Back in 1962, NASA engineers fought over whether to trust nuclear or chemical...

https://delta-wiki.win/index.php/The_Architectural_Burden:_Choosing_Between_One_Big_Ship_and_Modular_Assembly

Back in 1962, NASA engineers fought over whether to trust nuclear or chemical engines for the Moon. The public saw a seamless mission, but these memos reveal a mess of bruised egos and real technical fear