In all human history, only a dozen men have walked on the moon - one of them is Dr Edgar Mitchell.
He holds a doctorate in aeronautics and the record for the longest moon walk - nine hours out on the surface of the moon.
In short, he was one of NASA's star astronauts.
He believes that life does exist elsewhere in the universe, and that on at least one occasion, it has come to visit us here.
Namely, he is talking about the alien visitation in Roswell in 1947 - emphatically dismissed by NASA, the US military and the US government.
Campbell Live spoke to Dr Edgar Mitchell and asked him if we are really alone.