NASA's $17.5 billion proposed fiscal 2015 budget would maintain the U.S. space agency's plan to send humans to Mars by the 2030s, to study near-Earth asteroids and to send astronauts to the International Space Station.

"Through NASA's work at all of our centers, our nation is recognized for scientific and technological leadership and knowledge-sharing that improves lives all around the world," NASA Administrator Charles Bolden said Tuesday.

The White House proposal for NASA is 1% lower than the final fiscal 2014 budget budget, and about $600 million more than it received in 2013.

Nonetheless, the proposed 2015 proposed budget would keep NASA on the path it's been on for a few years, preparing to send humans to live, explore and work on Mars by the 2030s.

Bolden noted that NASA hit several milestones on that path this year.

For instance, it oversaw two missions by private commercial companies - SpaceX and Orbital Sciences -- to resupply the space station. NASA also pushed to prepare the Orion space capsule for its first test flight later this year. The capsule is to one day carry humans into deep space.

"This budget ensures that the United States will remain the world's leader in space exploration and scientific discovery for years to come," said Bolden. "The budget supports the administration's commitment that NASA be a catalyst for the growth of a vibrant American commercial space industry, and keeps us on target to launch American astronauts from right here in the U.S.A. by 2017, ending our reliance on others to get into space and freeing us up to carry out even more ambitious missions beyond low-Earth orbit."

Regaining the ability to send astronauts to the space station would mark a major milestone for NASA.

After NASA retired its fleet of aging space shuttles in the summer of 2011, the agency has been forced to rely on Russian partners to keep the orbiter supplied with astronauts, food, spare parts and science experiments.

Bolden pointed out today that NASA hopes to have its commercial partners ferrying astronauts, as well as supplies, to the space station by 2017, lessening its reliance on foreign government agencies.

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NASA's 2015 budget plan maintains Mars landing plans