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There’s some disagreement about what the last people to visit the moon said just before they left. It could be Gene Cernan telling Jack Schmitt, who was fiddling with a camera, “Now let’s get off. Forget the camera.” It could be what was spoken after that, which NASA’s official transcript of the Apollo 17 mission describes only as “[garbled].” Or it could be, as astronaut lore has it, a few colorful words from Cernan: “Let’s get outta this mutha.”

The point is, the NASA astronauts left the moon in 1972, and no one has been back since.

When the Apollo program ended, NASA turned its attention toward other parts of the cosmos. It built space stations and shuttles, designed powerful floating telescopes, and sent machines to fly past some planets and moons and to land on others. Today the moon, Earth’s closest companion, seems almost distant in comparison.

But Donald Trump’s administration wants to go back, and soon.

“At the direction of the president of the United States, it is the stated policy of this administration and the United States of America to return American astronauts to the moon within the next five years,” Vice President Mike Pence said this week.

Pence made the announcement in Huntsville, Alabama, the city that built the rocket that lofted Apollo astronauts toward the moon. In the most significant space-policy speech of the Trump administration so far, the vice president said the United States would establish a permanent base on the moon that would someday help Americans mount a mission to Mars.

As other leaders have done, Pence waxed poetic about the nation’s drive to explore the unknown. He lavished praise on NASA employees. He made Buzz Aldrin, the second man to walk on the moon, stand up so the audience could applaud him. But while the speech was big on the magic of space exploration, it was low on specifics. Pence left out something rather important: how the administration plans to fund this whole effort.

NASA received far more funding in the Apollo days than it does now; at the moon program’s peak, the agency’s annual budget accounted for more than 4 percent of federal spending. It’s less than half a percent today. NASA has poured plenty into exploration efforts in the past several decades, but one president’s policies usually get yanked back by the next. Little gets done in the meantime.

The latest NASA budget, $21.5 billion, is the largest in years. But the Trump administration had requested $19.9 billion, and it was Congress, the final arbiter on funding, who added the extra cash. And in its request for next year’s allocation, the administration actually proposed scaling back funding.

Pence said that to speed up the effort, the government would consider scrapping NASA’s own work and using commercial technology instead. The space agency has spent nearly a decade working on a rocket powerful enough to deliver astronauts to the moon, but it’s behind schedule and over budget. “If commercial rockets are the only way to get American astronauts to the moon in the next five years, then commercial rockets it will be,” the vice president said.

But the government would still have to pay the commercial companies for their services, and it’s unclear whether those firms would be ready in time—or even want to participate. To make a moon return happen under the current budget, the administration would need to propose making some cuts to major programs, such as its moon rocket—which has significant support in Congress—or even the International Space Station.

These are matters for lawmakers to figure out. But as they do, they will be forced to confront the clearest argument against spending all that money: Americans have been to the moon already. Why go back at all?

According to Pence, it’s more or less the same reason they went last time, during the height of the Cold War. The vice president’s rationale seemed to center, as it did during John F. Kennedy’s presidency, on national pride, prestige, and a sense of duty to keep outer space out of the hands of nations that aren’t like this one.

“The United States must remain first in space, in this century as in the last, not just to propel our economy and secure our nation, but above all because the rules and values of space, like every great frontier, will be written by those who have the courage to get there first and the commitment to stay,” Pence said.

The passage of time has coated the Apollo missions with a sparkling sheen. Polls show that support for the moon landing has risen over the years; 77 percent of people in 1989 thought the effort was worth it, compared with just 47 percent a decade earlier. Even in the thick of the Apollo years, Americans were skeptical, as the space historian Roger Launius wrote in 2003: “Consistently throughout the 1960s a majority of Americans did not believe Apollo was worth the cost, with the one exception to this a poll taken at the time of the Apollo 11 lunar landing in July 1969.”

A Pew Research Center poll in 2018 found that while most Americans believe it’s important for the United States to be a world leader in space exploration, 63 percent think NASA’s main focus should be climate research. Only 13 percent said sending humans to the moon should be a top priority.

Even Buzz Aldrin himself thinks it’s time to look beyond Earth’s gray companion, and toward Mars. “We’ve done the moon. We understand it better than anything else,” he said in a 2011 interview with Space.com. “We’ve got to stop thinking of short-term hurrahs and start thinking of long-term investments.”

Depending on whom you ask, there are many reasons to explore the moon, including some that aren’t tangled up in geopolitics. If human beings want to go anywhere in space, the moon seems like the most logical target—it’s the closest, after all. A journey to Mars could last as many as nine months, but a trip to the moon takes just a few days.

The moon offers some hope for self-preservation. A species living on two worlds has a better chance of surviving should catastrophe, such as the worst effects of climate change or an asteroid impact, befall it. The odds are even better if the species resides on three worlds, which would require some practice first, says David Spencer, an aerospace professor at Purdue University who worked at NASA’s Jet Propulsion Laboratory for nearly two decades. “If we go to Mars directly without going to the moon and establishing a permanent presence, I think we’re skipping a step,” Spencer says.

Some argue that robots could do a better and cheaper job of exploring the lunar surface. On Mars, rovers have crisscrossed plains and valleys and made significant discoveries. But people move much faster than a rover’s slow crawl—the Opportunity rover covered just 28 miles in 15 years—and they could provide fixes a machine can’t. NASA engineers probably wish they had someone around to jostle its Mars lander, which recently got stuck while trying to drill into the planet’s surface.

The moon has water—though it’s unclear how much—frozen away in the rock, including at the south pole, where Pence said astronauts would go. This would be useful only for lunar explorers, who could theoretically funnel this ice into life-support systems.

Earthlings might find use in another resource on the moon, an isotope called helium-3, delivered to the surface through powerful winds from the sun, which Earth’s magnetic field blocks out. Scientists have suggested transporting helium-3 back to Earth, where its nonradioactive properties could produce safer nuclear energy. But “it’s a very futuristic concept,” Spencer says. “I’m not saying this first return to the moon is going to lead directly to that. I think over the long term, there could be possibilities that could be really enabling.”

A lunar outpost, whether a city or a mine, would require years of effort, but there was no mention of that in Pence’s speech. The vice president said that Trump wants NASA to meet the 2024 deadline “by any means necessary,” but he didn’t discuss what would happen after.

“If all they do is that first mission, it will wind up very similar to Apollo,” Spencer says. “It’ll be Apollo with newer technology.”

The déjà vu in Pence’s speech was palpable. “We’re in a space race today, just as we were in the 1960s, and the stakes are even higher,” he said. As proof, he brought up China’s historic landing on the far side of the moon in January, and the United States’ costly reliance on Russian launch systems to deliver American astronauts to the ISS. “The first woman and the next man on the moon will both be American astronauts, launched by American rockets, from American soil,” Pence said.

In other words, the Trump administration wants to make the moon American again. The last president to set his sights on the moon, George W. Bush, called for a similar return in 2004, but he set the deadline for 2020, long after he’d leave the White House, taking his slogans with him. The fact that the Trump administration has picked 2024, the final year of a potential second term, is telling. Trump might be trying to produce a decisive accomplishment on a timeline that can’t be undermined by his successor.

But the rush is also part of a larger attempt to produce as many showy achievements in space as possible to bolster Trump’s legacy, an effort that began soon after he took office.

“The common thread among many of the policy options, transition and industry officials said, is a focus on projects able to attract widespread voter support that realistically can be completed during Mr. Trump’s current four-year presidential term,” The Wall Street Journal reported in February 2017.

Days after the inauguration, White House officials asked NASA to consider putting people on its first test of the Space Launch System, the beleaguered moon rocket, which would occur during a Trump term. The plan had been to wait until the second flight to make sure the first one, you know, didn’t blow up. NASA staff reviewed the option, but ultimately decided against it.

A few months after that, Trump reportedly asked the acting administrator of NASA whether the agency could send people to Mars in the next few years, a feat that would require buckets of money and probably defy the laws of physics. “But is there any way we could do it by the end of my first term?” Trump asked. “But what if I gave you all the money you could ever need to do it? What if we sent NASA’s budget through the roof, but focused entirely on that instead of whatever else you’re doing now. Could it work then?”

The moon seems far more achievable in comparison.

American astronauts made it to the moon eight years after Kennedy declared that the country should send them. It’s impossible to predict whether Trump’s plan will work and, if it does, whether the next president will decide to keep going. He or she might say, as Barack Obama did in 2010, when he scrapped Bush’s moon plans, that “we’ve been there before,” and that Americans should aim for somewhere else. After a triumphant return, the United States might find itself back where Gene Cernan left it decades ago, ready to blast off “this mutha.”

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