William "Willi" Mrazek (October 20, 1911 – February 8, 1992)[2] was a German-American loads engineer[2] and member of the "von Braun rocket group."

[3] Mrazek spent some military time after graduation on the Eastern Front, where he received a saber wound to his face;[2] following his injury, he began work at Peenemünde, which continued from 1941 to 1945.

[3] In 1946, Mrazek was one of the engineers and scientists invited to the United States through Operation Paperclip, arriving with von Braun's team at Fort Bliss on April 8.

Mrazek also reported to the Saturn V Project Manager as Chief Engineer for all development and fabrication work on the rocket from 1965 to 1970.

[3] While working on the Saturn V, Mrazek and his team clashed with American aviation companies who were subcontracted on the project.