With a Senate-passed NASA authorization bill pending on the House floor late Wednesday, the space agency's deputy administrator, Lori Garver, urged its approval to provide some clarity to the agency's leadership, and its 18,000 employees and thousands of contactor personnel.

The authorization had been held up for months because of substantial differences between the Senate version and the bill approved by the House Science Committee. But Science Chairman Bart Gordon relented this week, saying it was better to take up "a flawed [Senate] bill than no bill at all," to provide some stability for NASA and its employees.

The House was expected to pass the bill, as its supporters argued that Wednesday's session was their last chance to get the measure to the White House before Congress breaks for the midterm elections.

Although the Senate legislation rejects key elements of President Obama's plans to scrap the Constellation program to replace the space shuttle as the vehicle for human space exploration, Garver said it embraces "the best parts of the administration's proposals."

"We believe passing this bill really will provide a lot of certainty," Garver said at a House Aerospace Caucus luncheon.

Garver's view was echoed by Marion Blakey, president of the Aerospace Industry Association, who said "the months of uncertainty have led to job losses" in the aerospace industry. "It's time to end the uncertainty."

The Senate bill would reauthorize NASA for three years, with total funding going from just under $19 billion in FY11 to $20 billion in FY13.

Those totals are the same as the House version, but the two bills differ on specifics of how to replace the shuttles, which were supposed to be retired at the end of this year, but now are scheduled to make at least one more flight next year.

Obama's original space exploration plan would have ended the Constellation program conceived by former President George W. Bush. That would have consisted of a new heavy-lift rocket called "Ares" and a new crew capsule called "Orion." The two systems were similar to the Mercury, Gemini and Apollo systems that took U.S. astronauts into space for the first time and to the moon. Constellation had fallen years behind schedule and billions of dollars over budget.

Obama's proposal would have canceled plans to return to the moon and have developed systems for more limited human space exploration, and would have encouraged commercial capabilities to continue to service the International Space Station. But it would have left NASA dependent on Russia to take astronauts and cargo to the ISS for more than a decade, with advent of commercial capabilities uncertain.

As the House committee chairman, Gordon initially had opposed the Senate bill because he said it was "overly prescriptive" of the launch vehicle NASA must develop and required NASA to continue flying the shuttle, without providing additional funds.

Garver said there has been "a lot of bipartisan support" for NASA's plans and called the debate over that future "healthy."

If the authorization is enacted, she said the administration would have to work with the appropriations committees to resolve the problem of the unfunded added shuttle flights.

"That's why it would be good to get the guidance passed so we know what we're working with," Garver said, referring to the authorization.