As you may well expect, this vehicle has quite a story to tell.
While most people associate the Saturn launch vehicles with the Apollo program, the Saturns actually started development in 1956 as a productive way to occupy Werner Von Braun’s team at the Army Ballistic Missile Agency (now the Marshal Space Flight Center) after the authority to develop new ballistic missiles was stripped from them. Von Braun and the ABMA’s commander, General Medaris, decided that a worthy and worthwhile challenge was to develop a launch vehicle that could take heavy loads to low Earth orbit.
To save development cost, the first stage of the Saturn I (and subsequent Saturn IB) was built from a cluster of 8 70″ diameter tanks built with Redstone tooling surrounding a single 105″ diameter tank built with Jupiter tooling. This arrangement was cost effective, but led to the joke nickname of “Cluster’s Last Stand” for both the Saturn I and IB. The Saturn I only saw flight a few times, while its upgraded variant (with a more powerful second stage) the IB was folded into the Apollo program, and wound up being a workhorse from 1962 well into the 1970s. Its S-IVB second stage was also the third stage of the Saturn V rocket — easing the use of the Saturn IB as a testbed for the Apollo spacecraft and lunar module (as they in this way had the same launch vehicle interface for both launchers).
Ultimately, twelve complete Saturn 1Bs and parts of two others were built, although only nine of them flew. Five Saturn 1Bs supported the Apollo program, three lofted crews to the Skylab space station, and one flew the ASTP Apollo spacecraft to its international rendezvous in Earth orbit.
This vehicle on display at KSC is Saturn 1B serial number SA-209. It was kept in readiness to launch a rescue crew for all the Skylab missions, as well as for the ASTP mission. It also would have been used for a potential Skylab 5 mission, to re-boost the space stations orbit. Not having seen use in any of those scenarios, it was retired to its current display spot in the KSC Rocket Garden.