The Trump Administration’s plan to hand the International Space Station off to the private sector by 2025 probably won’t work, says a government auditor. It’s unlikely that any commercial companies will be able to take on the enormous costs of operating the ISS within the next six years, the auditor said.

NASA’s inspector general, Paul Martin, laid out his concerns over the space station’s transition during a Senate space subcommittee hearing May 16th, helmed by Sen. Ted Cruz (R-TX) and Sen. Bill Nelson (D-FL). During his testimony, Martin said that there’s just no “sufficient business case” for space companies to take on the ISS’s yearly operations costs, which are expected to reach $1.2 billion in 2024. The industries that would need the ISS, such as space tourism or space research and development, haven’t panned out yet, he noted. Plus, the private space industry hasn’t been very enthusiastic about using the ISS either — for research or for profit. “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 at the hearing.

“the scant commercial interest shown in the station over its nearly 20 years of operation gives us pause.”

President Trump’s budget request in February called for NASA to end direct federal funding for the ISS by 2025 as a way to free up funds for the space agency’s future projects. Currently, the space station costs NASA at least $3 to $4 billion each year to operate, and the administration wants to redirect that money to other things, such as developing new hardware to get back to the Moon. But rather than get rid of the ISS altogether, NASA proposed the idea of commercial companies taking over the station. Companies could operate the whole thing or parts of it. Or they could put up their own habitats instead.

However, Martin said today that transitioning the ISS to the private sector probably wouldn’t save NASA that much money, anyway. That’s because the space agency would still continue to send astronauts and cargo to and from the privatized space station (or any other commercial habitat that’s in low Earth orbit). And transportation is expensive. For instance, NASA has allocated $1.7 billion on transporting astronauts and supplies to the ISS in fiscal year 2018. “Any assumption that ending direct federal funding frees up $3 to $4 billion beginning in 2025... is wishful thinking,” Martin said.

Given all of these issues, Martin said NASA has an obvious alternative: extend funding of the ISS beyond 2024 — the year that the program’s budget is currently slated to end. Martin said his office found that many of NASA’s research goals for the station, such as studying space health risks and testing out new technologies, won’t be completed by then anyway; an extension would give the agency more time to get all these studies done. And Boeing, which built most of the ISS, maintains that most of the vehicle can last up until 2028, without major maintenance needed.

An extension is something that both Cruz and Nelson adamantly support. The two senators, both of whom represent states with major NASA centers that oversee the ISS, were vocal about stopping the administration’s plans. “Let me be clear: as long as I’m chairman of this subcommittee, the ISS will continue to have strong support — strong bipartisan support — in the United States Congress,” Cruz said in his opening statement. Nelson also said the administration’s proposal to end ISS funding is “dead on arrival,” arguing that the ISS is a critical platform needed for astronaut training and technology development. “If this plan to prematurely end the current ISS program moves forward, I fear that NASA’s expertise in these critical areas — expertise that we’re going to have to have if we’re going to Mars with humans and safely return — that that expertise is going to be lost,” said Nelson.

“Let me be clear: as long as I’m chairman of this subcommittee, the ISS will continue to have strong support.”

Cruz maintained that ending the ISS program early without a suitable replacement would be a disaster for NASA. “Prematurely canceling a program for political reasons costs jobs and wastes billions of dollars,” he said. He also argued that setting the 2025 date was an arbitrary decision not backed by science. At the hearing, the senator asked NASA’s associate administrator for human exploration, William Gerstenmaier, if the date was originally proposed by NASA or the administration. “It originated in the administration,” Gerstenmaier replied.

Extending the space station program comes with its own set of cons, though. The risk of a failure on the ISS goes up the longer it lasts in orbit, and keeping the program fully funded means NASA will continue to incur costs of $3 to $4 billion each year. Plus, the extension partially depends on NASA’s international partners, such as Japan and the European Space Agency, which cover 23 percent of NASA’s costs to maintain the ISS. And it’s unclear if they want to continue operating the space station either, according to Martin.

NASA’s other alternative is to get rid of the ISS altogether, by slowly taking it apart piece by piece and plunging that hardware safely into Earth’s atmosphere. But that’s not as easy as it sounds. De-orbiting the space station will be a three-year process that’s estimated to cost $950 million, according to the inspector general.

So any choice that NASA picks for the future of the ISS will require a lot of planning and money. Congress is still in the process of finalizing the budget for NASA for next year, and it seems likely lawmakers will try to keep the ISS around for a lot longer. But the space agency needs to know which route the ISS program is going to take. “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.