NASA says it plans to start studies of a flagship-class mission to Uranus by 2024, but cautioned that projected funding that is below the lower of two scenarios included in the decadal survey could constrain development of that mission. Credit: NASA/JPL-Caltech

WASHINGTON — As NASA takes the first steps to implement recommendations of the planetary science decadal survey, the agency is warning that projected funding for at least the near term will fall short of that’s report’s projections.

NASA’s planetary science division held a town hall online Aug. 18 to discuss its initial 90-day response to the planetary science decadal survey, released in April. That report recommended NASA continue its development of Mars Sample Return as a flagship mission and pursue new flagship missions to Uranus and Enceladus, an icy moon of Saturn.

The decadal included two funding profiles. A “recommended program” projected spending $41.1 billion on planetary science from fiscal years 2023 through 2032, enough to start work early in that decade on the Uranus flagship and, in the later years, the Enceladus mission. A “level program” projected spending $35 billion in the same period, enough to start work later in the decade on the Uranus flagship but not the Enceladus one.

In the town hall, Lori Glaze, director of NASA’s planetary science division, said the agency’s budget projections fall short of even the level program. While the decadal’s level program has the planetary science spending at NASA increasing to more than $3.5 billion a year by the middle of the decadal, the projection included in the agency’s fiscal year 2023 budget request keeps spending a little below $3.2 billion a year through 2026, rising to $3.3 billion in 2027.

“We have to keep in mind that the current planning budget we have now is short of even the level budget,” she said. “We’re just trying to set expectations for where we are now and the challenges we have going forward.”

She noted that the fiscal year 2023 request was still in the hands of Congress, although both a bill passed by the House Appropriations Committee in June and a draft Senate version would provide NASA’s planetary science programs with about $3.2 billion in 2023, very close to the agency’s request.

“The decadal is inspirational and we will continue to advocate for budgets to support the aspirational goals of the survey,” she said, “but to just have a little bit of reality, we need to recognize that some of the recommended activities may need to be pushed to the right a little bit.”

One example is the Uranus Orbiter and Probe flagship mission recommended by the decadal, which in its recommended budget would start almost immediately to enable it to launch in the early 2030s, allowing it to take advantage of a Jupiter gravity assist to shorten the travel time to Uranus.

“We are really excited about this,” Glaze said of the mission concept, but stated NASA would be taking a somewhat slower approach to its development. Mission concept studies will begin no later than fiscal year 2024 examining a range of options for the mission. “The timeline for that is probably going to put a launch no earlier than the early 2030s.”

Glaze added that NASA supports the other new flagship recommended by the decadal, the Enceladus Orbilander. “The guidance from the decadal survey is pretty clear that we need to get Uranus underway first,” she said, with no mission studies expected for the Enceladus flagship before fiscal year 2026.

NASA is still evaluating other aspects of the decadal survey, including its recommendations for missions such as a lunar rover called Endurance-A that would collect samples for later return to Earth by crewed Artemis missions as well as a Mars astrobiology lander mission called Mars Life Explorer.

It did support the decadal’s endorsement of the NEO Surveyor mission to search for near Earth asteroids despite cutting funding for the mission in its fiscal year 2023 budget proposal, delaying its 2026 launch by at least two years. The decadal, agency officials noted, was published a few weeks after the 2023 budget proposal.

“The ’23 funding is a challenge,” Glaze said. “We are going to be working hard to make sure we can confirm the mission and move out on NEO Surveyor.”

NASA is also acting on another decadal recommendation to continue the Mars Exploration Program beyond the Mars Sample Return mission. The agency said in its response that it plans to complete a “comprehensive architecture” for the program by the end of the year that can be carried out in parallel with Mars Sample Return, implementing insights from previous studies that recommended a series of missions to conduct Mars science.

However, NASA rejected a recommendation in the decadal to develop similar scientific exploration strategies for other solar system destinations, such as Venus and “ocean worlds” in the outer solar system. Such strategies should be developed by the scientific community through existing advisory committees, Glaze said. “We’re really excited that this decadal is focused on questions and not destinations, and we want to focus those important questions that are identified in the decadal.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...