The Juno V series of rockets were a design that was proposed in the late 1950s but cancelled. The rockets were multi-stage and, although they failed to reach production, their sections were used in other designs.

Juno V-A

Juno V-A was studied in 1958, as a new name for the Super-Jupiter rocket. The only difference was that the rocket's first stage would not have 4 E-1 engines, which were developed in 1957, but were cancelled and paved the way for the F-1

F-1 (rocket engine)

The F-1 is a rocket engine developed by Rocketdyne and used in the Saturn V. Five F-1 engines were used in the S-IC first stage of each Saturn V, which served as the main launch vehicle in the Apollo program. The F-1 is still the most powerful single-chamber liquid-fueled rocket engine ever...

 engine, which was used on the Saturn V rocket which took men to the moon

Moon

The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

. Instead, the Juno V-A would use the first stage of a Saturn I

Saturn I

The Saturn I was the United States' first heavy-lift dedicated space launcher, a rocket designed specifically to launch large payloads into low Earth orbit. Most of the rocket's power came from a clustered lower stage consisting of tanks taken from older rocket designs and strapped together to make...

 launcher to propel it into space and a whole Titan I

Titan I

The Martin Marietta SM-68A/HGM-25A Titan I was the United States' first multistage ICBM . Incorporating the latest design technology when designed and manufactured, the Titan I provided an additional nuclear deterrent to complement the U.S. Air Force's SM-65 Atlas missile...

 ICBM to continue the journey. Juno V-A was never developed, but all its stages were used on different launch vehicles, now retired as of today.

Juno V-B

Juno V-B, studied in the same year as Juno V-A, was proposed for lunar and interplanetary missions into space. It was just like the Juno V-A, except the third stage, originally the second stage of a Titan I booster, would be replaced with a Centaur C

Centaur (rocket stage)

Centaur is a rocket stage designed for use as the upper stage of space launch vehicles. Centaur boosts its satellite payload to geosynchronous orbit or, in the case of an interplanetary space probe, to or near to escape velocity...

 high-energy third stage. A year after Juno V-B's study, the booster received a new name: the Saturn A-1

Saturn A-1

Saturn A-1, studied in 1959, was projected to be the first version of Saturn I and was to be used if necessary before the S-IV liquid hydrogen second stage became available...

, which, like the Juno series of rockets was never built, but all its stages used on different launch vehicles, now retired as of today.