Twelve astronauts have walked on the moon during NASA's Apollo program: Neil Armstrong, Buzz Aldrin (Apollo 11); Pete Conrad, Alan Bean (Apollo 12); Alan Shepard, Edgar Mitchell (Apollo 14); David Scott, James Irwin (Apollo 15); John Young, Charles Duke (Apollo 16); and Eugene Cernan, Harrison Schmitt (Apollo 17). All manned moon landings occurred between 1969 and 1972. No humans have returned to the moon since Apollo 17 in December 1972.