They explored how quickly substances will ignite and flames will spread in microgravity. They also tested smoke detectors designed for the International Space Station. Critical point transitions are similar but are not so easily observed as they occur at uncommon temperatures and pressures. Each USMP mission has included an experiment that studies a critical point transition. As substances undergo these special changes, they display unusual properties.
Some substances become superconductors, which can carry electricity with no loss of energy.
Others become superfluids, which can carry heat without energy loss. Scientists want to learn more about these transitions because they may lead to inventions like energy cables that conserve power and more efficient transportation systems. Observing these unusual transitions is difficult on Earth because gravity distorts the results. Conducting the USMP experiments has helped scientists to better understand these extraordinary transitions. When metals are melted and then cooled, the solids they form are made up of crystals.