🚀 go-pugleaf

> For final injection, it occurs to me that using gaseous oxygen to "blow"
> the powdered aluminum in might be an option.

We concentrated on not letting the fuel and oxidizer mix outside the 
combustion chamber for safety reasons.  That scrapped LOX slurries and 
blowing the powder.  Another project team sprayed molten steel over a 
blast chamber when their methane/oxygen rocket accidently 
mixed propellants in the feed lines, which makes me feel pretty 
strongly about the safety criterion.

>
>What are the problems with using molten aluminum sprayed into the reaction
>area?  Keeping the aluminum molten in a vacuum should be relatively easy.

What are the weight and power penalties for keeping a tank of molten 
aluminum on your spacecraft?  Could be expensive.  But we kicked 
around some far-out ideas too--shaping the Al into fine wire and 
burning it off a spool or as a "wool", or feeding the power in through an 
airlock and burning it in pulses.

>Another source of information is the External Tank Study published
>by the Space Studies Institute. Cutting up ETs for their aluminum
>was listed as an option. Impulse of such an engine would be in the
>330 second range. Very viable as a Lunar based fuel source.

Is that for a pure Al/O2 engine?  The ETs have leftover H2 on board, 
which SSI might've been including.  The exhaust has to be almost all O2 
or the energy will be absorbed by the oxide particles with very little 
thrust resulting.  My 118 sec Isp calculation was for about 4% 
aluminum in the mass flow.


Karl
sold my soul to Uncle Sam . . . now marked down for resale.