Watched a ‘Making of’ documentary about it. Patricia Neal was interviewed about it, Michael Rennie had died years earlier.
She said they, her and Michael, thought the script was the most ridiculous thing they ever read! The director was angry because they were laughing so much, they had to do retakes on every scene multiple times.
Sci-Fi was looked down upon by ‘regular’ actors as being low-brow work................
Interesting. Thanks.