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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, Space-X, 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 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