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Bayesian Launch Vehicle Reliability

May 4, 2009


This brief analysis has been assembled to see what the effect would be on U.S launcher success record/standings relative to the rest of the world after the Shuttle and the Delta II systems are retired. This is a record of successfully attaining orbit, not spacecraft reliability once on orbit. The Bayesian "Probability of Success" or "p.o.s". is k(lv) +1/n(lv) +2 (see attached table), so that the risk of a launcher without much of a track record is accounted for and a launcher with, say, and 0 and 1 record, isn’t given a zero probability of success.


The original data used for the analysis is credited to Ed Kyle and his Space Launch Report and reliability statistics.


For further information contact Carey McCleskey at NASA Kennedy Space Center.



The table below shows the source data used to yield the prior bar-graph.



The result of removing the Shuttle and the Delta II from the data is as follows - the shift being from U.S. Composite at 0.9543 (realized success rate) to U.S. Composite at 0.8554, as compared to Foreign Composite Realized Success Rate of 0.9465.



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Website Contact: Edgar Zapata, NASA Kennedy Space Center