WASHINGTON — NASA officials are weighing the impact of appropriations legislation approved by the U.S. House of Representatives Dec. 8 that, if enacted, would fund an additional space shuttle flight and development of a new government-owned human spaceflight system and provide limited financial backing for companies seeking to provide commercial crew transportation services for the international space station.

If the Senate passes the measure as is, or at least adopts the bill’s NASA provisions, the space agency would receive $18.91 billion for 2011. While that is $186 million more than NASA received in 2010, it is $90 million less than the White House had requested for the agency for 2011.

NASA Chief Financial Officer Elizabeth Robinson said the agency is reviewing the House bill, H.R. 3082, for potential conflicts with the NASA Authorization Act of 2010 that U.S. President Barack Obama signed into law Oct. 11. Although both measures direct NASA to begin work on a heavy-lift rocket and crew capsule this year, there are some differences.

“You have to read both of the acts in concert wherever possible,” Robinson said in a Dec. 8 interview, citing language in the authorization act that sets a goal of developing a heavy-lift launch vehicle and multipurpose crew capsule by the end of 2016. While H.R. 3082 mandates development of the launcher and spacecraft, it sets no timeline for their completion. “So if there’s a provision of the authorization act that does not conflict with something in the appropriations bill, such as the goal statement … then that still stands,” she said.

The House adopted H.R. 3082, a so-called continuing resolution that with some exceptions would keep the U.S. government operating at 2010 spending levels through most of next year, by a vote of 212-206. The bill now awaits action in the Senate, where Democrats are considering a plan to offer a more ambitious omnibus spending bill as an amendment to H.R. 3082.

NASA and the rest of the federal government have been operating since Oct. 1 — the start of the government’s 2011 budget year — under a short-term continuing resolution set to expire Dec. 18.

Robinson said NASA is reviewing language in H.R. 3082 that gives the agency leeway to cancel the Moon-bound Constellation program even as the bill provides $1.2 billion to continue work on Constellation’s Orion Crew Exploration Vehicle and $1.8 billion to begin development of a rocket capable of delivering 130 metric tons to orbit. Obama proposed canceling Constellation in its entirety in his original 2011 budget request but has since backpedaled in some areas in the face of fierce resistance from lawmakers.

The appropriations bill specifies that work on the heavy-lift rocket include both the core and upper stages. The 2010 NASA Authorization Act directs the agency to focus initially on a core stage utilizing space shuttle and Constellation technology and to field a vehicle capable of lifting 70 to 100 metric tons into orbit without an upper stage.

“There is the stuff about the 130 metric tons and doing the upper stage and core elements together and simultaneously,” Robinson said of H.R. 3082. “That’s new language to us, and we’re still trying to figure out what it means.”

NASA planners have several new programs waiting in the wings that were conceived in anticipation of congressional approval of Obama’s new direction for the agency. The agency planned, for example, to take a fresh look at its heavy-lift requirements and in November awarded contracts to 13 companies to study various vehicle concepts and approaches.

But if the heavy-lift language in H.R. 3082 is enacted, NASA will have little choice but to pursue a vehicle that relies in part on the giant solid-rocket motors used today on the space shuttle, which was the approach under Constellation.

“If this becomes law, between the authorizers and the appropriators, I don’t know how much wiggle room NASA is going to have to say, ‘We’re going to go ahead and finish these studies and then we’ll go back and tell Congress what’s really going to work,’” said Jim Muncy, a former  Capitol Hill staffer who is now a space policy consultant here.

Provisions in the 2010 NASA Appropriations Act bar NASA from terminating Constellation contracts in the absence of a new appropriations bill that funds replacement programs. H.R. 3082 appears to give NASA the authority it needs to terminate Constellation-related contracts, but Robinson said: “I don’t think that’s our intent; it’s to have a transition.”

Robinson said a more likely scenario would see elements of Constellation, including Orion and the Ares family of rockets, absorbed by the new exploration architecture specified in the 2010 NASA Authorization Act.

“The authorization act tells us to go ahead with a Space Launch System,” Robinson said. “And so Ares itself, the name of the program will fade away and be transformed into this new program.”

The authorization act also directs NASA to fly an additional shuttle mission before retiring the fleet of orbiters next year. H.R. 3082 fully funds Obama’s nearly $1 billion request for the shuttle program in 2011, and adds $825 million to be used at the agency’s discretion for shuttle and other specific purposes, including launch complex development at NASA’s Kennedy Space Center, Fla., Wallops Island Flight Facility on Virginia’s eastern shore, and Orion and heavy-lift work.

Robinson says the $825 million added in the House bill is almost $200 million more than recommended in the 2010 NASA Authorization Act, and is enough to cover three shuttle missions next year: two that have long been on the manifest and the additional flight mandated by Congress.

“The authorization bill is very explicit. It says we shall fly the third flight,” she said. “So we would have to really not have a lot of money.”

Since Oct. 1, NASA has spent $357 million on the space shuttle program. Robinson estimates the program currently consumes a little less than $200 million per month, though NASA spokesman Joshua Buck said the figure tends to vary.

“There is no consistent monthly burn rate information,” Buck said in a Dec. 9 e-mail.

Robinson says shuttle spending has slowed since the budget year began. However, she noted that cracks discovered in Space Shuttle Discovery’s external tank in November, delaying that orbiter’s final mission to February at the earliest, will require repairs whose costs could drive up spending rates.

Ultimately, Robinson says the $1.814 billion recommended for shuttle in H.R. 3082 should be sufficient for three more flights in 2011.

Meanwhile, two companies developing space station resupply vehicles under the agency’s Commercial Orbital Transportation Services (COTS) program would divvy up a portion of $300 million that is provided in H.R. 3082, a sum that represents a 60 percent funding increase to the 4-year-old program.  The measure also provides $250 million to nurture development of commercial crew transportation systems, or half of what Obama requested and some $50 million less than the authorization measure recommended.