NASA's plans for manned spaceflight could get a boost from the economic stimulus package—but only if the Senate can convince the House of Representatives to reconsider its version of the bill.

The American Recovery and Reinvestment Act, as passed by the Senate on Feb. 10, would give NASA a total of $1.3 billion. Of that, $450 million would go toward closing the upcoming five-year gap in U.S. access to space created by the space shuttle's planned 2010 retirement date and the 2015 launch date of its replacement, the Constellation system.

The House version of the bill—passed on Jan. 28—allocates just $600 million to NASA, with no funds set aside for manned spaceflight. Now, the House and Senate will have to hash out their differences in a conference committee to agree on a final version. President Obama has asked the two houses of Congress to come to terms on a final agreement by Monday, Feb. 16.

Will NASA's manned space program come out a winner? "It's far too soon to tell," Jeff Foust, a space analyst at Futron says. "There's no guarantee that it will survive the conference." —Michael Belfiore

HOUSE: $600 million allocated to NASA

Science: $400 million. At least $250 million of this amount must be spent on environmental satellites recommended for launch by the National Academies. Fifteen proposed NASA satellites would quality for funding, including four—CLARREO, SMAP, ICESat-II, and DESDynl—pegged for launch between 2010 and 2013.

The money would help move the satellites from the drawing board to the launchpad and allow them to track such indicators of climate change as shrinking ice sheets, the amount of solar energy reflected back into space, and soil moisture with spectrometers, laser altimeters, and other instruments.

Aeronautics: $150 million. Research and development for the next-generation air traffic control system, dubbed NextGen, could get a boost here. The FAA hopes NextGen will update the nation's current airport-based radar systems with aircraft GPS-enabled transponders by 2020. With the system's projected cost of $20 billion, though, the stimulus won't make much of a dent.

Infrastructure repairs: $50 million. This amount is specifically allocated for repairing NASA facilities hit by Hurricane Ike in 2008.

SENATE: $1.3 billion allocated to NASA

Manned space missions: $450 million to help shorten the space-access gap caused by the retirement of the shuttle and the planned first flight of Constellation in 2015.

Science: $450 million for climate research and other space-based Earth science.

Aeronautics: $200 million.

Infrastructure: $200 million.