Saturday, July 08, 2006

Propellant from Lunar Soil

I think that using Lunar ice for rocket propellant is a serious waste of resources. All ice should be used for life support purposes, IMO (and in the opinions of many others). There are other materials on the Lunar surface that should be sufficient for escaping from the Luna. The Solar Empire Blog has already written a blog entry based upon this article.
It is well known how to get LOX into a rocket engine combustion chamber under pressure, but how would it be possible to get any of these fuels into a combustion chamber? Phosphorus and sulfur could actually be the easiest as they both melt and could be fed as liquids. Phosphorus melts at around 111o F. It has the advantage of auto-igniting with oxygen. Sulfur melts at 239o F, but if heated above 482o F, it will also auto-ignite with oxygen.

For aluminum and magnesium fuels, they would be in the form of a powder as their melting temperatures are too high. They could be injected into the combustion chamber with an inert carrier gas. We have built a rocket engine using carbon dioxide and magnesium powder for use on Mars that blows the magnesium powder via nitrogen gas into the engine's combustion chamber. This approach could also be used with magnesium or aluminum powder for a LOX-aluminum or LOX-magnesium rocket engine. An additional option available with aluminum is to suspend the aluminum powder in gelled LOX to form a monopropellant. This option is not available for magnesium as it is shock sensitive in LOX and will detonate.
This will not develop the thrust equal to an oxygen/hydrogen engine, but given the low gravity of Luna, this should be sufficient for blasting from that body.


  1. I agree to some extent. However, for launching initial solar missions from the lunar surface, some use of the hydrogen might be justifiable.

    Two other links of mine on the topic:

    Btw, thanks for your offer to link my blog.

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