In 1962, NASA engineers fought over nuclear, chemical, and electric propulsion....

https://dlf-ne.org/is-nuclear-propulsion-worth-it-just-to-shave-time-to-mars/

In 1962, NASA engineers fought over nuclear, chemical, and electric propulsion. It was a masterclass in professional stubbornness. I’ve sifted through the memos where 18 Nobel laureates argued about leaving Earth