WASHINGTON — Two weeks after New Horizons’ Pluto flyby, NASA planetary science funding took center stage during a July 28 House Science Committee hearing.

New Horizons Principal Investigator Alan Stern testified before the committee along with other planetary scientists and senior NASA leaders. The witnesses discussed the agency’s achievements in planetary science and its goals for future missions.

Rep. Brian Babin (R-Texas), chairman of the space subcommittee, applauded NASA’s efforts and criticized the White House for reducing planetary science funding, a decision that he says would limit future scientific missions beyond low Earth orbit.

“Unfortunately,” Babin said, “year after year, the Obama administration has consistently cut funding and deprioritized NASA’s space exploration and planetary science.”

The Obama administration is asking Congress for $1.36 billion for planetary science for fiscal year 2016, which begins Oct. 1. While that is $80 million more than the $1.28 billion the administration requested for 2015, it is nearly $77 million less than the $1.44 billion Congress ultimately provided. Under the 5-year budget plan the White House sent Congress in February, planetary science spending would steadily grow to $1.53 billion by 2020.

But that’s not fast enough for the GOP-controlled House Science Committee, which pushed a two-year NASA authorization bill through the House in June that calls for giving NASA’s Planetary Science Division $1.5 billion in 2016 and 2017. The bill, H.R. 2039, would cover these increases in part by reducing NASA’s request for its Earth science and space technology.

House Science Committee Chairman Lamar Smith (R-Texas) said H.R. 2039 restores “crucial funds to science and exploration accounts.”

House appropriators took a similar view in drafting the 2016 Commerce, Justice, Science appropriations bill this spring. That bill, which passed the full House in early June, included $1.557 billion for planetary science — a $120 million increase over this year’s budget.

The Senate, meanwhile, hasn’t been as generous towards NASA or its Planetary Science Division. The Senate Appropriations Committee passed its own Commerce, Justice, Science spending bill in June that would provide just $1.32 billion for planetary science — $236 million below what the House wants and $40 million below what the White House says NASA needs.

The House and Senate also remain far apart of total NASA funding. The House has approved $18.529 billion — the same as the White House requested — while the Senate bill includes $18.29 billion, or roughly $239 million less.

Rep. Donna Edwards (D-Md.), the space subcommittee’s ranking Democrat, said that the United States is making great strides to explore the solar system. “However,” she said, “that progress has been made possible in large part by the investments in technology development that our predecessors had the foresight to fund.”

NASA Administrator Charles Bolden has criticized the House’s proposal to cut Earth science spending. “Decimating Earth science and saying that we’re going to Mars is not the right way to do it,” he said in May.

Asked what NASA could do with the House’s allocation of $1.5 billion for planetary science, John Grunsfeld, NASA’s associate administrator for science, told the House Science Committee July 28 that it would use the additional funds to keep the competitively selected Discovery and New Frontiers line of planetary missions on track and possibly increase their cadence. NASA generally launches Discovery-class missions every two to four years and New Frontiers missions every five years.

Alan Stern testifying before the House Science Committee. Credit: House Science Committee screen grab
Alan Stern testifying before the House Science Committee July 28. (House Science Committee screen grab)

Stern testified that the public is largely supportive of planetary science missions. As proof, he cited the “viral” online presence of the New Horizons mission as well as the hundreds of media outlets that gave special attention to the Pluto flyby, putting Pluto’s picture on the front pages of newspapers and devoting airtime to hour-long TV specials.

Of particular interest to lawmakers was a future flagship-class mission Europa, which Grunsfeld says is scheduled to launch an orbiter to Jupiter sometime in the mid-to-late 2020s. Jupiter’s moon Europa is an attractive destination because the oceans beneath its icy crust could harbor life. “The goal will be to conduct detailed reconnaissance of Europa,” Grunsfeld said, “and to answer the big question, ‘Is Europa habitable?’”

Robert Pappalardo, a Europa mission project scientist with the Jet Propulsion Laboratory in Pasadena, California, told lawmakers that NASA had finished the first major review of the mission. Now NASA will work through 2016 to iron out more details, he said, which includes identifying science requirements, estimating costs and calculating a timeline.

House lawmakers want NASA to spend $140 million on Europa-related work in 2016, or about five times more than NASA says the project needs at this stage.

Jonathan Charlton is a SpaceNews.com editorial intern who has been logging a bunch of solo hours at the controls of Aviation.com. The Boston College senior is majoring in political science with a minor in hispanic studies.