U.S. Astronomers Ponder Science Priorities for the 2020s and Beyond

After a tumultuous decade, the nation’s astronomical community is once again preparing to rank its scientific priorities for at least the next 10 years.

Seeking life on Earth-like exoplanets, discerning the deepest origins of the cosmos, reading ripples in the fabric of spacetime—these are just a handful of the options that will battle for top spots in the community’s next Decadal Survey, an authoritative roadmap Congressional appropriators and federal agencies rely on for future planning. “Decadals don’t recommend everything—they make tough choices,” Caltech’s Fiona Harrison told Scientific American during the 233rd meeting of the American Astronomical Society. “There will be winners and losers.”

Harrison will co-chair the Astro2020 Decadal Survey on Astronomy and Astrophysics, which is managed by The National Academies of Sciences, Engineering and Medicine. Intended to set the agenda for U.S.-based astronomy and astrophysics research into the 2020s and beyond, the survey committee will make recommendations to NASA, the National Science Foundation (NSF) and the Department of Energy about which of many proposed projects should be funded. The federal government is among the most profligate spenders on fundamental space science worldwide, which means the importance of the Decadal Survey cannot be understated: In a very real sense, when the Astro 2020 committee makes its recommendations it will be choosing just how much—and what—humanity shall learn about the universe for many years to come, opening some windows on the cosmos as it slams others shut. This is why some astronomers are concerned by the still-embryonic Decadal Survey’s somewhat inauspicious start.

Consider, for instance, the record-setting shutdown of the federal government that prevented numerous agency scientists and representatives from attending the meeting in Seattle. But this is, in fact, the least of the Decadal’s woes; more worrisome are the pendulous budgets and clouds of uncertainty looming over two top recommendations of Decadals past—the James Webb and the WFIRST space telescopes. Additionally, the field itself is facing a messy reckoning from within, as aggravated astronomers fight to eradicate various forms of endemic, damaging harassment and discrimination. All together, such factors make this Decadal perhaps the most fraught in history. Still, “it’s important to be optimistic,” says the University of Arizona’s Marcia Rieke, who served as a vice chair of the 2010 Decadal. “Astro 2010 started during the 2008 [financial] crash,” she notes. “This survey report won’t come out until late 2020, early 2021, and it may be a completely different set of people running things.”

To Delay, or Not to Delay

Astro 2020—the sixth astrophysics Decadal Survey since 1964—almost did not happen on time. Cost overruns and a mounting pile of technical problems have delayed the launch of the Webb telescope, selected as the premier priority during the 2000 Decadal; and the WFIRST mission, a top-ranked project that emerged during the 2010 survey, is currently facing potential cancellation. These uncertainties, Webb’s status in particular, have made some senior NASA officials edgy. “I think it will be easier to do after Webb flies and is successful,” associate administrator of the space agency’s Science Mission Directorate, Thomas Zurbuchen, said last year when Webb’s oft-delayed launch date slipped again to 2021. “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.”

In other words, Astro 2020 is stymied by backlogged priorities that will almost certainly push the realization of its own recommendations well into the 2030s—dramatically expanding its temporal purview, for better or worse, and forcing scientists to guess what kinds of follow-up missions to prioritize. “The challenge with this survey is that we’re going to have to make some good guesses about what the Webb telescope will see,” Rieke says. “There’s some things we can kind of guess, but until we actually see what it discovers it’s hard to know for sure.”

Nevertheless, other voices prevailed over Zurbuchen’s preference for a delay, Harrison says. Many astronomers argued that maintaining the decadal cadence is crucial for both U.S. and international projects—that rather than delaying, it is better to produce a flexible, timely roadmap that can later be custom fit to suit various budget realities. “It’s important to have a united front, so that you can point to the document in the future and say, ‘look, we all agreed these are important priorities,’” says Renée Hlozek, a cosmologist at the University of Toronto. A collaborator on U.S.-based projects, Hlozek notes international endeavors will necessarily rely on and be impacted by the Decadal’s forthcoming recommendations. “There’s an incredibly large amount of brainpower focused on really carefully evaluating different science interests,” she says. “I feel like we need bold leadership, even bolder than before.”

Balancing the Roadmap

The most vexing part of the Decadal committee’s work will involve balancing projects across both scope and discipline. This includes evaluating four proposals for multibillion-dollar “flagship”-class projects, each vying to be the next great U.S. space telescope in a post-Webb era. Called Lynx, LUVOIR, HabEx and Origins, each of the four mission concepts is presently under intensive study by NASA-selected scientific teams. As well, several large, ground-based telescopes are lobbying for NSF support, including the Giant Magellan Telescope, the embattled Thirty Meter Telescope and an expanded, next-gen version of the iconic Very Large Array of radio telescopes in New Mexico. Also in the mix are 10 smaller, “Probe”-class missions (each estimated to cost less than $1 billion) angling for Decadal endorsement, plus a handful of other interests such as the burgeoning, charismatic discipline of astrobiology and the related search for “techno-signatures” produced by putative cosmic civilizations. “It’s a difficult problem, to distribute resources when there are all these disparate and really interesting science areas,” Amherst College’s Katherine Follette says.

She and others are also concerned about the balance of voices on the Decadal Survey committee, and the disconnect between senior astronomers—who may be retired by the 2030s—making decisions that will dramatically affect the resources and facilities available to junior researchers. Recently the National Academies convened a meeting aimed at addressing these and other Decadal-related concerns of graduate students, postdocs and pre-tenure faculty. Among the meeting’s goals was assessing the ways in which more junior scientists could contribute to the survey, which typically commands a heavy workload, without neglecting other aspects of their developing careers. “It’s important that the people who will be using the instruments and facilities that are prioritized in the Decadal have a voice,” Follette says, noting meeting participants did not reach a consensus about how to incentivize participation.

State of the Profession

Broadening the diversity of voices both in the survey and the field in general is a key priority for astronomers—and for the first time this Decadal iteration will include a fully funded “state of the profession” panel, intended to make very specific recommendations to federal agencies about improving the community. “You know, unless you live in a cave, that there are aspects of the state of our profession that aren’t right,” said survey co-chair Rob Kennicutt of the University of Arizona and Texas A&M, during a Decadal-focused “town hall” session at the Seattle meeting.

It is no secret astronomy and astrophysics suffer from a noticeable lack of diversity at all levels. During a meeting plenary panel, sociologist Julie Posselt of the University of Southern California highlighted the fact only 3 percent of astronomy PhD students between 2002 and 2012 were from traditionally underrepresented minority groups—despite those groups comprising 30 percent of the population.

Sexual harassment is another insidious scourge astronomers are hoping to nullify; it is so pestilential that this year, AAS prizewinner and University of Texas at Austin astronomer Caitlin Casey’s plenary lecture included statements printed at the bottom of her slides describing the damaging treatment she has endured from her mentors and colleagues. Many astronomers hope the Decadal Survey will include pointed, explicit recommendations about how to eradicate such harassment and its discriminatory kin. I think they’ll take it seriously, but I don’t think until they form the committee we’ll really know,” Follette says.

So far, only the two survey co-chairs—Harrison and Kennicutt—have been named. Over the next couple of months more scientists will be appointed to the main survey committee and to numerous, discipline-specific panels. They will then get to work reviewing the community’s collective—and sometimes conflicting—priorities, asserted in white paper wish lists supporting various hoped-for telescopes, projects and facilities, each potentially offering profound new scientific discoveries. And maybe, by the time the survey publishes its recommendations, that roadmap will also lay out a path toward more inclusive astronomy.

“I think the structure of the panels and the focus will tell us a lot about how seriously they’ll take that,” Follette says. “So we’re kind of waiting.”



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