A childhood belief about tv shows

The TV show "I Dream of Jeannie" featured Larry Hagman in the lead role of "Major Nelson," an astronaut. The show made such an impression upon me that I thought Major Nelson was a real astronaut that the show was based on. When I asked my father how many times Major Nelson went to the moon, he explained to me that he was just an imaginary character and didn't really exist. But to me "Nelson" sounded so much like a real astronaut's name, that I found it hard to believe. I later got a book out of the library about astronauts and searched all throughout it for any sign of a Nelson. Of course, I never found one. But I wonder--if one of those Apollo astronauts had the last name Nelson, would I have been convinced for a good while longer that Major Nelson was indeed a real astronaut? Hmmmm...