Apollo 11 astronauts Buzz Aldrin and Michael Collins have urged NASA to take a giant leap to Mars.
In one of their few joint public appearances, the crew of Apollo 11 spoke on the eve of the 40th anniversary of man's first landing on the moon, but avoided nostalgia. They instead spoke about the future and the more distant past.
Today, the three astronauts will get another chance to make the pitch for a Mars trip, this time to someone with a little more sway: President Barack Obama.
A packed crowd last night at Washington's Smithsonian Institution's National Air and Space Museum - 7,000 people applied in a lottery for 485 seats - didn't get the intimate details of the Eagle's landing on the moon with little fuel left, or what the moon looked like, or what it felt like to be there.
They got second man on the moon Buzz Aldrin's pitch for Mars. He said the best way to honour the Apollo astronauts "is to follow in our footsteps; to boldly go again on a new mission of exploration".
First man on the moon Neil Armstrong only discussed Apollo 11 for about 11 seconds.
He gave a professorial lecture titled "Goddard, governance and geophysics," looking at the inventions and discoveries that led to his historic "small step for a man" in the early hours UK time of July 21, 1969.
Mr Armstrong said 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".
Apollo 11 command module pilot Michael Collins, who circled the moon alone while Mr Armstrong and Mr Aldrin walked on it, said the moon was not interesting, but Mars is.
"Sometimes I think I flew to the wrong place. Mars was always my favourite as a kid and it still is today," Mr Collins said.
"I'd like to see Mars become the focus, just as John F. Kennedy focused on the moon."
The man who founded and directed Mission Control Houston, Christopher Kraft Jr, also jumped on the go-somewhere-new, do-something-different bandwagon.
"What we need is new technology; we have not had that since Apollo," Mr Kraft said as part of the lecture at the Smithsonian. "I say to Mr Obama: Let's get on with it. Let's invest in the future."
As the men of Nasa of the 1960s talked about new technology and new goals, the current Nasa is still looking back at the moon.
Nasa is still marching toward a goal of returning to the moon and putting a base there. The current plan is based on building new rockets that the former Nasa administrator called "Apollo on steroids," with an alternative - a derivative of the space shuttle - floating through the space agency.
Although they didn't directly criticise Nasa's current plans, Mr Aldrin and Mr Collins said the moon is old hat.
Mr Collins said he is afraid that Nasa's exploration plans would be bogged down by a return visit to the moon.
Mr Aldrin presented an elaborate slide detailing how to make a quick visit to the moon a stepping stone to visits to the Martian moon Phobos, Mars itself, and even some asteroids like Apophis that may someday hit Earth.
Mr Aldrin said he and Mr Armstrong landed on the moon 66 years after the Wright brothers first flew an airplane.
What he would like would be for humanity to land on Mars 66 years after his flight. That would be 2035.
And even though Mr Armstrong didn't talk about the future in his 19-minute discourse, Mr Aldrin dragged his commander onto the Mars bandwagon anyway.
"It was a great personal honour to walk on the moon, but as Neil once observed, there are still places to go beyond belief," he said. "Isn't it time to continue our journey outward, past the moon?"
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