically, most of the pipe is close to the edge, and at the edge the flow speed is zero. The thing is, fluid flow is non-linear. At 50 m/s you might get a far more turbulent flow (I'd have to do the math) which causes more mixing. – MSalters Jun 15 '18 at 14:05
  • @MSalters Optimistic? Sure, I just plugged numbers into some no-name calculator. But it's optimistic by a factor of 48,000 Even if turbidity stalls out 90% of the flow I'm still 3 or 4 orders of magnitude above the amount that can even be produced - let alone pumped - using electrolysis. – UIDAlexD Jun 15 '18 at 14:16
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    Why to transport oxygen from poles to equator? Is it cheaper than getting it from CO2 in atmosphere right in place where you need it? – Kozuch Feb 02 '21 at 18:37
  • @Kozuch: You produce the O2 at the poles when you react CO2 and H2O to form CH4. Since you already spent the energy there, you might as well pipe the O2 to your base. – MSalters Feb 04 '21 at 09:17
  • @MSalters OK. But the question is how much energy do you need to construct the pipe for O2 in comparison to O2 extraction from CO2 in place. Sure the pipe is fixed cost so the more oxygen you run through it the cheaper it will be in the end. Anyone calculated this? – Kozuch Feb 04 '21 at 11:57
  • This answer just makes me wonder why you wouldn't just make Methane/LOX at the poles and launch rockets from there. It's a short hop from anywhere on Mars with a methane rocket. – SafeFastExpressive Apr 04 '23 at 20:58
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Canals?

It's too cold on Mars for water to be liquid, so canals are not going to work.

Pipes?

...would need to be constantly heated, so they would require quite a lot of energy.

Hydrogen balloons?

The atmosphere on Mars is very thin. Hydrogen zeppelins would work in theory, but they would generate even less excess lifting force compared to their size than on Earth. But there are some interesting proposals for using balloons for mars exploration. Here is a paper about the topic.

ATVs?

You mean the Automated Transfer Vehicle from ESA? It might be better to use a cargo module which is actually designed to land.

But suborbital rocket flights for cargo transport might in fact not be as stupid as it sounds. The lower gravity and thinner atmosphere on Mars make them far more viable than on Earth. And you could repurpose a lot of the rocketry hardware which brought you to Mars in the first place.

...or do you mean in fact "All Terrain Vehicles"? Transporting cargo by rover will likely be the default solution for a while. An autonomous rover would take about a week to bring a load of ice from the pole to the equator. But it will be hard to design a rover with a range of 5000km, especially without fossil fuels.

Trains?

Building train tracks can be profitable if you want to transport very large amounts of material. But it's hard to calculate the break-even point in comparison to trackless trucks, especially because it's hard to calculate the cost of manufacturing rails on Mars.

But if you have a Mars colony of a sufficient development level that you have large-scale metallurgy capable of manufacturing thousands of km of steel rails and enough need for ice to justify the project, then it might be worth considering.

Philipp
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7

You don't need to. There's a lot of subsurface water ice at many mid-latitude sites, where that ice is easily accessible -- only a few meters down, sometimes even exposed, and mostly pure.

Mark Adler
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pipes

In addition to other answers, while most of the time Martian temperatures average below zero, they reach positive side of the Celsius scale every day on most of the surface. That means that pipes with enough freeze-proof storage tanks interspersed throughout their run, and active pumping (draining pipes dry at night) should in theory allow a cheap and reliable, but slow transport of water step by step, or rather - tank by tank.

loa_in_
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  • I'm wondering which stays longer though, the cold or the warm; and the duration of each on a single Sol? Would the average ambient temperatures allow for pipes to thaw before becoming cool again? If not then it's just as wasteful as heated pipes. – Magic Octopus Urn Jun 15 '18 at 11:15
  • According to Wikipedia (extrapolating a bit) temperature is positive for at most 2-3% of mean martian day. Addressing the second question: minimizing pipe thermal capacity would allow them to operate the moment ambient temperature rises above melting point (melting point temperature is a function of pressure as well) – loa_in_ Jun 17 '18 at 18:42
  • Seems like the dust storms would also need to factor into this. It would stink to build a pipe system assuming 2-3% ambient mean temp, then get a 2 year long dust-storm that freezes them permanently. – Magic Octopus Urn Jun 21 '18 at 13:56
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Moving the water requires energy and infrastructure. You'll want to liquefy the water and pipeline it around the planet to do that you'll need to heat it up which requires energy and infrastructure.

I'd propose putting enormous LFTR reactors on the poles and build a big pipeline around the entire diameter or mars. You dump the waste heat from the reactors into the ground to sublimate the CO2 out of the ground and thicken the atmosphere (still below the armstrong limit but every little bit helps). You use the tubes for 5 purposes:

  1. Data lines
  2. Electrical grid
  3. Supply pipeline
  4. ENORMOUS particle accelerator
  5. Gigantic electromagnet

The electromagnet will help to retain the newly thickened atmosphere and shield people from radiation. The data lines will keep the citizens happy with fast internet. The supply pipeline can be used to transport water, fuel, whatever around the planet, the particle accelerator will get scientists more interested in going to mars (read: more funding). Fission byproducts of a lftr reactor give you industrial exports (krypton-85 is a great ion engine fuel, iodine-131 and cesium-137 have medical applications, Plutonium-238 is useful in RTG's, etc..) Boom. You have a martian economy and some groundwork laid for terraforming.

Justin Braun
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  • I don't know what an LFTR reactor is. Can you add a link? Also, this deviates from an answer to the question as asked. I've asked about moving water, you're answering about adding an atmosphere and building a particle accelerator. – uhoh Jun 12 '18 at 15:06
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    https://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reactor

    Moving water requires energy and infrastructure, which the pipeline solves.

     – Justin Braun Jun 12 '18 at 17:07
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    +1 I see, thanks! In the future, use the @ function when addressing comments to someone in particular, that way they get a notification. I just found your comment by accident. Also, it's better to edit your post and add the information to it directly. Comments are considered temporary (if you look at the question, you'll notice two dozen of them have been moved just now). It's always best to include useful information directly into the original post where it's more likely to remain. – uhoh Jun 14 '18 at 12:49
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I see that many other answers or realistic propositions have been made. I would like to propose a rather out-there kind of idea. So the concept is that you could gather ice in some sort of bin with a deployable parachute large enough in size to slow the decent to an adequate speed in the Martian atmosphere. This bin could then be launched from near the poles via some sort of explosion. My guess is that the best bet would be to perform electrolysis to separate the water and recombine it to produce the desired explosion or crude fuel for a thruster. I am trying to gather information about the energy required to perform such a task here. Once that is accomplished, I could run a rough cost analysis. I will update this answer as soon as I can do so.

Note: This answer is not intended as an actual proposition, but is mainly created with the goal of having a place to present my analysis of this concept. Depending on the cost analysis, it may prove to be a legitimate solution to this transportation problem, however, it is likely far from the most efficient.

Gigaboggie
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  • This is more or less the suborbital hops idea that I suggested in a comment earlier. Probably better using a railgun or similar rather than an explosion, but it's energy either way. Slowing it down at the other end is a problem. The atmosphere is too thin to carry much energy away, and the kinetic energy per kg (about 5MJ) is enough to vapourise ice. I wondered about making an ice-covered lake in a crater and lobbing lumps of ice into that. The lake can absorb the energy and lose it slowly to the environment, while a nice warm (if slightly noisy) lake would be a nice thing to build next to. – Steve Linton Jun 12 '18 at 10:31
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It's a one-way ticket too. You want to be cultivating an ecosystem, and the water you pump into that ecosystem will be recycled. I've not really seen anyone else mention the fact that once you start bringing ice in from the poles (or wherever), there will begin to be an excess of it where it is being transported. For any long-term Mars solutions water processing plants and likely hydrolysis plants will be absolutely required. Once water has been moved to a settlement, and the levels of reserve water stabilize for the current population, there will be no need for additional water resources until more population arrives. The ISS is a great case study of this, it doesn't even have polar ice caps to mine, but you don't see the astronauts paying out the nose for bottled water either (hah, they pay in pee!).

It wouldn't be a J.P. Morgan style enterprise. I'd assume it would be more of a collective communal pool of resources until the surface of Mars was sufficiently populated. Even then, leaks could be minimal in terms of storage (liquid H2O). But you're right, anything dealing with low density gasses would be a constant replenishing war. I was just pointing out that to get to the point that a company had a monopoly on water we'd need a very large population density (colonization level, not outpost level).

Magic Octopus Urn
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  • You've never heard of leaks? Fuel will need hydrogen, discarded waste (plastic, unrecoverable organics, all kinds of nasty stuff...) There will always be a need for some amount of make-up water, even for a constant population. – uhoh Jun 15 '18 at 12:57
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    @uhoh I suppose you're correct, my main point was that it wouldn't be a J.P. Morgan style enterprise. I'd assume it would be more of a collective communal pool of resources until the surface of Mars was sufficiently populated. Even then, leaks could be minimal in terms of storage (liquid H2O). But you're right, anything dealing with low density gasses would be a constant replenishing war. I was just pointing out that to get to the point that a company had a monopoly on water we'd need a very large population density. – Magic Octopus Urn Jun 15 '18 at 13:11
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    Water will be needed for rocket propellant. – ikrase Jun 24 '20 at 10:45
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It might be cheaper to mine water (ice) on Ceres. Delta-V from Ceres surface to Mars transfer is less than for the suborbital hop from Mars pole to equator (according to the spreadsheet I got from here) and you could use an ion drive or mass driver or something for the main boost, since you aren't in a hurry to get out of a deep gravity well (Ceres escape is about 500 m/s).

Of course there is the problem of stopping again. Your ice blocks will be coming down at rather more than Mars escape velocity. I still quite like the idea of flooding a crater (and then letting a few meters of ice form on the top). The incoming ice shipments keep the bulk of the lake liquid (if you schedule them carefully) but the ice crust will reform pretty quickly and stop you losing too much by evaporation. You can probably use some of the heat from the lake to warm your habitat as well. Of course it is very important to hit the lake and miss the habitat.

Steve Linton
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