Figure 6

The measured flame-spread rate under various opposed flow velocity under (a) microgravity (μg) space station, \({X}_{{{\rm{O}}}_{2}}\) = 18.2% (Sample B16, 0.64 cm) and \({X}_{{{\rm{O}}}_{2}}\) = 17.5% (Sample B19, 0.64 cm), and (b) normal-gravity (1 g) Earth (1.27 cm) where flame cannot be sustained at \({X}_{{{\rm{O}}}_{2}}\) < 18.5%. Note that the scales of x axes in (a) and (b) are different.