Apollo 11 astronaut Michael Collins returned Tuesday to the exact spot where he flew to the moon 50 years ago with Neil Armstrong and Buzz Aldrin.

Mr. Collins had the spotlight to himself this time – Mr. Armstrong has been gone for seven years and Mr. Aldrin canceled. Mr. Collins said he wished his two moonwalking colleagues could have shared the moment at Kennedy Space Center's Launch Complex 39A, the departure point for humanity's first moon landing.

"Wonderful feeling to be back," the 88-year-old command module pilot said on NASA TV. "There's a difference this time. I want to turn and ask Neil a question and maybe tell Buzz Aldrin something, and of course, I'm here by myself."

At NASA's invitation, Collins marked the precise moment – 9:32 a.m. on July 16, 1969 – that the Saturn V rocket blasted off. He was seated at the base of the pad alongside Kennedy's director, Robert Cabana, a former space shuttle commander.

Mr. Collins recalled the tension surrounding the crew that day.

"Apollo 11 ... was serious business. We, crew, felt the weight of the world on our shoulders. We knew that everyone would be looking at us, friend or foe, and we wanted to do the best we possibly could," he said.

Mr. Collins remained in lunar orbit, tending to Columbia, the mother ship, while Mr. Armstrong and Mr. Aldrin landed in the Eagle on July 20, 1969, and spent 2 ½ hours walking the gray, dusty lunar surface.

A reunion Tuesday at the Kennedy firing room by past and present launch controllers – and Mr. Collins' return to the pad, now leased to SpaceX – kicked off a week of celebrations marking each day of Apollo 11's eight-day voyage.

At the Air and Space Museum in Washington, the spacesuit that Mr. Armstrong wore went back on display in mint condition, complete with lunar dust left on the suit's knees, thighs and elbows. On hand for the unveiling were Vice President Mike Pence, NASA Administrator Jim Bridenstine and Mr. Armstrong's older son, Rick. Mr. Armstrong died in 2012.

A fundraising campaign took just five days to raise the $500,000 needed for the restoration.

Calling Mr. Armstrong a hero, Mr. Pence said "the American people express their gratitude by preserving this symbol of courage."

In Huntsville, Alabama, where the Saturn V was developed, thousands of model rockets were launched simultaneously, commemorating the moment the Apollo 11 crew blasted off for the moon. Hundreds of youngsters attending Space Camp counted down ... "5, 4, 3, 2, 1!" – and cheered as the rockets created a gray cloud, at least for a few moments, in the sky.

Back at Kennedy, NASA televised original launch video of Apollo 11, timed down to the second. Then Mr. Cabana turned the conversation to NASA's next moonshot program, Artemis, named after the twin sister of Greek mythology's Apollo. It seeks to put the first woman and next man on the lunar surface – the moon's south pole – by 2024. President John F. Kennedy's challenge to put a man on the moon by the end of 1969 took eight years to achieve.

Mr. Collins said he likes the name Artemis and, even more, likes the concept behind Artemis.

"But I don't want to go back to the moon," Mr. Collins told Mr. Cabana. "I want to go direct to Mars. I call it the JFK Mars Express."

Mr. Collins noted that the moon-first crowd has merit to its argument and he pointed out Mr. Armstrong himself was among those who believed returning to the moon "would assist us mightily in our attempt to go to Mars."

Mr. Cabana assured Mr. Collins, "We believe the faster we get to the moon, the faster we get to Mars as we develop those systems that we need to make that happen."

About 100 of the original 500 launch controllers and managers on July 16, 1969, reunited in the firing room Tuesday morning. The crowd also included members of NASA's next moon management team, including Charlie Blackwell-Thompson, launch director for the still-in-development Space Launch System moon rocket. The SLS will surpass the Saturn V, the world's most powerful rocket to fly to date.

Ms. Blackwell-Thompson said she got goosebumps listening to the replay of the Apollo 11 countdown. Hearing Mr. Collins' "personal account of what that was like was absolutely amazing."

The lone female launch controller for Apollo 11, JoAnn Morgan, enjoyed seeing the much updated-firing room. One thing was notably missing, though: stacks of paper. "We could have walked to the moon on the paper," Ms. Morgan said.

Mr. Collins was going to be reunited later in the day with two other Apollo astronauts at an evening gala at Kennedy, including Apollo 16 moonwalker Charlie Duke, who was the capsule communicator in Mission Control for the Apollo 11 moon landing. The U.S. Space and Rocket Center in Huntsville also had a special anniversary dinner on tap Tuesday night, with Mr. Aldrin and other retired Apollo astronauts and rocket scientists.

Only four of the 12 moonwalkers from 1969 through 1972 are still alive: Mr. Aldrin, Mr. Duke, Apollo 15's David Scott and Apollo 17's Harrison Schmitt.

Get the Monitor Stories you care about delivered to your inbox. By signing up, you agree to our Privacy Policy

NASA spokesman Bob Jacobs said Mr. Aldrin, 89, bowed out of the launch pad visit, citing his intense schedule of appearances. Mr. Aldrin hosted a gala in Southern California last Saturday and planned to head directly to the Huntsville dinner. Mr. Aldrin and Mr. Collins may reunite in Washington on Friday or Saturday, the 50th anniversary of Apollo 11's moon landing.

This story was reported by The Associated Press. Science writer Seth Borenstein contributed from Washington.