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Green Rocket Propellant

October 29, 2009

A new rocket fuel, made of aluminum and ice, could have environmental benefits.


Firing up ice. I’m Bob Hirshon and this is Science Update.

Tiny aluminum particles, suspended in ice, could be the rocket fuel of the future. The fuel’s being developed by Purdue and Penn State Universities, NASA, and the Air Force. Purdue mechanical engineer Steve Son says it’s based on an old idea that’s somewhat counterintuitive.

STEVE SON (Purdue University):
You’re using water as a reactant in a combustion process. Whereas you typically think I’m gonna throw water on a fire to put it out. And in this case, the water is the oxidizer.

… Which means it keeps the aluminum burning, after a smaller engine melts the ice and ignites it. The exhaust is mainly hydrogen gas and aluminum oxide, which are much cleaner than today’s rocket fumes. Although the new propellant still needs work, it recently shot a nine-foot test rocket a quarter-mile into the air. I’m Bob Hirshon for AAAS, the Science Society.