Buzz Aldrin talks about the 'UFO' which the Apollo 11 crew saw on their way to the moon. He explains why they didn't describe it explicitly to Houston: "...those transmissions would be heard by all sorts of people and who knows what somebody would've demanded - we turn back because of aliens, or whatever the reason is."
Dr David Baker, senior Apollo scientist: "The possibility that you might encounter aliens in space has to be considered in a very sensible and positive and realistic way; there were a lot of people within the program who went off later and became convinced that UFOs existed."