New Rocket Fuel: Aluminum and - - - Water?!

"New Rocket Fuel Mixes Ice and Metal "
Space.com (October 21, 2009)

"Rocket propellant has barely changed in the more than 50 years since the launch of the first artificial satellite Sputnik. But a new mixture of nano-aluminum powder and frozen water could make rocket launches more environmentally friendly, and even allow spacecraft to refuel at distant locations such as the moon or Mars.

"The aluminum-ice propellant known as ALICE gets its kick from a chemical reaction between water and aluminum. Researchers hope that the hydrogen products of that reaction might go beyond launching rockets, and also feed hydrogen fuel cells for long duration space missions.

" 'In the bigger picture, we're looking at technology that can store hydrogen long term,' said Steven Son, a professor of mechanical engineering at Purdue University. 'Water is a nice, stable way to store hydrogen.'..."

Aluminum is used in rocket fuels now, because it's high ignition temperature helps shoot exhaust gasses out faster. What's new about this technology - aside from using water - is the size of the aluminum particles.

"...ALICE squeezes even more out of the aluminum by using nano-scale particles with diameters of 80 nanometers, or 500 times smaller than the width of a human hair. Such tiny particles combust more rapidly than larger particles to give an additional kick, and may allow easier control over a rocket's thrust.

" 'The nano-scale aluminum is really key to making system work,' said Timothee Pourpoint, a professor in the school of aeronautics and astronautics at Purdue. 'Using only micron-sized aluminum powder and water ice would not have worked.'..."

It's an exciting development - but far from being ready for launch vehicles.