All stages of Missiles and lower stages of Launch vehicles use Solid Rocket Propulsion system to impart velocity to the vehicle so that they can deliver the payload. Solid rocket motor consists of Motor case, insulation, liners, propellant grain, Ignition devices, igniters, seals (gaskets/‘o’-rings) and Nozzle system. The minimum service life requirement of any solid rocket motor is 10 years after casting of the propellant and/or after assembly of the rocket motor. Before the actual use of any missile, the rocket motor is subjected to different environmental conditions (temperature, oxygen etc) and vibrations during storage and transportation. The thermal expansion mismatches between the metallic case and the elastomeric propellant due to processing temperatures and diurnal and seasonal temperature variations causes thermal stresses at the interfaces as well as within the propellant itself. Ageing of propellant in rocket motors refers to their deterioration in physical, mechanical and ballistic properties with time. This is caused by the cumulative damage done to the grain. It can also caused by chemical changes with time, such as gradual depletion of certain liquid plasticizers or moisture absorption. The ability to carry stress or to allow elongation in propellant diminishes with cumulative damage. The aging limit is the estimated time when the motor is no longer able to perform its operation reliably or safely. The service life of the motor is not only dictated by the life of propellant but also by the interfaces in the rocket motor. Any debonds at the interfaces would increase the available burn surface area there by increasing the operating pressure beyond design pressure. The interfaces are not same at different locations of the large solid rocket motors. The present research focuses on service life prediction of large solid rocket motors by identifying critical locations of the rocket motor using finite element analysis, parametric study of different propellant compositions, liner and the interfaces through accelerated ageing studies and development of damage model from the test data.