Arthur Rudolph was a German rocket engineer and member of the Nazi party who played a key role in the development of the V-2 rocket. After World War II he was brought to the United States, subsequently becoming a pioneer of the United States space program. He worked for the U.S. Army and NASA where he managed the development of the Pershing missile and the Saturn rocket. In 1984 he was investigated for possible war crimes, and he agreed to leave the United States and renounce his US citizenship.