Researchers Found That Fire Burns Differently in Space Than on Earth

Since March 2009, the space agency’s Flame Extinguishment Experiment, or FLEX, has conducted more than 200 tests to better understand how fire behaves in microgravity, which is still not well understood. Fire is a different beast in space than it is on the ground. When flames burn on Earth, heated gases rise from the fire, drawing oxygen in and pushing combustion products out. In microgravity, hot gases don’t rise. So an entirely different process, called molecular diffusion, drives flame behavior. According to Dan Dietrich, FLEX project scientist at NASA‘s Glenn Research Center in Ohio, in space, molecular diffusion draws oxygen to the flame and combustion products away from the flame at a rate 100 times slower than the buoyant 

flow on Earth. Space flames can also burn at a lower temperature and with less oxygen than fires on Earth. As a result, the material used to put out space fires must be more concentrated, researchers said. To study fires in space, FLEX researchers ignite a small drop of heptane or methanol fuel in a special experiment rack aboard the space station. As the droplet burns, a spherical flame engulfs it, and cameras record the whole process.
source:www.space.com