Statistical reliability estimation of space launch vehicles: 2000–2022

Abstract

This research examines the reliability of space launch vehicles (SLVs) performing commercial, civil, and military space lift missions through trend analysis and a variety of statistical methods. Data sets obtained from the Seradata database are analyzed for trends by examining data subsets including launch date, sector (commercial, civil or military), launch country, intended mission orbit, SLV family, and failed subsystem. Evolving, time-dependent first-level Bayesian success rate analysis is performed to assess SLV reliability and performance trends on 1873 launches occurring during the period 1 January 2000 to 31 December 2022. It was determined that even with a near-exponential increase in launch events in the 2020s, the number of failures is less than 6% each year, with the average success rate being 95% annually. Overall, 56% of launches were sent into low Earth orbit (LEO) and 32% were sent into geosynchronous Earth orbit (GEO) or geostationary Earth orbit (GSO). Although SLVs servicing missions to these orbital regimes featured success rates above 92%, LEO launches accounted for approximately 73% of total launch failures, while GEO-GSO launches accounted for 18% of failures. Specifically looking at U.S. and Russian SLV families, the main subsystem responsible for failure was propulsion, which accounted for 72.3% of 47 reported launch failures. First-level and second-level (using method of moments) Bayesian techniques were performed on 37 launch vehicle families and it was found that vehicles with a high accrual of launches performed with a higher reliability than vehicles with a low number of launches, resulting in first-level success rates of greater than 90%.