NASA / Getty

The International Space Station was never meant to last forever.

This was a distant concern in late 1998, when the United States, Canada, Russia, Japan, and European nations started launching hardware into space to assemble the largest human-made structure in orbit around Earth. But as the years went on—as the station’s operations expanded, as humans lived and ate and slept inside its cozy modules, as equipment broke and was repaired—some of the station’s stewards started to think more seriously about its future.

The question of how to wind down the ISS has come up regularly in the last decade. At each turn, the United States has extended its operating lifetime, to beyond 2016, then through 2020, and then to 2024. Many had suspected operations would eventually receive another extension, until 2028, while the station’s contractors said aging hardware might become problematic for the humans onboard.

The Trump administration had a different vision. In February, the White House released a budget request that called for NASA to end funding for the ISS by 2025 and turn over some operations to private spaceflight companies. NASA would then be able to use the money it currently spends on the ISS for other projects, like next-generation rockets and deep-space missions, the reasoning went.

The proposal was unpopular with many scientists, astronauts, and politicians, particularly lawmakers whose home states house NASA facilities that support ISS operations. But the Trump administration doesn’t appear to be backing down on the plan, and it has a new spokesperson: Jim Bridenstine, the freshly sworn-in administrator of NASA.

Bridenstine has been in talks with “many large corporations” about forming a consortium that would assume responsibility for ISS operations and keep the station running as a commercial platform, he said an interview with The Washington Post published Tuesday.

“We’re in a position now where there are people out there that can do commercial management of the International Space Station,” Bridenstine said.

While the idea of privatizing some or all of the ISS is not new, the Trump administration is the first to formally endorse it in policy proposals. Bridenstine didn’t name any companies, and acknowledged that convincing private businesses to take on such an expensive venture won’t be easy. But the country has seven years to figure it out, he said, and “we have forced the conversation.”

Indeed, Bridenstine’s remarks in the Post will not be the last on this matter. But where the conversation goes from here will be interesting to see in the coming months—especially because the White House is largely alone in thinking this plan will work.

Last month, Paul Martin, NASA’s inspector general, told the Senate that he doesn’t think there’s a “sufficient business case” for commercial companies to take on the significant cost of managing the ISS, which requires between $3 billion and $4 billion a year. On top of that, it doesn’t seem like anyone’s even interested. “Candidly, the scant commercial interest shown in the station over its nearly 20 years of operation gives us pause about the agency’s current plans,” Martin said. He added that off-loading ISS operations likely wouldn’t save NASA as much money as the feds think, since the government would probably still have to pay for transporting astronauts and cargo to the station, which costs tens of millions of dollars a trip.

“The sooner that Congress and the administration agree on a path forward for the ISS, the better NASA will be able to plan,” Martin said.

Such agreement is unlikely. Bridenstine will likely find few friends on this issue in Congress, where the fate of the ISS falls not on party lines, but on state lines, creating some rare bipartisan opposition to the Trump administration. Among the most vocal critics of the White House proposal are Bill Nelson, the one-time astronaut and Democratic senator from Florida, home of the Kennedy Space Center that launches cargo to the station, and Ted Cruz, the Republican senator from Texas, home of Johnson Space Center and ISS mission control. Both have spent the last several months railing against the administration’s proposal to shut the space station down so soon. They and other supporters of the ISS say the orbital lab is a valuable hub for testing technologies that benefit humans on Earth and may, someday, keep them alive on long-duration missions to Mars.

But the problem is that the space station is also mightily expensive. Critics of operating the ISS past its prime say it’s a boondoggle that was built, in part, because the United States needed somewhere to send its space shuttles. NASA has received some small boosts in its budget in recent years, but the space agency will never have enough money to keep the ISS running for years and pursue its ambitions for new, deep-space missions at the same time. The cracks are already starting to show as NASA moves forward with its development of a rocket launch system and capsule, which together are supposed to send astronauts toward the moon. Each ride on the Space Launch System is expected to cost taxpayers about $1 billion.

“In order to keep funding one into the future, it’s very likely the other needs to be cut or significantly reduced,” says Laura Forczyk, a space analyst and the founder of Astralytical, a consulting firm. “Whoever put the 2025 date into the Trump administration’s ear is a fan of SLS/Orion.”

Forczyk worked for several years for the Center for the Advancement of Science in Space, a government-funded research organization that supports, among other things, commercial spaceflight efforts. “I can tell you firsthand how difficult it was to secure commercial interest in using ISS unless there was a grant ... even with a ‘free rocket ride,’ paid by NASA,” she says. “It’s all very expensive, and only the largest companies could afford to invest their own funds and were willing to take on the inherent risks.”

Plus, most commercial technology isn’t mature enough to take on running the ISS. While companies like SpaceX and Orbital ATK have successfully cornered the market on flying cargo to the ISS, few are working on developing space stations of their own. The first privately built space habitat, from Bigelow Aerospace, launched to the ISS for testing in 2016. And if commercial companies ever venture into the realm of stand-alone space stations, they’ll probably want to start fresh. By the mid-2020s, most ISS hardware will be 30 years old. Like with cars, it may seem more appealing to buy a new station rather than spend millions of dollars repairing an old one.

As the Trump administration tries to entice new participants, it seems to be ignoring existing ones: other spacefaring nations. The fate of the ISS will not be decided solely by the United States, but alongside its partners: Russia, Canada, Japan, and the 22 nations that make up the European Space Agency. If the U.S. government wanted to extricate itself from the project, it would need to do so within the framework of a 20-year partnership. And if those other nations want to jump ship, they have another option. Just last week, China announced that all members of the United Nations would be welcome to work on its future space station, which is supposed to begin operations by 2022.

The latest debate over the ISS is yet another reminder that the end of this mission can’t be delayed forever. There will come a time when the United States will no longer be able to keep pushing the deadline any further, and spacefaring nations will need to reckon, together, with the fate of this home they built for themselves. Someday, the space station will become just too expensive, or just too old, and its stewards will make the difficult decision to let it slowly coast down toward the Earth and plunge into its oceans.

When that happens, the United States might find itself in a strange situation. If the country hasn’t yet settled humans on the moon, or maybe even Mars, its human-spaceflight program will revert, suddenly, back to the 1960s. Americans will have machines in orbit and on the surfaces of other planets and moons, but their feet will once again be planted firmly on the ground.