"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,", which was released on Monday.
The space agency next year would invest $150 million as an initial investment in commercial capabilities that by 2025 would provide a "seamless transition" from NASA's existing ISS program.
Private businesses are already involved in several space projects.
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.
The U.S. has contributed roughly $100 billion to the ISS since its creation in the 1990s.
The $19.9 billion spending plan for 2019, up about $400 million from this year, seeks to refocus human exploration on the moon and shift responsibility for low Earth orbit missions to industry or worldwide partners.
President Trump wants NASA to focus more on human exploration to Moon and Mars and that is why it wants the space agency to give less emphasis on ISS in the coming years.
"The ISS is built for science and human exploration, it's not built for profit seeking", quipped Andrew Rush, the chief executive of Made In Space. Shown here: an artist's depiction of NASA's Deep Space Gateway in orbit near the moon.
Among the concerns amongst space experts about Trump's proposal are the legal liabilities an orbiting, inhabited space station could run into.
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About 2000 USA forces remain on the ground in Syria , allied to the Kurdish-led SDF alliance. "We are there to fight ISIS". A stronghold of Islamic State jihadists until late past year , the area was the group's main source of oil revenue.
A complete transfer to the commercial sector is a different matter, however.
But key US legislators and space experts are expressing concern about the plan.
The US government would create a $150m programme to help prepare private companies to take over space station operations over the next seven years, according to the document.
The International Space Station was photographed from the space shuttle Atlantis as a shuttle departed the orbiting complex for the final time in the early hours of July 19, 2011.
And SpaceX and Boeing are each developing spacecrafts to send astronauts to and from the space station.
While the budget plan said it places renewed support on returning humans to the moon, followed by human expeditions to Mars and elsewhere, no precise timeline and few details are provided.
The ISS, which orbits some 400 kilometres above Earth, is now supported in a joint project by the U.S., Russian, Japanese and European space agencies. "NASA is called to refocus existing activities towards exploration, by redirecting funding to innovative new programmes and support for new public-private initiatives", acting NASA Administrator Robert Lightfoot said in a statement.
NASA in 2022 hopes to launch the first portion of a small station to be placed in orbit around the moon.
The WFIRST telescope's cost estimates have ballooned to $3.6 billion and Hunter said it just got too expensive.