Fire safety for the Moon & Mars
Fire behaves differently off Earth.
Three decades of NASA microgravity combustion research — Skylab, Mir, the ISS, drop towers and the Saffire fires set inside empty Cygnus spacecraft — summarised, ranked and explained. Every number is tagged with the brief and page it came from.
What the evidence says
Seven interpretations, each backed by verbatim quotes and a confidence rating.
1g tests are not conservative
Materials can burn in orbit below the oxygen level that passes on Earth.
Airflow is the control knob
Too little flow starves the flame, a little flow feeds it, too much blows it off.
CO₂ may be weaker in microgravity than helium
The ISS extinguisher gas can radiate heat back into the fuel.
Gas is the main hazard, not heat
Saffire VI: temperature barely moved, but CO and CO₂ crossed crew limits.
Small flames can hide, then flare up
A dim blue flame on a thick, warm fuel can burn for minutes unseen.
Flames get pinned at edges — and cast an oxygen shadow
Thick fuels don't keep spreading; the upstream flame starves the ones behind it.
A flame can jump a 4.5 cm gap
Pre-heated material nearby can ignite across open space.
Top 5 most important papers
Default weights: safety 40 · realism 30 · recency 15 · data 15.
Preliminary Results from the Saffire VI Experiment
Saffire: A Novel Approach to Study of Spacecraft Fire Safety Using Un-manned Spacecraft
Results of Large-Scale Spacecraft Flammability Tests (Saffire 1 and 2)
CO₂ Suppression of PMMA Flames in Low-Gravity
Fire Safety Implications of Preliminary Results from Saffire IV and V
The evidence base
How realistic is each source?
14 of 24 sources report fires in real microgravity (Skylab, Mir, ISS, Cygnus, drop towers, parabolic flights). Ground proxies use low pressure or forced flow on Earth to imitate it.
How we score trust