As a boy growing up in Lancaster, S.C., Charlie Duke didn’t dream of walking on the moon.

Back then, there was no space program, noted Mr. Duke, an astronaut on NASA’s Apollo 16 mission.

A trained fighter pilot, Mr. Duke’s love of airplanes gradually transformed into a transfixion with space – a passion that kicked into high gear with President Kennedy’s 1961 challenge for the U.S. to reach the moon before the end of that decade.

The tragic failure of several space flight attempts early on — three Apollo 1 astronauts were killed in a fire during a test simulation in 1967 — served as motivation for astronauts, Mr. Duke said.

“Instead of being woe-is-me depressed, we pressed on,” he said.

Mr. Duke, who walked on the moon in 1972, shared his behind-the-scene experiences with a crowd of about 150 people at Fort Discovery’s Paul S. Simon Discovery Theater. He urged young people to dream of further space exploration.

“All the young ones, I hope we can motivate you and some of your generation to head into space when you come of age,” said Mr. Duke, who now is a businessman and travels the country giving speeches.

Mr. Duke, 74, said his most embarrassing moonwalk moment came when he dropped millions of dollars of experiment equipment on the lunar surface. Luckily, nothing was broken. He said his scariest moment was falling over backward because his equipment could have been damaged and potentially caused his death.

Fellow astronaut Buzz Aldrin’s description of the moon as “magnificent desolation” is apt, said Mr. Duke.

“The picture doesn’t capture the view – the awesome beauty of the Earth,” he said.

During Apollo 16, the team of three astronauts collected 213 pounds of specimens such as moon rock and sediment samples and drove a specially constructed car. Mr. Duke described the team’s landing position as on the “left cheek” of the man in the moon.

Jimmy Barton, 74, of Belvedere, S.C., attended the speech, sponsored by Merrill Lynch. He said he especially enjoyed Mr. Duke’s recollection of astronaut Thomas “Ken” Mattingly’s wedding ring nearly being lost in space.

Mr. Barton, who served in the Navy during the Apollo missions, said he has vivid memories of watching a moon landing.

“It was like a TV show. It seemed like this really isn’t happening, but you knew it was,” Mr. Barton said. “It was an adventure you always remember. This was the real thing – it wasn’t Hollywood.”

Ben Rhoden, 75, of Aiken, who attended with his wife, Jan, said there was a perception at the time of the moon landings that the money might not be well spent.

“All the technology we enjoy now really came out of those programs,” he said, echoing a point Mr. Duke made.

Mr. Duke predicted a not-too-distant future that would include space tours and said he hopes the U.S. will continue pushing the boundaries of space exploration.

“I think it’s something we should point for, and then on to Mars,” he said.