Six of the 12 interviewed in 2006.

Only 12 men walked on the Moon during the seven Apollo missions from 1969 to 1972.

In 2006, I had the opportunity to ask several about their experience. As we celebrate the 50th anniversary of Apollo 11’s inaugural Moon landing this year, their comments will remind us of one of humanity’s most remarkable scientific achievements.

From an early age, young Ed Aldrin had a natural curiosity about nature and he remembers being just six when he began collecting rocks because their smooth surfaces and delicate colors fascinated him. Four decades later, on July 21, 1969, now Colonel “Buzz” Aldrin would again find himself gathering rocks. This time, they were Moon rocks, 50 pounds worth that he and Neil Armstrong scooped up from the lunar surface and returned to Earth.

Of course, this historic first Moon mission in the Apollo 11 spacecraft was much more than a rock collecting field trip. For the people of the world who watched on black and white TV, it was an uplifting moment for humanity as the pair pressed the first human footprints into the dusty lunar surface.

“When Neil Armstrong and I stepped out onto the Moon’s surface, we were very much focused on what we were doing,” Aldrin told me. “Of course, we were aware of the bigger picture and the historic nature of our mission which was evident in Neil’s words ‘one small step for a man, one giant leap for mankind.’”

When his turn came to descend the lunar ladder, Aldrin said he summed up his feelings in two words.

“Magnificent desolation!” he said, “which indicated the magnificence of human beings who could build a machine to get them to the Moon. Yet the desolation of the lunar surface was truly unique compared to anything else I had seen on Earth.”

Despite the difficulty of the mission, Aldrin said one of the toughest parts was after touchdown back on Earth.

“For me, the most inconvenient part of our mission was when we returned to Earth and had to be quarantined,” he explained. “Astronauts from the first three moon missions were quarantined for 21 days after landing to prevent any germs that might be on the Moon from getting back to people on the Earth.”

Five months after Apollo 11 returned, Apollo 12 retraced the journey with Alan Bean (1932-2018) and Pete Conrad in the lunar module, Dick Gordon remaining in the Command Module.

Lunar Module pilot Bean told me how their mission employed the first nuclear-powered electric generator on the Moon’s surface.

“It contained plutonium which produced heat that was converted into electricity to operate our equipment,” he said. “Similar devices are used to power satellites and rockets that have to travel in space for many years. Solar panels wouldn’t be effective so far away from the sun.”

After leaving NASA, Bean became well-known for his space paintings.

“After a few years of painting, I thought I could make some texture in my paintings using moon boots and the hammer I had on the moon,” he told me. But his moon tools were in the Air and Space Museum, so he asked for them back. Then he had another idea.

“I had always wanted moon dust to put in my paintings but didn’t have any,” he said. “One day I was looking at the patches from my suit and backpack that (NASA) did give me, and I thought ‘Boy, they’re dirty’ and it dawned on me they’re dirty with moon dust!”

Bean was able to scrape off particles and incorporate the material into his paintings.

A friend who was the director of the museum where the Apollo 12 Command Module was on display gave him some foil that was still attached to the Lunar Module access hatch. His friend also noticed some “dust” at the bottom of the crate that had been used to ship the craft to the museum.

It was, said Bean, “the charred heat-shield remnants that had burned off in the 5,000-degree heat during re-entry from the Moon.”

He added this, the foil, and moon dust to his paintings, some of which today command prices over $400,000.

Jim Lovell, Jack Swigert and Fred Haise’s unlucky Apollo 13 never made it to the Moon due to an exploding oxygen tank. But their story did make a compelling book and popular 1995 movie.

“The movie was very accurate,” Lovell told me. “All incidents were true except the argument between Jack Swigert and Fred Haise. Some artistic license was introduced. In the movie, it appeared that Swigert was not trained to replace Ken Mattingly. That was not the case. It also appeared that toward the end of the movie, Mattingly figured out how to charge the Odyssey batteries. Actually, four people were involved.”

Lovell also enjoyed his brief cameo in the film. “Look for me at the end of the movie. I play the captain of the recovery ship!”

Following the ill-fated Apollo 13 mission, one might have expected the Apollo 14 astronauts to be a little uneasy.

“All of the Apollo 14 crew members were very alert and watching for signs of trouble and malfunction at all times,” LEM pilot Ed Mitchell (1930-2016) told me. “Although we followed Apollo 13 and were aware of the problems that prevented a lunar landing for that mission, our spacecraft had been thoroughly checked to prevent a similar malfunction from reoccurring.”

As Command Module pilot for Apollo 15, Al Worden orbited the Moon alone for nearly three days while the rest of the crew worked on the Moon’s surface. I asked him if being totally alone in space made him a little uneasy.

“Being alone during the flight was actually a good time for me, not scary, as we were so highly trained,” recalled Worden. “When I was alone, I was especially busy. On the few occasions when I had time to reflect while alone, I put my thoughts and feelings in a journal that later became my book.”

Worden also experienced another version of loneliness during a “walk” in space on Apollo 15’s return journey to Earth, while traveling at thousands of miles per hour outside the spacecraft.

“It’s possible because we are already going the same speed as the Command Module and there is nothing in space to slow us down -- no friction or wind,” he explained. “To keep us drifting off, we have a tether or rope attached to the ship.

“You don’t ‘walk’ in space, as there is no ground to step on!”

On the final three Apollo missions, astronauts took along a Lunar Roving Vehicle to explore the lunar surface a little further than previous missions.

“I was the navigator in the passenger seat of the LRV for Apollo 16,” Charlie Duke told me. “John Young was the driver. The rover was very sensitive in steering and it was easy to over control and skid. Our maximum speed on the Moon was 11 mph, and we could not go more than a few miles from the lunar module because if the LRV broke down, we would have to walk back! We did not have enough oxygen in our backpacks to go more than that. The rover was powered by batteries that were not rechargeable.”

One tradition which Apollo astronauts adhered to was planting the American flag on the Moon, the last being during the Apollo 17 mission.

“We had to pound hard on the top of the flagpole to get it to go into the lunar soil,” Lunar Module pilot and geologist Harrison Schmitt told me. “The soil had been compacted so much by small meteor effects, that there was no space between dust and rock particles.”

That material, however, might one day become a useful resource for our planet.

“The Moon’s surface layer of dust and rock contain energy resources that can be used here on Earth,” added Schmitt. “I believe the Moon and Mars can also both support human settlements in the future. Understanding the history of the Moon and Mars will tell us about the early history of the Earth, how life began on our planet, and maybe other places in the universe.”

When we spoke, Aldrin also said he believed we need to return to the Moon and continue on to Mars.

“I believe we should commit ourselves to a permanent colony or base on Mars, not just a few missions there,” he said. “Otherwise, how can we justify the costs? We will also need to develop a way to make fuel on Mars for the return trips. It would be expensive and probably impractical to send all the fuel there from Earth for the round trip.”

Those journeys, if they are ever to be realized, will be made possible by today’s young men and women. Aldrin offered some simple advice: “If you set your sight high, you may accomplish more than you ever dreamed possible, just as I did.”

Portions of these interviews originally appeared in the Chicago Tribune and the Christian Science Monitor.

Nick Thomas teaches at Auburn University at Montgomery, Ala., and has written features, columns, and interviews for over 750 magazines and newspapers. See www.getnickt.org.