In 1942, not long after the attack on Pearl Harbor, the poet Archibald MacLeish wrote an essay called “The Image of Victory,” in which he asked what winning the Second World War, the “airman’s war,” would mean for posterity. MacLeish believed that pilots could do more than bring victory; by literally rising above the conflicts on the ground, they could also reshape our very understanding of the planet. “Never in all their history have men been able truly to conceive of the world as one: a single sphere, a globe, having the qualities of a globe, a round earth in which all the directions eventually meet, in which there is no center because every point, or none, is center—an equal earth which all men occupy as equals,” he wrote. The airplane, he felt, was both an engine of perspective and a symbol of unity.

MacLeish could not, perhaps, have imagined the sight of a truly whole Earth. But, twenty-six years after his essay appeared, the three-man crew of Apollo 8 reached the highest vantage point in history, becoming the first humans to witness Earth rising over the surface of the moon. The most iconic photograph of our planet, popularly known as “The Blue Marble,” was taken by their successors on Apollo 17, in 1972. In it, Earth appears in crisp focus, brightly lit, as in studio portraiture, against a black backdrop. The picture clicked with the cultural moment. As the neuroscientist Gregory Petsko observed, in 2011, in an essay on the consciousness-shifting power of images, it became a symbol of the budding environmentalist movement. “Our whole planet suddenly, in this image, seemed tiny, vulnerable, and incredibly lonely against the vast blackness of the cosmos,” Petsko wrote. “Regional conflict and petty differences could be dismissed as trivial compared with environmental dangers that threatened all of humanity.” Apollo 17 marked America’s last mission to the moon, and the last time that humans left Earth’s orbit.

It was always part of NASA’s mission to look inward, not just outward. The National Aeronautics and Space Act of 1958, which established the agency, claimed as its first objective “the expansion of human knowledge of phenomena in the atmosphere and space.” NASA’s early weather satellites were followed, in the seventies and eighties, by a slew of more advanced instruments, which supplied data on the ozone layer, crops and vegetation, and even insect infestations. They allowed scientists to recognize and measure the symptoms of climate change, and their decades’ worth of data helped the Intergovernmental Panel on Climate Change conclude, in 2007, that global warming is “very likely” anthropogenic. According to a report released last month by NASA’s inspector general, the agency’s Earth Science Division helps commercial, government, and military organizations around the world locate areas at risk for storm-related flooding, predict malaria outbreaks, develop wildfire models, assess air quality, identify remote volcanoes whose toxic emissions contribute to acid rain, and determine the precise length of a day.

These seem like key functions of civilization as we know it, which is why scientists were deeply alarmed when Bob Walker, a ten-term former congressman from Pennsylvania turned senior adviser to President-elect Donald Trump, recently proposed that the division’s two-billion-dollar annual budget be “realigned.” “Earth-centric science is better placed at other agencies where it is their prime mission,” Walker told the Guardian in November. NASA, he said, should be focussing on deep-space research, which is to say anything beyond Earth’s orbit. Speaking to Scientific American, Walker clarified his position. “When we talk about ‘deep-space activities,’ we’re talking about planetary science and space-based telescopes and all those kinds of things,” he said. “There have been concerns among some of us that those sorts of NASA programs were robbed in order to concentrate on Earth science.”

Walker didn’t specify who “us” was, but he stressed that the proposal was “not ideological.” In October, however, he and Peter Navarro, a business professor at the University of California, Irvine, and another Trump adviser, had published an op-ed in Space News characterizing Earth observation as “politically correct environmental monitoring” and implying that the Earth Science Division has been engaging in partisan climate pandering rather than honest research. “NASA’s core missions must be exploration and science—and inspirational!” they wrote, recalling the conquering-hero spirit of the space race.

Dozens of scientists have since warned that cutting the division’s budget would have far-reaching, potentially devastating consequences. But how likely is it to happen? Kevin Trenberth, a senior scientist in climate analysis at the National Center for Atmospheric Research—and one of more than eight hundred researchers to sign a recent open letter urging Trump to act on climate change—told me that NASA’s contractors, being numerous and widespread, might be able to “mount a defense outside the scientific community.” That is, they could advocate for the division on the basis of the sheer number of jobs and functions that depend on its findings. “Many parts of NASA do more than one thing, and so there are often no clean lines,” Trenberth said. “But cuts would hurt. They would propagate into the NASA labs and especially into the university and corporate sectors through grants.” As for missions already in progress, he said, “how this plays out is murky.” Steve Cole, the division’s public-affairs officer, declined to speculate, noting that “there is very little substantive information about the new Administration’s plans for NASA at this point.”

NASA has always been beholden to the President’s agenda; its priorities drifted farther from Earth during the George W. Bush Administration, then back again under Barack Obama. But while this is a frightening time to contemplate the loss of satellites that monitor sea levels, there is also something subtler at stake. Trump once said, in an interview, “I don’t like to analyze myself because I might not like what I see.” Under his Administration, NASA may be forced to mirror this resistance to self-analysis. But can we really do without that perspective? We seem to need to see the planet as a whole in order to think about it as such.

Generations of astronauts, after looking at Earth from space, have professed a profound new understanding of it. Edgar Mitchell, who, in 1971, became the sixth man to walk on the moon, said, “From out there . . . international politics look so petty. You want to grab a politician by the scruff of the neck and drag him a quarter of a million miles out and say, ‘Look at that, you son of a bitch.’ ” Michael Collins, Neil Armstrong’s crewmate on Apollo 11, expressed similar sentiments in his memoir, “Carrying the Fire,” which was published in the midst of the Cold War. Seeing our home planet from afar, he wrote, prompted an epiphany: “The earth must become as it appears: blue and white, not capitalist or Communist; blue and white, not rich or poor; blue and white, not envious or envied.”

Mike Massimino, in his memoir, “Spaceman,” reports having spent almost a full day staring out a window of the Space Shuttle Columbia, watching sunrises and lightning storms (“like a form of communication, like a sequence, like the clouds are alien creatures speaking to each other in code”). On his second spacewalk, Massimino told me recently, he had a spare moment to “take in the view.” He recalls being struck not only by Earth’s incredible beauty—“We are living in a paradise”—but also by its fragility. From out there, he said, especially during night passes, “you can see the thinness of the atmosphere,” a bluish-green line. This sudden perception of Earth as a delicate, intricate system is so common among astronauts that the writer Frank White coined a term for it: the overview effect.

Astronauts are endlessly fascinating to me, in part because they have a knack for poignant quotations. Buzz Aldrin, for instance, described the lunar landscape as a vision of “magnificent desolation,” a grand phrase for a bleak truth. Unlike our paradisiacal, blue-and-white Earth, the moon has no atmosphere and no real sky—just gray dust and black space, such that color photographs from moonwalks appear mostly black and white, as though someone colorized the American flags after the fact. NASA brought six flags to the moon, on poles outfitted with horizontal crossbars so that the stars and stripes would show, as though caught in a nonexistent breeze. The flags are still there, but radiation is presumed to have left them in tatters—monuments to our love of Earth, or maybe just litter.