A speculative left brain thought: could our regolith fields be ’seeded’ with materials designed to retain the wind blown volatiles and make the process more efficient? Or would skimming fresh ground be more productive? A useful near term experiment would be to discover how quickly an area is replenished. And a wild right brain dream: if we are going to create big furrows in Tranquility, why not draw a picture! Mega graphics! Something big enough to see with a telescope but not the naked eye would seem to be appropriate! Note “E=MC^2″ has only two curves:)
/speculation
Finally I echo Jason hopes. The commission needs the testimony of someone who has quietly but passionately advocated a return to the Moon over (too) many years!
Fingers Crossed!
Dave

Thank you for sharing your thoughts on this blog. Your ability to state the importance of exploring the moon in the 21st century may be unmatched. I hope you have an opportunity to testify before the Augustine Commission.

Jason

Here’s a wild idea for the use of lunar resources. It may have no merit, but I found it interesting and would like to hear if any of it makes sense.

It seems that most of the elements present on the moon, not just volatiles implanted by the solar wind, may be used as part of various propellants, though not necessarily in the correct proportions and not without external hydrogen. 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.

Prediction of Performance of (Higher) Silanes in Rocket / Scramjet Engines.

- 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.

AMBR* Engine for Science Missions

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.

Preliminary Assessment of Using Gelled and Hybrid Propellant Propulsion for VTOL/SSTO Launch Systems
Theoretical Effects of Aluminum Gel Propellant Secondary Atomization on Rocket Engine Performance

The following article gives the average composition of the lunar regolith:

The average chemical composition of the lunar surface

The main elements are oxygen, silicon, aluminium and various other metals. Oxygen is of course an oxidiser. Silicon can be turned into silane if external hydrogen is provided or it can be used in powder form as an additive to a gel propellant. Aluminium and the other metals can similarly be used as metal-loading for gel propellants.

It looks as if nearly all of it could be turned into propellant, provided external hydrogen is supplied. This may seem no improvement over simply using hydrogen from Earth together with lunar oxygen, but it does mean that all of the regolith/ore could be processed into propellant, producing no slag. If the Isp of the resulting propellant is good enough, it may allow processing of the regolith to be moved to L1 instead of having to do it on the lunar surface.

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. This would work especially well for an architecture that wants to go to L1 anyway.

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