Role of Fault Tree Analysis in Risk Management of Launch Vehicle
- Paper number
IAC-05-D5.2.03
- Author
Ms. K. Santhamma, Indian Space Research Organisation (ISRO), VSSC, India
- Year
2005
- Abstract
Launch vehicle programme always poses safety implications from lift off till orbital injection. Prior to the launching of a missile or space booster, an assessment is normally required to be made on the in-flight hazards posed to life and property. The hazards can be caused by the unplanned deviation of the stage during flight / debris, resulting in instantaneous impact points (IIP), to fall over landmass / other facilities like oil wells etc. Risk is an expression of the probability of a mishap in terms of hazard probability and hazard severity. Analysis of risk implies identification of undesirable events, which could lead to materialization of hazards, analysis of the mechanisms leading to the undesirable events, estimation of undesirable consequences and frequencies with which they could happen. This paper describes the role of Fault Tree Analysis (FTA) to arrive at a quantitative measure of hazard probability with the help of a case study, where impact on land is taken as a mishap. For a qualitative measure, hazard severity can be categorized as catastrophic, critical, marginal or negligible. To have a quantitative measure of hazard severity, a measure based on the casualty area and density of the population of Landmass is adopted. The results of risk analysis are used in the risk management, allowing the comparison of estimated risk levels with those set as objectives in a particular activity (acceptable level). This helps in setting priorities for risk reduction strategies. The resulting risk estimates also indicates location of high risk areas and the overall level of hazards. This may result in a revised trajectory or a change in the vehicle configuration and /or partial or full evacuation from the high risk locations. A case study considered in this paper shows the usefulness of FTA in pinpointing the events where more stress can be given to reduce the possibility of occurrence of a failure by introducing severe tests and quality control measures.
- Abstract document