Here is what a small flame looks like in micro-gravity, such as you would experience on the International Space Station.
A flame in normal gravity is shown on the left, and one in micro-gravity on the right. In micro-gravity hot air does not rise like it does on earth and tends to produce more round and cooler flames.
I am pretty sure that there is no option in the BehavePlus fire behavior modeling program that allows the user to toggle gravity on and off.
