Combining computational-simulations with probabilistic-risk-assessment techniques to analyze launch vehicles

To assess the overall cost of a launch system the potential losses which may be incurred due to catastrophic failure should also be considered along with the manufacturing and operational costs. The potential for catastrophic failure may be determined by performing a probabilistic risk assessment. Launch vehicles operate under highly transient conditions. In addition, the complex nature of launch systems makes the task of determining the probability of failure responses and consequences, with any reasonable certainty, practically impossible. Launch vehicle dynamics may be studied by the use of computational methods, offering a solution for assessing failure responses. However, the deterministic nature of these methods makes their use incompatible with probabilistic risk assessment. This paper discusses a solution to this dilemma. A semi-deterministic methodology is proposed which combines these two technologies, computational simulation and probabilistic risk assessment, in a synergistic fashion. A matrix based interfacing mechanism was developed which allows information to be transferred from one analysis structure to the other. Although software may be developed to facilitate the transfer process, the methodology may be applied without having to modify any of the existing resources. As computer-based designing and testing becomes the rule and not the exception, this method may offer engineers the capability to integrate risk considerations directly into the design process. Assessing risk during the design phase has the potential of substantially reducing safety related maintenance costs.