Fire doesn’t play by Earth’s rules once you leave gravity behind. In this deep dive with Professor Michael Gollner, we unpack what the recent experiments at the ISS called SoFIE-MIST taught us about solid fuel flammability in microgravity—how tiny ventilation, oxygen levels, and pressure shifts determine whether a flame spreads, stalls, or vanishes. The details are surprising: blue “bubble” flames, two distinct extinction points, and sustained burning at oxygen levels that would fail to ignite on Earth.

We walk through the entire setup: PMMA rods chosen for clean, uniform burning; a compact wind tunnel inside the ISS hardware; ceramic heaters delivering 1–3 kW/m² to probe incipient behavior; and a control strategy that often lets the flame’s own oxygen consumption carry the chamber gently to extinction. Along the way, you’ll hear how constraints drive design—why rods beat flats, why halogen lamps didn’t fly, how crew time is minimized with robotic runs—and how data is captured without weighing anything. Opposed-flow flame spread becomes a window into fundamentals: radiative preheating, thermal thickness, and the delicate balance between convective loss and feedback when buoyancy is gone.

The implications stretch to future habitats and vehicles. As spaceflight moves toward longer missions and more commercial operators, safety will hinge on accurate flammability limits under low ventilation and non-Earth atmospheres. We connect the dots to normoxic choices, partial‑g research on the Moon and Mars, and the growing need for space fire engineering that’s grounded in real data. If you care about spacecraft safety, materials selection, and the science behind early fire detection, this conversation is right for you.

If you want to learn more, do it here:

• a brilliant article at the Berkeley website
• NASA Glenn website about the SoFIE programme
• Episode 75 with David Urban on spacecraft fire safety
• QA session 5 - brainstorming martian habitat fire safety

Cover image credit: NASA, Igniting a 12.7 mm sample at 21% oxygen under 100 kPa ambient pressure in microgravity. From article https://engineering.berkeley.edu/news/2024/12/nasa-funded-project-offers-new-insights-into-fire-behavior-in-space/

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