The successful Ariane 5 ECA launch on 29 August 2013 carrying Eutelsat 25B/Es’hail 1 commercial communications satellite and the Indian Navy’s Gsat -7 communications satellite marked the 57th continuous Ariane 5 launch success in its current successful run.
Commercial satellite operators and their insurers are actually much more impressed by a good recent reliability record for commercial launch vehicles rather than one from the past. Thus, while the very reliable Soyuz (which Arianespace also now operates) still holds the outright record of continuous launch successes at 100 flights flown in the 1980s (see table below), in fact, with its current run of 57 good flights, the Ariane 5 can be said to be the “Reliability King” of commercially offered launch vehicles.
Of the other contenders Russian/Ukrainian rockets (e.g. Proton, Zenit etc) have shown weaknesses with quality control which has prevented them reaching the “Nirvana” state of near perfect reliabilty that most Western launch vehicles eventually achieve after a few initial flight failures. As a result of this trend difference, the Russian government and its Roscosmos space agency are now taking active steps to improve Russian rocket reliability.
Comment by David Todd: The Flightglobal/Ascend space analyst team actually identified ...