Studied in 1959, the Saturn B-1 was a four-stage concept rocket similar to the Jupiter-C, and consisted of a Saturn IB first stage (powered by eight Rocketdyne H1-b engines), a cluster of four Titan I first stages used for a second stage (equivalent to four LR-89-5 engines), a S-IV third stage (with six RL10 engines) and a Centaur high-energy liquid-fueled fourth stage (with two RL10A-1 engines).
Like its proposed predecessors, the Saturn B-1 never flew and neither did the Titan cluster stage. The S-IV stage however flew on the Saturn I.
See also List of space launch system designs
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