On the 40th anniversary of the first moon landing, President Obama thanked the Apollo 11 crew for its courage and promised to keep the space program alive for future generations of space pioneers.
At the White House Monday afternoon, the president welcomed Neil Armstrong, Buzz Aldrin and Michael Collins, the crew of the first manned mission to land on the moon. They were joined by NASA administrator Charles Bolden, a former astronaut, who was confirmed as the first African-American head of the agency last week
"I think it's fair to say that the touchstone for excellence in exploration and discovery is always going to be represented by the men of Apollo 11," said President Obama. "The country continues to draw inspiration from what you've done."
He recalled welcoming home Apollo astronauts when he was child in Hawaii and said his grandfather would point to them as examples of American ingenuity and perseverance. He also affirmed support for NASA and vowed to make math and science "cool again."
NASA isn't just about feeding our sense of curiosity, he said, but it also has practical applications.
"On this 40th anniversary, we are all thankful and grateful for what you've done," he said. And as other generations look up at the sky, he said, "we want to make sure NASA is going to be there for them when they want to take their journey."
Apollo Astronauts: Renew Commitment to Space
Earlier in the day, at a gathering at NASA's headquarters Monday morning, astronauts from various Apollo missions gathered and defended the space program and called on public leaders chart a course for manned missions to Mars.
Not only would the challenge reinvigorate the country's spirit of adventure and exploration, it could jump-start the economy, they said.
"If a little bit of the stimulus flows toward space, which is a program that brings technology and knowledge back to the people of the Earth, it [would be] part of the stimulus program that would really pay off with a lot of dividends," said Jim Lovell.
Charles Duke, who flew with Apollo 16 in 1972, also said that investing in the space program is investing in the country's future.
"There was not one dime spent on the moon, it was spent in America," he said. "It created technology that we all enjoy today," he said, adding that his BlackBerry has 65,000 times the memory of their Apollo computers. "We should continue to invest some resources as a nation into the future like every company does."
"We opened the door to future of exploration by touching down on another body," said Aldrin, but he said the country now needs to target Mars.
Aldrin, a long-time futurist and proponent of traveling to Mars, suggested creating a plan for sending people on a one-way mission to Mars, saying it is four to 10 times more expensive for explorers to return to Earth.
While the former Apollo 11 astronauts have set their sights on sending astronauts to Mars, the current mandate, laid out by President Bush and so far backed by President Obama, is to send unmanned probes to Mars in the short term, with a goal to eventually use the moon as a base for human exploration of Mars and beyond.
Mr. Bush announced a "vision for space exploration" in 2004, after the loss of the shuttle Columbia. He proposed returning astronauts to the moon by 2020, and then going on to Mars, but he did not give a target date.
At a presentation Sunday night on the topic, he said," It was a great personal honor to walk on the moon, but as Neil once observed, there are still places to go beyond belief. Isn't it time to continue our journey outward, past the moon?"
How Would NASA Fund Mars Mission?When asked how NASA would budget such ambitious plans, the astronauts fought back, defending the technological discoveries yielded by the Apollo program and citing the relatively small financial commitment needed to keep space exploration alive.
Less than one penny out of every dollar Americans send to the federal government in income taxes goes to support space, said Apollo astronaut Eugene Cernan who flew to the moon in 1972.
"You decide whether that's worth it," he challenged.
Cernan said that he and his colleagues were "the luckiest people in the history of the modern world," and with that gift came a responsibility.
"The response is to give that back in some way or another ? to those who follow in our footsteps. To once again see what has never been seen before," he said.
Lovell acknowledged that at the height of the Cold War, the country was unified behind the common goal of reaching the moon, and it's difficult to re-create those conditions.
Astronauts: Mission Now Is to Inspire Young People
But that momentum, he said, hurtled the astronauts to the moon and led to technology in use today.
Now that he and his colleagues are in their retirement years, he said, "our main mission now is to inspire the young people."
The goal of reaching Mars could unify the public the way the moon mission did in the 1960s, he said.
"It's the other moon that we now have conquered."
In 1994 a military space probe called Clementine, sent to map the moon as a way of testing sensors for possible Defense Department use, found evidence of ice in the shadowed corners of craters near the moon's south pole. In 1998 a NASA probe called Lunar Prospector was sent to confirm Clementine's findings, and as it orbited the moon it found evidence of large amounts of ice in the lunar soil.
If there is frozen water there -- H2O -- it can be used for drinking, or broken down into its components of hydrogen and oxygen for fuel, air to breathe, and myriad other uses.
The astronauts comments came as public debate about the value of the Apollo program still simmers.
40 Years Later: Debate Continues"Why are we wasting billions of dollars on the space program?" ask many visitors to ABCNews.com and other Web sites. Forty years after Neil Armstrong took that one small step on the lunar surface, NASA still provokes the same argument.
"For all the trillions of dollars we have spent on the space program, all we have are some moon rocks, several tons of space junk and a dozen and a half or so dead astronauts," wrote someone commenting on a recent ABCNews.com story about a space shuttle mission.
In fact, public opinion has always been split. In a July 1967 Harris poll, two years before the first moonwalk, 43 percent of Americans favored the effort, 46 percent opposed -- hardly a rousing endorsement. And in 1970, a year after the landing, 56 percent said it had not been worth its allotted $4 billion a year for nine years.
President Kennedy, who set America on coursefor the moon, spoke resoundingly in its support:
"Space science, like nuclear science and all technology, has no conscience of its own," he said in a 1962 speech at Rice University in Houston. "Whether it will become a force for good or ill depends on man, and only if the United States occupies a position of pre-eminence can we help decide whether this new ocean will be a sea of peace or a new terrifying theater of war."
But even Kennedy was less of an enthusiast than he led the nation to believe. In a 1962 audio tape from the Oval Office, later discovered by the staff of the John F. Kennedy Library in Boston, he brushed off suggestions from NASA's then-chief James Webb that the space program should be about more than beating the Soviet Union to the moon.
"This is important for political reasons, international political reasons, and this is, whether we like it or not, an intensive race," Kennedy is heard saying on the tape.
"Otherwise, we shouldn't be spending this kind of money, because I'm not that interested in space."
President Kennedy was "not that interested" in space? Every president since has found lukewarm support.
Space Race: Debate Still Rages
"I don't think it's changed particularly," said Roger Launius, a senior curator at the Smithsonian Institution's National Air and Space Museum and former chief historian at NASA. Polls have consistently shown about 60 percent of the American people support the space program -- though the number always drops into the 40s when people are asked about the cost.
"We like it," said Launius. "We just don't want to pay for it."
NASA has a frequent answer to its critics: that even at $20 billion a year, it consistently spends less than half of 1 percent of the federal budget; that space exploration has led to thousands of technological spinoffs and employed hundreds of thousands of Americans; and that even if the money were diverted to tackling social problems, it would not solve them.
Launius said the arguments fall flat with many people. When historians try to understand great missions of exploration, he said, "We're essentially reduced to four 'G' words: God, Gold, Glory, and Geopolitics." Nations send out explorers when they want power or material return. "Right now, we don't have that."
Polls show Americans have warmed over time to the memory of Apollo. Since 1979, the number of people saying the moon landings were worth the cost has risen from 41 percent to 65. Launius says there is not organized opposition to the space program, the way there is to other efforts; there just isn't ringing support. Millions of Americans still question Kennedy's decision.
So we come back to his famous 1962 speech at the Rice University football stadium.
"But why, some say, the moon? Why choose this as our goal? And they may well ask, 'why climb the highest mountain? Why, 35 years ago, fly the Atlantic? Why does Rice play Texas?'"
The crowd roared.
"We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard," Kennedy said, "because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win."
ABC News polling director Gary Langer and The Associated Press contributed reporting for this story.