The white house proposal released on Monday says, "The budget proposes to end direct United States financial support for the International Space Station in 2025, after which NASA would rely on commercial partners for its low Earth orbit research and technology demonstration requirements".
But it also includes $150m (£108m) to "encourage commercial development" at ISS to replace American payments.
The idea is to ensure a seamless transition from government-funded ISS operations to an outpost using new components, or even elements of the current space station, that would be operated as a base for private sector innovation, global cooperation and NASA experiments and research needed for eventual flights back to the moon and on to Mars.
Democrat senator Bill Nelson of Florida, who was once an astronaut himself, said "turning off the lights and walking away from our sole outpost in space" made no sense.
NASA now spends about $3 billion a year on station operations and support, maintaining the U.S. segment of the outpost, supplying spare parts and other critical cargo and buying seats aboard Russian Soyuz spacecraft to ferry U.S., European, Canadian and Japanese astronauts to and from the outpost.
It also calls for $10.5bn for "an innovative and sustainable campaign of exploration" leading to "the return of humans to the moon for long-term exploration and utilization followed by human missions to Mars and other destinations", according to a Nasa review.
"We're building capability for the eventual human exploration of deep space and the moon is a stepping stone", NASA's acting chief financial officer Andrew Hunter said in a Monday news conference.
The International Space Station has hosted astronauts since 2000.
The budget also confirms the cancellation of five Earth-science missions proposed for termination previous year.
The Trump administration has submitted its budget proposal to congress for approval.
The space station is scheduled to operate through 2024.
Boeing, along with Elon Musk's SpaceX, are both in the process of developing crew transportation systems to enable US astronauts to travel on an American-made space vehicle-currently the USA pays Russian Federation $80 million per seat to travel on Russia's Soyuz spacecraft. President Barack Obama extended that model to hire Boeing and SpaceX to fly astronauts there.
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". The supersize Space Launch System rocket being built by NASA to send astronauts beyond low-Earth orbit - along with its Orion crew capsule - would get $3.7 billion under this budget.
When that mission launches, it will be the first human mission to the Moon since Apollo 17 in 1972. The budget for the mission was already being trimmed down after it was found to be getting too costly.
Hertz also added that only way to preserve the USA space agency's ability to meet the established target cost and deliver the project on time is to maintain progress against the existing plan, should Congress decide against Trump's proposal to eliminate WFIRST.