Apollo AS-203

Apollo AS-203 was NASA’s second uncrewed Saturn IB flight and an orbital test of the S-IVB stage and instrument unit. Launched July 5, 1966, without an Apollo spacecraft, it used an aerodynamic nose cone to study supercold liquid-hydrogen behavior, pressure and slosh in weightlessness, restart conditions for the Saturn V upper stage, and related fuel-cell experiments; the six-and-a-half-hour mission met its objectives.