When firefighters want to extinguish a blaze, they often douse it with water. Astronauts on board the ISS, however, are experimenting with a form of water that does the opposite. Instead of stopping fire, this water helps start it.
“We call it ‘supercritical water,” says Mike Hicks of the Glenn Research Center in Ohio. “And it has some interesting properties.”
Water becomes supercritical when it compressed to a pressure of 217 atmospheres and heated above 373 degrees C. Above that so-called critical point, ordinary H2O transforms into something that is neither solid, liquid, nor gas. It’s more of a “liquid-like gas.”
“When supercritical water is mixed with organic material, a chemical reaction takes place—oxidation.” Says Hicks. “It’s a form of burning without flames.”