Neil Armstrong, the first man to walk on the moon, has died at the age of 82, his relatives have said.
I am, and ever will be, a white socks, pocket protector, nerdy engineer. I take a substantial amount of pride in my profession’s accomplishments
A statement from the family said he died following complications resulting from cardiovascular procedures.
Mr Armstrong commanded the Apollo 11 spacecraft that landed on the moon on July 20, 1969.
He radioed back to Earth the historic news of “one giant leap for mankind”.
Mr Armstrong and fellow astronaut Edwin “Buzz” Aldrin spent nearly three hours walking on the moon, collecting samples, conducting experiments and taking photographs.
In all, 12 Americans walked on the moon from 1969 to 1972.
Mr Armstrong was a quiet, self-described nerdy engineer who became a global hero when as a steely nerved US pilot he made his “one giant leap for mankind” with a small step on to the moon.
In those first few moments on the moon, during the climax of a heated space race with the then-Soviet Union, Mr Armstrong stopped in what he called “a tender moment” and left a patch to commemorate Nasa astronauts and Soviet cosmonauts who had died in action.
“It was special and memorable, but it was only instantaneous because there was work to do,” Mr Armstrong told an Australian TV interviewer this year.
“The sights were simply magnificent, beyond any visual experience that I had ever been exposed to,” Mr Armstrong once said.
The moonwalk marked America’s victory in the Cold War space race that began on October 4 1957, with the launch of the Soviet Union’s Sputnik 1, a satellite that sent shock waves around the world.
Although he had been a Navy fighter pilot, a test pilot for Nasa’s forerunner and an astronaut, Mr Armstrong never allowed himself to be caught up in the celebrity and glamour of the space programme.
“I am, and ever will be, a white socks, pocket protector, nerdy engineer,” he said in February 2000 in one of his rare public appearances. “And I take a substantial amount of pride in the accomplishments of my profession.”
A man who kept away from cameras, Mr Armstrong went public in 2010 with his concerns about President Barack Obama’s space policy that shifted attention away from a return to the moon and emphasised private companies developing spaceships.
He testified before Congress, and in an e-mail to The Associated Press he said he had “substantial reservations”.
Mr Armstrong’s modesty and self-effacing manner never faded.
When he appeared in Dayton, Ohio, in 2003 to help celebrate the 100th anniversary of powered flight, he bounded onto a stage before 10,000 people.
But he spoke for only a few seconds, did not mention the moon and quickly ducked out of the spotlight.
He later joined former astronaut and Senator John Glenn to lay wreaths on the graves of plane inventors Wilbur and Orville Wright. Mr Glenn introduced Mr Armstrong and noted it was 34 years to the day that Mr Armstrong had walked on the moon.
“Thank you, John. Thirty-four years?” Mr Armstrong quipped, as if he hadn’t given it a thought.
Mr Armstrong’s moonwalk capped a series of accomplishments that included piloting the X-15 rocket plane and making the first space docking during the Gemini 8 mission, which included a successful emergency splashdown.
In the years afterward, Mr Armstrong retreated to the quiet of the classroom and his Ohio farm. Mr Aldrin said in his book Men From Earth that Mr Armstrong was one of the quietest, most private men he had ever met.
At the time of the flight’s 40th anniversary, Mr Armstrong again was low-key, telling a gathering that the space race was “the ultimate peaceful competition: USA versus USSR. It did allow both sides to take the high road, with the objectives of science and learning and exploration.”
Mr Glenn, who went through jungle training in Panama with Mr Armstrong as part of the astronaut programme, described him as “exceptionally brilliant” with technical matters but “rather retiring, doesn’t like to be thrust into the limelight much”.
The 1969 landing met an audacious deadline that President John F. Kennedy had set in May 1961, shortly after Alan Shepard became the first American in space with a 15-minute suborbital flight. Soviet cosmonaut Yuri Gagarin had orbited the Earth and beaten the US into space the previous month.
The end-of-decade goal was met with more than five months to spare. “Houston: Tranquility Base here,” Mr Armstrong radioed after the spacecraft settled onto the moon. “The Eagle has landed.”
“Roger, Tranquility,” the Houston staffer radioed back. “We copy you on the ground. You’ve got a bunch of guys about to turn blue. We’re breathing again. Thanks a lot.”