In January, a bipartisan deal that capped total U.S. government spending for 2014 and 2015 led many to believe that Congress would pass its spending bills on time. Instead, an election-year fight over amendments in the Senate has derailed the budget process and the Republican-controlled House of Representatives has all but given up expectations that the U.S. will have a timely budget for 2015.
There are twelve matching committees in both the Senate and the House that have jurisdiction over various parts of federal spending. The House's Commerce-Justice-Science (CJS) committee, which oversees NASA, passed its part of the budget in April. The Senate's CJS committee had delivered its bill to the floor just before the process broke down in June, and the Senate has yet to pass any bills funding the government in 2015. Anything it does pass needs to be meshed with equivalent bills from the House and voted on again. Time for all of this to happen is running out: Congress recesses for the month of August, comes back together in September, but then is in full campaign mode during October.
According to reports in The Hill, the House is now preparing a continuing resolution (CR), which essentially extends government funding at 2014 levels. No details are released yet, but it is likely that any CR would last through the November elections.
Despite the fact that a CR extends 2014 funding, federal agencies are commonly directed to spend at a rate commensurate with the lowest-proposed budget from those proposed by the Senate, House, and White House. So despite the fact that both chambers of Congress have proposed more spending for NASA than the White House, a CR would essentially limit spending to the White House's reduced level for its duration. If this is a short CR, it is likely that this impact will be minimal, but it is still disruptive.
But for The Planetary Society's most immediate concern—NASA's planetary exploration program—Dave Schurr, NASA's Deputy Director of Planetary Science stated that a short-term CR would have a minimal impact on planetary missions. This implies that despite the absence of MER Opportunity and the Lunar Reconnaissance Orbiter from the White House's base budget in 2015, both missions will likely continue. Europa, which would receive $100 million in the House's NASA budget and $0 in the Senate's version, can continue to use last year's $80 million to smooth over any rough patches.