Validating requirements for the reliability of new versions of the block-DM-type upper stages taking into account the results of the operation of prototypes

The paper presents basic provisions of the procedure for verifying quantitative requirements for the reliability of the block DM-type upper stages based on flight test results taking into account lessons learned from the operation of prototypes. The procedure is based on combining statistical data in the form of binomial statistics on the results of flight tests of the newly developed modification of the upper stage with the results of the prototype operation. The math model used to combine statistical data takes as its basis the achievable significance level of the testing criterion for the hypothesis that binomial samplings belong to one entire assembly. The paper discusses the use of a truncated sequential testing plan for statistical monitoring of the product quality in order to make a decision on the completion of the upper stage flight tests taking into account the results of the prototype operation. The use of this plan allows to reduce the number of launches needed within the framework of flight tests in order to confirm the specified requirement for the probability of faultless operation of the upper stage in flight.