Tags: Rocket.
Studied in 1968 by Marshall Space Flight Center the Saturn V-B was considered an interesting vehicle concept because it nearly represents a single-stage to orbit booster but is actually a stage and a half booster just like the Atlas. The booster would achieve liftoff via five regular F-1 engines; four of the five engines on the Saturn V-B would be jettisoned and could be fully recoverable with the sustainer stage on the rocket continuing the flight into orbit.