An American astronaut. On July 20, 1969, Buzz Aldrin became the second person on the moon, after Neil Armstrong, on Apollo 11. Aldrin arrived on the moon 15 minutes after Armstrong. Once on the moon, Armstrong and Aldrin set up seismic, solar wind and laser-ranging experiments, collected samples and took photographs. They conducted a short telephone conversation with President Nixon, and they unveiled a plaque on one of the legs of the lunar module celebrating Apollo’s achievement for all mankind.