What program was Wernher von Braun credited with inventing and did Helmut Gröttrup help in managing? 
Helmut Gröttrup:  He was a manager for Wernher von Braun in the V-2 rocket program. Wernher von Braun: Wernher Magnus Maximilian Freiherr von Braun (March 23, 1912 – June 16, 1977) was a German, later American, aerospace engineer and space architect credited with inventing the V-2 rocket for Nazi Germany and the Saturn V for the United States.
V-2 rocket program