Under the administration's budget proposal, released Monday, NASA would stop paying for the space station by 2025.
The proposal also calls for spending $150 million in 2019 to "encourage commercial development" and tee up companies to take over. It would be dubbed the Commercial LEO (Low-Earth Orbit) Development program.
The administration wants to focus on exploring deep space — sending people back to the moon and perhaps beyond. The budget proposal calls for $10 billion to "support human space exploration and to pursue a campaign that would establish U.S. preeminence to, around, and on the Moon."
The White House considered asking for $19.6 billion overall for NASA, 2.6% more than in the current fiscal year. Last week, the administration decided to ask for another $300 million, bringing the total to $19.9 billion, NASA chief financial officer Andrew Hunter said.
The proposal doesn't call for NASA to abandon the space station entirely. The agency would work with "commercial partners" for research and other projects.
But it's not clear how much NASA would do after 2025. Nor is it certain how the agency would spend the $150 million for commercial development that was suggested in the budget proposal.
"I won't pretend that we're exactly precise," Hunter told the media Monday when he was asked about how that money could be spent. "We have a lot of work to do."
The proposal to privatize the space station doesn't come as a big shock. Rumors about ending federal funding have circulated for some time, and The Washington Post reported on the plans over the weekend.
The space station is an international partnership, and it's not clear what privatizing the U.S. portion would mean for the other countries.
Plus, it's up to Congress to pass a budget, not the president. So the White House's proposal is more a statement of priorities -- and not everyone is happy with it.
Republican Senator Ted Cruz of Texas, who chairs the Senate Subcommittee on Space, said last week that it had to be "numbskulls" at the Office of Management and Budget who proposed ending federal funding for the space station, The New York Times reported.
And the Commercial Spaceflight Federation, which represents companies like Elon Musk's SpaceX and Jeff Bezos's Blue Origin, said defunding the station before 2028 "would not allow sufficient time" for a private sector transition.
Putting $150 million toward commercial development for the space station would be a "great indication" the administration is confident in what the private sector can do, CSF executive director Tommy Sanford told CNN.
But finding companies to run U.S. operations cost-effectively by 2025 would be a heavy lift.
"It's a good place for the conversation to begin," said Andrew Rush, CEO of Made in Space, which uses 3D printing to build hardware for space. But he's said he not convinced the industry could bear the financial burden of maintaining the space station by the mid-2020s.
Robert Bigelow, the founder of Bigelow Aerospace, a private company that has its own module attached to the space station, praised the budget proposal.
He said the move would put the U.S. on course to "do something exciting" in space for the first time in years, adding that his company is "ready" to partner with NASA on its moon efforts.
But pulling NASA funding would likely still have an effect on the space station's future.
The American lab on board the ISS -- called the U.S. National Laboratory -- already conducts experiments partly paid for by private industry, but those experiments could get much more expensive if federal funding is cut off.
Right now, all researchers who send experiments to the space station get a free ride and free labor. NASA pays for launch costs and astronauts' time to run the experiments.
The government-funded Center for the Advancement of Science in Space, which manages the lab, has selected 190 payloads since 2012, and 106 have involved a commercial research project. Drug companies like Merck and Eli Lilly have used the space station to research medications.
CASIS said Monday it doesn't know what a commercially run space station would look like, but "looks forward to working with both the Administration and Congress on the future of the International Space Station."
In a statement, the center pledged to keep working to educate the public on "the critical role this research platform plays in the development of a robust and sustainable economy in low Earth orbit."
Rocket builders SpaceX and Orbital ATK have contracts with NASA to complete supply missions without crews.
And SpaceX and Boeing are each developing spacecrafts to send astronauts to and from the space station. The proposed budget would continue support for those endeavors, NASA acting administrator Robert Lightfoot said Monday.