A member of the first team to set foot on the moon, astronaut Buzz Aldrin is a staunch advocate of space exploration who once publicly punched a man who claimed the lunar landings were a hoax.

"Beautiful, beautiful. Magnificent desolation," he said as he became the second person -- just minutes after Apollo 11 commander Neil Armstrong -- to set foot on another world on July 20, 1969.

Broadcasting from the moon, Aldrin urged listeners worldwide "to pause for a moment and contemplate the events of the past few hours, and to give thanks in his or her own way."

A devout Christian, he took communion while the spacecraft was on the moon, using a travel kit provided by his Presbyterian pastor, although this was not revealed until years later.

A fighter pilot who flew combat missions during the Korean War, an astronaut who set a space walking record, and the founder of a private rocket design company, Aldrin also battled alcoholism and depression after his days in space were over.

In a well publicized incident in 2002, he punched film maker Bart Sibrel, who claims the six Apollo lunar missions were elaborate hoaxes. Sibrel had approached Aldrin outside a hotel in Beverly Hills, California, calling him "a coward, a liar and a thief" and challenging him to swear on the Bible he had walked on the moon.

Aldrin told AFP that his voyage to the moon had profoundly changed his life, and questioned his beliefs about God and creation.

The unique experience had redefined his spirituality into one of a "much broader universality."

He came to believe in the idea of "an Einstein, cosmic, religious, spiritual, higher power intelligence having somehow created the entire universe, and we are but a small part of that, with our concepts of deity maybe not consistent with the overall creation."

After quitting the NASA program, Aldrin set up Starcraft Boosters, Inc. a rocket design company, and ShareSpace, a foundation that aims to promote affordable space tourism.

He wrote an autobiography entitled "Return to Earth," as well as a history of the Apollo program titled "Men from Earth," and, together with science fiction author John Barnes, "The Return" and "Encounter with Tiber."

And he has just brought out a new book "Magnificent Desolation: The Long Journey from the Moon."

Now 79, the former astronaut has also written children's books on space, he's an avid user of Twitter and he recently recorded a song with hip hop artist Snoop Dogg called "Rocket Experience," seeking to inspire a new generation with the desire to conquer space.

Born in Montclair, New Jersey on January 20, 1930, Aldrin was educated at the prestigious West Point military academy in New York state.

He joined the US Air Force, and flew 66 combat missions in the Korean War, shooting down two enemy fighter jets.

He earned a doctorate in Astronautics from the Massachusetts Institute of Technology, and devised manned space rendezvous techniques that were later adopted by NASA.

In 1963, he was picked to join the select corps of early US astronauts, and six years later he set a record -- now broken -- for the longest space walk by spending five and a half hours outside the spacecraft during the Gemini 12 orbital mission.

He was the back-up command module pilot on Apollo 8, man's first flight around the moon, and on July 20, 1969 he made the historic moon walk with Armstrong.

He logged a total of 4,500 hours flying time, 290 of them in space.

After retiring from NASA, the Air Force and from his position as commander of the test pilot school at Edwards Air Force Base, Aldrin remained a strong advocate of space exploration.

A crater on the moon, near the Apollo 11 landing site is named in his honor.