On Dec. 7, 1972, NASA launched its final human mission to the moon. Forty years later, Apollo 17 commander Eugene Cernan says he'd love to give up his claim-to-fame as "the last man on the moon."
"I'd like to be able to shake the hand of that young man or young woman who replaces me in that category," Cernan told NPR. "But unfortunately, the way things have gone and the way things are looking for the future, at least the near-term future, that won't happen in my lifetime. And that truly is disappointing."
As he prepared to take his final steps off the moon, Cernan said "we leave as we came, and, God willing, as we shall return: with peace and hope for all mankind."
"And I think God is still willing and do believe we will return," Cernan said this week. "I just didn't think the timetable would be as long as it is."
His crewmate and fellow Apollo 17 moonwalker, Harrison Schmitt, feels the same way.
"I certainly would have to be honest and say that I didn't think it would be 40 years," says Schmitt, "and actually it's going to be quite a bit longer than that."
NASA ended the Apollo program because the space race was over, the Nixon administration wanted to save money, and NASA was eager to do new things, like building a reusable space shuttle and an orbiting station.
"There was no groundswell of public opinion saying let's continue flights to the moon or start going to Mars," says John Logsdon, a space historian at The George Washington University. "The public was a little tired of the space program by the time of Apollo 17 and was ready to move on to other things."
Logsdon attended the launch of Apollo 17 and remembers how its powerful rocket lit up the night sky. "It was really a thrilling experience," he says, but there was also "a sense of melancholy that a great program, the Apollo trips to the moon, was coming to an end."
But for the astronauts, it was a still a glorious mission Schmitt and Cernan sang on the moon, as they explored and drove around in a lunar buggy. Four decades later, Schmitt says he still can see the beautiful lunar valley that he and Cernan were in, with mountains all around.
"They were illuminated by as brilliant a sun as you can imagine," recalls Schmitt, "and of course hanging over the southwestern mountain was this small, apparently small, planet that we call the Earth."
For awhile, under President George W. Bush, NASA did start work on another moon shot. The goal was to return by 2020 and set up a lunar base, to prepare for an eventual Mars mission.
But after President Barack Obama took office, a blue-ribbon panel said the effort had been way under-funded and was behind schedule. So President Obama set NASA on a different course to go beyond the moon and send people to explore new places. The first target set was a near-Earth asteroid.
NASA is currently developing a large rocket, and a crew vehicle, to do just that, says NASA deputy administrator Lori Garver: "And we are working on refining this capability, allowing us to take those first steps as soon as possible, to an asteroid and on to Mars."
The first launch of the big rocket is scheduled for 2017. Garver says that the test flight will send the new crew capsule looping around the moon and back though it won't carry any people.
NASA's plans have a lot of people feeling unconvinced. "NASA is building the capabilities for deep space exploration without a very clear sense of how they are going to be used, probably with inadequate budgets, and on a schedule that doesn't make much sense," says Logsdon.
This week, a new report from the National Research Council said there's a real lack of support for a manned asteroid mission both in Congress and in NASA's rank-and-file.
"This is not generally accepted. It hasn't been explained to them why this is the goal," says Albert Carnesale of the University of California, Los Angeles, who chaired the committee that wrote the report. "There is no broad acceptance of the asteroid as the next principal destination for spaceflight, despite the fact that the President has indeed said so several times."
Many people like Logsdon think there's plenty of science left to do on the moon and that it's still the best stepping stone to Mars.
"All the other spacefaring countries, when they think about a destination for exploration, say 'Moon first,'" says Logsdon. "The United States is the only country that says 'Not Moon first.'"
When asked when humans might revisit the moon, NASA's deputy administrator answered by talking about the private sector like a new company named Golden Spike.
Yesterday, Golden Spike announced plans to sell private flights to the lunar surface, with two-person trips costing around $1.5 billion. "And they say by 2020," says Garver. "So we would of course be very excited for Americans next to land on the moon."
Golden Spike is led by former NASA executives like planetary scientist Alan Stern. He says the company will exploit existing rockets and technology.
Stern acknowledged that people would be skeptical. "I think that's only natural," he said at a press conference to announce the new venture.
But he says his company has done a market study that suggests 15 to 25 nations could be potential customers. "I can guarantee you, this can be a money-making business, if we sell the right number of expeditions," says Stern.
Stern declined to say how many trips they need to sell, but said it's more than a few. "We need to sell a bunch," said Stern. "But we do not need to sell ridiculous numbers."
Golden Spike's board of directors is chaired by Gerry Griffin, a former NASA flight director for Apollo moon missions. Its advisors include former House Speaker Newt Gingrich and former U.N. ambassador Bill Richardson.