Complex sentence: Helmut Gröttrup (12 February 1916--5 July 1981) was a German electrical engineer and assistant of Wernher von Braun in the V-2 rocket-project.
Split into simpler sentences: Helmut Gröttrup (12 February 1916--5 July 1981) was a German electrical engineer. He was an assistant of Wernher von Braun in the V-2 rocket-project.