On May 2, during a three-day meeting of the National Academies Space Studies Board (SSB), board members and NASA Science Mission Directorate (SMD) leaders debated the future of decadal surveys for space science. The board serves NASA by channeling the expertise of the scientific community into decadal surveys and other studies, which guide formulation and implementation of NASA’s science mission portfolio.
Attendees pondered the lessons the community should learn from two recent setbacks to flagship astrophysics missions: the delay in the launch of the flagship James Webb Space Telescope (JWST) and the de-scoping of the Wide Field Infrared Survey Telescope (WFIRST).
SMD head Thomas Zurbuchen reiterated his view that the National Academies should delay the next astronomy and astrophysics decadal survey, which is currently scheduled to begin this year and finish in 2020. More broadly, he urged the board to consider moving beyond its current paradigm of building decadal surveys around single, large missions intended to accomplish much of the next decade’s science. Zurbuchen instead encouraged the board to embrace more innovative approaches.
NASA Science Mission Directorate leaders, from left, Associate Administrator for Science Thomas Zurbuchen, Earth Science Division Director Mike Freilich, Astrophysics Division Director Paul Hertz, Acting Planetary Science Division Director Lori Glaze, and Heliophysics Division Chief Scientist Jim Spann address members of the National Academy of Sciences’ Space Studies Board on May 2.
(Image credit – Mike Henry / AIP)
Much of the debate at the meeting centered around Zurbuchen’s proposal to delay the decadal survey, which he first floated at Space Science Week at the National Academies in March after NASA announced JWST’s launch would be pushed back to 2020.
Zurbuchen observed that JWST and WFIRST are set to dominate the NASA Astrophysics Division “queue” for most of the next decade, should WFIRST proceed. He argued,
It’s really hard to do a visionary and a great decadal while half of the decade is basically allocated for, so we have very little free energy for the rest of the decade.
Zurbuchen also urged the board to break from the tradition of structuring the astronomy and astrophysics decadal survey around a single, large strategic mission — what he called a “build the next one big thing” approach. This would push NASA in a new direction, since the agency is already studying four mission concepts for a future large space telescope to guide the survey committee’s deliberations.
More broadly, Zurbuchen made a plea to the board to think innovatively and be “ambitious,” cautioning it against falling into the trap of repeating “the same patterns from the last two or three decades” and using “the same paradigm.” He encouraged bold risk-taking, explaining,
Whenever you sit on a panel in which you have tremendous financial constraints, it is very easy to get into a realm where you are intellectually conservative as well. That’s the problem I’m trying to address.
Several board members resisted Zurbuchen’s proposal to delay the survey. Board chair and Caltech physicist Fiona Harrison said that among astrophysicists “there is a strong sense there has been a tremendous amount of change in science since [the last decadal survey] with the discovery of gravitational waves and in many other fronts.” She said many in the community are ready for a survey that will revisit the state of the field and take another look at the direction of its science.
Princeton astrophysicist Adam Burrows took the strongest stand against a delay, saying there is a “great deal of enthusiasm for getting on with the job and getting the decadal survey out” in the astrophysics community and “no strong feeling for delay.” While he conceded that arguments can be made for delaying the decadal, he said such arguments are “usually wrong.”
University of California, Los Angeles astrophysicist Ned Wright suggested that the survey committee could benefit from a more realistic appreciation of NASA’s budgetary and schedule constraints. He recounted that the last astrophysics decadal survey erred when it proposed WFIRST without fully understanding that JWST’s budget would crowd it out. “What went wrong is we didn’t have a good handle on how much JWST was going to cost,” he concluded.
Perhaps more sympathetic to Zurbuchen’s views, Larry Paxton, head of geospace and Earth science group at Johns Hopkins University’s Applied Physics Laboratory, observed the last solar and space physics decadal survey also struggled with a lack of “free energy,” which he said led to weak recommendations. That survey committee, he said, ultimately developed a roadmap several years later with more specific recommendations.
Asked to weigh in on the subject by Harrison, Astrophysics Division Director Paul Hertz clarified,
NASA’s highest priority isn’t to delay the decadal survey. Our priority is to ensure that we get a decadal survey that’s quality, that’s visionary, that’s science-rooted, that’s ambitious, that provides the government with the priorities we need to lead the world in doing astrophysics in space.
Attendees highlighted the recently completed decadal survey on Earth observations from space as an alternative model for structuring a decadal survey.
The board members heard directly from the co-chairs of that survey’s committee, former NASA Chief Scientist Waleed Abdalati and Global Weather Corporation Chief Technology Officer Bill Gail, who discussed their strategy of identifying seven broad categories of “target observables” rather than setting priorities for scientific research or specific mission concepts.
NASA Earth Science Division Director Michael Freilich called the survey, which guides his division’s efforts, “brilliant” and “thoughtful.” He said their approach gives the division flexibility in determining how to best obtain priority observations and in scaling or adapting the recommendations to future budget outcomes and management strategies.
The Earth Science Division has moved away from the use of large strategic missions in recent years in favor of larger numbers of less expensive satellites.
A rendering of the NASA Astrophysics Division’s WFIRST with a background image of a spiral galaxy. Currently in formulation, WFIRST will search space to gain greater knowledge about dark energy and exoplanets, which circle distant stars.
(Image credit - European Space Agency / Hubble Space Telescope / NASA / Nick Rose)
In the Astrophysics Division, two of NASA’s largest science missions, JWST and WFIRST, are currently struggling to meet cost expectations, and JWST’s schedule was recently pushed back by over a year.
JWST, which will observe the first galaxies formed after the Big Bang, has grown in cost considerably from a 2009 baseline of $4.4 billion, and has been delayed multiple times since an original expected launch in 2014. Most recently, it has faced technical issues related to spacecraft integration. After an independent schedule review released in March found it would not meet its 2018 target launch date, the mission is now expected to launch no earlier than May 2020. A separate independent review board chaired by former Martin Marietta President Tom Young will issue a report by early June assessing what is necessary to ensure JWST’s success in the final stages of its development and launch, including whether it will breach its $8 billion development cost cap set by Congress.
Zurbuchen defended the decision to delay JWST’s launch as critical to ensuring the mission is successful. He assured the board that the mission is close to completion and “all the hardware is there,” but said the delay is necessary to provide sufficient time for spacecraft integration and thorough testing. A “highest-priority” mission such as JWST should not be rushed, he said, arguing that the delay is not the worst-case scenario, but rather,
The worst thing I’m thinking about is launching this amazing telescope, this national jewel … and it’s not working. And we look back and say did we do everything we could have to make it successful. I want the answer to that question to be yes.
Zurbuchen said that many of the management processes that have been put in place to control WFIRST’s costs were learned from the agency’s experiences in managing JWST. Rather than taking the “do the best science you can no matter the cost” approach it took with JWST, he said NASA is approaching the formulation of WFIRST more cautiously.
In the fiscal year 2019 budget request, the Trump administration has proposed to cancel WFIRST in view of “higher priorities.” NASA has defended the decision, saying the mission’s science goals could be pursued by other, less expensive means. Should Congress cancel the mission, NASA says it would release a call for proposals for medium-scale “probe class” astrophysics missions instead. Although Congress has not made its decision, the fiscal year 2018 appropriations law provided continued funding for WFIRST and reaffirmed its commitment to abiding by decadal survey recommendations.
