AlLOx Fuel

[Rhyshaelkan]

Perhaps a question that could be answered by those in the field of chemistry and rocketry.

Will powdered Aluminum stay in suspension in liquid oxygen? Or will it settle. Can an agitator keep it in suspension so that it can be pumped to an ignition area. Or am I completely missing the point on how Aluminum and Oxygen are burned as fuel.

Edit:
http://www.wickmanspacecraft.com/moon1.html

It seems I was on the right trail.

"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.

Our company has made LOX-aluminum monopropellant and determined that it is not shock sensitive. It burns in a controlled manner such that it could be fed into the combustion chamber without the flame in the chamber flashing back up into the propellant tank. The viscosity of the LOX-aluminum monopropellant was no higher than 300 cps and decreased to 100 cps with increasing shear rate. A centrifugal pump with backward leaning blades could be used to pump the monopropellant. This type of pump is commonly used to pump slurries. One of the technical issues to resolve was whether the aluminum powder would settle in the gelled monopropellant. Our tests showed that there was no indication of settling in a six to seven hour period, which was the time limit of the tests."

[sgeos]

I recently stumbled across the same link. Does anyone have any more information on a LOX-Aluminum monopropellant? It seems to me that working on this might be more useful than seeking water because aluminum appears to be plentiful on the moon.

[Rhyshaelkan]

In my research of papers regarding this mono-propellant. Making the powdered aluminum was the most difficult step. I made this post before the detection of so much hydrogen on the Moon. Estimates say 600 million tons of water at one pole alone. Enough to launch a space shuttle each day for the next thousand years or so. So for now I leave AlLox alone. I theorize that in short order(ten to fifteen years) after starting lunar water mining operations. That we will have moved on to mining water ice for fuel from NEOs. We might also see the rise of powerful versions of electric propulsion. Both point to finding alternatives to hydrolox long before we burn through Luna's supply.

Research on the cold traps by Dr. Paul Spudis also point to the fact that minute traces of water have migrated in the high vacuum and low-g of the Moon. Once trapped in those shadowed areas they will not leave, short of an impact. But might migrate back to the cold traps anyway. So the cold traps might even replenish themselves over time(hundreds of years).

AlLox mono-propellant might be used in small reaction control rockets for massive vessels of the future. Think a 10000 ton solar electric tug for the inner solar system or nuclear tug for the outer solar system.

[sgeos]

I'm not convinced that there will not be competing uses for water. Competing uses for anything drive the price up.

Unless water is easy enough to extract to obtain on demand, capacity will exist to extract only a certain amount of water within a given timeframe and there will be a limited water economy. Obviously there will be an incentive to invest in more infrastructure to the extent the product (water) can be profitably obtained. The upshot is that I suspect it is likely that there will not be enough water to do everything that wants to happen, and it will have to rationed. (Prices have the effect of rationing things.)

The production of powdered aluminum will also certainly suffer from constraints, but the constraints will be different. Obviously, all of that is very hypothetical. Nobody can say how prices will shake out without heading up there and giving it a shot, but it seems like an AlLox monopropellant should have a place somewhere in a space economy.

[Rhyshaelkan]

but it seems like an AlLox monopropellant should have a place somewhere in a space economy.

Yes I started this thread because I wanted to get over that hump of launching everything from Earth. By finding some sort of fuel. Then all we need to do is get things to LEO. As opposed to all the way to the lunar surface, and back. On one "tank of petrol."

Due to the delta-v requirements I think hydrolox will be used for Orbit Transfer Vehicles. The ISP of AlLox keeps it tied to less transit intensive functions. So I envision hydrolox moving stuff from LEO to other orbits. While landers and lunar hoppers(hopping from one surface location to another) will run on AlLox since they can refuel more often.

If we question the need for hoppers, consider this. We find an asteroid impact crater with high levels of platinum. We set up automated mining. Automated hoppers can bring the ore back to a central processing plant. Therefor not having to build multiple processing plants everywhere.

The automated miners need maintenance? Hop some technicians over to repair. Without having to build a whole aero/hydroponics suite to sustain those workers. They pile back in the hopper and come home.

[sgeos]

I believe the site linked to above mentions something about constructing rails from lunar concrete. Do you think it would make sense to do something like construct a freight train that runs on AlLox? It sounds like AlLox could be a choice fuel for vehicles that do not leave the moon. Could magnesium LOX make more sense?

In any case, whoever manages to set up a lunar LOX plant is going to be rich.

[joertexas]

In any case, whoever manages to set up a lunar LOX plant is going to be rich.

I dearly hope so...

JR

[sgeos]

The alternative is that lunar LOX production is trivial to the extent anyone can have it on demand. In that case, there would be no money in it.

Is there a consensus on what the components of a lunar LOX plant would consist of?