Moon Colonization is Over 72 Times Easier Than Mars Colonization

Mars has a launch window every 26-months. The round trip travel time to the moon is about 11 days. This means that you could send 72 round trips to the moon for every launch window to Mars.

Doug Plata has also described how greenhouses can be made on both Mars and moon. The moon greenhouse would use LEDs and other different solutions than the Mars greenhouse.

The Moon and Mars would both have accessibility, water, fuel and food for future colonists.

67 thoughts on “Moon Colonization is Over 72 Times Easier Than Mars Colonization”

  1. I think the big luxury-level O’Neill colonies pretty much assume self-replicating tech by default (but keep in mind that simpler orbital colonies also fit within O’Neill’s wider ideas).

    Granted, with self-rep tech we could also reach luxury-level accommodation on Mars, and pretty much anywhere else.

    I guess my main point is that in terms of living conditions, short of terraforming, Mars and O’Neill won’t be much different at any given technology level (though cheaper “per brick” can also translate to bigger and better per dollar). That and the whole presentation/believability/public-opinion thing in the last paragraph of my previous post.

    edit: Come to think of it, terraforming probably needs self-reps too. So then it’s terraforming vs luxury-level O’Neill – again, not much different in terms of living conditions.

    Pretty much agree with the rest of your points.

  2. Assuming that the gravity on Mars is enough to allow human health and reproduction, (Yet to be established!) the per capita infrastructure requirements for life on Mars will be much lower than for an O’Neil colony.

    I don’t see the infrastructure requirements for life in O’Neil colonies at reasonable population densities being feasible without something close to self-reproducing factories. You just need an absurd amount of material per person.

    The other argument for Mars, as a backup for Earth, is that it’s far enough away from Earth that the disaster that destroys life or civilization on Earth, (An asteroid strike, nuclear war, nasty pandemic.) stands a good chance of not taking out Mars.

    And being so far away, the push to achieve self-sufficiency will be heavier. For colonies around the Earth, or on the Moon, trip times from Earth are short enough that you’re likely to get caught up in whatever is going to happen to Earth, and likely to cut corners because self-sufficiency won’t be seen as economically essential.

    So, for the specific purpose of achieving a second basket for Humanity’s eggs ASAP, Mars has big advantages. In the long term, O’Neil colonies are better. But Mars has its advantages.

  3. A Mars habitat would be the same submarine, or likely a lot more cramped and less comfortable. At most, you’d occasionally “come ashore” onto an inhospitable, mostly frozen desert, where you can’t even breathe without special equipment.

    Here’s a counter-argument in favor of O’Neill:
    how would you feel about living the majority of your life in a 5 star hotel, with its own golf courses and parks and so on, but you can’t leave the premises?

    Obviously, the reality of O’Neill is somewhere in between, or maybe off to the side. The devil is in the details (edit: and the sale is in the marketing).

    I think the bigger issue for public opinion is presentation and believability. Most people are too pessimistic about O’Neill, imagining it closer to your cramped sub image. Tell them the luxury image and they’ll dismiss it as unbelievable. At the same time, their view of Mars and other planets is over-romanticized – biased by their experience of Earth.

  4. The 2nd, hidden and possibly unintended point in your post is that natural resources aren’t the limit to human prosperity.

    We can live long and prosper with little more than CHON, which is quite abundant. Not infinite, but with future recycling asymptotically approaching 100% (in maybe a century or two – a blink of an eye in human history terms), it may as well be so.

    (Yes, the rarer elements are useful for all sorts of exotic stuff, but I’m willing to bet CHON can approximate and maybe surpass most of them given a clever enough arrangement of atoms. Besides, by definition, the rare stuff is only a tiny fraction of our stuff.)

  5. True enough, but there weren’t then and no-where near enough elephants today to be slaughtered every year, for their tusks, to provide ivory for making fine pianos. As an example. Sure, we invented a kind of plastic that’d have convincing layers and nice oyster-cream color, which could be sawn and polished to make artificial ivory key-covers, but still … that NATURAL resource is long gone.  

    One could easily riff on the same, for whale-oil, which used to be THE go-to-fuel for city street lamps, house ‘kerosene’ lamps and so on. It was used until the 1960s as the indispensable lubricating agent for top-shelf camera lenses, reflex shutters, watches and so on. Whales, being depleted and looking — without regulation — to be an extinction destined genera, were saved, and the fine scientists at Bayer, Chevron and so on figured out how to make synthetic cetyl alcohol and other cetacean lubes. And paraffin for candles. But the NATURAL resource has been exhausted.  

    Redwood trees.  Big old-growth forests — exhausted.  
    Enormous 2 meter diameter elms, oaks, chestnuts — exhausted.
    The supply of cobalt is entirely limited — insofar as we know…
    … to whatever the Congo indentured slaves dig up. 85% from there.
    The supply of still-somewhat-rare-earths — limited.
    The supply of the REALLY rare elements, very much so. 

    The point is clear… right?

    ⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  6. Yup, I got that one wrong. A bit of research assured me there actually IS enough light on Mars for a significant range of crops.

    Geeze, this backyard I can’t get vegetables to grow in must be dimmer than I realized!

    Still given the chance of that natural light going away for weeks or months at a time really does advise just going with LED illumination, I think powered by a SPS.

    Solar power satellites around Mars should be easier than Earth, the surface stationary orbit is so much lower.

  7. It is not either-or, it is both. First the moon outposts and learn a lot of lessons you can apply to Mars for long-term colonies. Then on to the belt and the moons beyond.

    The first step is to make escaping the gravity well of Earth affordable and ordinary. Elon is doing well on that count so far.

  8. Our resource-starved future is always in our future. According to authorities in 1970 we should all be dead by now, thanks to the resource-starved future living in their heads.

    In the future, outer space will be on the seafloor too. The resources there would floor you.

  9. I use Musk as an example of someone who has stated things about Mars being *required* for human survival. It is supposed to be an obvious example, not a claim. I also cite the late Steven Hawking for similar thoughts about interstellar travel, to those other planets. They are so intent on these for *human survival* that my point is: O’Neill solves the problem, so they must not be aware of O’Neill. Seems to be no other explanation for that position of needing planets. If O’Neill is correct, the future looks very different!

  10. That is a very small scale effort, getting there first, and is certain to be inefficient because it involves humans. I have no problem with those sort of things, but they are like tourism economically. Paid for by effort from outside the main Space economy. Mars will suffer the fate of the Moon, left alone when the bragging rights are gone.
    The whole outlook of the resource-starved future is countered by the possibilities O’Neill revealed. Start with Space Solar Power to solve global heating, a popular topic!

  11. Personally I think people living in big cities are insane, O’Neill cylinders could be much nicer – but it would come down to little details like population density.

  12. I have no expectations about popular thought on these matters. The basics about Space are counter intuitive, let alone the O’Neill stuff. *Orbit* and *scale* unknown to most. But the ELEO prospect is quite unlike you describe, and will have the first settlements, as opposed to work camps, in Space. After that, let the market decide. How would you feel knowing you could spend one solid hour looking out of the ISS window?

  13. i’m not picking on you, but … we really ought to use Earth’s moon’s name for disambiguation. 


    Its a good name.  
    And the people going there definitely are LUNA-tics. 

    ⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  14. I think Andrew makes a valid point — there are a lot of foodstuffs crops that work on a fraction of 1 overhead Sol. Indeed, some interesting studies done in the 1960s showed that so long as “the plants” have a summation of solar energy, combined with no ‘end-of-cycle’ triggers (cold days, cold nights, shortened daylight, yada, yada), they can produce ‘normally’ if given only 25% of normal light on a 300% long growth-year.  

    Doesn’t work for all of them, but I doubt bananas are in Mars’ future. 

    And by the time we get there en masse, well … the geneticists of Earth will have figured out work-arounds even for bananas.  

    ⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  15. Yah, O’Neill habitats are really good ideas, to be sure. Still, the prospect of having another planet to ‘engage’ is pretty compelling at least from an ordinary human’s perspective.  

    Here’s a test: how would you feel about living the majority of your life aboard a perpetually submerged submarine? One that theoretically is large enough and ‘pod’ enough to make its own foodstuffs, oxygen from seawater, and who-the-hêll knows about power. But never breaches the surface.

    That’s what an O’Neill cylinder is all about, at least to the 80% point.

    It just doesn’t have the appeal, the ‘imagination coefficient’ that growing potatoes on Mars with one’s poo does.  (Yes, I did really like the movie)

    ⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  16. “what mars gets us” is mostly bragging rights. Like how Getting Man onto The Moon fell completely off the rest of the world’s space programs after the US planted a flag on Luna, what … 6 times?  

    Anyway, bragging rights, and an arguable sovereignty claim. 
    Sovereignty aught not to be dismissed, in our resource-starved future.

    ⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  17. “Martian light levels would require a significant degree of concentration to be usable for agriculture.”

    Incorrect, the light levels at midday over most of the Earths surface are far above the levels required for efficient photosynthesis, and as Mars has little in the way of clouds overall light levels on Mars are fine for plant growth.

    Yes dust storms would destroy a crop if using direct solar.

    “And, not enough Martian atmosphere to prevent meteors from landing with destructive force, even small ones.”

    About 100% (99.99%?) of meteors striking Earth burn up before getting to the levels of atmospheric gas density that exist at the Martian surface.

  18. You will have to see SpaceX. Some irrational idea that Mars is a lifeboat for humanity. Others used to say Musk supported other things, but I don’t really care. My message is simple: Forget Mars!

  19. Martian light levels would require a significant degree of concentration to be usable for agriculture. Not saying you couldn’t do it, but it would. Maybe you could put solettas in orbit, and avoid having to clean them? That could bring light levels at the colony site up to Earth levels, and warm things up, too. But with the potential for permanent dust devils.

    Then there’s the question of what light levels are like on Mars during one of those dust storms. A problem for both agricultural light and solar panels.

    And, not enough Martian atmosphere to prevent meteors from landing with destructive force, even small ones.

    So my conclusion is, even on Mars you’d use buried greenhouses with LED illumination. Probably using some combination of local nuclear power for emergency backup, and orbiting SPS.

  20. With 95% CO2 and 4.5% (N2 + Ar), I’d say the Martian atmosphere is pretty useful. Combined with Martian water and an energy source, it can produce breathing air, plant food (which translates to human food), rocket fuel, plastics, chemicals, and eventually advanced carbon materials.

  21. Nor is it a problem in Space where radiation shielding is used, or is part of the structure. That is why Al and glass O’Neill Island 3 habs are the size they are, the structural thickness of the bubble skin is the same as the shielding needed. No extra cost!

  22. I’m a huge proponent of lunar and/or asteroidal ISRU, which you describe. The question of where to settle, Space or Earth (or another far more difficult planet such as Mars) is the O’Neill question. ELEO needs no shielding. Moon does, or you are quite limited to lava tubes. So build a mass driver from lunar resources and use it. Or capture a small asteroid, from free Space. The main resource of free Space is that it is not on a tiny planet!

  23. I see the moon as a much more viable tourist and scientific hub than Mars. But for long term colonisation it would be Mars. I think the potential for Moon tourism is HUGE. Only two days transit! Science-wise, surely the side facing away from the Earth must have some big advantages for Astronomy.

  24. Free space has no immediate resources so everything has to be shipped in. Planetary surfaces have resources at 0 km/sec delta-v. Four metric tons of parts shipped to LEO = four metric tons of parts. Now, four metric tons of shipped to Lunar = one metric tons of spare parts on Luna, true. But that one ton of spare parts could keep a 10-ton telerobot functioning producing 100 tons of metals = 100 tons of parts. So, each one ton shipped to the Moon = 25 x more parts than doing the same to LEO. How would you respond to that argument.

  25. One cubic meter of rock can yield 5 million 2mm x 1cm x 1cm pieces. 5 million pieces means that only one out of 1,500 people get to own a piece of the Moon. Still more rare than diamonds. 5 million x $100 each = $1/2 B. Nothing to sneeze at.Then stretch out the value by offering pieces of more unique Moon rocks.

  26. Bingo! However, the kJ/mol needed to extract oxygen from metals is considerably higher than electrolyzing water. So we’ll get the oxygen during the production of propellant from water.

  27. Thanks Andrew. Those were roughly the same counter-points that I would have said.

    But just one more thing to add. Regolith covering over the habitats (most for radiation) also serve as good shields for micrometorites.

  28. Hi Mark. Please familiarize yourself with the data from multiple lunar missions especially the LCROSS mission:

    We already know that, in Cabeus Crater, water ice concentrations get to about one part per 18. Another mission indicates water ice on the surface. Cabeus Crater is within eight hours or so drive to one of the so-called “Peaks of Eternal Light” (PEL-D). So, whereas I do advocate for surface prospecting missions to find the very best locations, we already know enough to warrant developing the hardware to go there.

  29. Yes, bootstrapping/ISRU is another really big key. I organized a track of speakers addressing this issue. That is at:

  30. Who does Musk envision paying for all of those flights? This is not a rhetorical question if you have watched his presentations. In his Guadalajara presentation he stated that the people who would go are at the intersection between those who could afford to go and those who wanted to go. So ticket sales by people who have worked in Earth-based markets previously and who have saved up the money to go. So, it’s people’s savings. Retirees will be over-represented.

    Their motivation will probably be that of personal significance in being a part of that elite group of humans to have the opportunity to establish a new world for humanity. If that motivation doesn’t appeal to you, don’t just assume that it logically follows that it would appeal to no one else. With 7.5 billion people, there will be plenty enough who will want to go.

  31. The shattered silica is certainly no problem for plants…even if what you are saying was true which I doubt…a little heat and all those sharp edges disappear. Not that silica is required for plants…at least in large amounts. You can use aeroponics to grow plants. You just have to find the right minerals grind them up and make solutions for misting on the roots.

  32. Of course, even two planets is too small. One plus O’Neill Space is quite large, however. An important realization. And, self sustaining is given for O’Neill, as Earth could never support. Earth will, however, rely increasingly on O’Neill.

  33. Small pieces will sell fine at first, but larger better looking stuff would be needed as the novelty wears a little.
    I think they could get large sums for 2mm slices of meter wide rocks. Stuff that looks good. Especially pieces of meteorites mounted in a frame you can put on your wall.
    Still, in my mind, this is not a proper big picture economic reason to go, just a crutch until they can support human life indefinitely and in an expanding way. Not saying they should not make and ship stuff to Earth in exchange for a few luxuries, just that everything critical should be derived there. You really are not a 2 planet species, if, when you kill 1, the other also dies.

  34. What we need to do first is to do a good assay of the moon to see what we are working with. As for water, there might me water deep within the moon. We need to drill a few holes to see.

  35. “There’s very little water ice on the Moon, . . ”
    Probably wellover a billion tons of it.
    “. . .Moon has no source of oxygen,”
    Water has the chemical formula H2O.
    “Moon has 3x less gravity than Mars, so humans will likely experience the same health issues that ISS astronauts have, not good for long-term habitation.”
    A valid point, though just as higher artificial gravity can be created on the Earth it can be created on the Moon.
    “There’s 2x more solar radiation on the Moon than Mars, so shielding is going to be harder.”
    That’s just silly, solar radiation can be blocked with a coat of paint.
    “The Moon has no atmosphere to stop micrometeors from destroying your habitat domes.”
    Micro meteors will damage – much as abrasive Martian dust would.
    “the Moon dust is so abrasive, space suits will be useless within days.”
    Yes things need to be kept clean, likely a thin disposable oversuit would be a good idea.
    “whereas Lunar regolith will kill plants due to the abrasive silica crystals, . . ”
    That’s a fiction.
    Mars has dust storms that block Sunlight for days, Mars has a deep gravity well that makes leaving it difficult, Mars has an atmosphere that is of little use other than to increase heat loss far more than a vacuum.

  36. Seriously? Easy engineering problems to solve. You will never make Mars closer. For one, the spacesuits can have plastic /rubber baggies over them…and they can dock with vehicles…where you climb in and out of them. No need for Moon dust to get in. And you mostly would be in vehicles anyway. Driving along, you decide you want to pick something up. There will be a robot arm to do that. Point a laser at what you want and an AI manipulated arm grabs the target and puts the target in a box…faster than you can say “That looks intriguing. I bet the guys at home would like a look at that”. Wandering on foot will not be a high priority. They will fly or drive…even ambulate in legged machines.
    And the main point to anatomy is developing recycling efficiency and mineral extraction and refining technology that we can use to build habitats, in Antarctica, in the ocean, in the Earth, asteroids, all over the place. Being tied to rivers, dumping in the ocean and the air and limited by resources, is a stage we need to get over.
    Rocket fuel? Fission powered propulsion after mass driver puts the ships in lunar orbit. You could use anything for the Fission to heat and blast out the back. No oxygen required. Other than what you need for the humans and other biological systems. Squandering it as propellant is just silly. And even if you wanted to go chemical. There are probably a million other highly exothermic reactions that don’t involve oxygen.

  37. Astronomical amounts of water and C on the Moon, enuf to get started before comet and asteroid capture. O from processing metal, a waste product.
    Neither Moon nor Mars match free Space for settlement, for the reasons you present.

  38. If you do not realize the O’Neill “space-based habitats” are possible, Mars is a desperation goal. Musk is clear.

  39. They are not exclusive! I think a keyring with a chunk of Moon in it, made on the Moon from lunar glass and metal, numbered, would sell like hotcakes. For a while.

  40. You would earn a lot more just cutting and polishing little pieces of Moon rock and selling it here. $1,000 an oz. would not be far fetched. What scientist or romantic doesn’t want a piece of the Moon?

  41. So, how exactly do we get a self-sustaining colony on the Moon?
    There’s very little water ice on the Moon, and it’s all at the poles, most of it will need to be used to make rocket propellant.
    Moon has no source of oxygen, whereas Mars’s atmosphere is 95% CO2, which can be compressed and plants will be perfectly happy. On the Moon, all air must come from Earth.
    Moon has 3x less gravity than Mars, so humans will likely experience the same health issues that ISS astronauts have, not good for long-term habitation.
    There’s 2x more solar radiation on the Moon than Mars, so shielding is going to be harder.
    The Moon has no atmosphere to stop micrometeors from destroying your habitat domes.
    Plus, the Moon dust is so abrasive, space suits will be useless within days.
    Lastly, Martian regolith contains everything plants need to survive, whereas Lunar regolith will kill plants due to the abrasive silica crystals, it might as well be ground up glass.

    Mars on the other had, has enough water ice to create lakes, rivers, and shallow seas, more than enough to sustain humans, plants for centuries and still make rocket fuel.
    Mars has 38% of Earth gravity, which should be enough to survive for years with the right exercise regiment.
    Mars has less solar radiation than the Moon, and it has a thin atmosphere to stop micrometeors.
    Mars atmosphere also contains CO2, which will be used to grow plants in a greenhouse.

  42. The radiation is a big problem everywhere but ELEO, ELO and Earth surface. Just live in Space, as O’Neill proposed, on the *inside*.

  43. I generally agree, but would do only the minimum on the Moon, other than solar and mining. However, tourism is a pure cash cow at the small scales we need to get started, and should not be denigrated!

  44. I like the Moon scenario a lot. It seems like a much better first stepping stone to space-based industry, habitats, and resource development. The gravity well is much shallower, so it would be easier to mine on the moon and lift into orbit than from Earth, as well as lower payloads to the surface. And it’s much closer to earth-based shipping and control. The lava tubes could be very useful, more sunlight, etc. etc.

    Not sure what Mars gets us in the (relatively) near term. More gravity? More possibilities for terraforming?

  45. I prefer the Moon, but not just for an umbilicaled colony. We need self sustaining. And Ideally we need mining and manufacturing on the Moon. These things have to have the prospect of gain…at some point. I don’t mean tourism…that is ultimately waste. And launches must be going toward self-sufficiency…rather than carrying the seeds of dependency. Relying on gifts from another world, is very tenuous. Politics change, companies have their ups and downs.
    The Moon is fantastic for solar. Better than even the people who are looking at it recognize.
    And it is the ideal place to build large spacecraft (using materials mined from the Moon)…really big stuff. Mostly assembled in lunar orbit from components launched by mass drivers.
    We can launch stuff to Mars to say we were there. But it is hard to find a genuine use at the moment.

  46. Of course, the first thing is ISRU, lunar or asteroidal. Then Al Globus’ Equatorial LEO for actual settlement, aka colonization. Work habs to set up ISRU are not settlements.

  47. It is possible to cover a Mars habitat by just putting up a fence that slows the wind dramatically. Then the sand will just fall right there burying whatever you have near it. You don’t need a tractor or much of anything.
    And you do want it buried because the sand in the wind is moving at very high speed. It won’t blow you over, because the air has so little mass, but the little particles can sand blast everything, potentially doing a lot of damage. Even windows might be a bad idea. They could end up etched, and unusable. Video cameras with many spare thin outer lenses, might be preferable. Or perhaps sapphire lenses or diamond coated lenses, you can just clean off.

    The “72 times harder” claim is a silly claim. I’d give it about a 6 times harder. But these things are subjective. In both cases you need to make an environment that can provide what you need to survive. Resupply is just a stupid paradigm. In both cases you must plan way ahead. Whether there are launch windows or not, is not a big deal. And sometimes deadlines are good things. You can track to see if you are meeting objectives in a timely manner, motivate people because they now know everyone is counting on them to get their little piece of the puzzle done…

    Solar would be much easier on the Moon. The distance from the sun and the blowing particles make solar bunch more of a headache. Nuclear would be equally difficult. Most of that difficulty would be getting permission to get it launched.

  48. I prefer Moon over Mars because:
    Near continuous Sunlight at the poles,
    Vacuum is better for machinery than a thin atmosphere,
    extremes of temperature in close proximity is more useful to industry than a 24 hour cycle of modest temperature changes,
    The view of Earth is far better,
    It’s not just the time to get there, it’s the radiation over that time.

  49. O

    As I have been saying, it is all about throughput. The amount of stuff that can be delivered by one Starship over a given time.

    Throughput matters intensely because you need to amortize the cost of the Starship over the payloads delivered. Longer flights to Mars mean less chance to amortize the cost of the ship. This is probably why Musk is talking about sending Starships to Mars at the end of their lives.

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