The Saturn II was a series of proposed American Expendable launch vehicles, proposed by North American Aviation in 1966, derived from the Saturn V rocket that was used for the Apollo lunar program. There was a large payload gap between the Saturn IB's 19,000 kg low-earth orbit capacity and the two-stage Saturn V's 100,000 kg capability. In the mid-1960s NASA's Marshall Space Flight Center initiated several studies to extend the capabilities of the Saturn family. The studies examined a number of Modified Launch Vehicle configurations based on the Saturn IB and Saturn V launch vehicles as well as Intermediate Payload launch vehicles based on modified Saturn stages. Martin Marietta, Boeing and North American were three of the companies that provided responses. North American considered the best way to fill the gap was to use the Saturn V's second stage, the S-II, as the first stage of an intermediate launch vehicle. The basic concept of the Saturn II was to save money by ceasing production of the Saturn IB rocket, and replacing it with launch vehicles built entirely with current Saturn V components. This would allow closing down production lines for the S-IB first stage, and would allow for more efficient integration of rocket systems. It would have replaced the Saturn IB, which had a maximum payload capability of 46,000 pounds, for launching spacecraft into low Earth orbit. Wikipedia [ - ]

The Saturn II was a series of proposed American Expendable launch vehicles, proposed by North... [ + ]