Hybrid Propulsion is an attractive alternative to conventional liquid and solid rocket engines. This is an active area of research and technological developments. The potential wide application of the hybrid engines opens the possibility for safer and more flexible space vehicle launching and manoeuvring. The fundamental combustion issues related to further development of hybrid rockets are discussed in the present paper. The emphasis is made on the properties of the potential polymeric fuels and their modification. The fundamentals of polymeric fuel combustion and the flammability Characteristics are discussed
