How to put out a fire in space

The US National Aeronautics and Space Administration (NASA) is conducting a series of experiments on the space station to learn how to put out fires in space.

Fires in space burn at lower temperatures, more slowly, and with less oxygen than in normal gravity. Photo: NASA

According to Discovery, a fire breaking out on a human spacecraft would cause panic. Putting out a fire on board is not as simple as grabbing the nearest fire extinguisher and spraying it on the flames.

Flames behave very differently in zero-gravity or low-gravity environments. On Earth, rising currents of hot air pull combustible material away from the flame and draw oxygen toward it. This is why a candle flame looks like a teardrop.

"In space, the fire burns in all directions like a ball, making it difficult for astronauts to find where the fire is. If you have a smoke detector on Earth, it's usually placed on the ceiling because the smoke rises. In zero gravity, the smoke goes in all directions," said Daniel Dietrich, an expert at NASA's Glenn Research Center.

When astronauts plan to leave Earth orbit, they need to learn how to put out fires in space. In 1997, a fire broke out in an oxygen tank on the Russian spacecraft Mir, forcing nearby crews to evacuate. The fire burned for 14 minutes before running out of fuel.

Fires in space burn at lower temperatures, more slowly, and with less oxygen than in normal gravity. This means that the fuel used to extinguish the fire must be in high concentrations. Astronauts on the International Space Station (ISS) regularly practice fire prevention, using CO2 fire extinguishers.

Dietrich and Forman Williams of the University of California San Diego, USA, are conducting the Flame Extinguishing Experiment 2 (FLEX2) program on the ISS. The goal of this program is to find better fire-fighting equipment in outer space, making space travel safer.

"Experiments in Earth orbit will help develop fundamental knowledge for designing space travel," Williams said.

The first FLEX tests took place between 2009 and 2014. During the FLEX2 program, the team conducted experiments remotely inside the Destiny science module (the part that holds the racks for science projects). They lit small fires and studied how they burned in different concentrations of surrounding gases.

The results showed that two common fuels on spacecraft, methanol and heptanes, will burn when there is at least 12-13% oxygen concentration in the spacecraft. Meanwhile, humans need a minimum of about 14-15% oxygen to survive.

Knowing exactly when the fire goes out would help engineers create better fire-fighting equipment and help astronauts make better decisions if disaster strikes, including changing the gas mixture inside the module to put out the fire.

According to VnExpress