Unable to pass an annual spending bill in this legislative session, the U.S. Congress approved a temporary government funding measure Tuesday, cutting nearly $300 million from NASA's expected budget and potentially limiting action on new space exploration programs.

Atlantis is being prepared for launch in the summer of 2011, but NASA is struggling to find money to pay for a final shuttle flight. Credit: NASA-KSC

President Obama was expected to sign the continuing resolution late Tuesday, ensuring the government remains functioning before the current budget expires at midnight.

The temporary budget funds the federal government through March 4 near fiscal year 2010 levels. For NASA, that means an annual budget rate around $18.7 billion if the continuing resolution was extended through fiscal year 2011, which began Oct. 1 and runs for 12 months.

The continuing resolution came after Senate Republicans thwarted attempts by Democratic leaders to pass a full-year budget.

Federal funding beyond March 4 will be decided by the next Congress. Incoming Republican leadership in the House of Representatives has vowed to roll back discretionary spending to fiscal year 2008 levels, setting the stage for a budget battle in the opening weeks of the next Congress.

The legislation passed the Senate by a 79-16 vote Tuesday afternoon, and the House agreed to the continuing resolution several hours later.

The continuing resolution does not include amendments for NASA, meaning the space agency will receive roughly the same budget as in fiscal year 2010. It also does not explicitly direct NASA to commence development of a government-owned heavy-lift rocket and multi-purpose crew vehicle for space exploration missions.

The exploration programs were included in the NASA authorization act passed by Congress and signed into law by President Obama in October. But the authorization is only a budget blueprint, and specific funding levels must be decided in appropriations legislation.

Congress did not pass any full-year appropriations bills before recessing for the Christmas holiday, leaving NASA in limbo as agency officials attempt to overcome significant differences in the continuing resolution and the authorization act.

The authorization budget called for $19 billion for NASA in fiscal year 2011, upping cash for an extra space shuttle mission, commercial crew and cargo programs, and initiating a redesigned space exploration program.

Sen. Bill Nelson, a Florida Democrat, told NASA and Obama administration officials earlier this month that a multi-month continuing resolution should not add any major burdens to NASA's goals for the next year.

"If we just get a continuing resolution of fiscal year 2010, NASA's funding there is $18.7 billion," Nelson said in a hearing in early December, anticipating a continuing resolution similar to the measure passed Tuesday. "That is, in this context of this economic recession that we're in, $300 million less than a $19 billion authorization. That's 1.67 percent of the total authorization."

"That funding level for the next fiscal year will be right about at where it is in the authorization bill," said Sen. David Vitter, R-La., in the Dec. 1 hearing. "So this should be a simple task if we really all want to accomplish it. And so the proof will be in the pudding if it gets done."

The flat funding in the continuing resolution will also challenge NASA's efforts to address new costs on several programs, including the James Webb Space Telescope and an expanded Earth observation satellite system.

Another hurdle facing NASA is language carried over from last year's appropriations prohibiting the agency from terminating parts of the Constellation moon program or starting new efforts.

Officials are reviewing how best to proceed as the agency tries to reconcile the competing authorization and appropriations legislation.