WASHINGTON — In her last scheduled space hearing with the Senate Commerce, Science and Transportation Committee Sept. 13, retiring U.S. Sen. Kay Bailey Hutchison (R-Texas) asked whether NASA might be better off paring back its diverse portfolio of programs and focusing exclusively on human exploration and science missions.

“Is NASA’s mission too broad to be able to fully fund the priorities and should we, in the next NASA authorization, look at splitting NASA?” Hutchison asked witnesses during a hearing on the agency’s space exploration plans.

Hutchison, a longtime NASA champion whose 19 years in the Senate will end come January, asked “as an example” whether NASA’s aeronautics program might be better off in the Defense Department. NASA devoted $570 million of its $17.8 billion budget to aeronautics research in 2012.

She also pressed the hearing’s panel of witnesses — two prominent scientists and a propulsion company executive — to suggest programs that should be de-emphasized in order to free up more money for space exploration and science.

None of the witnesses would play favorites with NASA’s portfolio, and all three argued against splitting up the agency.

Charles Kennel, a former senior NASA official who chairs the National Research Council’s Space Studies Board, said that NASA’s $5 billion Science Mission Directorate can do world-class science with the budget it has.

“I believe that the way the science program is funded, with about $5 billion, gives us a shot at leadership in each of the fields that we are pursuing,” Kennel said. However, he stressed that “the science program would suffer tremendously if it were cut off from and made separate from the human spaceflight program.”

Pratt & Whitney Rocketdyne President Jim Maser also made a case against a split.

“If we still think it’s important and someone else [besides NASA] is doing it, we’re still not saving any money,” Maser said. “So if the objective is to work with a limited budget, I’m not sure splitting it off from NASA and getting somebody else to do it will steady that.”

Maser did suggest that NASA’s international partners could share more of the financial burdens of space exploration.

“Maybe some of the suffering can be shared with international collaboration,” he said. “We have to decide which areas are relevant for that.”

NASA Advisory Council Chairman Steven Squyres, a planetary scientist who led NASA’s 2003 Mars Exploration Rover mission, leaped to the defense of NASA’s Aeronautics Research Mission Directorate.

“I have personally come to the opinion that the NASA aeronautics program is really one of NASA’s shining jewels,” Squyres said. “If you look at NASA’s budget and you ask yourself, ‘What are the things that the agency does that most directly benefit the taxpayers in their daily lives?’ it’s hard to find anything better than the aeronautics program.”

Hutchison, one of the architects of the NASA Authorization Act of 2010 that ordered NASA to build the Space Launch System (SLS) heavy rocket and its companion Multi-Purpose Crew Vehicle, is leaving the Senate in January before that legislation expires.

Dan Leone is a SpaceNews staff writer, covering NASA, NOAA and a growing number of entrepreneurial space companies. He earned a bachelor’s degree in public communications from the American University in Washington.