7 thoughts on “A Brief Tutorial On Lunar Resources”

  1. Is there no easy route to convert Alumina (Al2O3) back into fuel? There’s raw iron, but I can understand prefering to use the iron structurally instead of forcing the reverse-Thermite reaction.

    A mighty deep well to convert the alumina, but getting energy should really be markedly easier that the other issues.

  2. The article was pretty light (perhaps he shouldn’t have broken it into so many pieces). I did like the bit about hydrogen which along with carbon are two critically scarce elements on the Moon. Given that regolith mining is possible (especially if helium 3 becomes popular), then ISRU hydrogen would be available for human use. That makes life on the Moon a bit easier.

  4. Certainly would be interesting if the way around a monopoly was to mine it in space.

  5. Here’s another wild idea, based on the fact that pretty much all of the moon may be used as propellant, though not necessarily in the correct proportions. A bunch of hyperlinks coming up in a separate post. Use of advanced and unconventional propellant combinations may lead to much more benefit from lunar ISRU and maybe even more efficient ISRU itself.

    Two combinations are of particular interest:

    – Silane + H2O2
    Higher silanes + H2O2 are expected to be a dense, space storable and hypergolic propellant combination with better Isp and lower toxicity than MMH/NTO. This is useful for science missions, but since both silicon and oxygen are plentiful on the moon, this propellant combination would also benefit substantially more from lunar ISRU.

    – MMH/Al/NTO gels
    Under the ISTP project NASA is developing an advanced MMH/NTO engine called AMBR for science missions. The goal is to increase the Isp to about 375s in the next ten years or so. One of the more advanced techniques under consideration is use of gelled propellants, with significant amounts of metal powders combined with the MMH. Depending on the mass fraction of the metal, Isp and density can be increased.

    Again, a second effect is that a larger mass fraction of the fuel can be sourced from ISRU. MMH consists entirely of elements that are rare on the moon, whereas aluminium is plentiful. Mass fractions of up to 70% metal are a serious possibility. For high metal fractions, the Isp drops but this is likely more than compensated for by the increased potential for ISRU.

    The following article gives the average composition of the lunar regolith:
    […]

    It looks as if nearly all of it could be turned into propellant. If this is true, then it may make sense to export ore & regolith to L1/L2 for processing there. Establishing the initial infrastructure there is cheaper than doing it on the lunar surface, because of the lower delta-v. Also, with uninterrupted sunlight and cheaper solar panels it would be much easier to generate massive amounts of power. You would still need some propellant production on the surface, but the scale could be reduced.

  6. https://iti.esa.int/iti/fileUploadForm.do?action=viewer&proposalId=1001&contentType=5
    Prediction of Performance of (Higher) Silanes in Rocket / Scramjet Engines.

    http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090001339_2008047216.pdf
    AMBR* Engine for Science Missions

    http://gltrs.grc.nasa.gov/reports/1998/TM-1998-206306.pdf
    Preliminary Assessment of Using Gelled and Hybrid Propellant Propulsion for VTOL/SSTO Launch Systems
    http://pdf.aiaa.org/jaPreview/JPP/1996/PVJAPRE24074.pdf
    Theoretical Effects of Aluminum Gel Propellant Secondary Atomization on Rocket Engine Performance

    http://adsabs.harvard.edu/full/1973LPSC….4.1159T
    The average chemical composition of the lunar surface

  7. Electrolysis is the classic way of getting aluminium out of alumina. Unfortunately, ideally it requires cryolite, a flourine compound probably rare on the Moon.

    However; for use in space it really doesn’t matter what the exhaust is. One idea floating around is to use unsorted lunar regolith as a propellant and just about anything else (solar?) as the energy source. The mooted engine is essentially a mass driver optimised for propulsion use; meaning high velocity and low propellant usage.

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