The 1960 Wehrner von Braun biopic I Aim for the Stars has a credit for a “Maj. Paul F. Mertz” as a technical advisor. So far, I haven’t been able to turn up any biographical info on him. Possibly he’s still alive, but possibly not. I haven’t been able to find his name associated with anything concerning US rocket development–or anything else.
He was described as “ret.”, i.e., retired, in 1960 (according to the Internet Movie Database), so there would be a strong likelihood that he is now dead.
The Paul Mertz that you are inquiring about died May 12, 1997. He was born June 17, 1918 in St Paul Minnesota. His father was Michael J Mertz (d. 1954) and mother was Wilhelmina T (Geering) Mertz (d. 1980). He had two brothers (John, William) and three sisters (Margaret, MaryJane and Elizabeth). All siblings except for one sister have died. He had been stationed at White Sands Missile Base in the Signal Corp at the time. That’s the “S.C” in Paul F. Mertz, Maj. USA (S.C.).