Reliability products for Space Launch Vehicle safety assessments

United Launch Alliance (ULA) launches Atlas V and Delta IV Space Launch Vehicles from Cape Canaveral and Vandenberg Air Force launch facilities. Air Force Range Safety office approval to launch is based on compliance to Range Safety regulations and review of reliability and safety assessments. There are specific reliability requirements for Flight Safety Systems. The airborne Flight Termination System (FTS) has a reliability goal of a minimum of 0.999 at the 95 percent confidence level. The Airborne Range Tracking System (RTS) reliability requires a minimum of 0.995 at the 95 percent confidence level for transponder systems and 0.999 at the 95 percent confidence level for global positioning systems. Ordnance barriers used for safety devices are required to demonstrate a reliability of 0.999 at the 95 percent confidence level to prevent inadvertent initiation of the receptor ordnance. Use of MIL-HDBK-217 and statistical testing methods are prescribed to arrive at the reliability of safety critical components. ULA performs component and system level reliability assessments and subcontractors are required to perform FMEA and FMECA to assess the reliability of their products at box level. Piece parts reliability at the component level is required for safety critical items. Federal Aviation Administration requires similar assessments for commercial launches. This paper discusses the importance of some of these requirements, the reliability products and their use to develop safety assessments.