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American presidents, when they talk about the country’s space program, often reach for grandiose terms. John F. Kennedy spoke of setting sail on a new sea, and Lyndon B. Johnson of “space pioneers” bound for a “glorious New World.” George H. W. Bush likened space missions to Christopher Columbus’s voyage across the Atlantic, and George W. Bush harkened back to the expedition of Lewis and Clark. Bill Clinton and Barack Obama talked of exploring the next frontier.

Donald Trump, too, has picked up this theme of American expansionism, and pushed it even further. “In reaffirming our heritage as a free nation, we must remember that America has always been a frontier nation. Now we must embrace the next frontier: America’s manifest destiny in the stars,” Trump said earlier this year, during his State of the Union address. This summer, after the first American astronauts to fly on a SpaceX capsule launched to the International Space Station, the White House’s Twitter account cheered Americans as those “who pursued our Manifest Destiny”—capital M, capital D—“into the stars.”

In mentioning manifest destiny, Trump has resurrected an idea most commonly found in history books. This was the philosophy that white Americans used to describe their westward expansion in the 19th century, led by their conviction that they were ordained by God to spread their will across the continent. The doctrine ignored the existence and rights of the Indigenous people in their path, who were driven from their homes and slaughtered. This philosophy, premised on racist beliefs of the past, doesn’t align with any of America’s ambitions in space exploration today.

American exceptionalism has underpinned this country’s experiment in outer space since its beginnings; the Apollo astronauts launched toward the moon in the name of national glory, not pure scientific discovery. But when Trump invokes manifest destiny, his long record of bigotry and association with white supremacists starts to infuse America’s future in the cosmos. The use of language that defined a painful chapter in American history excludes people from an endeavor that, in recent decades, NASA has pushed to open to all. When leaders draw from that narrative, they don’t inspire the broadest participation in one of America's most impressive projects. They stunt the possibilities of the future instead.

A president’s words about space are, in part, a recruitment tool. In the 1960s, Kennedy's soaring rhetoric about the space race helped make NASA a destination for some of the country's most talented engineers. But the people who came to be involved in America’s burgeoning space effort, from astronauts and engineers to lawmakers and executives, were nearly all white men. When the Apollo 11 crew took off in the summer of 1969, only one woman was in the control room at Cape Canaveral, and she was white.

The space-shuttle era, which began in the early 1980s, was meant to change those demographics, at least for the astronaut corps. The space shuttles were roomy and made regular trips into space, and their larger crews became more representative of the American population. NASA flew its first female, Black, and Asian astronauts to space that decade. Inside the agency, women and people of color would have faced the same discrimination they might have in any other workplace of that era, but NASA cultivated an image as an equal-opportunity employer.

In 2006, during the George W. Bush administration, NASA formally adopted a new vocabulary that many of its workers were already using as more women became astronauts: Spaceflight with astronauts would officially be known as “human” or “crewed,” not “manned.” Leland Melvin, a retired NASA astronaut, often uses this anecdote to convey the power of language: When he once asked a group of young children if any of them wanted to be astronauts, only boys raised their hands. The girls, they told him, thought the job was reserved for men. “From that point on, whenever I showed Neil Armstrong saying, ‘One small step for man, one giant leap for mankind,’ I always changed the language” to humankind, Melvin told me recently. “You just don’t know what little girl in that room is going to say, ‘Oh, that’s just for the men.’”

I wrote about this phenomenon last year, and when I asked NASA to comment, the agency was quick to rebuke the outdated use of “manned” spaceflight. “Now if we could just get others to follow suit,” a spokesperson told me. But when I asked NASA to comment this summer on the White House’s use of “manifest destiny,” it sidestepped the question. “We were excited to have the President and Vice President at Kennedy Space Center to witness the historic launch and capture this important moment in American history,” Matthew Rydin, a spokesperson for the NASA administrator’s office, wrote in an email. Earlier this year, after Trump used the term in his State of the Union address, Jim Morhard, NASA’s deputy administrator, by way of explanation for the president’s choice of words, tweeted a skewed interpretation of the concept. Manifest destiny, he said, “was the belief that the United States was destined to promote democracy & free enterprise across North America.”

If language that marks space exploration as male territory can count out little girls, language that codes white can exclude people of color. Young Americans who dream of working for NASA someday—or for SpaceX or Blue Origin—could easily be deterred by terminology drawn from the country's colonial history. “Native kids, when they hear the words colonizing and pioneers and the frontier, that makes the hair on the back of their neck stand up,” says John Herrington, a retired NASA astronaut and the first enrolled member of a Native American tribe to go to space.

In recent years, a movement has been growing to rethink the vocabulary that describes humankind's dreams for an off-Earth future, specifically to weed out language closely associated with colonialism. A popular argument against this effort points out that, unlike Earth, the other planets and moons of the solar system are uninhabited. If life exists on these worlds, it’s most likely in the form of tiny microbes, easily squashed under a spacesuited foot. What’s so bad about saying we should colonize Mars when there’s no one there anyway?

Even if Martians aren’t going to protest our arrival, space exploration presents plenty of other opportunities for the exploitative dynamics of the colonial era to reemerge. Colonial-era travel spread invasive species across the planet; space-era travel could seed earthlings all over the solar system. Last year, for instance, an Israeli spacecraft crash-landed on the surface of the moon and spilled several thousand dehydrated tardigrades, microscopic animals that can survive extreme conditions. The creatures had been snuck aboard by a space entrepreneur who was only supposed to contribute a DVD-size compilation of human knowledge. “Technically, I’m the first space pirate,” he said when news of the stowaways was revealed, much to the horror of space lawyers and planetary-protection researchers. Connecting colonial language to space travel also helps shore up expansionist behavior on Earth: For the past six years in Hawaii, astronomers and local protesters have been locked in a standoff over the construction of a new telescope near the site of Mauna Kea, on land that native Hawaiians consider sacred.

“It’s a real failure of imagination to just keep recycling really harmful language and saying that it doesn’t matter because space is somehow different,” says Lucianne Walkowicz, an astronomer at the Adler Planetarium, in Chicago, and the organizer of the 2018 Decolonizing Mars conference. “We are still human beings, even if we go to space.”

If astronauts are the elite of space workers, in the future a less powerful class could form, and language associated with exploitation and domination could make those people that much more vulnerable. “The use of this language can give policy makers and decision makers excuses to do bad things because it’s in the name of these really lofty things,” Divya Persaud, a planetary scientist at University College London who has written about the meaning of language in space domains, told me. Asteroid miners, for instance, would be dependent on their faraway employers for health care, safe working conditions, and, quite literally, life support. Oversight can be dicey when your operations are millions of miles away from the only planet with regulatory agencies (that we know of).

People are drawn to sweeping rhetoric, wrapped up in fate and higher purpose, because it offers romantic ways of thinking about places they’ve yet to visit. But bringing God into space exploration, as the concept of manifest destiny does, complicates the issue even further. “It does hurt. This idea of It’s provenance; it’s inspired by God—they are taking it out of a human aspect and saying, ‘Hey, we’re being led by something else, something that’s greater than we are,’” Herrington says. “Take ownership and responsibility for what you’re doing. Don’t say somebody else is making us do it.”

The way past manifest destiny and other colonial-era language can be simple: Be specific. Just as crewed is a more accurate word than manned, other phrases could easily sub in for the more outdated ones. “Instead of trying to say ‘settlement on Mars’ or ‘colony on Mars,’ why don't we just say, ‘We sent 12 astronauts to Mars?’” Persaud said.

Melvin, who is Black, suggested pitching space exploration as something to benefit all humankind, not just the United States. He’s seen Earth as it truly is, a borderless place set against the boundless darkness of space. “You’re watching the world below you while you’re breaking bread with French, German, Russian, Asian American, African American [astronauts]—people from all around the world working together as a team,” Melvin said. “And you know that if Yuri does something wrong, or I do something wrong, or Peggy does something wrong, we can all die.”

American leaders have, at times, sold space exploration as an international effort, as a boon for all humankind, as a push for scientific discovery. But in the U.S.—and Russia and China and India and other spacefaring nations—space travel is still a nationalist project. This spring, when NASA launched astronauts from U.S. shores for the first time in nearly a decade, the agency’s leaders pointed out, over and over, that the job was done by “American astronauts on American rockets from American soil.” And the next people to go to the moon, NASA officials have emphasized, will be Americans, and so will the first visitors to Mars.

Language matters. When presidents speak of the country’s spirit and its space program in the same breath, when they yoke America’s strength to its feats beyond Earth, they end up describing the nation both as it exists today and as they imagine it in the future. By borrowing from a time when the dominant philosophy staked out American land for white settlers at the expense of the people who already lived there, Trump shows his hand about whom he believes the future of this country is for, whether here on Earth or on worlds beyond.

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