Astro2020 Decadal Survey: Priorities for Small and Mid-Scale Projects

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Aside from its highest-profile recommendations, the latest astronomy and astrophysics decadal survey recommends priorities for small and mid-scale projects, with a particular emphasis on time-domain and multi-messenger astronomy. It also calls for increased spending on technology development.

Decadal survey chart of timeframes

A chart from the astronomy and astrophysics decadal survey showing timeframes for recommended programs and the anticipated initiation of science operations for recommended large-scale projects. Click to enlarge.

(Image credit – National Academies)

The most ambitious projects recommended by the new National Academies decadal survey for astronomy and astrophysics are not expected to begin science operations until the 2030s and 2040s. However, NASA and the National Science Foundation will start making decisions in response to survey recommendations much sooner, many of them in support of smaller-scale and mid-scale projects.

One top priority the survey expects will be addressed through such projects is time-domain astronomy, which involves observations of short-lived and variable phenomena. Coordinated, rapid-response observations have become especially important as “multi-messenger astronomy” has matured, with scientists now able to correlate electromagnetic and neutrino emissions with gravitational-wave signals alerting them to sudden events such as neutron-star mergers.

The survey also more generally recommends steps to bolster astronomy’s smaller-scale “sustaining programs” and “technology foundations.” It specifically calls on NSF to expand and strategically tailor its support for mid-scale astronomy projects and for both NASA and NSF to increase funding for technology-development grants.

NASA time-domain program

Creating a “Time-Domain Astrophysics Program” at NASA is the decadal survey’s “highest-priority sustaining activity for space,” which is a separate category from its priorities for large-scale “space frontier” missions.

The survey explains, “While ground-based measurements by observatories large and small are essential, several key capabilities that must be sustained to enable time-domain and multi-messenger astrophysics can only be realized in space. The most important of these are wide-field gamma-ray and X-ray monitoring, and rapid and flexible imaging and spectroscopic follow-up in the X-ray, ultraviolet, and far-infrared. In addition, space platforms can be designed to access much of the sky at any given time, essential for the study of short-lived transients or rapidly variable sources. Space missions can also observe near-continuously compared to ground-based telescopes.”

According to the survey, projects of this nature could be supported through the NASA Astrophysics Division’s Explorer program, which funds the division’s least-expensive space missions. The survey states some missions might be more expensive than what the Explorer program generally supports, but that they would still cost only about half as much as the “probe” missions with $1.5 billion cost caps that the survey also recommends. In addition, the survey notes that NASA could join international efforts, pointing to the example of the Space Variable Objects Monitor, a joint French-Chinese mission to study gamma-ray bursts that is targeted for launch in 2023.

Overall, the survey envisions NASA would spend between $500 million and $800 million on time-domain efforts over the next decade. It also makes clear that such funding should be allocated on top of the Explorer program’s current budget, which it suggests has reached an appropriate level.

NSF mid-scale programs

Deep Symoptic Array illustration

An illustration of the proposed Deep Synoptic Array 2000, a radio telescope facility designed to conduct surveys of the sky, detect transient fast radio bursts, and function as a “multi-messenger discovery engine.” The project was submitted as a white paper to the decadal survey and is expected to cost about $96 million to build. A precursor project, DSA-110, was funded in part through NSF’s mid-scale program

(Image credit – C. Carter / DSA)

Augmenting and expanding NSF’s support for mid-scale astronomy projects is the survey’s “highest-priority sustaining activity” for ground-based astronomy. The survey notes that it does not prioritize between mid-scale and large-scale facilities for new projects, stating both are “essential for an optimal, balanced program.”

The survey recounts that within the last decade NSF has established both a Mid-Scale Innovations Program (MSIP) within its Astronomical Sciences Division and an agency-wide Mid-Scale Research Infrastructure (MSRI) program. These programs cover projects with costs ranging from $4 million to about $100 million, but the survey notes that MSIP has tended to support lower-cost projects and has been funded at a lower overall level than was recommended in the last decadal survey.

Pointing to the large number of compelling white papers submitted to the survey proposing mid-scale projects, the survey recommends that NSF now ramp up annual MSIP and MSRI funding for astronomy and astrophysics projects to about $50 million in total.

The survey further recommends that both programs prioritize certain kinds of projects along three “tracks.” One track would be open to any kind of proposal, a “sustaining instrumentation” track would focus on telescope components, and the third track would focus on projects that address designated “strategic priorities.”

Within the strategic priorities track, the survey states the top priority for the next 10 years should be to fund projects supporting time-domain astrophysics. It also identifies two other, co-equally ranked priorities: highly multiplexed spectroscopy, which it describes as an important complement to large astronomical surveys, and radio instrumentation. In general, the survey expects such projects would be at the higher end of the mid-scale cost range, though it notes white-paper proposals for time-domain astronomy tended to have costs of between $4 million and $40 million.

Technology development

Observing that new technologies are “crucial building blocks without which observational capabilities would stagnate,” the survey recommends increasing support for programs that support technology development. These include NASA’s Astrophysics Research and Analysis (APRA) program and Strategic Astrophysics Technology (SAT) program, as well as the Advanced Technologies and Instrumentation (ATI) program in NSF’s Astronomical Sciences Division.

Concerning APRA, the survey observes the program tends to offer technology grants of between $200,000 and $400,000, which it states is insufficient to launch new research labs. It recommends increasing funding for the Detector Development and Supporting Technology components of APRA by about 50%, or $4 million, prioritizing increased grant size.

The survey recommends steady funding for SAT. Noting SAT has previously focused on technology for future flagship missions, it also suggests the program pivot to supporting probe-class missions in light of the survey’s separate recommendation that NASA create a dedicated maturation program for flagships.

Lamenting that ATI’s annual budget has dwindled to about $6 million in recent years, the survey recommends NSF almost immediately hike it to $14 million and ramp it up to $20 million by 2028 (in 2020 dollars). The survey observes that diminished funding has meant researchers the program funds often have to cobble together multiple sources of support and rely on their access to existing research infrastructure, which has made the program less useful for early-career researchers.

The survey also broadly endorses funding technology development for gravitational-wave detectors and eventually supporting a next-generation version of the NSF-funded IceCube neutrino detector in Antarctica. However, it does not offer specific funding recommendations for those efforts since they would be supported through NSF’s Physics Division and are therefore outside the survey’s official scope.

Agencies face competing demands for budgets

Rubin Observatory night shot

The Rubin Observatory was the previous decadal survey’s top recommendation for ground-based astronomy and it is now nearing completion. New projects to be initiated in the next decade will complement the observatory’s survey capabilities, but its operating costs are also expected to put a severe strain on NSF’s budget for astronomical sciences.

(Image credit – Bruno C. Quint / Rubin Observatory / NSF / AURA)

As NASA and NSF consider their next moves, they will have to balance smaller-scale activities with the early demands of larger recommended projects and programs, including potentially:

  • NASA’s Great Observatories Mission and Technology Maturation Program
  • NASA’s new class of “probe” missions
  • NSF’s contribution to the U.S. Extremely Large Telescope program
  • NSF’s contribution to the Cosmic Microwave Background Stage 4 experiment, and
  • Exploratory work on a next-generation version of NSF’s Very Large Array

In addition, the budget for NSF’s Astronomical Sciences Division is already heavily burdened by the operating costs of large facilities. The survey warns the impending start of science operations at the Daniel K. Inouye Solar Telescope and Rubin Observatory will turn the situation into a “full crisis.” It therefore recommends NSF add no other large facilities to its portfolio until it implements a plan to either increase the division budget appropriately or create some other mechanism for covering operating costs.

Meanwhile, NASA has proposed to immediately free up about $85 million per year in its Astrophysics budget by terminating the Stratospheric Observatory for Infrared Astronomy (SOFIA), citing the airborne telescope’s low scientific productivity relative to its high operating costs. The survey endorses that proposal, stating it found “no evidence that SOFIA could transition to a significantly more productive future,” but Congress may continue to support the mission, as it has in the face of previous proposals to end it.

It will take several years for NASA’s and NSF’s overall plans for responding to the survey’s recommendations to come fully into focus, though agency leaders have already signaled some of their initial thoughts.

Anticipating the survey and SOFIA’s termination, NASA reserved $76 million to respond to survey recommendations in its latest budget proposal. Astrophysics Division Director Paul Hertz said last month that he was planning to present an update on actions in the current fiscal year at the American Astronomical Society’s January meeting and that NASA will present further details after it releases its budget request for fiscal year 2023. He said a fuller response to the survey will follow later in 2022.

Debra Fischer, the new director NSF’s Astronomical Sciences Division, said last month that pandemic-related cost increases for large projects currently in progress could affect the agency’s ability to fund new large projects in the near-term. However, she also noted that NSF is in any case unlikely to propose funding the Extremely Large Telescope program before fiscal year 2025, in view of the survey’s recommendation that NSF first commission a review of the viability of each of the program’s two telescopes.

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