AS-203

AS-203 (or SA-203) was an unmanned flight of the Saturn IB rocket on July 5, 1966. It carried no Apollo Command/Service Module spacecraft, as its purpose was to verify the design of the S-IVB rocket stage restart capability that would later be used in the Apollo program to boost astronauts from Earth orbit to a trajectory towards the Moon. It successfully achieved its objectives, but the stage was inadvertently destroyed after four orbits.