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The NASA Mars 2020 mission, featuring a rover named Perseverance, emerged from the recommendations of the previous planetary science decadal survey. Its development problems have created budgetary pressures on other parts of NASA’s Mars exploration program. (credit: NASA/JPL-Caltech)

Planning the next decade of planetary science missions

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Had their original plans held up, hundreds of planetary scientists would have filed into a ballroom last month at a hotel in the Houston suburb of The Woodlands, Texas, that was hosting the annual Lunar and Planetary Science Conference. That town hall meeting there would have formally started the planetary science decadal survey, the once-a-decade effort to chart priorities for the next decade of NASA’s planetary science program.

“The Hill takes these incredibly seriously, as do the agencies,” Hartman said of decadal surveys.

Those plans, though, were undone by the coronavirus pandemic, which forced the cancellation of the conference in early March. Instead, hundreds of planetary scientists, now working primarily from home, logged into a webcast March 16 to kick off a two-year effort to craft those priorities.

The decadal surveys, in planetary science and other space science disciplines, have taken on almost legendary authority over the years. “The Hill takes these incredibly seriously, as do the agencies,” Colleen Hartman, director of the National Academies’ Space Studies Board (SSB), said in remarks in that online town hall meeting.

The upcoming survey, spanning the period of 2023 to 2032, will be in many respects similar to previous decadals, said Lori Glaze, director of NASA’s planetary science division, during the webcast. That includes a broad survey of the field and identification of the most important questions to be answered. That will ultimately lead to a ranking of large flagship-class mission concepts and destinations for medium-class New Frontiers missions.

The upcoming decadal, though, will feature some changes based on the formal “statement of task” to the SSB by NASA and the NSF for the decadal. One of the biggest will be a greater emphasis on astrobiology and planetary defense, given their growing importance, and budgets, in NASA’s overall planetary science program. That’s recognized in the decadal survey’s formal title: “Planetary Science and Astrobiology Decadal Survey 2023-2032.”

“There is an increased emphasis on the astrobiology part of our program, which spans beyond even planetary science, and is increasingly becoming an important part of NASA’s work,” Glaze said. “We’re also placing explicit emphasis on our planetary defense program, which over the last few years has grown.”

Other changes, she said, include that recommended missions be formally “clearly traceable” to science goals and objectives identified in the decadal, as well as decision rules to accommodate changes in projected budgets or new discoveries or technology developments that might lead to reconsideration of mission concepts over the next decade.

The planetary science decadal will also examine the role of human spaceflight, particularly the Artemis lunar exploration program, can play in advancing planetary science goals. “There are a lot of capabilities that human exploration can bring and enable to planetary exploration, so we’re looking for some feedback on how we can work with human exploration to leverage that capability and enhance our science return,” Glaze said.

The upcoming decadal survey will study collaboration both with international partners and other parts of NASA. A final additional will examine the “state of the profession,” such as demographics and issues facing those working in the field, similar to a review in the ongoing astrophysics decadal survey.

At the time of the webinar, the SSB was just about, but not quite, ready to officially begin the decadal. Hartman said the survey work formally starts when it receives funding from NASA, and that funding was working its way through the procurement process at NASA Headquarters.

“So far we’ve been told to stay the course,” Harrison said of guidance agencies have provided to the astrophysics decadal survey regarding the effects of the pandemic.

Last week, the SSB started to solicit white papers from the planetary science community on scientific topics or other issues to be considered by the survey, with a deadline of July 4. It also requested nominations to serve on the decadal’s main steering committee and various panels, with a deadline of May 1.

The SSB also hoped that, despite the current disruptions at the start of the planetary science decadal survey, they could still finish the survey on schedule and release it at the Lunar and Planetary Science Conference in March 2022.

However, the experience of the astrophysics decadal survey, called Astro2020, suggests there may be delays. That survey was expected to complete its work and release the final report in early 2021. However, during a March 31 meeting of the National Academies’ Committee on Astronomy and Astrophysics, the decadal’s two co-chairs warned that that pandemic could delay their final report.

“We began seeing the impacts around the second week of March,” Rob Kennicutt, one of the co-chairs of the astrophysics decadal, said, as in-person meetings became remote ones due to the pandemic. But those panels, and other since, are moving more slowly, since the remote meetings aren’t nearly as efficient as those held in person.

“What does this mean for the overall schedule of Astro2020?” he said, noting he and co-chair Fiona Harrison were going through “scenario planning” about how the pandemic might affect the schedule for the study. “We’re just going to roll with the punches and see what our constraints are.”

The pandemic, they added, has not affected the content for the decadal itself. “So far we’ve been told to stay the course,” Harrison said of guidance the agencies funding the survey, including NASA, have provided to the committee.

Mars issues

The planetary science decadal, while an influential guide for NASA’s planetary science programs (and Congressional willingness to fund them), is not always the final word on what missions get flown, and when, particularly when there are budgetary issues.

That’s the case with NASA’s Mars exploration program. Problems with the Mars 2020 rover mission—itself based on the last planetary science decadal’s recommendation—led to cost overruns that affected other Mars missions. “The FY20 budget appropriation, though very favorable for us, was significantly overstressed supporting some problem resolution that we had in multiple areas on the 2020 mission,” Jim Watzin, director of NASA’s Mars exploration program, said at a March 9 meeting of NASA’s planetary science advisory committee.

The final allocation of funding among NASA planetary science programs for fiscal year 2020 hasn’t been released yet, as it is pending approval of an operating plan by Congress. But Watzin said there was “austerity across the portfolio” of Mars missions. “Every other element of the program was tapped to support the problem resolution” with Mars 2020, he said.

The agency’s fiscal year 2021 budget request, released in February, included funding to start work on a Mars sample return campaign, building on the Mars 2020 rover mission. It also included funding for a new orbiter mission, called Mars Ice Mapper, but curtailed funding for the Curiosity rover and effectively ending the Mars Odyssey orbiter mission.

“The FY21 budget that the president just recently submitted overall is extremely favorable for the Mars program, but available funding for extended mission longevity is limited,” Watzin said. “We had some very difficult decisions to make to balance the budget within the constraints that we had.”

“Some people said, ‘Wait, that’s not in the decadal,’” said Zurbuchen of Mars Ice Mapper. “I like to tell people that not every mission we’re doing is in the decadal, especially small missions.”

The decisions to cut Curiosity and end Mars Odyssey have faced sharp criticism from the Mars science community. “Some hard choices sometimes have to be made,” Glaze said when asked about those cuts at a March 31 meeting of the National Academies’ Committee on Astrobiology and Planetary Science. “We’re working very hard to try and find ways to keep them going, but it’s a challenge to fit things within the constraints that we have within the budget.”

The cuts were particularly jarring since the budget proposal included funding for Mars Ice Mapper, a new mission concept that would launch in 2026 featuring a communications relay payload to support missions on the Mars surface as well as a Canadian-provided radar instrument to look for subsurface ice deposits that could be of use by future human missions.

That mission, though, wasn’t widely discussed in the Mars science community prior to its inclusion in the budget proposal. It also wasn’t mentioned in the decadal survey.

“Some people said, ‘Wait, that’s not in the decadal,’” said Thomas Zurbuchen, NASA associate administrator for science, of the mission at a March 12 meeting of the NASA Advisory Council’s science committee. “I like to tell people that not every mission we’re doing is in the decadal, especially small missions.”

Zurbuchen argued that the mission was responsive to a midterm review of the most recent planetary science decadal, which called for a “robust communications infrastructure” in Mars orbit. A communications relay mission would cost $200–250 million, he estimated, and adding the Canadian radar instrument would not significantly increase the mission’s cost to NASA.

“This is nowhere near the billion-dollar type of mission,” he said. “I personally have no interest in making this a billion-dollar mission.”

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