Kennedy's speech in 1962 to put a man on the Moon before the end of the decade wasn't simply a bolt out of the blue. NACA had been looking at pre-Apollo concepts before NASA was founded in1958. I believe(?) the first sketches of the Apollo Command Module (CM) were made in 1957. They were doing wind tunnel tests at Ames of the CM before 1960. It's not widely known but the CM is actually an older design than Mercury and Gemini.

Kennedy made his speech only after his advisors told him the goal was achievable. Keep in mind, when Kennedy made his speech, there was already a huge, extremely expensive infrastructure in place to develop ballistic missiles and military reentry vehicles. In the building next to mine at NASA Ames is this huge pebble heated blow-down wind tunnel that reached hypersonic Mach number. It was built in the late 1950s and was once the pride of NACA. Just about every hypersonic vehicle that ever flew was tested in it, e.g. early ballistic missile RVs, Apollo, the Space Shuttle, etc. To make a modern duplicate of this old wind tunnel would cost at least a hundred million dollars. Unfortunately it's now a wreck and full of spider webs. Reactivating these old junk heaps will require millions of dollars and years to do. Only a few people realize that we'll need to do this. Almost everyone is still mesmerized by the myth that computer simulation alone is a viable alternative to actual experimentation and flight tests. This is an evil myth propagated by bean counters because computers are much cheaper to run than actual experimental facilities.

Gary