ABSTRAKT

In a search for new storable high performance propellants for the European Space Agency (ESA), the solid oxidizer Hydrazinium Nitroformate (HNF) was identified as a very promising ingredient for a new storable composite propellant, currently in its development phase. Two distinct advantages of HNF based propellants over presently used Ammonium Perchlorate (AP) based propellants were the basis of this promise: a very high specific impulse which dramatically increases the performance of the solid propellant and chlorine free exhaust products which prevent the formation of HCl in the environment.
Modern solid rocket motors are generally based on AP in a hydroxy-terminated polybutadiene (HTPB) binder system. Replacement of the AP with HNF will, as indicated above, result in performance gains, chlorine free exhaust products, and a reduced smoke trail; whereas it represents a relatively small change in composite propellant production (all existing knowledge and production infrastructure for HTPB based systems can be kept in place). Early investigations in the USA, during the 1960s, seemed to indicate that HNF could not be combined with HTPB. However, recent studies performed at TNO Prins Maurits Laboratory show that acceptable propellants can be produced using this combination. A summary of the results obtained with HNF/HTPB formulations will be presented.