New Aluminum-Ice Rocket Propellant Tested

eldavojohn writes "With the problem of moving conventional rocket fuel to the Moon and Mars on their minds, researchers from Purdue and Penn State successfully tested and demonstrated the use of aluminum-ice (ALICE) as fuel. In a paper from last August they outlined how it would work (PDF), and now they know it does. Space.com also has more information on the paper and how nano-scale aluminum functions as a fuel."

Comments

Old news, but not to /.

[confused one]

MIT Technology Review is a little late here. This was covered by numerous sources back in October. Surprisingly, I can't find it in the /. archives; so, it may not be a dupe.

Re:Old news, but not to /.

[deglr6328]

mhmmm old news http://www.youtube.com/watch?v=-b7siH1Ausc

"Enhance"?

[John Hasler]

> The oxygen and hydrogen in water molecules enhance the combustion of the
> aluminum.

"Enhance"? Um, the water _is_ the oxidizer.

Re:"Enhance"?

[John Hasler]

> ...more oxygen...

There is no oxygen present except for that in the water molecules.

Thermite + Water Vapor = BOOM

[Azarael]

For a neat visual presentation of the physics they're relying on, Mythbusters did an experiment on the explosive power of thermite powder and water vapor http://www.youtube.com/watch?v=BnHR4cMXiyM.

Re:ALICE?

[Ethanol-fueled]

You may be too young to remember, but it was acceptable and even funny to beat your wife in the '50's.

Get off my lawn or one of these days...POW! Right in the kisser!

Re:ALICE?

[Speare]

For those not in on the joke, see very early US television comedy, "The Honeymooners." Its characters were the original inspiration for the cartoon Flintstones, which might give you an indication of the age of this joke.

Its seeing things like this ..

[OzPeter]

that highlight the safety instructions I've had at Aluminium plants. You never, ever, ever drop anything like used aluminium cans into the feed that is headed for melt shop as any bit of liquid still in the can will cause a rather powerful explosion

Re:Its seeing things like this ..

[mangu]

You never, ever, ever drop anything like used aluminium cans into the feed that is headed for melt shop as any bit of liquid still in the can will cause a rather powerful explosion

It's also a known rule that you use sand, never water, to extinguish a fire where molten aluminum is present.

However, the biggest danger from dropping aluminum cans in the melt is from the steam expansion, not from burning aluminum. Having *any* humidity at all where molten metal runs, any metal, not just aluminum, will produce large quantities of steam, which will expand explosively throwing molten metal all around.

I know this from personal experience, when I was about twelve years old I was burned while melting lead to make fishing weights. I dropped the mold in water to cool it and the next time I poured metal in it I got a spray of molten lead right in my face. Lucky me, none of it hit my eyes.

Re:In other words

[TheRaven64]

Really? Because hydrogen is the most common element in the universe, and oxygen is also pretty close to the top of the list (third most abundant element overall). Comets contain a lot of water ice. Aluminium is on of the three most common elements in the Earth's crust, but it's not nearly as common as hydrogen and oxygen in the universe at large.

Re:In other words

[TheRaven64]

Volatile means that it vaporises easily, not that it burns (although vaporising at room temperature and reacting with oxygen make things easy to burn). Aluminium does not become vapour easily and so is non-volatile. If you mix it with rust and light it with a magnesium flame, it will burn pretty well though...

Re:There is

[ceoyoyo]

Rocket fuel = concentrated energy.

However you get that energy, you can have rocket fuels that are nasty pollutants or rocket fuels that are not, and rocket fuels that produce exhaust that is a nasty pollutant or not. Hydrogen + oxygen = water is probably the best, but some of the solid fuel rockets are nasty. Both the reactants and the products are a little more toxic than "may be linked to brain disease [but we drink it anyway]."

Besides, most aluminum plants are located near some cheap source of energy specifically because aluminum requires so much electricity to refine. The really cheap sources of lots of energy tend to be hydroelectric, not fossil fuel. Boeing isn't based in Seattle because they like the weather.

Isp and Exhaust Velocity

[Baldrson]

Assuming a 2 to 3 Al to H2O molar ratio, it looks like the exhaust velocity is about 900 m/s so the Isp is about 90s.

If that's right, that sucks compared to normal mixtures.

Of course, if you're lifting off the moon or asteroids, it may be ok.  Mars?  Probably not.

Computing case 1
Fixed enthalpy-pressure equilibrium - adiabatic flame temperature

Propellant composition
Code  Name                                mol    Mass (g)  Composition
34    ALUMINUM (PURE CRYSTALINE)          2.0000 53.9631   1AL
976   WATER                               3.0000 54.0458   2H  1O
Density :  1.458 g/cm^3
3 different elements
AL H  O
Total mass:  108.008918 g
Enthalpy  : -7944.26 kJ/kg

24 possible gazeous species
8 possible condensed species

                       CHAMBER
Pressure (atm)   :     340.230
Temperature (K)  :    3166.569
H (kJ/kg)        :   -7944.256
U (kJ/kg)        :   -8685.762
G (kJ/kg)        :  -33443.801
S (kJ/(kg)(K)    :       8.053
M (g/mol)        :      35.507
(dLnV/dLnP)t     :    -1.00584
(dLnV/dLnT)p     :     1.13099
Cp (kJ/(kg)(K))  :     3.30500
Cv (kJ/(kg)(K))  :     3.00720
Cp/Cv            :     1.09903
Gamma            :     1.09264
Vson (m/s)       :   900.11114

Molar fractions

AL                   6.0290e-004
ALH                  9.2486e-004
ALH2                 2.8353e-005
ALH3                 2.1470e-005
ALO                  2.4478e-005
ALOH                 5.6133e-003
AL(OH)2              3.4527e-005
AL(OH)3              3.1024e-006
AL2                  1.4157e-006
AL2O                 1.3669e-003
AL2O2                1.1545e-005
H                    1.0276e-002
HALO                 2.7342e-006
HALO2                3.5370e-007
H2                   7.2954e-001
H2O                  7.8723e-003
O                    3.5048e-007
OH                   4.1466e-005
Condensed species
AL2O3(L)             2.4364e-001

Re:Reading comprehension.

[John Hasler]

> Burning Iron Oxide+Reactive= Thermite.

No. Iron oxide+aluminum=thermite. Rust catalyzes the reaction between potassium chlorate and sugar. Mix your fuel in a rusty container and it may ignite while you are mixing it.

A glass container is a good choice, but wash it when you are finished. We once mixed fuel in an ashtray and then failed to clean it...

Re:ALICE?

[Have Brain Will Rent]

And it's worth pointing out that in the show the character being quoted never hit his wife and in fact spent a lot of time begging and toadying toward her.