In the run up to 20 July 1969, Neil Armstrong, the commander of Apollo 11, and Buzz Aldrin, pilot of the lunar module which set the pair down on to the moon's surface, had been at loggerheads over would venture out on to the moon's surface first. A preliminary checklist written by Nasa had Aldrin as the first person stepping out of the lander door, a position he lobbied hard to retain. But protocol dictated that Armstrong, as mission commander, should exit first. In the end, the situation was determined by the layout of the module. Armstrong happened to be sitting closer to the door; in their bulky spacesuits, the two men would have had a job to swap positions.
Even then, the pair knew how the moment would define them. And this week, as President Obama has sought to sell his administration's policy on space flight, they have once again been shown in opposing lights.
On the one side is Armstrong, who says he thinks that Obama's plans to cancel a space-flight programme known as Constellation, which aimed to send astronauts back to the moon by 2020, would be "devastating" for the US. In a letter made public earlier this week, co-signed by Apollo 13 commander James Lovell and Apollo 17 commander Eugene Cernan, he said that the new focus on long-term projects to Mars, and the passing of short-distance space flight to the commercial sector, would trash the reputation of American space travel. "While the President's plan envisages humans travelling away from Earth and perhaps toward Mars at some time in the future, the lack of developed ... spacecraft will assure that ability will not be available for many years," they wrote.
On the other side was Aldrin – second out of the module, perhaps, but first to the Obama administration's defence. "The truth is that we have already been to the Moon – some 40 years ago," he wrote, in a letter published by the White House. "The President's program will help us be in this endeavour for the long haul and will allow us to again ... achieve new and challenging things beyond Earth."
Aldrin, who was rewarded yesterday with a flight to Cape Canaveral aboard Air Force One, also wrote a USA Today comment piece emphasising his "respect" for "other astronauts' ... different views". But there was no doubt that he and his fellow pioneer were once again at loggerheads. There is Armstrong – stoic, exhibiting a Salingeresque rejection of media attention – and then there is Aldrin, a man who sank into alcoholism after the lunar landings, and who launched a high-profile publicity campaign for his autobiography, The Long Journey Home from the Moon, last year.
"Armstrong was always the more conservative of the two, someone who was inclined to stick to the straight and narrow," says the space-travel expert Andrew Smith, author of Moondust: In Search of the Men Who Fell to Earth. "This is one of the reasons he was selected to command the mission. He was reliable and steady. Aldrin was always a maverick. One of his colleagues, Mike Collins [the third member of the Apollo 11 crew] used to talk about what a snappy dresser he was. He had always been a creative thinker and would find a different way of reasoning things out. He found himself to be an outsider in the astronaut community as a result."
Their differences run through the reasons the two men were selected for their respective roles on Apollo 11, through to the direction their lives took after returning to Earth. Upon his return, Armstrong seemed unmoved by the way his crew's endeavours were being treated as a publicity circus. "I had hoped the impact would be more far-reaching," he said at a Nasa press conference in July 1970. "We all seem to be sort of tied up with today's problems." Of his new status as "hero", he said: "It's not that I feel uncomfortable; it's just that I find there's inadequate time to do all the things I'd like to be doing."
He ended up becoming something of recluse, partly inspired by his obsession with legendary US aviator Charles Lindbergh. "I think he saw the results of being an idol when he researched Lindbergh's experience," said Lovell, in an interview with The Washington Post in 1999. "He didn't want to have his life change. He decided to be very reclusive, but that's also his nature." After time as an academic, and the odd appearance on TV and at Nasa reunions, Armstrong has mostly retained a low profile.
Aldrin, meanwhile, rejoined the US air force, where he had previously been a fighter pilot, but languished in his role as commander of a test pilot school. He quit at 42, started drinking, had an affair, and suffered depression which led to the end of his marriage. He went though another marriage and divorce, before eventually finding a new life as a car salesman, and undergoing a recent renaissance in his public profile.
"I inherited tendencies in different directions [depression and an addictive personality], and those directions, if you feed them with a life of perfection and discipline and then remove that all of a sudden – it's probably going to go back to some of the more deep-seated concerns about self-worth and achievement," he said in an interview last July.
Aldrin's garrulousness and support for space travel are well-known. It is unclear why Armstrong has chosen to speak out now, especially since most commentators say Obama's proposals are well thought out. "Aldrin seems to be way ahead in terms of the way US space travel should be going," continues Smith. "Armstrong is just thinking about the here and now of getting back to the moon. It's strange because, despite his place in history, he is less obsessed by the moon than Aldrin has been; he has spent most of his time running from the celebrity. Aldrin trades on it."
And to Smith, the public nature of their disagreement was unexpected – on one side, at least. "I am surprised this has come from Armstrong," he said. "He has always refused to tell anyone what travelling to the moon meant to him. But he's a very intelligent and personable man in the right circumstances.
"Maybe he felt more strongly about it than we thought. Maybe he's got a more emotional connection to it as he's got older."