In space, a fire’s flame burns equally in all directions creating a burning globe rather than a flickering flame.
This occurs because fire experiences zero gravity in space! On Earth, as a fire consumes oxygen, the hotter air rises because it weighs less, and the cooler heavier air sinks. In space, there’s no such thing as lighter or heavier air. Thus, the heated air around the fire moves uniformly in all directions causing the fire to grow spherically (and to burn slowly).
Sugar, Glenn. “Fire in Space Explanation.” Message to the author. 26 July 2016. Text message.