Three astronauts instrumental in the groundbreaking U.S. space program of the 1960s and 70s gathered at the Paris Air Show on Tuesday to celebrate the 50th anniversary of Apollo 11, the mission that first put a man on the moon.

Walter Cunningham, 87, who was part of the Apollo 7 mission, Al Worden, 87, who flew with Apollo 15, and Charlie Duke, 83, who walked on the moon with Apollo 16, recounted their extra-terrestrial experiences before a captive airshow audience.

Worden, who orbited the moon alone for days in 1971, holds the feat of having been the world's most isolated human, while Cunningham is notable for being part of a team that talked back to Mission Control in 1968, getting them blacklisted from future flights.