What Does Fire Look Like in Space?

It may be considered dangerous to study fire on the International Space Station, as it's a confined, artificially oxygenated environment, but scientists conducting Flame Extinguishment Experiments (FLEX) believe understanding combustion and how to put out fires in space could be a matter of life or death.

Researchers in the FLEX program have been trying to better understand how flames behave in space since March 2009, according to a NASA news release. So far, more than 200 tests have been conducted in a sophisticated, contained chamber on fundamentals of flames and how best to manage them.

"We hope to gain a better knowledge of droplet burning, improved spacecraft fire safety and ideas for more efficient utilization of liquid fuels on earth," Principal Investigator Forman Williams, University of California, San Diego, said in the release. "The experiments will be used to verify numerical models that calculate droplet burning under different conditions."

Scientists use either a small droplet of heptane or methanol in a microgravity chamber to observe the flame's behavior. Take a look:

As you can see, the flame burns for about 20 seconds as a sphere before the fuel runs out. But it's not just the spherical shape of the flame that's intriguing. The researchers report seeing that some burning continues even after the heptane flame disappears.

"Thus far the most surprising thing we've observed is continued apparent burning of heptane droplets after flame extinction under certain conditions; currently, this is entirely unexplained," said Williams, who has studied combustion for more than 50 years according to the release.

Researchers have found flames in space burn at a lower temperatures, lower rates and require less oxygen. This means higher concentrations of extinguishers must be used to snuff the flame.

[H/T Popular Science]