Milton William Rosen (July 25, 1915 – December 30, 2014) was a United States Navy engineer and project manager in the US space program between the end of World War II and the early days of the Apollo Program. He led development of the Viking and Vanguard rockets, and was influential in the critical decisions early in NASA's history that led to the definition of the Saturn rockets, which were central to the eventual success of the American Moon landing program. He died of prostate cancer in 2014.