An experiment, called Confined Combustion, intends to improve fire safety on the International Space Station and future manned missions to the Moon. This research is to help predict how fires might spread in low gravity. Dr Paul Ferkul of the Universities Space Research Association, who is working on the project, said: “That is the immediate and most practical goal since NASA can use the knowledge to improve material selection and fire safety strategies.” Gravity normally pulls colder denser air to the base of the flame, displacing hot air, which rises.
According to the Guardian, the experiments, which began on Christmas Eve, involve a fan blowing air through the box to provide oxygen. The experiments are testing two fuels fabric comprised of cotton and fibreglass, and clear acrylic plastic sheets and testing how different air flows and sizes of box alter the combustion rates. The fires are lit inside a box within a box, to ensure safety. In the 15 experiments conducted so far the flame has burned for between one and 22 minutes. Previous work that was done by the same team has revealed that, contrary to expectations, some materials would be more flammable on the moon due to the lower buoyancy. Because for some materials, the convection flow is so fast that it extinguishes the flame on Earth. However, when transferred to the moon, the flow could hit a sweet spot where it is fast enough to draw in fresh oxygen but not so fast that the fire is blown out. The experiments are designed to provide better predictions of how different materials behave in low gravity environments.
These experiments could give new insights into the basic science of combustion, such as the chemistry of soot formation and how gas radiates from flames. “The equations become significantly easier if we get rid of buoyancy,” said Ferkul. “We can look at some of the underlying physics that is sometimes masked by buoyancy. Soot is a very difficult thing to unravel.” Ferkul also stated “Living on the moon is a different environment from space station and Earth, and fires will behave differently there. There’s reason to believe that fires could be more dangerous on the moon than on Earth.”
According to the Smithsonian, the data obtained aboard the space station through experiments such as comparing how fire spreads on flat objects versus spherical ones will help engineers better understand the behavior of fuel and flames on Earth. Where approximately 75 percent of our power comes from some form of combustion. NASA scientists are quite excited about the potential applications for this unprecedented type of combustion they observed in space this past spring. When certain types of liquid fuel catch fire, they continue to burn even when the flames appear to have been extinguished. The fuel combustion occurs in two stages. The first fire burns with a visible flame that eventually goes out. But shortly afterward, the fuel reignites, taking the form of “cool flames” that burn at lower temperatures and are invisible to the naked eye.