I don't recall that quip, but I do recall an episode of "Space 1999" decades ago titled "The Catacombs of the Moon" where they discover a vast underground cave

I don't recall that quip, but I do recall an episode of "Space 1999" decades ago titled "The Catacombs of the Moon" where they discover a vast underground cave system, (which turns out to be the hibernation place for a civilisation of aliens, IIRC)... The episode always had me intrigued as to whether the moon actually could have a large cave system that could be hermetically sealed and inhabited by humans to save on shipping tons of building materials out there.