“WFIRST and Webb are as similar to each other as the Malibu that I drive and the Ferrari my neighbor drives. They’re both cars, but they’re really different classes of both cost and complexity.” Thomas Zurbuchen, NASA associate administrator for science. Credit: NASA/Aubrey Gemignani

WASHINGTON — Two months after suggesting the next major review of priorities in astrophysics research and missions to achieve those goals be delayed, the head of NASA’s science directorate says that study should stay on schedule.

In a May 25 tweet, Thomas Zurbuchen, NASA’s associate administrator for science, said he concluded that the next astrophysics decadal survey, known as Astro2020, should not be delayed after reviewing an “analysis” from the National Academies.

Upon receiving @theNASEM analysis wrt the timing of #Astro20, I directed the @NASA team to start the decadal process now! I hope that the US Astrophysics community takes this as an opportunity to come together as one and plan a decade of discovery and exploration – the best yet!

— Thomas Zurbuchen (@Dr_ThomasZ) May 25, 2018

“I hope that the US Astrophysics community takes this as an opportunity to come together as one and plan a decade of discovery and exploration – the best yet!” he wrote.

That analysis was a letter sent to Zurbuchen May 24 from Fiona Harrison, chair of the National Academies’ Space Studies Board. The letter, based on feedback from the astronomical community, recommended that the start of Astro2020 not be delayed.

“I have informed my counterparts at National Science Foundation and Department of Energy, NASA’s co-sponsors of Astro2020, that NASA is ready to proceed with initiating the 2020 Decadal Survey on Astronomy and Astrophysics,” Paul Hertz, director of NASA’s astrophysics division, said in a letter to astronomers after Zurbuchen’s announcement.

Zurbuchen first suggested that Astro2020 be delayed in late March, after NASA announced the latest delay in the launch of the James Webb Space Telescope. With the spacecraft now expected to launch around May 2020, its early science results won’t be ready in time to influence the content of the Astro2020 report, slated for release in late 2020.

Uncertainty about the fate of NASA’s next large astrophysics mission, the Wide-Field Infrared Survey Telescope (WFIRST), also factored into the proposal to delay the decadal. NASA’s 2019 budget request proposed cancelling the mission, but Congress provided funding for the mission in its final 2018 spending bill, and a House bill for fiscal year 2019 also funds the mission.

“I think it will be easier to do after Webb flies and is successful,” Zurbuchen said of Astro2020 during a May 2 meeting of the Space Studies Board. “It’s very hard to do a visionary and a great decadal while half the decade is already allocated for, and some of the big strategic missions have not cleared the queue.”

Many astronomers were opposed to such a delay, though. They argued that waiting until after JWST was in operations wasn’t needed, since it was unlikely any early science observations would significant affect the findings of the study. The survey identifies the top science issues in astrophysics for the next decade and prioritizes proposed spacecraft missions and terrestrial telescopes to carry out that research.

NSF, which uses the decadal to prioritize investments in ground-based observatories, was opposed to a delay. In addition, there were practical concerns, particularly if a delayed astrophysics decadal survey took place at the same time as one for planetary science, whose next decadal is planned for completion in 2022.

“The NSF has made clear that they would like to start on time,” said Marcia Rieke, co-chair of the Committee on Astronomy and Astrophysics, at the May 2 Space Studies Board meeting. “Anecdotal discussions among various astronomers imply that astronomers would like to move ahead and start on roughly the current schedule.”

Zurbuchen, in a blog post on the NASA website May 29, said he suggested the delay out of concerns that the astrophysics community was adopting a “defensive strategy” because of the concerns about JWST and WFIRST. “It would be a lot easier to do a decadal when there is a clear success is sight, than when two or more challenges are pulling the collective psyche of the community down,” he wrote.

He added he was also concerned that the decadal, whenever it takes place, reflect the diversity of the astrophysics research community. “[A] strategy cannot be important if it is put together by representatives of the top-10 University programs, and by a community group that is all male and has an average age north of 65!” he wrote. “Diverse groups make better strategies, and provide better alignment and buy-in.”

The National Academies, which carries out the decadal survey, has not selected any members of the committee for Astro2020. The current schedule calls for selecting a survey chair by December, followed by the rest of the committee and any subpanels that support the overall effort.

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...