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Science

Liquid Oxygen from Lunar Rocks 93

Posted by timothy from the mine-the-moon dept.
SIInudeity writes "A South African chemical engineer has come up with a way to produce liquid oxygen from lunar rock. Oosthuizen is a co-inventor of the Ilmenox process, named after the process' ability to produce oxygen from the lunar mineral ilmenite. The process extracts oxygen from moonrock, which are metal-oxides that may contain up to 30 or 40% oxygen. By means of electro-chemical equipment, which has now been patented, the oxygen and the metal in the moonrock are split."
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Liquid Oxygen from Lunar Rocks More

Liquid Oxygen from Lunar Rocks

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  • MoonBase! (Score:4, Informative)

    by MindStalker ( 22827 ) <mindstalker AT gmail DOT com> on Wednesday December 15, 2004 @09:21AM (#11091835) Journal
    Moon Base here we come!

    And that other Zappa kid too.
  • It's a shame that he patented this now. I doubt he'll ever see it used during the patent period.

    • Re:It's a damn shame... (Score:1, Insightful)

      by Anonymous Coward
      Actually, this may be one of the few times patents are mentioned in a slashdot story where a patent is actually appropriate!

      In any case, patent or no, I also can't see it getting much use in the next decade. If a lunar base is built soon, the Ilmenox process would obviously be useful. But just how many devices could possibly be needed? Even repeated missions which leave a lot of equipment behind would only amount to a handful being used.
    • I think you ACs read some sarcasm into my above statement. It wasn't intended.

      I really do mean that it's a shame that this guy won't make any money from this process. It's a great idea. He should be rewarded.

  • Glossed over in the summary (Score:5, Interesting)

    by wowbagger ( 69688 ) on Wednesday December 15, 2004 @09:26AM (#11091879) Homepage Journal
    Glossed over in the /. summary is the fact that the output of this process is not JUST LO2, but also titanium (and presumably aluminum) metal, as well.

    So not only do you get air to breath, you get materials with which to build your base.

    Set up a base running this process, add a Lunar beanstalk to L1, and you have a cheap source of material for building items in Earth orbit.

    I wonder if adding a spinner (i.e. a cable in orbit, the ends of which do not terminate on any celestial body but instead are allowed to rotate freely) could be used to reduce the delta-V even furthur - use the lunar beanstalk to launch to earth orbit, rendezvousing with the spinner to get the delta-V to enter LEO, and storing the energy in the spinner to launch items later.
    • Good point about the metal byproducts (even if the metal wasn't easily refined, a metal/rock mixture might be a semi-ductile and vacuum-weldable material for building blocks, and I'd mod you insightful if I had pionts), but shipping to LEO doesn't require rotating skyhooks; aerobraking is more than sufficient.

      One problem with rotating skyhooks is that anything that's long enough to keep accelerations comfortable for people passes through the inner Van Allen belt too much. You're either going to be limited

      • Cargo only (Score:4, Interesting)

        by wowbagger ( 69688 ) on Wednesday December 15, 2004 @10:25AM (#11092445) Homepage Journal
        The idea of using the spinner is for cargo only - low energy transfers from lunar surface to LEO.

        By using a spinner, you can save the energy from an incoming cargo as rotational kinetic energy in the spinner, rather than pissing it off as heat in an aerobraking maneuver.

        You can then use the rotational energy to launch other items back out of Earth's gravity well.

        The biggest arguement against using the moon as a base of operations is the delta-V required to get to the lunar surface from earth. But delta-V is only expensive when you have to expend non-reusable reaction mass (and the energy to drive it). When you use skyhooks of various forms (spinnners, beanstocks, etc.) your reaction mass is reusable (the reaction mass is the skyhook), and you can frequently reuse the energy from an incoming cargo - greatly reducing the costs.

        True, a manned craft is still expensive as you don't want to follow the slower, lower energy paths - but if you can reduce the mass of the manned craft by shipping nonliving support mass (food and fuel) via slow orbits you can reduce the cost of the manned ship to a managable level.
        • The cost from the moon to earth orbit and back (from earth orbit to the moon) is small. In orders of magnitude smaller than the price to leave Earth's well.
          I can't see how you store that energy in spinners, or how spinner energy can launch anything off Earth.

          To launch out of earth with a sky hook requires technology we don't yet possess (cables built of nanotubes or other super-strong material)
          • I can't see ... how spinner energy can launch anything off Earth.
            So what? That was never the claim.

            Hopefully, being stuck at the bottom of one of the strongest gravity fields in the solar system is a temporary condition. (Only the Sun, Jupiter, and Neptune have higher surface gravity than Earth.)

            • Only the Sun, Jupiter, and Neptune have higher surface gravity than Earth.

              And Saturn. Plus Earth just barely beats out Venus.
              • And Saturn. Plus Earth just barely beats out Venus.

                I think the grandparent poster was making a distinction between the value of g at the surface verses the value of g at a fixed distance from the planet's center. Saturn's massive, but might not be as dense as Jupiter, allowing for a lower value of g. I'm not sure about Venus though; I was taught in school that they are "celestial twins" nearly identical in mass and size.

                • Well, Saturn is really nowhere near as massive as Jupiter, and is also much less dense. Anyway I think most people would be surprised to learn that they would weigh the same (or much less) everywhere in the solar system except Jupiter:
                  • Jupiter: 236%
                  • Neptune: 112%
                  • Earth: 100%
                  • Saturn, Venus: 91%
                  • Uranus: 89%
                  • Mercury, Mars: 38%

                  Until you get to Mercury and Mars, your weight is remarkably consistent. This, of course, comes with the caveat that the "surface" of the gas giants is taken to be the

              • NASA [nasa.gov] disagrees. Saturn and Venus both have surface gravity about 9% less than that of Earth.

                Anyway, it's really a moot point. I only said it because it makes a good sound bite. Surface gravity is not a good measure of the difficulty of leaving a gravity well. Escape velocity is a better measure, and atmospheric drag should probably be factored in too. Besides, the "surface" used for the gas giants is the tops of the clouds, which is really not a meaningful altitude.

                • Interesting, my Googling turned up a value of 1.07 for Saturn here [gsu.edu] and here [utexas.edu], so I assumed that 1.07 was the correct value. Further googling reveals estimates of Saturn's surface gravity ranging from 0.74 [nasa.gov] to 1.19 [comcast.net].
                  • Wow that's weird indeed. The numbers don't add up on any of the links you provided, nor on NASA's sites. For instance, on the link I provoded [nasa.gov], they give these numbers:
                    • Radius = 9.45 x Earth
                    • Mass = 95.2 x Earth
                    • Computed gravity: M/R^2 = 1.066
                    • Given gravity: 0.916

                    Go figure.

                    Anyway, what I find remarkable is that one's weight is practically the same on so many planets. Only on Jupiter would you feel much heavier, and you need to go to Mars or Mercury before you feel more than 20% lighter. (60%

          • I can't see how you store that energy in spinners...

            It's like a gravity-assist maneuver, with the cable substituting for gravity. The skyhook's high-energy state is an elliptical orbit, its low-energy state is closer to a circular orbit. The ends of the skyhook are moving relative to its center of mass (of course). When a piece of cargo comes from high orbit, it comes by on a tangent to the path of the high end of the skyhook as it whips by. The cargo carrier latches on, which shifts the center of mass o

            • Think about SpaceShipOne as an Earth-Luna transfer vehicle ... or not. A cable moving through hypersonic velocities at 100km will be experiencing drag like crazy. There's no way you'd have a skyhook dip down into the outer atmosphere without some sort of propellantless boost mechanism (say, electromagnetic boost against earth's magnetic field), and even still, 100km would a bit extreme.

              With current (and even soon-forseeable tech), skyhooks are only good for environments in which they don't pass through a

              • A cable moving through hypersonic velocities at 100km will be experiencing drag like crazy.

                Except that it wouldn't be moving at hypersonic velocities; it would be accelerating hard, but it would barely be moving at all.

                If you consider 3 G as the acceptable limit for people, a skyhook with its end stationary at the lowest point and the center of mass moving at 16,000 MPH (allowing for altitude and some excess velocity) would need to extend 1738 km from the center of mass. Re-entry interface for the Space

                • I disagree.

                  First off, what "reentry" is considered for the space shuttle is irrelevant - what is relevant is the density, and at what altitude. I have a handy air density calculator for any altitude that I made by merging the formulae for different portions of the atmosphere that I was able to find on the net into a single coherent formula. It gives us the following values, starting with 100km (the altitude of SS1):

                  100km: 5.62e-6 kg/m^3
                  120km: 5.42e-7 kg/m^3
                  150km: 1.63e-8 kg/m^3
                  250km: 5.89e-11 kg/m^3
                  400k
                  • I started to check some of your figures and found gross errors starting with your atmospheric densities. My CRC Handbook of Chemistry and Physics (55th ed.) lists density values almost an order of magnitude lower than your calculator does for the lower altitudes:

                    100 km 8.0e-7 kg/m^3
                    120 km 5.0e-8 kg/m^3
                    150 km 3.0e-9 kg/m^3

                    Et cetera. I found this a bit odd, so I decided to confirm with the Standard Atmosphere table in the CRC Handbook of Tables for Engineering Science, 2nd ed. This book yielded these figu

                    • Ack, something happened to my response to this? I think it was because I tried to post code. Blah, I'll try to sum it up really quickly, and omit the code.

                      1) Notice how your data results are quite incongrous. I found the same problem when establishing my model; all of the different models give different results. Why? Because all of them are true; the density of the upper atmosphere varies greatly, depending on latitute, season, and further up, the geomagnetic index and solar X-ray flux.

                      2) We'll use 1
                    • What are those units, Newtons? (Notice that I listed units on everything, because I don't think anyone should have to ask me for further explanations in order to reproduce, or find errors in, my results.) Incidentally, .57 cm^2 is the cross-sectional area; the diameter was about .85 cm.

                      Okay, suppose you have 0.28 N of average drag. At a speed of 7050 m/sec (about 16,000 MPH) the required reboost power is... less than 2 KW. (In actuality it's much less. The draggy parts are at low altitude and moving at low

                    • All units are newtons; sorry, as a programmer, I get lazy sometimes when writing just quick scripts, and that was direct output ;)

                      > Incidentally, .57 cm^2 is the cross-sectional area

                      Ok, then multiply my numbers by 1.5; I didn't bother to check your tensile strength numbers and just assumed they were correct, so I didn't come to a diameter on my own, and just grabbed the first figure that you gave ;)

                      > Okay, suppose you have 0.28 N of average drag ... making overly optimistic assumptions on *everyth
                    • ... and I need to post more, because I should know that I can't assume anything about the background of the people here (even when they are posting on space matters).

                      It's not an issue of power.... It's an issue of propellant.

                      So don't use propellant. The space environment is a dilute plasma, and is electrically conductive. Pump electrons through the tether to push against the magnetic field and complete the circuit through the plasma. This was fictionalized [davidbrin.com] 22 years ago; it has at least one effort at com [tethers.com]

                    • For the third time now, I have already discussed propulsion off of Earth's magnetosphere. It doesn't exist. We haven't even successfully deorbited anything yet using the magnetosphere, although we have projects in the works. Boosting from the magnetosphere is harder. I have little doubt that it will be done one day. But, pretending like it can happen now is misleading.

                      I find it somewhat insulting that you're pretending that I don't know about space, and then mentioning magnetospheric propulsion, when
                    • Jamming and kickback are engineering details. Someone neglected to put spring or elastomeric dampers in the load path (none of the designers were fly fishermen, I'll bet). Those failures probably could have been prevented at a relatively low cost, but nobody gave them the thought or engineering analysis to have them dealt with. Look at your own list of examples; are you really claiming that we aren't wiser now?

                      A long, massy tether has the advantage that it has to be tapered and the amplitude of any wave wi

    • This could be a good idea for Mars travel, since you'd want to be travelling very fast, and expending alot of energy.

      I think the moon is too close for something like this to be profitable. You'd gain the kinetic energy of the ship moving from earth to the moon or back, but there's not much of it.

      How does a ship rendevous with such a thing? Isn't is supposed to be a tense cable, spinning faster than it's orbit 'should' be?
      An incoming ship is supposed to 'catch on', exchanging energy with the spinner?
      sounds
      • The spinner is spinning as it orbits. The incoming cargo picks a point on the spinner that, at the time of arrival, has the same velocity at the object.

        Thus, only the acceleration changes - and it is possible to "loosely" grab the cable and slid for a short distance, spreading the change of acceleration over a period of time and reducing the "jerk" (d^3S/dt^3, or da/dt) felt by the cargo.

        But since it *is* cargo, not people, the jerk is not a problem.

        Assuming the incoming cargo is moving faster than the s
        • Yes, but you only have one chance to grab the spinner. If the cargo fails, it has to turn around (somewhere else, I assume. days if not weeks, then).

          I'm not sure I totally understand how this works. I understand the cargo shifts the orbit of the spinner, and has to put him back in place when he finishes, no? (or rather, the spinner's mass has thrusters)

          I was thinking of cargo drops. Won't it be very cost effective to chop large blocks of moon rock and toss them to Earth? (re-usable ceramic container and p
          • The shift in the orbit of the spinner is small - the spinner is assumed to have much more mass than the cargo.

            Usually, you will use the spinner to boost some other cargo going outward, so the net effect is zero.

            Grabbing the spinner is easy - at the time you are grabbing it your relative motion is zero or pretty close to it.
      • I know it's nitpicky, but it's spelled "rendezvous". I only point it out because on the moon, we are excellent spellers.
    • So not only do you get air to breath, you get materials with which to build your base.

      Set up a base running this process, add a Lunar beanstalk to L1, and you have a cheap source of material for building items in Earth orbit.

      I noticed this as well. If a moon base with this technology is established, might it be economical not just to throw the Ti up to L1, but down to Earth? A quick search on titianium mining [google.com] turns up a whole lot of problems with current terrestrial methods, primarily because the most
      • There's something that I don't get about this article. Current aluminum and titanium ARE refined electrolytically. What did this person do, apart from try to capture the oxygen? Did this person simply "invent" the addition of a pump and tank? Because that's what it sounds like.

        The problems with electrolytic refinement on a moon base are significant. First off, there's the mass issues; aluminum oxide is dissolved in molten cryolite (I'm not sure what they do for titanium). To build any significant siz

  • Assuming a moon base is set up to mine the metal and oxygen for futher development and exploration, what happens when we start running out of moon to mine?

    Who owns the resources produced?

  • Re: (Score:2, Funny)

    by account_deleted ( 4530225 )
    Comment removed based on user account deletion

    • Re:Great news (Score:5, Insightful)

      by artifex2004 ( 766107 ) on Wednesday December 15, 2004 @09:54AM (#11092144) Journal
      I think I speak for everyone when I say that terraforming the moon has to be a major priority if we're to, erm, get away from this planet.


      No, you don't. While it may be useful and even practical to develop industry on Luna, I can't think of a real reason to terraform it. Mars, on the other hand, is a much better candidate for terraforming, or at least modifying to create some atmosphere and agriculture sufficient to meet population demands.

      Besides, the primary reason to get off the planet is preservation of the species. Terraforming Luna, which due to its proximity would very possibly be catastrophically affected by any major cataclysm of extra-terrestrial origin affecting Earth, really does not meet this goal.
      • Comment removed based on user account deletion

        • You don't think that having a huge vacation resort in orbit around the Earth, with theme parks and man-made oceans (read: no Great White Sharks, but lots of good diving), and Earth-like gravity so even old people can go there, would be a good thing?

          No, I don't! Not until we have a permanent, self-sufficient off-world presence further out in the solar system, at least.

          Terran resource levels will be the bottleneck towards our drive outward. Spend your resources (including time) on pleasure domes, and wha

      • I can't think of a real reason to terraform it.

        It's safer. Maximum distance from the Earth to the Moon is ~385,000 km. Maximum Earth-Mars distance is ~378,000,000 km, or roughly 1000 times that. The lightspeed lag from Earth to the Moon is 1 second. The maximum lag from the Earth to Mars is 1000 times that - or almost 20 minutes.

        However, it depends what you mean by terraforming. It's not "terraform-able" - meaning "make it look like Earth" - it can't hold an Earth-like atmosphere for more than a few year

    • Re:Great news (Score:4, Insightful)

      by bhima ( 46039 ) <Bhima,Pandava&gmail,com> on Wednesday December 15, 2004 @10:55AM (#11092765) Journal
      Here is where we pause and allow to think about the implications of making the moon 6X more massive...

      ....

      ....

      Done, good we can move to this 'moon' when it rips the earth apart.

  • Good. Now where do you get the hydrogen? Nitrogen? (Score:3, Insightful)

    by human bean ( 222811 ) on Wednesday December 15, 2004 @09:59AM (#11092185)
    This is good in at least we won't need to ship the O2, but where are we going to find the other little necessities of life (and most rocket fuel)?
    • It's not actually necessary to combust anything to get a rocket going. Rockets work by ejecting mass and using the reaction force to accelerate. As long as you have something to eject (the O2 in this case), and a means to propel it from yourself, you're fine.

      See ion engines for example, which eject tiny particles at tremendous speed to get going. No combustion involved, just electrical acceleration of ionized particles.

      So a rocket engine could be built with solely a heat source and an inert propellant tha
      • living on the moon, and an occasional bath. To tell the truth, I wasn't considering rocket propellant. I was considering living.

        Oh, and to get a high specific impulse, you want your propellant gas to have as low a molecular weight as possible, which is one of the reasons that H2 is used as a rocket fuel. The O2 is just there to heat it up, so to speak.
    • It's not much, but the Moon has 100 ppm nitrogen and 50 ppm hydrogen. I think whether or not water ice is available on the Moon is also an open question.

      Anyways, it's quite possible that not -everything- would be available in situ. However, having available oxygen helps quite a bit in terms of required mass. Heck, about 90% of water's molecular weight is oxygen. For other things you can just import and recycle them.

  • Only "potentially" oxygen? (Score:3, Insightful)

    by Ender_Stonebender ( 60900 ) on Wednesday December 15, 2004 @10:03AM (#11092226) Homepage Journal
    From the article:
    Oosthuizen said sand samples from Namakwa Sands has successfully been used in experiments to produce titanium metal and potentially oxygen.

    So they've managed to split the metal out, but don't have the oxygen as straight O2 yet? The article is a bit short on details on this. If so, it's not going to be useful until he figures out how to get O2 (or H2O) through chemical reactions with whatever he's got now.

    --Ender
    • IANAC:
      If you take out the oxygen from the metal oxide, it will form into O2 (liquid, in this case, because we're on the moon). Heat it up and it becomes pure (lethal) oxygen.

      You'll need quite a bit of H2 to mix it with.
      If H2 will be present, some water will form on it's own (no?). Anyway, O2 and H2 will form H20 and give you some energy while they're at it (Fuel cell).

      There's less Hydrogen than Oxygen on the moon, so you might need to bring excess H2.

      Question:
      Can't fusion be used for this? If you heat up

      • IANAC (...) Heat it up and it becomes pure (lethal) oxygen.

        Since when is pure oxygen lethal? It was used on the Apollo missions, it is used in hyperbaric chambers (at more than atmospheric pressure, I might add), and it is used by military pilots flying high-altitude aircraft to remove the nitrogen from their blood before they fly.

        The only thing dangerous about pure oxygen is the fire risk - if that is why you consider it "lethal", then perhaps you might want to check the fuel tank on your car.

        • Urban legends run deep.
          Pure oxygen is only lethal to infants, and I think it ussualy only causes blindness anyway.
          • That's not entirely true. Adults can live on 100% oxygen at 1 bar for a while, but it does damage the lungs, after say, a couple of days on it.

            It's a bit safer at lower pressures like Apollo used, but even then, it's not ideal.

            I get the impression that the issue with infants is more that their lungs aren't fully formed, and so the doctors have to administer it at above 1 bar to get enough oxygen into them. So, there's both mechanical damage as well as the oxygen toxicity. And it doesn't only cause blindne

            • It's a bit safer at lower pressures like Apollo used, but even then, it's not ideal.

              The partial pressure of O2 is all that matters. Apollo used pure O2 at 5psi, which approximates closely the partial pressure of O2 at sea level.

              The danger is related to depressurization accidents. If what you're losing is 66% inert gas (assuming 33% O2 and 66% inert at 15psi), there's a much better chance of detecting the loss before it becomes a problem. OTOH, if you're breathing pure O2, you won't get the bends while

              • The partial pressure of O2 is all that matters. Apollo used pure O2 at 5psi, which approximates closely the partial pressure of O2 at sea level.

                For short term survival yes, say a week or so. For long term, as in weeks/months/years, the extra nitrogen seems to protect the lungs in some way.

                But you can certainly reduce the absolute air pressure down to 1/2 atmosphere or less.

                Adding the nitrogen back in also reduces flammability issues- the inert nitrogen conducts heat away and makes things harder to burn.

                • For short term survival yes, say a week or so. For long term, as in weeks/months/years, the extra nitrogen seems to protect the lungs in some way.

                  Searching around, I can only seem to find references to pure O2 at greater than the sea level partial pressure (probably because divers won't encounter pure O2 at sea level ppO2). Can you point me to references to sea level partial pressure O2 and the lungs in a pure O2 environment?

  • More reasons to build a Moonbase before Mars (Score:4, Interesting)

    by Jtheletter ( 686279 ) on Wednesday December 15, 2004 @10:10AM (#11092294)
    I've said before that the US space program should build a permanent moonbase before we attempt to send people on an extended expedition to Mars. It would give us the opportunity to practice for the Mars mission in a simulated Martian environment much closer to any we've created on Earth, with the added benefit that if something goes wrong the crew would be seven days away from help, instead of seven months.

    Could this new invention/process be the argument that finally makes people realize the usefulness of such an intermediate step before we race off to the red planet? Besides the ability to produce their own breathable air from lunar rocks for sustained occupancy, the base could double as a fueling station, producing liquid oxygen for the ISS for breathing, fuel, etc. It might even become practical to use such a base as the staging location for the actual Mars mission. It would be much easier to do in-space assembly of a Mars super-ship with a low-gravity (as opposed to the microgravity of orbit) "Factory" available on the moon, shuttling pieces to the ship in lunar orbit.

    We've had the technology to setup a permanent presence on the moon for some time, I want to see it happen just for the cool factor, but I think there's plenty of scientific and exploration reasons. Maybe now that the moon can be used to actually produce something we will take advantage of that. Here's hoping.

  • "Invention"? (Score:3, Insightful)

    by adeyadey ( 678765 ) on Wednesday December 15, 2004 @10:27AM (#11092458) Journal
    I would like someone to look at that more closely - there are some well known age-old methods already around for chemically extracting oxygen from oxides & other minerals..

    Maybe when we go to the moon, we should leave all the patents on earth!
    • Not only that, but where is he going to get the electricity from?

      He's going to need megawatts.

      Solar? Expensive to ship to the moon, and only gives a fraction of a kilowatt per square meter.

      Nuclear? How does he plan to get rid of the waste heat in the vacuum of the moon's surface?

      There's a reason that aluminum extraction is done next to hydroelectric schemes... no hydroelectric on the moon, that's for sure :-)

      • Solar works a whole lot better when theres no atmosphere in the way.

        Nuclear: the same way the sun does, radiation instead of convection. Plus the moon is essentially an enormous heatsink. And it's also less relevant when there's nothing to 'burn'.
      • Solar? no atmosphere, plenty of power - far better than the hottezst desert on earth.. remember we only need enough to make fuel for one rocket, and O2 to breath, over a longish period..

        My problem is with the patent - is this really such an original idea?
        • It's not that it can't be done- it's that it is expensive to do. Forget launch costs for the moment- how much would a photovoltaic panel cost on earth that can deliver a megawatt? It's going to cost more than that on the moon.

          remember we only need enough to make fuel for one rocket... over a longish period..

          Yes, but oxygen gets used up by a rocket; and as I said, electrolysis is phenomenally inefficient- nearly all of the energy ends up as heat, rather than with O2 formation.

          Whereas:

          O2 to breath can b

  • So by the time we start using the moon as a base for traveling to Mars, the patents will have expired and we can use the tech for free. Thanks! (Sometimes researching years ahead of the need doesn't pay off.)

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