At Nasa’s invitation, Collins yesterday spent the golden anniversary of the Apollo 11 mission launch at Kennedy Space Centre’s Launch Complex 39A in Florida.
He marked the precise moment – 9:32am on 16 July 1969 – that their Saturn V rocket departed on humanity’s first moon landing.
Fellow astronaut Buzz Aldrin, the only other surviving crew member, had been due to attend, but cancelled at the last minute.
Mission commander Neil Armstrong, who rounded out the crew on that fateful mission and took the first lunar footsteps, was also absent, having died in 2012.
Collins said he wished Aldrin and Armstrong could have shared the moment at the pad.
It was “a wonderful feeling to be back”, the 88-year-old astronaut said.
“There was a difference this time,” he said. “I want to turn and ask Neil a question and maybe tell Buzz Aldrin something, and of course, I’m here by myself.”
Aldrin, 89, had cited a legal fight with his family and disagreements over the direction of a foundation named in his honour in missing a similar event at Kennedy Space Centre in July last year. During the mission itself, Collins had remained in lunar orbit tending to Columbia, the mother ship, while Armstrong and Aldrin landed in the Eagle on 20 July 1969.
The pair spent two hours walking on the Moon’s grey, dusty lunar surface. Collins recalled of the launch: “Apollo 11 was serious business, we crew felt the weight of the world on our shoulders.
We knew that everybody would be looking at us, friend or foe.”
After the countdown, the crew members were lifted into the sky by 7.5 million pounds of thrust.
His return yesterday 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 Armstrong wore is back on display in mint condition.
On hand for the unveiling were US vice-president Mike Pence, Nasa chief Jim Bridenstine and Armstrong’s son Rick.
A fundraising campaign took just five days to raise the $500,000 (£402,800) needed for the restoration.
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.