THE WOODLANDS, Texas — NASA officials praised “historic” funding levels for its planetary science programs in the administration’s fiscal year 2018 budget request at a conference March 20, even as some scientists in attendance worried about how that budget would affect other agency programs.

A town hall meeting known as “NASA Night” at the Lunar and Planetary Science Conference here was NASA’s first opportunity to discuss a budget blueprint released by the White House March 16 that included $1.9 billion for planetary science, part of an overall $19.1 billion request.

That amount is a 16 percent increase over the $1.63 billion planetary science received in a fiscal year 2016 spending bill. NASA is operating under a continuing resolution that funds programs in the 2017 fiscal year, which started last Oct. 1, at 2016 levels through April 28.

“This is historic,” said Jim Green, director of NASA’s planetary science division. “We’ve never had a proposed budget this high. This also is the highest increase in any organization at NASA this year.”

Green offered few additional details about how that $1.9 billion would be allocated among various missions and other programs in his division, saying those details would be released in May in the detailed budget statement. The administration’s budget blueprint also offered few specifics beyond support for the Mars 2020 and Europa Clipper missions, and stating it would not fund a Europa lander mission.

Green also said little about a proposed new Mars orbiter mission that would launch in 2022 to take over the imaging and communications roles currently filled by the Mars Reconnaissance Orbiter, launched in 2005. Work on such a mission would need to start soon in order to be ready for a 2022 launch. “What we’ll have to do is wait until all the budget details are released” in May, he said.

He did provide an update on an effort to make greater use of small satellites for planetary missions. Green said NASA had selected 10 proposals, from 102 submitted, for studies of concepts of smallsat missions to the moon, planets and asteroids. Several more, he said, could be funded depending on what NASA is appropriated for the remainder of the current fiscal year.

That work, he said, is part of a broader effort within NASA’s Science Mission Directorate to make greater use of smallsats. “The Science Mission Directorate is moving forward, in I think an aggressive way, to develop a directorate-wide approach,” he said. The NASA associate administrator for science, Thomas Zurbuchen, chaired a study by the National Academies released last year — prior to him joining the agency — that examined the potential applications of cubesats for science activities.

While the budget outlook for NASA’s planetary science programs was much brighter than just a few years ago, when scientists attending the NASA Night event worried about cuts in missions and research funding, many at this town hall instead objected to plans in the budget proposal to close NASA’s Office of Education and to cut more than $100 million from the agency’s Earth science program.

Green said little about those proposed cuts, other than to note that closing the Office of Education does not directly affect education activities funded within the Science Mission Directorate, which were restructured a couple years ago. “I think we’ve made really great steps to hang on to our educational funding,” he said.

Several of those attending the town hall meeting used the question-and-answer session to criticize the cuts despite the windfall proposed for their own research areas. “I personally feel that it’s very shortsighted to be excited about this planetary science budget, because planetary science does not live in isolation,” said Nancy Chabot of the Johns Hopkins University Applied Physics Laboratory, a comment that generated applause from the audience.

“We cannot be just supporting planetary science,” she said. “This will be a short-term gain, potentially, but a long-term loss if the science community in the United States is not strong everywhere, all around.”