WASHINGTON — The short-term spending measure under which NASA will operate for the next two months forces the U.S. space agency to fund the Moon-bound Constellation program it seeks to abandon, but also gives NASA broad discretion to put new money into existing programs and a limited authority to shift funds between accounts to address budget problems that crop up.

With Congress unable to enact a 2011 budget by the time the new fiscal year began Oct. 1, NASA and other federal agencies have kept operating at their 2010 funding levels under a series of short-term spending measures, or continuing resolutions, the latest of which expires March 4. NASA Chief Financial Officer Elizabeth Robinson said the continuing resolution, or CR, that Congress passed before adjourning in December gives NASA about $276 million less in 2011 than proposed in the $19 billion budget plan U.S. President Barack Obama sent Congress last February. It also keeps the agency subject to a year-old ban on terminating Constellation contracts or from initiating new projects or programs until Congress gives its approval in a subsequent spending bill.

“So many things are balancing under a CR because we have now this essential two-month funding constraint,” Robinson said in a Jan. 4 interview, adding that after March 4, the agency will have no funding until Congress either passes a new appropriation for 2011 or adopts another continuing resolution. “We also have to be prudent because of course we don’t know what the final [funding] amounts will be, and so it makes one cautious.”

Robinson said the agency is spending just shy of $200 million a month on Constellation’s Ares 1 rocket and Orion crew capsule, money she said is targeted at technologies that could be incorporated into a new heavy-lift launch system and multipurpose crew vehicle mandated in the NASA Authorization Act of 2010, the only piece of NASA legislation enacted last year. That measure, which Obama signed into law Oct. 11, recommended Congress provide $3.86 billion for NASA’s Exploration Systems Mission Directorate (ESMD) programs in 2011, though the current CR would provide just $3.74 billion for that purpose in the current budget year.

“Under a CR you’re constrained to last year’s level, which in ESMD’s case is about $122 million below the authorized level for those same activities,” she said, referring to the three-year NASA Authorization Act.

Robinson said it is too early in the year to determine which exploration projects might suffer as a result of the shortfall, and that the balancing act going on within NASA over the next two months could mean some exploration projects are shortchanged in order to pay for planned funding boosts in others, which could include NASA’s Commercial Orbital Transportation Services program  and Commercial Crew Development (CCDev) 2 effort.

NASA started CCDev in 2009 with $50 million in economic stimulus money to mature technologies intended for crewed spacecraft and launchers. Despite budget uncertainties, NASA hopes to continue the effort this year with a second round of awards in March totaling $200 million.

Phil McAlister, NASA’s commercial crew planning lead at agency headquarters here, said while prohibitions in the 2010 appropriations legislation prevent the agency from initiating a full-scale commercial crew procurement effort, under the CR the agency has authority to continue funding CCDev projects in 2011.

“We’re still precluded from doing a new start, and the full-up commercial crew program is considered a new start,” he said in a Jan. 4 interview. “We have to abide by the law.”

However, even if the agency is forced to continue operating under a continuing resolution for the remainder of the year, McAlister said he is confident CCDev 2 could be funded.

“There is the ability for us to fund CCDev 2 in certain continuing resolution circumstances,” he said.

Space technology development is another area that could be considered a new start, given that NASA recently centralized its technology development initiatives within a new account managed by the Office of the Chief Technologist. However, Robinson said NASA’s legal counsel determined recently that many of these space technology initiatives are not new.

“This is sort of a different organizational approach, and so they have said that it is not a new start,” she said. However, finding the $350 million authorized for space technology in 2011 within the funding ceilings set by the CR could prove challenging.

“It’s subject to the same funding uncertainties everything else is,” she said, referring to the new office. “They can move ahead bureaucratically but they can’t go sign a bunch of checks.”

Robinson said some programs within NASA’s Science Mission Directorate could come up short under the CR, particularly Earth  science missions slated for a funding boost in 2011. Congress appropriated $4.5 billion for science in 2010, some $500 million less than requested in Obama’s 2011 spending plan. The bulk of that increase — about $380 million — was targeted for the directorate’s Earth Science Division.

NASA’s $5 billion James Webb Space Telescope could also consume more money in 2011, pending the outcome of an internal review of the flagship astronomy mission that an independent panel recently said could be at least $1.5 billion over budget.

Robinson said NASA’s science divisions have been “prudently managing all of these various moving pieces and have been able to get through the first quarter with limited impact on programmatic plans.”

However, she added that NASA has authority under the CR to shift up to 10 percent of funds from other parts of the agency to keep its science programs on track.

“We’re actually right now trying to investigate whether or not we may need to do something centrally to help them, but we’re not near that decision yet,” Robinson said.

Robinson also said the CR does not hinder plans to conduct an extra space shuttle mission to the international space station this year as called for in the NASA Authorization Act because the $3.1 billion appropriated for the orbiter in 2010 is sufficient to cover the added cost.

NASA spokeswoman Stephanie Schierholz said in a Jan. 4 e-mail the agency “is taking necessary steps to maintain its capability to conduct this mission in 2011 and has formally directed the Space Shuttle and International Space Station Programs to protect the ability to do so.”