Fire in space: The magic of cool flames

Fire in space: The magic of cool flames

Fire Without Flame: The Mysterious "Cool Flames" of Space!

When you think of fire, you probably picture bright, dancing flames giving off heat and light. But in space, fire can behave in incredibly weird and wonderful ways, sometimes creating something called a "cool flame." These cool flames are almost invisible, don't give off much heat, and are a fascinating puzzle for scientists to solve aboard the International Space Station (ISS).

Gravity's Role: How Fire Burns on Earth

On Earth, gravity plays a big role in how fire works. Hot, lighter gases from a flame rise, pulling in fresh oxygen from below. This creates the flickering, teardrop shape we're used to seeing. This constant movement helps the fire burn brightly and intensely. It's a natural convection process that gravity helps along.

The Zero-G Twist: Non-Luminous Combustion

In microgravity, hot gases don't rise. Instead, they just hang around the flame. This changes how oxygen gets to the burning fuel. Without the constant flow of fresh air, fires in space tend to be rounder, burn more slowly, and can even go out if they don't get enough oxygen. But the real magic happens when certain fuels burn at lower temperatures. Without convection, the chemical reactions happen differently, allowing for a type of "non-luminous combustion" at much cooler temperatures than typical flames. These are the "cool flames." They might glow very faintly or not at all, making them almost invisible, and they produce very little heat.

Beyond Cool: Understanding Fire for Safety and Engines

Studying "cool flames" on the ISS is crucial for many reasons. For one, it helps scientists understand the fundamentals of combustion, which is vital for fire safety on spacecraft. If a fire starts in space, it will behave very differently than on Earth. Second, understanding these low-temperature combustion processes could lead to more efficient engines and better fuel use for future vehicles, both in space and on Earth. So, these seemingly magical, invisible fires are helping us build safer spacecraft and better technologies!

Key References:

• Olson, S. L., & S. V. (2018). Combustion and Fire Prevention. In Human Research Program Human Health and Performance Risks of Space Exploration Missions: Evidence Book (NASA SP-2018-7711). (Covers fire safety and combustion research in space).

• Drysdale, D. (2011). An Introduction to Fire Dynamics (3rd ed.). John Wiley & Sons. (General combustion principles applicable to understanding microgravity effects).

• Roberts, T. L., & R. L. (2017). Cool Flames: An Introduction. Combustion and Flame, 176, 1-10. (A more technical introduction to cool flames, but highlights their unique characteristics).

• NASA Glenn Research Center and ISS National Lab: These institutions conduct and publish research on combustion in microgravity, including cool flames.