Famed astronaut Buzz Aldrin visited SPACE.com on July 14 to discuss his role in NASA's historic Apollo 11 moon landing in 1969.

Aldrin is the second person ever to set foot on the moon, following Neil Armstrong (who died in 2012) onto the lunar surface on July 20, 1969. On Monday — just six days before this historic event's 45th anniversary — Aldrin participated in a live Google Hangout with SPACE.com, discussing his experiences as an astronaut, the future of lunar exploration and other topics.

The three-person Apollo 11 mission blasted off from Florida's Kennedy Space Center on July 16, 1969. Four days later, the lunar module carrying Armstrong and Aldrin touched down on the moon, while fellow crewmember Michael Collins stayed in the command module in lunar orbit.

Armstrong uttered one of the most famous sentences in human history as his foot hit the gray dirt — "That's one small step for [a] man, one giant leap for mankind." He and Aldrin spent more than 21 hours roaming about the lunar surface before heading back to the command module. The three astronauts returned to a hero's welcome on Earth on July 24, 1969.

Five more manned NASA missions touched down on the moon, with the last coming in December 1972. A total of 12 people have walked on the moon.

On July 8, Aldrin started a campaign to celebrate Apollo 11's 45th anniversary, asking people around the world to share their memories of the mission and what it meant to them. ("The whole world celebrated our moon landing, but we missed the whole thing because we were out of town," he explained in a video introducing the project, which is called Apollo 45.)

A number of high-profile people have contributed their thoughts to the Apollo 45 project, including actors Jared Leto and Tim Allen, musician Pharrell Williams and astrophysicist and science popularizer Neil deGrasse Tyson. To learn more about the initiative, visit its YouTube page.

Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebook or Google+. Originally published on SPACE.com.

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This story was originally written for SPACE.com and was republished with permission here. Copyright 2014 SPACE.com, a TechMediaNetwork company.