If you're looking for programs where mistakes were not made, Apollo is not the program to choose. I highly recommend visiting Kennedy Space Center some time where they go in-depth on how close it came to never happening after Apollo I. https://en.wikipedia.org/wiki/Apollo_1

That being said, I'm a big proponent of "you can't make ICBM's carrying humans 100% safe", but you sure can try your best.

Apollo killed three astronauts. NASA learned some lessons from that and the rest of the program was safer, although still extremely risky.