Supercritical fluids may be the key to waste disposal in space
Because of the floating poop debacle that took place during the Apollo 10 mission, NASA dedicated a lot of resources to find a better and more efficient way of disposing waste in space. There is one substance that could present a clean, fast method for breaking down waste.
That is water. Fluids have a stage called a critical point, in which the pressure is high enough, so it has no distinct liquid and gas phases but is below the amount required to compress it into a solid form. This turns it into a supercritical fluid, which is very good at dissolving materials.