I thought the Saturn V rocket was designed by a German
Yes, although by the 1960s when he was working on the Saturn project, Wehrner von Braun may have regarded himself as a first-generation American, having emigrated there in 1946. After all, the vast majority of Americans today are the descendants of immigrants during the last couple of centuries.
In case anyone here has not looked at the specification and performance of the Saturn V, it is truly astonishing - still the most powerful vehicle ever created:
https://en.wikipedia.org/wiki/Saturn_V