If Neil Armstrong spent just 11 seconds talking about walking on the Moon during a rare public appearance in Washington late on Sunday – on the eve of yesterday's 40th anniversary of the first Apollo landing – it was surely more than modesty. More likely, it was because he thought Nasa's future was more important than its past.
Still, lunar nostalgia has its place, especially this week. Buzz Aldrin, who followed Armstrong on to the Moon's surface on 20 July 1968 and who was beside him again at the National Air and Space Museum on Sunday, recalled that their mission had been "a symbol of what a great nation and a great people can do if we work hard and work together".
Armstrong said that the space race that had been played out during the height of the Cold War and which culminated in his walking on the Moon 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".
But Armstrong, Aldrin and the other still surviving Apollo alumni have had something more urgent to say these past few days: don't let the spirit of Apollo die. There are more bold steps to be taken and more frontiers to be broken.
It is a message that was repeated at an anniversary press conference in Washington yesterday and carried a few hours later by Aldrin, Armstrong and the third Apollo 11 crew member, Michael Collins, into the White House, to the man who might have the power to reinvigorate (and sufficiently fund) Nasa: Barack Obama.
These pioneers of space exploration are anxious that the new President of the United States borrow something of the nothing-is-impossible bravado that President John F Kennedy showed when he first vowed in 1961 to send a man to the Moon.
They want him to set just such a goal again, but this time with a new destination: the Red Planet.
"Sometimes I think I flew to the wrong place. Mars was always my favourite as a kid and it still is today," Collins said. "I'd like to see Mars become the focus, just as John F Kennedy focused on the Moon."
Aldrin told an audience of nearly 500 at the museum on Sunday night: "The best way to honour and remember all those who were part of the Apollo programme is to follow in our footsteps; to boldly go again on a new mission of exploration."
He repeated his call for missions to Mars yesterday.
"There may be life on Mars and if there is, it's damn sure we ought to go there and look at it," Aldrin, 79, told reporters. "When we get there, if we don't find any life on Mars, from that point on there will be life on Mars because we'll bring it there, whether it's germs and leftover urine bags, whatever it is."
Eugene Cernan, a member of the Apollo 17 mission and the last man on the Moon, concurred. He moreover displayed disappointment that a Mars visit had not already happened. Recalling that the Apollo programme was ended in the 1970s, he said: "I really believed we'd be back on the Moon by the end of that decade and on our way to Mars by the turn of the century. My glass has been half empty for three decades at least.
"We need to go back to the Moon," Cernan said, accompanied at a news conference by half a dozen other Apollo astronauts. "We need to learn a bit more about what we think we know already, we need to establish bases, put new telescopes on the Moon, get prepared to go to Mars. Because the ultimate goal is to go to Mars."
Returning to the Moon is indeed on the Nasa calendar, at least in theory. While the current Space Shuttle fleet faces final retirement next year, the intention for now is to develop the new Constellation space programme that is meant to establish a lunar base by 2020 as a stepping stone to voyages beyond, including to Mars.
That, at least, was the course that the Bush administration set. Since Mr Obama came to office, however, a new review has been set in train for Nasa.
Though Aldrin, Armstrong and Collins were surely welcomed as national heroes into the Oval Office yesterday, they will have met a President who is under extraordinary pressure to find ways not to spend more federal dollars. Universal healthcare coverage interests Mr Obama more than the universe.
At least Nasa on this anniversary was able to say that it had men in space. Astronauts David Wolf and Thomas Marshburn were due to conduct a space walk to attach tools to the International Space Station.
Less glorious, however, was the Shuttle crew's other task for the day: fixing a blocked toilet.
Where are they now? The Apollo astronauts
Buzz Aldrin, 79 Apollo 11: An author and lecturer, he also heads the ShareSpace Foundation to promote possibilities for private space exploration – including space tourism with eventual hotel accommodation on the Moon.
Neil Armstrong, 78 Apollo 11: Famous for his reluctance to embrace his hero image, he has nonetheless made occasional public appearances. After leaving Nasa he taught engineering and helped in the Challenger disaster inquiry.
James Lovell, 81 Apollo 13: A highlight of post-Nasa life may have been consulting on Apollo 13, the film that had him played by Tom Hanks. He opened a restaurant in Illinois, Lovell's Steakhouse, and worked in telecommunications.
Alan Bean, 77 Apollo 12: 40 years after walking on the Moon, he is still reliving the moment – on canvas. Bean is a painter who has been exhibited in Washington and whose works try to capture the astronauts' experience.
Frank Borman, 81. Apollo 8: Staying aloft, he left Nasa to become chairman of the now defunct Eastern Airlines. He was a goodwill ambassador to Europe and Asia for President Nixon. Now rebuilds and flies antique aircraft.
Michael Collins, 78. Apollo 11: He became director of the Smithsonian National Air and Space Museum which hosted a reunion between him, Buzz Aldrin and Neil Armstrong on Sunday. Also wrote a book about the mission, Liftoff.