Basement 3D Printer Builds Are Too Easy. Try Building One on Mars.

[Tony Stark Elon Musk] envisions us sending one million people to Mars in your lifetime. Put aside the huge number or challenges in that goal — we’re going to need a lot of places to live. That’s a much harder problem than colonization where mature trees were already standing, begging to become planks in your one-room hut. Nope, we need to build with what’s already up there, and preferably in a way that prepares structures before their inhabitants arrive. NASA is on it, and by on it, we mean they need you to figure it out as part of their 3D Printed Hab Challenge.

The challenge started with a concept phase last year, awarding $25k to the winning team for a plan to use Martian ice as a building material for igloo-like habs that also filter out radiation. The top 30 entries were pretty interesting so check them out. But now we’re getting down to the nitty-gritty. How would any of these ideas actually be implemented? If you can figure that out, you can score $2M.

Official rules won’t be out until Friday, but we’d love to hear some outrageous theories on how to do this in the comments below. The whole thing reminds us of one of the [Brian Herbert]/[Kevin J. Anderson] Dune prequels where swarms of robot colonists crash-land on planets throughout the universe and immediately start pooping out building materials. Is a robot vanguard the true key to planet colonization, and how soon do you think we can make that happen? We’re still waiting for robot swarms to clean up our oceans. But hey, surely we can do both concurrently.

67 thoughts on “Basement 3D Printer Builds Are Too Easy. Try Building One on Mars.

    1. Hmm, you raise an interesting problem with a potentially huge benefit oddly so…
      ie. Conventional iron/steel making reacts charcoal with iron oxide(s) as the Carbon favours oxygen
      ahead of the iron under the appropriate temperature & fluxes ie Slag – moderators etc

      It might well be possible, under the appropriate catalysis conditions to combine iron oxides with
      CO2 or even methane (CH4) as the process for producing that has been well studied, so
      overall you react Fe2O3 or Fe3O4 with CH4 (taking a bit away from that sue as a propellant
      for any return journeys) and end up with iron rich in hydrogen (some embrittlement unless also
      high in Carbon & allows) which might not be a problem as its compressive strength is high
      – ie Skycrapers, hmm twin towers.

      Or liberate the H2 so it can then re-combine with the initial O2 from producing CH4 to end
      up with large swimming pools on Mars – double hmm :-o) !

      I have a sneaky feeling bacterial means to extract Iron Sulphide might be far easier energy
      wise & re infrastructure & power density requirements, getting iron from Iron Sulphide trivial
      (english spelling of sulphide not US – yeah I know both separated by a common language)

      Either way it sounds feasible, have to put this past my eldest doing a PhD in Chem Eng
      & get his input from my other son doing Physics honours split at two unis 15Kms apart :P

      More interested in wondering what it would be like diving into & swimming in pools of water
      under a martian sunset at one third gravity – yay dah future & drive there in a Tesla of course :D

      1. I think that there are more problems to living on Mars than where to live.

        The five main elements for life on Mars are:
        Oxygen – Atmosphere is 95% CO2 and the crust appears to be mostly Iron Oxide. So Oxygen on Mars is everywhere, just not in a readily usable form by humans, not with out processing (plants can generate this!).

        Nitrogen – 2.7% of the Atmosphere, so easily accessible from everywhere on the planet.

        Carbon – Atmosphere is 95% CO2, so available, just needs to be converted into a useful form for humans.

        Hydrogen – Only really available at the poles 140 K (-133 °C, -207 F) at the winter pole, probably gets up to about 170 K (-103 °C, -153 F) during summer). Dry ice, which requires temperatures of about 148 K (-125 °C, -193 F), which forms at the poles during the winter, may partially sublimate during the summer months, and make it a bit easier to access the water.

        Energy – lots and lots and lots of energy, luckily we have a local star that provides a lot of that.

        (other elements are required to sustain human life, calcium, phosphorus, potassium, sulphur, sodium, chlorine, magnesium, and trace amounts of boron, chromium, cobalt, iodine, iron, manganese, molybdenum, selenium, tin, vanadium, zinc, …)

        The lack of a magnetosphere means that Mars has a very thin atmosphere (~ 0.6% of earth’s at sea level. And that means that extracting gasses will be at least 166x harder (more energy) than it would be on earth from it’s atmosphere.
        Another consequence of no magnetosphere also means that its surface is bathe directly with high energy from the Sun. And UV-C, which shreds DNA probably makes it to the surface and, will make living above ground not really practical.
        The average temperature on Mars is about 218 K (-55 C, -67 F). We are creatures made mostly from water, so again not an idea place for humans.

        On the bright side, Martian surface temperatures during the day in the summertime may reach peaks, around the equator, of almost 300 K (27 C, 80 F). And having people on Mars would ensure the continued existence of the human species if all life here is destroy for whatever reason.

        I think that drilling deep into the surface may be a more practical solution, sort of upside down skyscrapers. Go deep enough and the daily/seasonal temperature fluctuations become negligible. The high energy particles from our Sun would be attenuated to similar levels as on earth. It may not be good psychologically living deep underground, but there are many practical advantages, especially if near the poles.

        1. I should probably clarify that Dry ice sublimates at −78.5 °C (−109.3 °F) at Earth atmospheric pressures. The temperature I gave above was for sea level (zero elevation) on Mars at 6.1 millibars atmospheric pressure.

          1. Now that really begs a question. Where exactly is “sea level” on Mars? There is no sea. A little Google Fu tells us that the Martian equivalent is called the Areoid, an equipotential surface of the Goddard Mars Gravity Model. Huh? Ok, so imagine a sphere extending out from the center to 3,396,000 meters. Roughly the average level around the Equator. So 6.1 millibars there, roughly 12.4 millibars at the lowest point at Hellas Crater. The lowest pressure year round settlement on earth at La Rinconada, Peru, 5100 meters, is around 550 millibars. Nothing grows up there, and it’s not much fun doing anything akin to work. Half of us regular folks feel the effects of altitude sickness at 600 millibars. To get close to 1 earth atmosphere you need to dig down to around 60 Kilometers, which, according to estimates, puts you through Mars crust and into the mantle. Temperature wise, you’re pretty screwed.
            If you were to dig down maybe 10 Kilometers you could have stable, livable temperatures but you’d still need a sealed pressure habitat, and digging through all that olivine garnet would not be cheap or quick.
            The more I look into it, the more I see shallow, subsurface pressurised habitats as the way to go. With very large solar collectors to maintain heat, energy and release the water from the polyhydrated sulfates.

          2. @Piecutter I was not suggesting to tunnel down 60km more like 3 meters underground, where there is enough matter all around to smooth out fluctuations in temperature. To increase the pressure, compressors would be required to bring up the level at least to stop water boiling so that plants could convert CO2 into O2 for us humans – lots and lots of solar panels.

          1. Why? To hold in a teraformed atmosphere? My understanding is that even the least optimistic estimates put the time it would take an earthlike atmosphere to disipate from Mars at centuries. If (and this is a huge if) future people have the ability to give Mars an earth-like atmosphere it would probably be easier to just top it off every 100 years or so than it would be to create a magetosphere.

            Remember, Mars has been around for billions of years. It had lots of time to lose it’s original air.

        2. The only good thing about the -55 C (sorry I’m German, so I stick to Celsius^^) is, that probably the low pressure insulates you quite well compared to earth conditions. Therefore the main loss of energy (unless being in a sand storm) should be long wave IR radiation.

      2. Iron oxide I hear you say? One of most common elements on earth is aluminium, I’m sure one can guess where this goes …

        I suspect easiest way is to bounce enough free celestial bodies with mostly ice as their primary element into collision course with Mars. Impact generates enough heat to evaporate the ice releasing water/snow into the atmosphere. Keep this going and at some point we have dense enough gas sphere able to sustain liquid water, then clouds and voilá water.

        I also wonder why would they try to build anything above Martian ground. Why not just carve habitats into mountains and use the thermite reaction to produce heat?

        1. Two problems with “bounce enough free celestial bodies with mostly ice as their primary element into collision course with Mars”

          1. Mars has no magnetosphere. So any gas not really close to ground will be blown away by our solar wind (stream of charged particles flowing outward from the Sun). Because of this Mars can never have an atmosphere, not unless we could generate an artificial planetary scale magnetic field somehow. This is needed to deflect the charged particles away, and stop the atmosphere from being blown away.

          The temperature that water is a liquid on Mars, due to the low pressure, is restricted to the range 0 to +10 °C. So if you aimed for the poles the water would stay there as blocks of ice. And if you aimed at the equator it would instantly boil and be blown away by the solar wind.

          As for Thermite, it takes a massive amount of energy here on earth to purify Aluminium, and it is that energy that is being released as it strips away the oxygen from the iron oxide during the reaction. Aluminium production plants are generally placed right beside the cheapest electricity generators because they use so much energy. The shipping costs, of the purified ore, are insignificant compared to the electricity costs. I do not think that it would be an efficient use of energy resources on Mars. but it is thinking outside the box and I do love that.

          1. sorry “And if you aimed at the equator it would instantly boil and be blown away by the solar wind.”
            Should be:
            And if you aimed at the equator, during the summer (daytime), it would instantly boil and be blown away by the solar wind.

    1. In terms of fuel, there isn’t a big difference between reaching the moon and reaching mars from Earth’s surface. Mr. Stark described his reasons for Mars vs. any other solar system body – more Earth-like gravity, something resembling our atmosphere, and relatively moderate temperatures and air pressures.

  1. Can ice be printed on Mars? I can’t imagine it existing as a water phase, it would be a solid it or it would be floating away.

    It would probably be far easier to put down a double walled bag, fill the inner bag with compressed air and the outer bag with liquid water that you allow to freeze. Extra points if the bags can be recovered and reused by colonists.

    1. There are seasonal, very local rivulets of liquid water on mars but I’m more concerned with sublimation of these structures.
      Assuming no Terraforming, the martian atmosphere is ~600 Pa, Temperature range of -155 – 20C you’re going to cross the phase barrier naturally, then factor in comfortable human temperatures on the inside of the Hab, you need some barrier to keep the water you’ve spent valuable resources mining from drifting away. Sure plastic film is lightweight, but to make any sizeable structure will still require many pounds ($$$) of it and shipping is a bitch.

      Maybe (if you must) 3D printing some sort of concrete made from local resources, but normal casting methods might require less equipment to be viable.

    2. I don’t know of many people whose home 3d printers start out with liquified plastic either. Why would they have to start with liquid water as opposed to just melting the ice as they extrude?

  2. Just being contrarian here, but just because you have a 3D printer doesn’t mean you have to use it for everything.

    It might be easier to cast bricks or blocks or even prefab floors, walls and ceilings from raw Martian materials, at least for the initial settlement.

    If you must use a 3D printer, then maybe you could 3D print prefab floors, walls and ceilings for assembly on site. You can add all the ventilation, wiring and plumbing during printing. Then you can use a several smaller printers instead of one that must cover an entire worksite.

    1. IMO 3D printing structures only have an (very theoretical) advantage* if you print them in place. If you’re going the prefab route, casting primitive shapes to be moved by heavy equipment or human power will be much less resource intensive.

      * – I have yet to see a 3D printer that didn’t require lots of alignment prior to printing. Other heavy equipment functions even when misaligned since the operator can compensate on the fly. Or, when need be, crudely aligned with percussive maintenance.

    2. I think the whole point of 3D printing a building in an unbreathable atmosphere is you don’t risk lives until something has to be repaired. I wouldn’t want to pour concrete manually wearing a delicate spacesuit.

      1. Any suit that is resistant to micrometeroid impact should have a reasonable service life doing construction work.
        Sure you’re not going to be digging ditches in such a restrictive suit but the simple solution to that is, don’t.
        A dedicated construction rover would make labor easier and less dangerous.
        The Apollo era suits had a Beta cloth exterior and modern suits are covered in Nomex as will the Constellation suits to be used on Orion missions.
        A lot of things can be said about suit design, but I wouldn’t list fragile near the top.

  3. It was my understanding that one of the major obstacle to colonizing Mars, (aside from the voyage) was the lack of water. Why would you build your habitat out of such a valuable resource, when it would be just as if not easier to make it out of the Martian surface.

    1. But is it as easy to make it from the ‘Martian surface’. (I guess by surface you mean soil and/or rock)

      Ice has a much lower melting point. It kind of sounds like you are saying why does your home 3d printer use plastic when Si is the most common element in the crust of the Earth? Because the melting point of glass is too high.

      1. There was a guy, featured on HAD a few years ago, who made his own special 3D printer. It used fresnel lenses aimed at a pile of sand. It used focussed sunlight to melt the sand into glass. For each layer, more sand was added, like laser-sintered 3D printing uses. Something like that might be handy for basic structures on Mars or the Moon.

        1. It would be interesting to know if that method would be more or less effective on Mars. There is less sunlight but also less atmosphere to steal away the heat from the sintering point. I’ll bet it would actually work better.

  4. I thought about this long and hard, and concluded, as others have, that 3D printing for the sake of it is idiotic, I then devised several methods of generating large atmospheric containment spheres that would have no risk of leaks. But there is no way I am going to share any of my original designs with NASA, again.

    1. Yeah this.

      Also got some ideas for material efficient habitats. Saving the best ones.

      For a freebie, “igloos” in quotes because it just means a house or dwelling, but y’all know what I’m talking about… and ice needn’t be the thing to make them of.

  5. We need to forget about sending people, we’re not built for space. Just on the cosmic radiation coming from out side our solar system will kill you before you get there. Robots are the only and best way…….

    1. I think the issue is long term survivability of the species. Asteroid strike, environmental collapse, global thermonuclear war, contagion, etc. are all viable threats to extinction on a long enough timeline.

      I left sun burnout off purposely as Mars doesn’t escape that catastrophe.

      1. But you are avoiding his point, why send people when you can send robots, because until Mars can be made Earth like the people living their will be dependent on Earth anyway and robots can get started on “taming” Mars without all the extra infrastructure humans need to live and work there.

        1. Well when there are huge numbers of different tasks to be done, robot tech might not be there yet. When you’re looking at sending 10 different special purpose robots you start thinking that it’s just easier to send humans. Unless they are NASA single purpose humans that aren’t allowed to go off program to save themselves. ( ie keep NASA out of it until they have a massive culture change.)

        2. Mars does not have to become earth-like for humans to prosper there. If we end up gathering energy with photovoltaic panels and growing food underground with LED illumination, one problem is solved. Martians don’t have to live as Earthlings do. The environment demands something different, but that different is livable with hard work and innovation. There really ARE people who don’t go nuts spending most of their time underground, rarely going outside. It becomes the new comfortable normal for them and all is well. We are more diverse than you think and I am convinced that a certain portion of humanity could thrive there.

          1. 30% (LED efficiency) of 25% efficient solar panel collection of the light available from the sunlight which is way less than earth is a horribly stupid way to do things. Especially when you have to carry those acres of panels there.

            Be far better to have surface farms even if living quarters are underground. It’s potentially possible that some crops might not need to be in a controlled atmosphere. Particularly if areas of increased insolation by solar mirrors in orbit was arranged. (And those can be huge but light mylar over stick structures.)

          2. I think you are working with stale data on your efficiency percentages. LED’s are much higher than 30% efficient and photovoltaics (the best ones in the labs are into the 40%’s and they become more efficient the colder they get). I still think the agriculture is going to be forced underground because of the simple fact that the temperature will have to be kept above freezing for anything to grow. All of the energy that goes into the LEDs will be useful. The part that becomes light drives the photosynthesis process. The part that becomes heat warms the room. Life on earth basically comes to a stop when the temperature gets below freezing with the exceptions running on reserves built up in warmer seasons. On Mars there are almost no above freezing warmer seasons. That should force things underground or at least into a cleverly constructed greenhouse that can handle the winds. (but what about radiation?) As for photovolaics, we would need to make a front-burner issue of becoming able to manufacture them on Mars using local materials. Until then, atomic generators might be a good idea. You mentioned Mylar. I like making stuff with it but it is horrible with high winds. I’ve seen the winds of Nebraska tear it to shreds in short order and that’s a gentle breeze compared to the winds on Mars. (at least the air is thinner) Still surface or underground, we go with what works and I’m sure there is a good solution in at least one of these contexts.

          3. @ Foxxpup

            PVs into LEDs is inefficient no matter how you slice it.
            Average solar irradiance on Mars is > On Mars there are almost no above freezing warmer seasons.
            The equator regularly gets near 20C.

            >>…that’s a gentle breeze compared to the winds on Mars
            Hollywood has lied to you.
            Average density of the Martian atmosphere is 0.020 kg/m^3
            Maximum wind speed measured by Viking I is 30 m/s ~67 mph. Averages depend on season and range from 2-10 m/s, very similar speeds to Earth.
            Using the wind load formula:
            Fw = PdA = 0.5 ρ v^2 A
            Fw = 0.5(0.020 kg/m^3)(30 m/s)^2 A = 9 N/sqm

            The strongest Martian dust storm barely registers as wind load here on Earth. It’s a Gentle breeze according to Beaufort.

          4. It looks like you are more informed about the weather on Mars than I am and its great to know that temperatures do get hight enough in some places on a regular basis. I’d still be sceptical about light-duty structures on the surface. Generally in my experience, if it bends or flops around, it will ultimately break so whatever gets built on the surface will have to be very rigid to last so any Mylar structure will have to be strung very tight to have a chance.

            As for PV’s, I see no other choice but to use them short of using atomic. We may be up against that wind issue again if we make them too thin, but regardless we will have to find ways to make huge quantities of them and put up with the fact that we are getting half the power that we would get near the Earth. It will be interesting to see if LED “powered” plants grown underground will do better than Sol “powered” plants on the surface. Surface plants would have to be more radiation resistant and I’m sure there is a production price to pay for that. Tests like these are what should be going on in the laboratories right now rather than people like us just sitting around talking about it. Actually its the kind of science the average Joe with a bit of science/tech skills could do in their basement. (Simulating the Mars surface radiation would be a bit of a challenge :-) ) I’m still betting on the viability of underground agriculture. PV will quickly become a minor factor in the production process once things get going well. The huge affect of a warmer, radiation protected, controlled environment should pay big dividends but it is more work up front compared to growing on the surface. Perhaps growing on the surface is a good way to start followed by growing underground once enough panels/tunnels can be built. Time and experience will tell. :-) The right super-plant in either context could swing the issue. Its going to be fascinating to watch this mater unfold. :-)

          5. Not sure why my post got chopped. Sorry for the double post.
            @ Foxxpup

            PVs into LEDs is inefficient no matter how you slice it.
            Average solar irradiance on Mars is <600 W/sqm. So even if we get PVs to increase efficiency to 50% by the time the first colonists depart, we're down to 300 W/sqm. At the moment LEDs put out around 350 lm/W with a theoretical max of 683 lm/W for green LEDs.
            For fruiting plants you need 20k-100k lm/sqm (aka lux) to get any yeild. This is ignoring inherent inefficiency due to the fact that plants don't use the whole spectrum (look up PAR for more info) but that we can still pick lights that are the right temperature 3500k, 5000k, 6500k depending on the plant.
            Assuming all your light is in the PAR, you need at a minimum 20k lux which translates to 40 w/sqm if we assume 500 lm/W, partially to make the math nice, partially as it's ahead of todays eficiency but less than the theoretical max.
            Again, thats 40 W per meter of growing space. That's over 100 sqm of solar panels that need to find their way to Mars — per square meter of growing space. Sure you don't have to worry about the neighbors complaining about eyesores but a 1 sqm PV panel weighs 10kg. Even if we halve that since it's NASA/SpaceX/ESA & they have better stuff than consumers, that's half a metric tonne in solar panels, per meter of grow space. There won't be any payload weight left for actual research or

          6. First, I really appreciate your willingness to express what you know about this subject. :-) The whole matter makes me wonder if there isn’t a path from electrostatic potential to sugar production in some life form somewhere. If we could bypass LED’s and the photosynthesis process we should be able to gain a lot of efficiency. I’ve also read about experimental chemical solar cells that store the energy up chemically which sound like something bacteria could work with but also sounds like something that needs to stay above freezing, at least for the bacteria. (sounds like higher maintenance than PV’s however) Also, if you are right about the wind being less of a problem, then mylar reflectors could concentrate sunlight onto the precious PV’s to get them up to full production. There would be tracking and maintenance issues, but it could reduce interplanetary shipping mass. Its all fascinating stuff. I wish I was younger and not ADHD. I’d be right in there trying to work out a solution.

            I can’t say everything about Elon Musk is good, but he sure can get people going, inspired to do new and ambitious things, and that’s good. He’s no messiah. He’s more of a Thomas Edison, Steve Jobs type. He knows how to herd talented minds toward a goal and “get-er-done” :-) This whole project would seem like an extravagant waste of resources, but it gets people dreaming and people on Earth need to dream about something good in the future to work towards. Like the 80’s astronaut in the LEGO movie, many of us have an intense built up desire to make a SPACESHIP!!! and go out in it. Mr Musk is drawing on that resource. :-)

            Again, thanks for sharing. :-)

  6. I have a mental image of digger robots, excavating hobbit-holes into the hillside. The waste soild is crushed, melted, and extruded by 3D printers to make surface structures. This would probably look like a robot with diarrhea.
    Is there enough silicon in Martian soil to make glass windows? Or more solar cells?

  7. Mars has dirt. Send a robot with a big tank of glue and a brick mold to fill with layers of dirt sprayed with just enough glue to bind it together.

    Inflate domes. Spray with glue, blow dirt onto it. Repeat until desired thickness is reached. Since Mars has some atmosphere, blowing would work. On the Moon the process would have to be tossing mechanically, like an airless paint sprayer.

      1. What do you make your inflatable dome out of that can handle the heat necessary to sinter iron?

        Also.. I’m guessing that regular martian surface dirt probably doesn’t have THAT much iron in it. I don’t think you are going to make metal that way but maybe glass…

        1. NASA have all kinds of heat resistant inflatable materials. A ten second Google search turns up this:

          It’s effectively a heat resistant blanket able to withstand temperatures of over 1,649 C. The meting point of iron is a hundred below that, but we don’t have to even go that high to sinter it.

          But I think your point about glass is a good one. There’s way more silicon in the regolith than iron. The end goal is just a strong structure that we can pile more dirt on top of.

    1. That’s a lot of glue to ship a very long way. How many horses must die to make your new home? Maybe the water is the glue. That would be one way to use less water, instead of martian ice castles make martian mud castles. On the other hand, if you want to recycle it later you now have dirty frozen water rather than clean.

    1. What, really? Sulphuric acid clouds and a surface temperature that can melt lead, are two reasons. Somebody way back did propose floating cities in the Venusian atmosphere though. Still pretty dangerous.

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