Pathways to Discovery in
Astrophysics for the
Committee for a Decadal Survey on Astronomy and Astrophysics 2020 (Astro2020)
Space Studies Board
Board on Physics and Astronomy
Division on Engineering and Physical Sciences
A Consensus Study Report of
THE NATIONAL ACADEMIES PRESS
This study is based on work supported by Grant FA9550-19-1-0330 with the Air Force Office of Scientific Research, Grant DE-SC0019513 with the Department of Energy, Contract NNH17CB02B with the National Aeronautics and Space Administration, and Grant AST-1852611 with the National Science Foundation. Any opinions, findings, conclusions, or recommendations expressed in this publication do not necessarily reflect the views of any agency or organization that provided support for the project.
International Standard Book Number-13: 978-0-309-46734-6
International Standard Book Number-10: 0-309-46734-9
Digital Object Identifier: https://doi.org/10.17226/26141
Library of Congress Control Number: 2023938874
Cover design: Tim Warchocki.
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Suggested citation: National Academies of Sciences, Engineering, and Medicine. 2023. Pathways to Discovery in Astronomy and Astrophysics for the 2020s. Washington, DC: The National Academies Press. https://doi.org/10.17226/26141.
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COMMITTEE FOR A DECADAL SURVEY ON ASTRONOMY AND ASTROPHYSICS 2020 (ASTRO2020): STEERING COMMITTEE
FIONA A. HARRISON, NAS,1 California Institute of Technology, Co-Chair
ROBERT C. KENNICUTT, JR., NAS, University of Arizona and Texas A&M University, Co-Chair
JULIANNE DALCANTON, University of Washington
TIM DE ZEEUW, Leiden University
ANDREW S. DRIESMAN, Johns Hopkins University Applied Physics Laboratory
JONATHAN J. FORTNEY, University of California, Santa Cruz
GABRIELA GONZÁLEZ, NAS, Louisiana State University
JORDAN A. GOODMAN, University of Maryland
MARC P. KAMIONKOWSKI, NAS, Johns Hopkins University
BRUCE A. MACINTOSH, Stanford University
JACOBUS M. OSCHMANN, Independent Consultant
RACHEL A. OSTEN, Space Telescope Science Institute, Executive Officer
LYMAN A. PAGE, JR., NAS, Princeton University
ELIOT QUATAERT, NAS, Princeton University
WANDA A. SIGUR, NAE,2 Independent Consultant
RACHEL SOMERVILLE, Flatiron Institute
KEIVAN G. STASSUN, Vanderbilt University
JEAN L. TURNER, University of California, Los Angeles
PIETER VAN DOKKUM, Yale University
ELLEN G. ZWEIBEL, NAS, University of Wisconsin–Madison
1 Member, National Academy of Sciences.
2 Member, National Academy of Engineering.
PANEL ON COMPACT OBJECTS AND ENERGETIC PHENOMENA
DEEPTO CHAKRABARTY, Massachusetts Institute of Technology, Chair
LAURA B. CHOMIUK, Michigan State University
DANIEL E. HOLZ, University of Chicago
RAFFAELLA MARGUTTI, Northwestern University
JULIE McENERY, NASA Goddard Space Flight Center
PETER I. MÉSZÁROS, The Pennsylvania State University
RAMESH NARAYAN, NAS, Center for Astrophysics | Harvard and Smithsonian
ELIOT QUATAERT, NAS, Princeton University, Steering Committee Liaison
SCOTT M. RANSOM, National Radio Astronomy Observatory
TODD A. THOMPSON, The Ohio State University
PANEL ON COSMOLOGY
DANIEL EISENSTEIN, NAS, Harvard University and Sloan Digital Sky Survey III, Chair
LINDSEY E. BLEEM, Argonne National Laboratory
MARC P. KAMIONKOWSKI, NAS, Johns Hopkins University, Steering Committee Liaison
RACHEL MANDELBAUM, Carnegie Mellon University
MIGUEL F. MORALES, University of Washington
DANIEL M. SCOLNIC, Duke University
MATIAS ZALDARRIAGA, NAS, Institute for Advanced Study
KATHRYN M. ZUREK, California Institute of Technology
PANEL ON GALAXIES
DANIELA CALZETTI, NAS, University of Massachusetts Amherst, Chair
MICHAEL BOYLAN-KOLCHIN, The University of Texas at Austin
HSIAO-WEN CHEN, University of Chicago
ANN E. HORNSCHEMEIER, NASA Goddard Space Flight Center
SUSAN A. KASSIN, Space Telescope Science Institute
AMANDA A. KEPLEY, National Radio Astronomy Observatory
CHARLES C. STEIDEL, NAS, California Institute of Technology
DANIEL K. STERN, NASA Jet Propulsion Laboratory
TOMMASO TREU, University of California, Los Angeles
PIETER VAN DOKKUM, Yale University, Steering Committee Liaison
DAVID H. WEINBERG, The Ohio State University
PANEL ON EXOPLANETS, ASTROBIOLOGY, AND THE SOLAR SYSTEM
VICTORIA S. MEADOWS, University of Washington, Chair
DAVID A. BRAIN, University of Colorado Boulder
IAN J.M. CROSSFIELD, Massachusetts Institute of Technology
COURTNEY D. DRESSING, University of California, Berkeley
JONATHAN J. FORTNEY, University of California, Santa Cruz, Steering Committee Liaison
TIFFANY KATARIA, Jet Propulsion Laboratory
KATHLEEN E. MANDT, Johns Hopkins University Applied Physics Laboratory
MARK S. MARLEY, NASA Ames Research Center
BRITNEY E. SCHMIDT, Cornell University
CHRISTOPHER C. STARK, Space Telescope Science Institute
PANEL ON THE INTERSTELLAR MEDIUM AND STAR AND PLANET FORMATION
LEE W. HARTMANN, University of Michigan, Chair
SEAN M. ANDREWS, Smithsonian Astrophysical Observatory
PHILIP J. ARMITAGE, Stony Brook University
BRUCE T. DRAINE, NAS, Princeton University
KAITLIN M. KRATTER, University of Arizona
KARIN M. SANDSTROM, University of California, San Diego
SNEZANA STANIMIROVIC, University of Wisconsin–Madison
ELLEN G. ZWEIBEL, NAS, University of Wisconsin–Madison, Steering Committee Liaison
PANEL ON STARS, THE SUN, AND STELLAR POPULATIONS
SARBANI BASU, Yale University, Chair
NANCY S. BRICKHOUSE, Center for Astrophysics | Harvard and Smithsonian
ADAM BURGASSER, University of California, San Diego
JULIANNE DALCANTON, University of Washington, Steering Committee Liaison
JENNIFER A. JOHNSON, The Ohio State University
R.T. JAMES McATEER, New Mexico State University
ELISA V. QUINTANA, NASA Goddard Space Flight Center
LOUIS-GREGORY STROLGER, Space Telescope Science Institute
PANEL ON AN ENABLING FOUNDATION FOR RESEARCH
DAVID N. SPERGEL, NAS, Princeton University, Chair
MICHAEL BLANTON, New York University
KELLE L. CRUZ, Hunter College
MARK J. DEVLIN, University of Pennsylvania
MEGAN E. DONAHUE, Michigan State University
KEITH A. HAWKINS, The University of Texas at Austin
ALINA A. KIESSLING, Jet Propulsion Laboratory
KARIN ÖBERG, Harvard University
ANGELA V. OLINTO, NAS, University of Chicago
BERNARD J. RAUSCHER, NASA Goddard Space Flight Center
RACHEL SOMERVILLE, Center for Computational Astrophysics, Flatiron Institute, Steering Committee Liaison
JAMES M. STONE, Institute for Advanced Study
PANEL ON ELECTROMAGNETIC OBSERVATIONS FROM SPACE 1
MARCIA J. RIEKE, NAS, University of Arizona, Chair
RUSLAN BELIKOV, NASA Ames Research
REBECCA A. BERNSTEIN, Carnegie Institution for Science
LESTER M. COHEN, Center for Astrophysics | Harvard and Smithsonian
NIKOLE K. LEWIS, Cornell University
BRUCE A. MACINTOSH, Stanford University, Steering Committee Liaison
AMY MAINZER, University of Arizona
MARK P. SAUNDERS, Independent Consultant
EVGENYA L. SHKOLNIK, Arizona State University
GEORGE SONNEBORN, NASA Goddard Space Flight Center
C. MEGAN URRY, NAS, Yale University
PANEL ON ELECTROMAGNETIC OBSERVATIONS FROM SPACE 2
STEVEN M. KAHN, Stanford University, Chair
LISA BARSOTTI, Massachusetts Institute of Technology
ALLISON BARTO, Ball Aerospace and Technologies Corporation
MICHAEL BAY, Bay Engineering Innovations
MARTIN ELVIS, Center for Astrophysics | Harvard and Smithsonian
CHARLES J. HAILEY, Columbia University
CHRYSSA KOUVELIOTOU, NAS, The George Washington University
CHARLES R. LAWRENCE, Jet Propulsion Laboratory
S. HARVEY MOSELEY, JR., Quantum Circuits, Inc.
RESHMI MUKHERJEE, Barnard College
LYMAN A. PAGE, JR., NAS, Princeton University, Steering Committee Liaison
GORDON J. STACEY, Cornell University
PANEL ON OPTICAL AND INFRARED OBSERVATIONS FROM THE GROUND
TIMOTHY M. HECKMAN, NAS, Johns Hopkins University, Chair
DAVID A. BEARDEN, Jet Propulsion Laboratory
DAVID CHARBONNEAU, NAS, Harvard University
SUVI GEZARI, University of Maryland
ANDREA M. GHEZ, NAS, University of California, Los Angeles
JENNY E. GREENE, Princeton University
J. TODD HOEKSEMA, Stanford University
JACOBUS M. OSCHMANN, Independent Consultant, Steering Committee Liaison
RICHARD W. POGGE, The Ohio State University
MASSIMO ROBBERTO, Space Telescope Science Institute
NATASCHA M. FÖRSTER SCHREIBER, Max Planck Institute for Extraterrestrial Physics
DAVID R. SILVA, The University of Texas at San Antonio
PANEL ON PARTICLE ASTROPHYSICS AND GRAVITATION
JOHN F. BEACOM, The Ohio State University, Co-Chair
LAURA CADONATI, Georgia Institute of Technology, Co-Chair
DAVID Z. BESSON, University of Kansas
GABRIELA A. GONZÁLEZ, NAS, Louisiana State University, Steering Committee Liaison
JORDAN A. GOODMAN, University of Maryland, Steering Committee Liaison
ELIZABETH A. HAYS, NASA Goddard Space Flight Center
N. JEREMY KASDIN, University of San Francisco
DAVID B. KIEDA, The University of Utah
ANDREA N. LOMMEN, Haverford College
BRIAN D. METZGER, Columbia University
JAMES H. YECK, University of Wisconsin–Madison
NICOLAS YUNES, University of Illinois at Urbana-Champaign
PANEL ON RADIO, MILLIMETER, AND SUBMILLIMETER OBSERVATIONS FROM THE GROUND
ANDREW J. BAKER, Rutgers, The State University of New Jersey, Chair
JACQUELINE N. HEWITT,1 Massachusetts Institute of Technology, Vice Chair
HÉCTOR G. ARCE, Yale University
RAVINDER S. BHATIA, Thirty Meter Telescope
TRACY E. CLARKE, Naval Research Laboratory
MATT A. DOBBS, McGill University
DAVID L. KAPLAN, University of Wisconsin–Milwaukee
DANIEL P. MARRONE, University of Arizona
LYNN D. MATTHEWS, Massachusetts Institute of Technology Haystack Observatory
JOAN R. NAJITA, NSF National Optical-Infrared Astronomy Research Laboratory (NOIRLab)
RICHARD L. PLAMBECK, University of California, Berkeley
JEAN L. TURNER, University of California, Los Angeles, Steering Committee Liaison
PANEL ON STATE OF THE PROFESSION AND SOCIETAL IMPACTS
MARGARET M. HANSON, University of Cincinnati, Co-Chair
ENRICO RAMIREZ-RUIZ, University of California, Santa Cruz, Co-Chair
GURTINA BESLA, University of Arizona
PATRICIA T. BOYD, NASA Goddard Space Flight Center
KATHRYNE J. DANIEL, Bryn Mawr College
MARTHA P. HAYNES, NAS, Cornell University
JEDIDAH C. ISLER, Dartmouth University
RACHEL L. IVIE, American Institute of Physics
KATHRYN V. JOHNSTON, Columbia University
CASEY W. MILLER, Rochester Institute of Technology
JESÚS PANDO, DePaul University
JULIE R. POSSELT, University of Southern California
JANE R. RIGBY, NASA Goddard Space Flight Center
WILLIE S. ROCKWARD, Morgan State University
KEIVAN G. STASSUN, Vanderbilt University, Steering Committee Liaison
1 Resigned from the panel on April 16, 2020, and did not participate in the panel’s deliberations or the writing of its report.
DECADAL SURVEY ON ASTRONOMY AND ASTROPHYSICS 2020 (ASTRO2020) STAFF
JAMES LANCASTER,3 Director, Board on Physics and Astronomy
GREGORY MACK, Senior Program Officer, Board on Physics and Astronomy, Steering Committee Co-Study Director and Panel on Compact Objects and Energetic Phenomena
ABIGAIL A. SHEFFER, Senior Program Officer, Space Studies Board, Steering Committee Co-Study Director and Panel on Electromagnetic Observations from Space 2
DIONNA WISE, Program Coordinator, Space Studies Board, Steering Committee and Panel on State of the Profession and Societal Impacts
MIA BROWN, Research Associate, Space Studies Board, Steering Committee
ALAN ANGLEMAN, Senior Program Officer, Aeronautics and Space Engineering Board, Panel on Particle Astrophysics and Gravitation
SHENAE BRADLEY, Administrative Assistant, Computer Science and Telecommunications Board, Panel on Galaxies
MEGAN CHAMBERLAIN, Senior Program Assistant, Space Studies Board, Panel on Electromagnetic Observations from Space 2, Panel on Optical and Infrared Observations from the Ground, and Panel on Particle Astrophysics and Gravitation
ARTHUR CHARO, Senior Program Officer, Space Studies Board, Panel on Radio, Millimeter, and Submillimeter Observations from the Ground
DWAYNE DAY, Senior Program Officer, Aeronautics and Space Engineering Board, Panel on Electromagnetic Observations from Space 1
GREG EYRING, Senior Program Officer, National Materials and Manufacturing Board, Panel on the Interstellar Medium and Star and Planet Formation, Panel on an Enabling Foundation for Research, and Panel on State of the Profession and Societal Impacts
SANDRA GRAHAM, Senior Program Officer, Space Studies Board, Panel on Stars, the Sun, and Stellar Populations
GAYBRIELLE HOLBERT, Program Assistant, Space Studies Board, Panel on Stars, the Sun, and Stellar Populations
AMISHA JINANDRA, Associate Program Officer, Board on Physics and Astronomy, Panel on Exoplanets, Astrobiology, and the Solar System
CHRISTOPHER JONES, Program Officer, Board on Physics and Astronomy, Panel on Exoplanets, Astrobiology, and the Solar System
JAMES MYSKA, Program Officer, National Materials and Manufacturing Board, Panel on Cosmology
DANIEL NAGASAWA, Program Officer, Space Studies Board, Panel on State of the Profession and Societal Impacts
ERIK SAARI, Administrative Assistant, Board on Army Research Development,4Panel on Compact Objects and Energetic Phenomena, and Panel on Exoplanets, Astrobiology, and the Solar System
ERIK SVEDBERG, Senior Program Officer, National Materials and Manufacturing Board, Panel on Galaxies, and Panel on Optical and Infrared Observations from the Ground
2 Since April 2021.
* We want to thank the following: Senior Scholar and former Board on Physics and Astronomy Board Director Donald C. Shapero; Christine Mirzayan Science and Technology Policy Fellows Sara Crandall and Emily Moravec; and Lloyd V. Berkner Space Policy Interns Jacob Abrahams, Robert Bullard, Benjamin Cassese, Lily Davey, Katherine Dzurilla, Phoebe Kinzelman, Tarini Konchady, Sarah Moran, Osase Omoruyi, Genevieve Payne, and Cindy Vo.
3 Retired May 2021.
4 Until November 30, 2019.
LINDA WALKER, Program Coordinator, Board on Physics and Astronomy, Panel on Cosmology, Panel on the Interstellar Medium and Star and Planet Formation, Panel on an Enabling Foundation for Research, Panel on Electromagnetic Observations from Space 1, and Panel on Radio, Millimeter, and Submillimeter Observations from the Ground
BOARD ON PHYSICS AND ASTRONOMY
ANDREW J. LANKFORD, University of California, Irvine, Chair
MEIGAN ARONSON, University of British Columbia
WILLIAM BIALEK, NAS, Princeton University
JILL DAHLBURG, Naval Research Laboratory (retired)
SALLY DAWSON, Brookhaven National Laboratory
LOUIS F. DIMAURO, The Ohio State University
WENDELL T. HILL III, University of Maryland
ALAN J. HURD, Los Alamos National Laboratory
CHUNG-PEI MA, University of California, Berkeley
ANGELA VILLELA OLINTO, University of Chicago
DAVID H. REITZE, California Institute of Technology
SUNIL SINHA, University of California, San Diego
RISA H. WECHSLER, Stanford University
WILLIAM A. ZAJC, Columbia University
JAMES C. LANCASTER,5 Director
COLLEEN N. HARTMAN,6 Director
NEERAJ P. GORKHALY, Associate Program Officer
AMISHA JINANDRA, Associate Program Officer
CHRISTOPHER J. JONES, Program Officer
RADAKA LIGHTFOOT, Finance Business Partner
GREGORY MACK, Senior Program Officer
LINDA WALKER, Program Coordinator
SPACE STUDIES BOARD
MARGARET G. KIVELSON, NAS, University of California, Los Angeles, Chair
GREGORY P. ASNER, NAS, Carnegie Institution for Science
ADAM S. BURROWS, NAS, Princeton University
JAMES H. CROCKER, NAE, Lockheed Martin Space Systems Company
MARY LYNNE DITTMAR, Coalition for Deep Space Exploration
JEFF DOZIER, University of California, Santa Barbara
MELINDA DARBY DYAR, Mount Holyoke College
ANTONIO L. ELIAS, NAE, Orbital ATK, Inc.
5 Retired May 2021.
6 Since April 2021.
VICTORIA E. HAMILTON, Southwest Research Institute
CHRYSSA KOUVELIOTOU, NAS, The George Washington University
DENNIS P. LETTENMAIER, NAE, University of California, Los Angeles
ROSALY M. LOPES, Jet Propulsion Laboratory
STEPHEN J. MACKWELL, American Institute of Physics
DAVID J. McCOMAS, Princeton University
LARRY J. PAXTON, Johns Hopkins University
ELIOT QUATAERT, NAS, Princeton University
MARK SAUNDERS, Independent Consultant
BARBARA SHERWOOD LOLLAR, University of Toronto
HOWARD SINGER, National Oceanic and Atmospheric Administration
HARLAN E. SPENCE, University of New Hampshire
ERIKA B WAGNER, Blue Origin, LLC
PAUL D. WOOSTER, Space Exploration Technologies
EDWARD L. WRIGHT, NAS, University of California, Los Angeles
COLLEEN N. HARTMAN, Director
ALAN ANGLEMAN, Associate Director
ALEXIS BHADHA, Financial Assistant
MIA BROWN, Research Associate
MEGAN CHAMBERLAIN, Senior Program Assistant
ARTHUR CHARO, Senior Program Officer
SANDRA GRAHAM, Senior Program Officer
GAYBRIELLE HOLBERT, Senior Program Assistant
MEG KNEMEYER, Senior Finance Business Partner
DANIEL NAGASAWA, Program Officer
CELESTE A. NAYLOR, Information Management Associate
TANJA PILZAK, Manager, Program Operations
ANDREA REBHOLZ, Program Coordinator
ABIGAIL SHEFFER, Senior Program Officer
DAVID SMITH, Senior Program Officer
DIONNA WISE, Program Coordinator
The summary charge for the Committee for a Decadal Survey of Astronomy and Astrophysics (Astro2020; hereafter the “steering committee”) reads as follows:
The National Academies of Sciences, Engineering, and Medicine shall convene an ad hoc survey committee and supporting study panels to carry out a decadal survey in astronomy and astrophysics. The study will generate consensus recommendations to implement a comprehensive strategy and vision for a decade of transformative science at the frontiers of astronomy and astrophysics.
The complete statement of task and its scope is provided in Appendix A of this report. The steering committee, with inputs from 13 expert panels encompassing the breadth of astronomy and astrophysics, was specifically asked to (1) provide an overview of the current state of astronomy and astrophysics science, and technology research in support of that science, with connections to other scientific areas where appropriate; (2) identify the most compelling science challenges and frontiers in astronomy and astrophysics, which shall motivate the committee’s strategy for the future; (3) develop a comprehensive research strategy to advance the frontiers of astronomy and astrophysics for the period 2022–2032 that will include identifying, recommending, and ranking the highest-priority research activities; (4) utilize and recommend decision rules, where appropriate, that can accommodate significant but reasonable deviations in the projected budget or changes in urgency precipitated by new discoveries or unanticipated competitive activities; (5) assess the state of the profession, including workforce and demographic issues in the field, identify areas of concern and importance to the community, and where possible, provide specific, actionable, and practical recommendations to the agencies and community to address these areas.
Astro2020 was sponsored by the National Aeronautics and Space Administration (NASA), the National Science Foundation (NSF), the Department of Energy (DOE) Office of High Energy Physics, and the Air Force Office of Space Research (AFOSR). These federal agencies all participate in different aspects of the U.S. space- and ground-based astronomy and astrophysics program. Internally, the decadal survey effort at the National Academies was a joint project of the Board on Physics and Astronomy and the Space Studies
Board. This is the seventh decadal plan for astronomy and astrophysics conducted over the history of the National Academies.
The scope of the science assessed by the decadal survey is broad, encompassing all aspects of observational, theoretical, and computational astronomy, including ground-based solar observations, but specific activity recommendations were limited to those administered by the NSF Division of Astronomical Sciences and the NASA Astrophysics Division. Scientific areas in astronomy and astrophysics pursued by the DOE Office of High Energy Physics were also included in the study, but activity recommendations were limited to NSF and NASA as described above.
The committee was also tasked with assessing three space projects, the Nancy Grace Roman Space Telescope (formerly Wide Field Infrared Survey Telescope), Athena (Advanced Telescope for High-Energy Astrophysics), and LISA (Laser Interferometer Space Antenna)—the latter two being European-led missions with significant NASA participation. These three projects were highly ranked priorities for the 2010 New Worlds New Horizons decadal survey, also called Astro2010, and are under development but not yet launched.1 The committee was invited to comment on the status and future direction of NASA support for these projects, but they were not considered together with nor ranked against new projects proposed for the coming decade. Likewise, the survey was invited to consider the status and evolution of ongoing programs within NASA’s program of record.
STUDY PROCESS AND PARTICIPANTS
Organization of the Astro2020 decadal survey, including the steering committee and 13 expert panels, began with the appointment of the co-chairs in late 2018. The steering committee consisted of 20 members, including the co-chairs. Members were selected to cover as fully as possible the scientific scope of the survey, the range of observational (ground, space, and particle/gravitational astrophysics) and theoretical disciplines, as well as technical and managerial background in space and/or ground-based facilities, and to comprise as representative a group of experts as possible in terms of individual, institutional, and geographical demographics. National Academies policies governing potential conflicts of interest by steering committee and panel members were strictly enforced. In particular, broad and open-minded thinkers were sought out as opposed to advocates for individual missions or subfields. The role of the Executive Officer was also redefined for this survey to that of a full voting member of the steering committee, with additional administrative and coordination responsibilities as part of the leadership team.
All meetings and deliberations for the survey operated under a code of conduct to guide discussions. This code of conduct was developed in addition to the National Academies policy on sexual harassment and bullying for committee members, panelists, and meeting attendees, and in addition to a code of conduct for National Academy of Sciences members. The statement includes a recognition of strongly held, possibly differing opinions; a dedication to open dialogue and open exchange of ideas; and professional, civil, and collegial treatment of colleagues so that an open exchange of ideas can occur.
During the course of the panel and steering committee meetings, a number of public information-gathering sessions were held. These included briefings by the agencies (NASA, NSF, DOE), invited presentations by selected projects to the program panels, and other informational sessions sponsored by the other panels or the steering committee. Throughout the survey, the representatives of all three agencies urged the committee to be “ambitious”2 and “aspirational,”3 and the committee hopes that it has risen to this challenge.
1 National Research Council, 2010, New Worlds, New Horizons in Astronomy and Astrophysics, The National Academies Press, Washington, DC.
2 Presentation to Astro2020 committee by Paul Hertz, NASA Astrophysics Division, July 2019.
3 Presentation to Astro2020 committee by Ralph Gaume, NSF Division of Astronomical Sciences, July 2019.
The charges of the expert panels were similar to those of the Astro2010 survey, but with a few important changes. The number of science panels was increased from five to six to accommodate the very rapid growth over the previous decade of exoplanetary astronomy and multi-messenger astrophysics, while preserving balance across all subject areas. The basic programmatic panel structure from Astro2010 was also retained, except that the Panel on Electromagnetic Observations from Space was divided into two panels, in order to accommodate the very large number of project proposals and community white papers in that area. Last, two new panels for Astro2020 were appointed—the Panel on an Enabling Foundation for Research (program panel) was charged with evaluating cross-cutting supporting programs (e.g., grants programs, laboratory astrophysics, data archiving and data science, computation, theory), and the Panel on State of the Profession and Societal Impacts (SoPSI) was charged to advise the steering committee on this specific area in its statement of task. These 13 appointed panels (six science, six program, and one state of the profession) comprised 127 members. In addition, a steering committee “liaison” member was appointed to each panel to facilitate the flow of information and communication between panels and the main survey committee. The liaisons participated in the panel discussions but did not hold formal voting rights. In all, 141 individuals participated in the panel deliberations with a purpose of providing input to the steering committee. Each panel drafted its own report, with suggestions for the steering committee to consider, as it held its own deliberations to reach its recommendations for the main report. To underscore the importance of the panel reports, they have been published together with this main report as appendixes.
The science panels were asked to provide a brief review of the current state of the science in their topic areas and determine four important science questions to be addressed in the next decade and one area that shows great promise for discovery. The program panels were charged to assess the ability of current and proposed projects under consideration to address the science panels’ questions and discovery areas, to comment on the Technical, Risk, and Cost Evaluations (TRACEs) of the proposed projects, to identify key areas of technical development or precursor research activities, and to discuss the balance of small, competitively selected activities versus larger strategic investments needed to address the science questions. The program panels were not asked to prioritize or rank projects, but rather to suggest to the steering committee the projects with the best potential to realize the capabilities needed to address the science panels’ questions and discovery areas. The SoPSI panel was asked to gather information on the health and demographics of the astronomy and astrophysics community and make actionable suggestions to the steering committee on the topics of demographics, diversity and inclusion, workplace climate, workforce development, education, public outreach, and relevant areas of astronomy and public policy. Further information about the charges to the panels is found in Appendix A.
The information-gathering and deliberative phases of Astro2020 were carefully coordinated. Members of the astronomical community were invited to submit white papers to the survey, and these papers formed the foundation and starting point for all of the panel deliberations. In the first phase, 572 science white papers were received in early 2019. A second call for “activity, project, or state of profession consideration” (APC) white papers in July 2019 elicited 294 responses. Every white paper was assigned to and read by one or more of the panels.
The panel meetings themselves were phased. The science panels each held two formal meetings, the program panels each held three formal meetings, and all held several additional teleconferences. Meetings of the science panels took place during the second half of 2019, so that the priorities emerging from the reports of those panels could be incorporated into the program panel deliberations. The science panel chairs presented their findings to the steering committee and the program panels at a face-to-face meeting in December 2019 and delivered their written reports in early 2020. The program panels’ meetings began in November 2019, and they presented their results to the steering committee in May 2020 and delivered initial written reports in June 2020. The SoPSI panel met and deliberated on an independent schedule,
including holding a public listening session at the American Astronomical Society meeting on January 6, 2020. The SoPSI report was fully incorporated into the overall deliberations and prioritization phases of the steering committee activities.
During the course of the panel deliberations, a number of other inputs were received, and these were especially important for the program panels. After an initial review of all projects proposed for a given panel area, the panels issued requests for information (RFIs) from selected projects to obtain more detailed information that was initially provided in the respective APCs. These included all of the large space and ground “flagship” proposals and selected examples of smaller projects. Selected projects were also invited to present summaries to their respective program panels in public sessions. Many of these projects then underwent a detailed TRACE study, conducted by an independent contractor (The Aerospace Corporation). This independent analysis was mandated by the 2008 NASA Authorization Act, which “directs the Administrator to enter into agreements periodically with the National Academies for decadal surveys to take stock of the status and opportunities for Earth and space science discipline fields and aeronautics research and to recommend priorities for research and programmatic areas over the next decade.”4 Additionally, the act “requires that such agreements include independent estimates of life cycle costs and technical readiness of missions assessed in the surveys whenever possible.” In-house analyses of technology readiness, risk, and cost estimates provided by the project teams themselves supplemented this analysis. Details of the TRACE process are provided in Appendix O of this report. This process was formerly labeled “Cost and Technical Evaluation” (CATE) and was conducted for recent National Academies surveys in planetary science and solar and space physics, as well as Astro2010.
The schedule for this review was impacted by two outside events—a 35-day government shutdown from December 2018 to January 2019, and the COVID-19 pandemic beginning in 2020. The shutdown happened just as science white papers were being solicited, so the deadline for submissions was delayed by a month. The impacts of the COVID-19 pandemic were much more severe. The initial disruptions in March and April 2020 occurred when the program panels were completing their final meetings. Final panel deliberations were held virtually, and delivery of the panel reports to the steering committee were delayed by up to 2 months as everyone adjusted to the new reality of working, caring for children, teaching, and performing service to the community, all while under a stay-at-home order. The greatest impact was on the deliberations of the steering committee, which needed to replace its remaining schedule of four 3- to 4-day face-to-face meetings (out of six total) with more than 20 all-day Zoom meetings. Early into the pandemic, the survey co-chairs and National Academies’ staff decided not to allow the disruptions to compromise the quality or integrity of the survey, and the inevitable result was a several month delay from the original schedule. Included in these virtual meetings were presentations of preliminary results by the program and SoPSI panels during the summer of 2020.
After the panel reports were received and assembled, the steering committee proceeded with the main prioritization discussions, fully informed by the panel reports. The steering committee addressed a few additional topics that were not taken up in full by a program panel (e.g., satellite constellations and radio frequency interference). In such cases, working groups were appointed within the steering committee or by committee and cross-panel working groups. The steering committee’s deliberations were aided by the introduction of innovative strategies to assist in reaching consensus in the virtual environment necessitated by COVID-19, such as online voting tools, collaborative online document editing, the utilization of various videoconferencing features, and asynchronous deliberations (Figure P.1).
4 H.R. 6063—National Aeronautics and Space Administration Authorization Act of 2008, P.L. 110-422, Section 1104, https://www.congress.gov/bill/110th-congress/house-bill/6063.
The completion of an undertaking of this scale and importance relies on the contributions of many, and we conclude this introduction by thanking some of the key people. The members of the steering committee, the panel chairs, and the members of the panels contributed tirelessly to the effort, even after the onset of the pandemic extended the timetables and the complexity of their activities. One individual in particular, Executive Officer Rachel Osten, provided extraordinary service as a logistical and scientific coordinator, valued committee member, and advisor to the co-chairs, and is amply deserving of special mention.
The foundation materials for Astro2020 were the 867 science and activity, project, and state of profession consideration white papers, which were contributed by thousands of authors from around the astronomical community. The quality of those papers testified to the effort and thought that went into their preparation, and we express our heartfelt thanks to everyone who participated in this effort and made this a truly community-based survey.
We are also grateful to the members of our sponsoring agencies, especially Ralph Gaume at the National Science Foundation, Paul Hertz at NASA, and Kathleen Turner at the Department of Energy, and their staffs for sharing their time during the early phases of the survey to provide comprehensive background information and guidance, and for responding to our many requests for further background and statistical information.
The Technical, Risk, and Cost Evaluations assessments of the large projects considered by Astro2020 were carried out by the Aerospace Corporation, and we thankfully acknowledge the contributions of their team members, including, in particular, Randy Persinger and Matthew Marshall. We also thank the many experts who generously contributed their help to the steering committee or its panels as consultants. These include Steven Battel (Battel Engineering), who provided early advice on the setup of the survey processes, and Justin Jonas (South African Radio Astronomy Observatory), Joseph McMullin (Square Kilometre Array Organisation), James Moran (Harvard-Smithsonian Center for Astrophysics), and Antony Schinckel (Commonwealth Scientific and Industrial Research Organisation), who provided expert technical advice to the Panel on Radio, Millimeter, and Submillimeter Observations from the Ground. Sherard Robbins (University of Arizona) kindly served as the facilitator of the Panel on State of the Profession and Societal Impacts listening session at the American Astronomical Society meeting.
The scientific vision and recommended strategic program arising from this process are presented in the remainder of this report and will not be summarized here. As with all of the preceding astronomy and astrophysics surveys, difficult choices were necessary, but that is the main reason for conducting these decadal reviews.
We hope that we have provided not only an ambitious, inspirational, and aspirational vision and roadmap for the coming decade but also a pathway toward realizing even greater objectives in the future.
Fiona Harrison and Robert Kennicutt, Co-Chairs
Committee for a Decadal Survey on Astronomy and Astrophysics 2020
This Consensus Study Report was reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise. The purpose of this independent review is to provide candid and critical comments that will assist the National Academies of Sciences, Engineering, and Medicine in making each published report as sound as possible and to ensure that it meets the institutional standards for quality, objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process.
We thank the following individuals for their review of this report:
1 Member, National Academy of Sciences.
Science Panel Appendixes
Program Panel Appendixes
Panel on Electromagnetic Observations from Space 1
Panel on Electromagnetic Observations from Space 2
Panel on Optical and Infrared Observations from the Ground
Panel on Particle Astrophysics and Gravitation
Panel on Radio, Millimeter, and Submillimeter Observations from the Ground
Panel on State of the Profession and Societal Impacts
Although the reviewers listed above provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations of this report nor did they see the final draft before its release. The review of this report was overseen by Charles F. Kennel, NAS, University of California, San Diego, and Rosalba Perna, State University of New York at Stony Brook. They were responsible for making certain that an independent examination of this report was carried out in accordance with the standards of the National Academies and that all review comments were carefully considered. Responsibility for the final content rests entirely with the authoring committee and the National Academies.