The launch of the SA-5 on January 29, 1964 was the fifth Saturn I launch vehicle. The SA-5 marked a number of firsts in the Marshall Space Flight Center-managed Saturn development program, including the first flight of Saturn I Block II vehicle with eight aerodynamic fins at the bottom of the S-I stage (first stage) for enhanced stability in flight. This also was the first flight of a live S-IV (second or upper) stage with the cluster of six liquid hydrogen-fueled RL-10 engines. the first successful second stage separation, and the first use of the Launch Complex 37.