WASHINGTON — The U.S. Senate is expected to take up a temporary spending bill Dec. 21 that would effectively freeze funding for federal agencies at 2010 levels through March 4, according to a summary of the $1.2 trillion measure posted on the Senate Appropriations Committee website Dec. 19.

The stopgap spending measure will be offered as an amendment to a continuing resolution covering the remainder of fiscal year 2011 that was approved by the U.S. House of Representatives Dec. 8. The spending rate in the Senate version, if extended through the end of the year, would represent a $1.16 billion increase over 2010 spending levels, according to the bill summary.

Unlike the House bill, H.R. 3082, the Senate amendment does not weigh-in on NASA, which could mean the agency will be forced to operate in the coming months at spending rates proportional to the $18.72 appropriated for all of 2010. In addition, NASA would be prohibited from initiating new programs, and could be required to continue spending about $200 million per month on the Moon-bound Constellation program U.S. President Barack Obama sought to abandon in the $19 billion budget blueprint for 2011 that the White House sent lawmakers in February.

H.R. 3082, a continuing resolution that would fund U.S. government agencies through Sept. 30, provides an additional $186 million for NASA over 2010 levels and allows the agency to terminate Constellation and initiate new programs.

The government has been operating under a continuing resolution approved Dec. 17 that expires Dec. 21. If the Senate obtains the 60 votes needed to pass the new stopgap spending measure, it would be sent back to the House for consideration. If lawmakers there reject it or make additional changes, the bill would return to the Senate for further action.