Spacecraft Fire: Flame-Ball Stability Map (2D)

A purely 2D companion to the 3D microgravity flame simulator: instead of rendering the flame as a 3D particle shell, this model solves the same diffusion-limited combustion balance directly and draws the raw solution as two linked 2D views. The left panel is a radial cross-section through the flame sheet — fuel concentration falling, oxidizer concentration rising, and temperature peaking exactly where they cross, the same profile shape NASA's FLEX and SoFIE experiments measured aboard the ISS. The right panel is a live fuel-supply-vs-cabin-oxygen flammability map, plotting your current settings against the shaded region where a diffusion-limited flame ball can actually sustain itself. Tune fuel vapor supply, cabin O₂ concentration and ambient pressure to watch the Damköhler number cross the critical threshold in real time — and see exactly why a flame that looks stable can silently drift toward self-extinction, or toward a hazardous oxygen-enriched regime, without any change in gravity at all.