Michael Jason Shaw is given the perilous assignment to masquerade as an SS officer in order to infiltrate the German military, stop production of the V-5 rocket, and prevent a Nazi scheme, the Omega Deception, to cripple the United States. Original.
I had such a hard time following the time and the people and than he added people for just a chapter and never heard from them again because they only did one thing for the story line.
An interesting detail viewpoint from an inside the SS undercover operative in Peenemunde and on a German sub. The author couldn't separate the function of theology, so this became a theological inspiration hung on a pretty intriguing WWII suspense story. I don't remember and didn't research whether stainless steel and sarin gas had been developed for use by late 1942.