Fire is a very serious threat in any confined volume but particularly so when a crew is confined in a spacecraft far from Earth, where there is little or no possibility of receiving aid or being rescued. Therefore, every measure must be taken to prevent a fire from happening. Even with material controls and other fire prevention measures, fire detection, suppression, and clean-up systems must be provided on spacecraft to allow the crew to respond to a fire. Unlike flames in normal gravity, fires in low gravity are not supported by the strong pumping of oxidizer and fuel into the flame zone and the subsequent pumping of the reactants out of the reaction zone. The lack of buoyancy allows a flame to propagate at lower air velocities than on Earth that changes the transport of oxygen into the flame, heat transfer to the fuel surface, and transport of heat out of the reaction zone. Under these conditions, the flame spread can occur at conditions and with characteristics that are not duplicated readily in normal gravity because of the large buoyant flows generated by the flame. Differences in flame characteristics also impact requirements for fire detection and suppression of spacecraft fires. Of course, any fire response protocol must be compatible with the other spacecraft systems such as the Environmental Control and Life Support System (ECLSS).