Earth Day may fall later this week, but as far as former NASA astronaut Edgar Mitchell and other UFO enthusiasts are concerned, the real story is happening elsewhere.

Mitchell, who was part of the 1971 Apollo 14 moon mission, asserted Monday that extraterrestrial life exists, and that the truth is being concealed by the U.S. and other governments.

He delivered his remarks during an appearance at the National Press Club following the conclusion of the fifth annual X-Conference, a meeting of UFO activists and researchers studying the possibility of alien life forms.

Mankind has long wondered if we’re “alone in the universe. (But) only in our period do we really have evidence. No, we’re not alone,” Mitchell said.

“Our destiny, in my opinion, and we might as well get started with it, is (to) become a part of the planetary community. … We should be ready to reach out beyond our planet and beyond our solar system to find out what is really going on out there.”

Mitchell grew up in Roswell, New Mexico, which some UFO believers maintain was the site of an alleged UFO crash in 1947.