Even 45 years later, Buzz Aldrin has detailed memories of the Apollo 11 mission, when he became the second man to set foot on the moon.
Dishing about the moment he saw an "unidentified" object floating outside his Apollo capsule, Aldrin wrote:
On Apollo 11 en route to the Moon, I observed a light out the window that appeared to be moving alongside us. There were many explanations of what that could be, other than another spacecraft from another country or another world -- it was either the rocket we had separated from, or the 4 panels that moved away when we extracted the lander from the rocket and we were nose to nose with the two spacecraft. So in the close vicinity, moving away, were 4 panels. And I feel absolutely convinced that we were looking at the sun reflected off of one of these panels. Which one? I don't know. So technically, the definition could be "unidentified."
Aldrin first recounted his UFO anecdote during a Science Channel program in 2005. At the time, UFO enthusiasts were apparently upset that Aldrin had not shared the information sooner.
During his Reddit AMA, Aldrin also took time to proclaim his hope that humans will travel to Mars in the near future.
"There is very little doubt, in my mind, that ... the next monumental achievement of humanity will be the first landing by an Earthling, a human being, on the planet Mars," Aldrin wrote, adding that he expects an international team to establish a presence on the red planet.
Aldrin added that a "collection of the best" individuals from around the world should land on Mars and establish a permanent settlement, rather than representatives of a private company with an eye on space tourism -- such as Elon Musk's SpaceX.
I have considered whether a landing on Mars could be done by the private sector. It conflicts with my very strong idea, concept, conviction, that the first human beings to land on Mars should not come back to Earth. They should be the beginning of a build-up of a colony / settlement, I call it a "permanence." A settlement you can visit once or twice, come back, and then decide you want to settle. Same with a colony. But you want it to be permanent from the get-go, from the very first.
Should NASA send astronauts back to the moon? Aldrin said that's probably not the best use of resources. Instead, he said, the U.S. should direct its focus further into space and establish colonies and labs on Mars.
Read Aldrin's full discussion -- including his favorite space-related movie and his scariest moment in space -- on Reddit.