Obviously this is a fairly broad question, as I'm sure that conclusion wasn't reached at one moment, but what are some noteworthy occurrences of people not just looking into space, but really understanding that we could GO there? Its a surprisingly difficult question to google and get a focused answer.
hi! not discouraging other contributions on this topic, but you can get started on these earlier posts
development of Astronautics
What do people from past centuries say about man ever walking on the moon? - a link to a comment on Lucien; myths; 17th c Bernard Le Bovier de Fontenelle & John Wilkins
At what point in time did we realize that exploration of space could be a real possibility? How much did we actually know about space before actually being able to go there physically or sending a probe? What was the very first thing sent into space? - 13th c Zakariya al-Qazwini; 1752 Voltaire; mid-late 19th c scifi & science
Before Americans sent a man to the moon in 1969, what did people believe was on the moon? Did they believe it was inhabited by anything? Did they believe the composition of the moon was different (e.g. moon made of cheese)? - 19th/20th c scifi & science
in 1924 if you mentioned to someone (someone from the Anglo sphere) the words either “spaceship” or “space- alien” do you think it's likely (more than 50-50) that you would have had to explain the concept to them before going on? - 19th/20th c scifi & science
related topics of possible tangential interest
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