re: 2001 A Space Odyssey question
2001 was filmed in 1968, 33 years before 2001. We were less than a year away from landing humans on the Moon. 33 years prior to 1968, Goddard's rockets had just broken the sound barrier, and reached heights of 1 mile.
It was not that outlandish to assume that by 2001 we'd have the large-scale space transportation and nuclear propulsion required to make the movie a reality. NERVA and other nuclear rocket programs were in development, and being tested. It was a matter of assumption in 1968 that full-scale lunar work and eventual Mars programs would be coming down the line.
Where that all went is a whole different subject.