KSC Next Gen Site ___Questions? Comments? Launch Vehicle Reliability 

May 4, 2009 Keywords: Launch Vehicle Reliability, Launch, Launcher, Dependable, Dependability, Reliable, Reliability, Success, Failure, Rate, Demonstrated, Predicted, Shuttle, Delta, Atlas, Soyuz, Falcon, SpaceX, Probability 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, minus the graph/sorting, and the subtraction effect/analysis is credited to Ed Kyle and his Space Launch Report and reliability statistics. The table below shows the source data used to yield the prior bargraph. 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.
_____________________ Also see: _____________________ Website Contact: Edgar Zapata, NASA Kennedy Space Center 
