WASHINGTON: The 2019 budget estimate for NASA announced by the Donald Trump administration on Monday puts the agency on a path to lead the return of Americans to the Moon with a goal to send humans to Mars. Nearly half of the proposed $19.9 billion budget -- $10.5 billion -- is earmarked for "an innovative and sustainable campaign of exploration and lead the return of humans to the Moon for long-term exploration and utilisation followed by human missions to Mars and other destinations," according to a NASA overview. "In short, we are once again on a path to return to the Moon with an eye toward Mars. 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. "We are leveraging multiple partners both here at home and internationally in developing a sustainable approach where the Moon is simply one step on our truly ambitious long term journey to reach out farther into the solar system to reap the economic, societal, and expanding knowledge benefits such an endeavour will bring," Mr Lightfoot added. While NASA will move forward with plans to create a new space station around the Moon -- the Lunar Orbit Platform-Gateway - the budget confirmed earlier reports indicating plans to end funding for the International Space Station (ISS) in 2025. "This budget proposes for NASA to ramp up efforts to transition low-Earth activities to the commercial sector, and end direct federal government support of the ISS in 2025 and begin relying on commercial partners for our low-Earth orbit research and technology demonstration requirements," Mr Lightfoot said. "Further, drawing on the interests and capabilities of our industry and international partners, we'll develop progressively complex robotic missions to the surface of the Moon with scientific and exploration objectives in advance of human return there," he added. Mr Lightfoot said that the Space Launch System rocket and Orion spacecraft are critical backbone elements for moving farther into deep space. "Their momentum continues this year toward the first integrated launch of the system in fiscal year 2020 around the Moon and a mission with crew in 2023," Mr Lightfoot said. When that mission launches, it will be the first human mission to the Moon since Apollo 17 in 1972.