President Barack Obama and astronaut Buzz Aldrin led tributes Saturday to the famed Apollo 11 commander Neil Armstrong, the first man on the moon, lauding him as a reluctant but true American hero. Armstrong, who died from complications following cardiac bypass surgery, was praised for his willingness to embrace and then conquer challenges that had once seemed impossible.
"When he and his fellow crew members lifted off aboard Apollo 11 in 1969, they carried with them the aspirations of an entire nation," said Obama, who was two weeks short of his eighth birthday when the historic mission succeeded.
"They set out to show the world that the American spirit can see beyond what seems unimaginable - that with enough drive and ingenuity, anything is possible," he added in a statement.
"When Neil stepped foot on the surface of the moon for the first time, he delivered a moment of human achievement that will never be forgotten."
Aldrin, who with Armstrong was watched by an estimated global television audience of 500 million as they gingerly bounced on the moon's surface in their chunky spacesuits, praised his comrade's skill, dedication and selflessness.
"I know I am joined by millions of others in mourning the passing of a true American hero and the best pilot I ever knew," Aldrin said, noting that his thoughts were with Armstrong's devastated but proud family.
The third Apollo 11 astronaut - Michael Collins, the command module pilot who orbited the moon while his crewmates landed - said Armstrong "was the best, and I will miss him terribly."
Armstrong, a Korean War veteran who was decorated by 17 countries and received a slew of US honours, was never comfortable with the world-wide fame that stemmed from the Apollo 11 mission, and he shied away from the limelight.
"He didn't feel that he should be out huckstering himself," John Glenn, the first American to orbit Earth told CNN, recalling Armstrong's legendary humility.
"He was a humble person, and that's the way he remained after his lunar flight, as well as before," the former Ohio senator added.
For the United States, the Apollo 11 mission was a Cold War maneuver, a bid to fulfil the vow made by President John F. Kennedy that NASA could overtake the pioneering Russian space program and put a man on the moon.