Some of the design concepts used in the Atlas ICBM have been refined and utilized in the high-energy upper stage Centaur vehicle. In addition, development of the Centaur vehicle required significant advances in cryogenic technology Although the Atlas/Centaur vehicle development required many advancements in technology, most of the present operational techniques have much in common with other launch vehicles. A brief description of the configuration and checkout will be given. The unique design features of the Atlas/Centaur launch vehicle will be reviewed, and their impact on handling, checkout, and launch operation will be examined in this paper.The continuous advancements in technology in the Atlas/Centaur Program imposed stringent requirements on the test and data management systems. A Unified Test Plan, while eliminating superfluous testing, ensures a comprehensive analysis of the performance of every element of the system. The data management system ensures that all available data are current and readily retrievable at any point in the test cycle. A brief review of these systems and their effectiveness will be given.Launch frequencies for the Atlas/Centaur have varied from simultaneous operations on both launch pads to extended downtimes. This has required considerable flexibility in management planning to minimize launch crew size and attendant launch costs. The manning level required to maintain the facilities and conduct the checkout and launch operations will be discussed.