President Donald Trump wants to raise NASA's budget to $25.2 billion for the fiscal year beginning in October, an increase of 12 percent.

Nearly half that total would fund activities directed toward getting humans first to the moon, then to Mars. The budget requests $3.3 billion for human lunar landers, part of NASA's Artemis program, which aims for a lunar landing in 2024. The new documents would also cut several long-targeted program and introduce a mission that would study ice on Mars.

The details come from materials released Monday by the Office of Management and Budget, or OMB, as part of the administration's budget request, an annual submission to Congress that lays out the president's vision for the federal government and begins the budgeting process.

"This is a 21 century budget worthy of 21st century space exploration and one of the strongest NASA budgets in history," NASA Administrator Jim Bridenstine said during a State of NASA event unveiling the budget. "If the president's support for NASA wasn't clear before, it sure is now."

NASA was expected to post more detailed materials about its budget request later Monday. A fact sheet is available here.

Related: In photos: President Donald Trump and NASA

A boost for the moon and Mars

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"NASA’s top-priority mission is to return American astronauts to the moon by 2024 and build a sustainable presence on the lunar surface as the first step on a journey that will take America to Mars," the NASA section of an OMB document outlining the administration's 2021 budget request read. "The budget redirects funds from lower-priority programs to fulfill the President’s promise to get Americans back to the moon."

The budget request would support NASA's massive Space Launch System rocket as a backbone for deep space exploration, but it would postpone funding the "Block 1B" upgrade required for larger missions, attributing the decision to the fact that Block 1B isn't necessary for a human lunar landing.

The administration also expressed support for partnerships with commercial companies in space exploration, although details will not be available until NASA's full report is published. Also notably missing from the OMB summary document is reference to planetary science missions, with the exception of Mars.

Robotic exploration of Mars would explicitly be supported in the summary document, as would be the Mars Sample Return mission, which NASA would like to follow its Mars 2020 rover to bring pieces of the Red Planet into Earth's laboratories. In addition, the OMB document introduces a new Mars Ice Mapper mission that could help NASA prioritize landing sites for astronauts.

It's important to remember that the president's budget request is just that, a request. NASA's funding comes directly from Congress, which isn't obligated to match the request in any way. Congress hasn't shown much enthusiasm for several of the president's space priorities, particularly the Artemis program.

The Senate and House committees overseeing NASA have released authorization bills — which represent big-picture priorities, not the allotment of money, much like the president's budget request — neither of which would require the 2024 landing deadline. Congress has tended to favor Mars exploration and a more conservative timeline.

Familiar NASA budget cuts return

The budget request would cut several NASA projects that Trump's budget requests have targeted for several years, including the Stratospheric Observatory for Infrared Astronomy (SOFIA) airplane-mounted instrument, the Office of STEM Engagement and the Wide Field Infrared Survey Telescope (WFIRST), currently planned to launch in the mid-2020s. The Office of STEM Engagement and WFIRST have been canceled by the president's budget requests and reinstated by Congress on multiple occasions.

The same is true of two Earth science missions that would also be eliminated in the president's 2021 budget request: the Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission and the Climate Absolute Radiance and Refractivity Observatory (CLARREO) Pathfinder. NASA announced last week that it had selected SpaceX to launch the PACE mission in 2022. The Trump administration has repeatedly tried to eliminate the PACE, CLARREO Pathfinder and WFIRST space telescope missions over the year. The flying SOFIA telescope, a joint project with the German Aerospace Center, similarly faced cancellation in the Obama administration's 2015 budget request.

Under Trump, NASA's annual budget has increased from about $19 billion during his first year to $22 billion for the fiscal year that began in October, according to The Washington Post. The fiscal year 2021 budget process is also expected to provide the first details of the total estimated cost of the Artemis program and an initial schedule for milestones within it. Congress has been pushing Bridenstine for such details for months, but he has deferred, pointing them to the budgeting process. The initial OMB documents posted continue to elide those details.

Email Meghan Bartels at mbartels@space.com or follow her @meghanbartels. Follow us on Twitter @Spacedotcom and on Facebook.