President Barack Obama has proposed a five-year budgetary freeze on NASA's spending keeping it at $18.7 billion levels annually till 2016.
But NASA's administrator Charles Bolden told reporters that 'commitment ot human spaceflight and research would be maintained'.
"This budget requires us to live within our means so we can invest in our future."
"It maintains our commitment to human spaceflight and provides for strong programs to continue the outstanding science, aeronautics research and education needed to win the future," he said, adding the budget supports a reinvigorated path of innovation, technological development and scientific discovery.
The NASA budget includes $4.3 billion for the Space Shuttle and International Space Station programs, $5 billion for science, $3.9 billion for future exploration systems and $569 million for aeronautics research.
"This budget demonstrates the administration's commitment to maintaining NASA's leadership role in space," deputy administrator Lori Garver said.
"It puts us on a path to out-innovate, out-educate and out-build the rest of the world."
The budget supports the transition of the space shuttle program's workforce and facilities when the fleet retires this year after 30 years of service.
Among the program's many historic accomplishments is the construction of the International Space Station.
The station will operate until at least 2020, allowing NASA to fully use it as a technology test-bed and national laboratory for human health research.
While continuing to work with its international partners on station activities, NASA will select a non profit organisation to stimulate, develop and manage research activities on the US portion of the station.
NASA has prioritised funding for its partnership with the commercial space industry to facilitate crew and cargo transport to the station.
Companies will innovate to provide safe, reliable and cost effective access to low Earth orbit. NASA also will invest in the flight systems to take humans beyond low Earth orbit, including a deep space capsule and heavy lift rocket, and key research and technology to enable the long journeys.
NASA's science budget supports new missions and continued operations of the many observatories successfully studying Earth and space.
The agency will launch the Mars Science Laboratory in fiscal year 2012 and continue work on a wide range of astrophysics, heliophysics and Earth science missions.
The 2012 budget request continues NASA's commitment to enhancing aviation safety and airspace efficiency, and reducing the environmental impact of aviation.
NASA also remains dedicated to developing the next generation of technology leaders through vital programs in science, technology, engineering and mathematics.
"We had to make some tough choices, but the budget gives us a plan for sustainable and affordable exploration," said NASA's Chief Financial Officer Elizabeth Robinson.