White House budget plans are zeroing in on zeroing out federal funding for the International Space Station by 2025, to free up money for a Deep Space Gateway in lunar orbit.

The plan is already generating opposition from those who want to leave the door open for continued government involvement in the space station beyond 2025, including Sen. Bill Nelson, D-Fla.

“If the administration plans to abruptly pull us out of the International Space Station in 2025, they’re going to have a fight on their hands,” Nelson, the ranking Democratic member of the Senate Commerce, Science and Transportation Committee, said in a statement.

“Such a move would likely decimate Florida’s blossoming commercial space industry, which is one of the reasons why Congress has directed NASA to look at extending the ISS to 2028 and to provide a plan to help scientists and researchers continue experimenting in low-Earth orbit beyond that,” Nelson said.

As described by The Wall Street Journal and other media outlets, the White House’s draft spending proposal for fiscal year 2019 would call for ending direct funding for space station operations by 2025 and transitioning to commercial provision of spaceflight capabilities in low Earth orbit.

At the same time, NASA would ramp up a campaign focused on the vicinity of the moon, known as cislunar space, to “establish U.S. pre-eminence to, around and on the moon.”

Details of the budget proposal could change between now and the Feb. 12 release date.

NASA already has begun talks with space station partners on the cislunar outpost known as the Deep Space Gateway, which is likely to be built in cooperation with Russia and other nations. Popular Mechanics reported that officials from NASA and other space agencies gathered in Tokyo over the past few days to plan for construction in the 2020s.

NASA sees the Deep Space Gateway as a steppingstone to Mars missions in the 2030s. (To be fair, that’s what they said about the International Space Station when it was being planned.)

For more than a decade, White House officials have struggled with the tension between continuing to spend roughly $4 billion annually on the International Space Station and shifting some or all of that money to boost space travel beyond Earth orbit.

So far, the space station partners have committed to keeping the station funded only through 2024, but as Nelson said, the door is still open for an extension to 2028. A variety of commercial space ventures have been pushing for greater clarity about NASA’s plans so they know what’s likely to get funded during a given time frame.

There’s a chance that one of those ventures might be interested in taking over operation of a U.S. segment of the space station.

Robert Bigelow, the billionaire founder of Bigelow Aerospace, said in a tweeted statement that the debate over defunding the space station “doesn’t have to be a zero-sum game.”

“ISS operations should continue, provided there are aggressive initiatives to use commercial platforms for human space operations in parallel with the continued use of the ISS until such time that NASA can safely relieve itself of the enormous financial burden,” Bigelow said.

NASA is currently testing Bigelow Aerospace’s expandable space module on the space station, and Bigelow has proposed sending up more modules under the terms of a public-private partnership.

The space agency is also funding an assortment of studies looking at the options for the Deep Space Gateway and other beyond-Earth-orbit habitats under the aegis of its NextSTEP-2 program. Just today, Sierra Nevada Corp. reported that it has signed contracts with NASA, in partnership with Aerojet Rocketdyne and ILC Dover, to design and develop an on-the-ground prototype for a deep space habitat by 2020.

Other NextSTEP-2 partners include Bigelow Aerospace, NanoRacks, Orbital ATK, Boeing and Lockheed Martin.

Clarification for 11:10 p.m. PT Jan. 25: In an earlier version of this report, I speculated that ventures such as NanoRacks and Axiom Space might be interested in taking over the operation of a U.S. segment of the space station. But in a tweet, Axiom’s Amir Blachman said his company wasn’t considering that option. “We are building the commercial successor to ISS (a new space station),” he wrote.