Ballistic Performance Assessment Is a Must for Shelf Life Assessment of Rocket Motors

In the course of rocket motor service life assessment number of different propellants of a certain rocket motor have been examined and analyzed. This paper describes the testing, collects together the results from a number of naturally aged propellant charges to enable reasonable life predictions to be made. The Investigations have been carried out with double based rocket propellants with a view to obtaining predictive data for safe use life of the rocket motors containing these propellants. The examination and analysis procedure, chemically, mechanically and ballistically for accelerated aged propellant charges has been devised to give a comprehensive picture of the future properties of the propellant charge. The chemical and mechanical safe lives of all propellants examined, when stored under normal conditions is more than adequate to meet any sensible requirement. The results for this investigation indicate that a safe life in excess of 30 years is to be expected. The ballistic properties have been thoroughly determined over a temperature range of (-20°, +20°, +50°C) for both test and whole rocket motors. All that can be said is that although the chemical and mechanical properties of these propellant charges are not significantly changing with age and factors connected with them are unlikely to prove life terminating, ballistic properties testing on the other hand is prove life terminating. Taking into consideration this mode of failure, it is evident that the rocket motors under this investigation could have the existing service life of 20-30 years extended subject to satisfactory ballistic properties. The new data increases the confidence that most of the rocket motors will achieve an extended service life, others have to be subjected to periodic investigations.