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Astronomy and Astrophysics in the New Millennium (2001)

Chapter: 1. Recommendations

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Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
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1
Recommendations

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

INTRODUCTION

ASTRONOMY AND ASTROPHYSICS IN THE NEW MILLENNIUM

The new millennium marks a turning point in the history of efforts to understand our place in the universe. The heavens have been a source of fascination for humanity for thousands of years, but only in the last few centuries has it been possible to take the measure of the stars—and only in the last few decades, to take the measure of the entire universe. The scientific and technical revolution that has enabled this enormous progress is accelerating. We can anticipate major new discoveries in the early decades of the new millennium, but more importantly we can anticipate major advances in our understanding of the universe—its origin, its evolution, its ability to support life, its destiny. What is the nature of the matter and energy in the universe? What happened at the dawn of the modern universe, when the first stars and galaxies formed? How are black holes formed? How do stars and planets form, and how do planets evolve to create habitats suitable for life? How does the astronomical environment affect Earth? These questions are all part of the fabric of science, cutting across traditional disciplines and government agencies and connecting the universe from the smallest to the largest scales. Addressing them will require interactions of astronomy with many other disciplines, including physics, mathematics, computer science, and biology. The interaction with physics is particularly important since all objects in the universe—and indeed the universe itself—are governed by the same fundamental physical laws. Answering these questions will alter the perception of our place in the universe, just as the advent of the heliocentric theory did centuries ago. The search for the answers can also capture the imagination of the public and inspire interest in science, thereby helping to create a more scientifically literate citizenry.

ACCOMPLISHMENTS OF THE 1990S

The past decade saw an unprecedented number of important astronomical discoveries. Some highlights include:

  • Discovery of planets orbiting other stars; about three dozen are now known.

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×
  • Determination of the interior structure of the Sun from observations of its seismic activity. These results confirmed theoretical models of solar structure throughout most of the Sun to within 0.1 percent and support the hypothesis that the observed deficit in the number of neutrinos from the Sun arises because they have a non-zero mass.

  • Discovery of the Kuiper Belt, a large group of small, primitive bodies in the outer solar system predicted by theory. The Kuiper Belt is probably the source of most short-period comets and contains a unique fossil record of how the solar system formed.

  • Observation of the impact of Comet Shoemaker-Levy 9 on Jupiter, providing a dramatic illustration of the potential effects of such impacts on Earth.

  • Discovery of “brown dwarfs,” cool stars too small to sustain nuclear reactions in their interiors.

  • Discovery of the theoretically predicted phenomenon of gravitational microlensing, in which the brightness of background stars is amplified by the gravitational effects of intervening objects of stellar mass.

  • Discovery that gamma-ray bursts originate in the very distant universe and that they produce afterglows at other wavelengths, as had been predicted theoretically.

  • Discovery of massive black holes in the nuclei of galaxies, including our own Milky Way, thereby confirming theoretical predictions that such massive black holes must be common.

  • Discovery of young galaxies at redshifts greater than 3, revealing the dramatic evolution of galaxies from the early universe to the present.

  • Discovery of theoretically predicted tiny fluctuations in the background radiation left over from the Big Bang on scales from 100 million to 10 billion light-years, the seeds of subsequent structure formation.

  • Measurement of the expansion rate of the universe to an accuracy approaching 10 percent and determination that there is not enough matter to stop the expansion of the universe.

  • At the end of the decade of the 1990s, evidence suggesting both that the universe is “flat,” as expected in inflationary cosmologies, and that its expansion is accelerating owing to the presence of “dark energy.”

THE LEGACY OF THE PREVIOUS DECADAL SURVEY

Planning and investment over the past decade are now providing ripe opportunities for advancements and discoveries in the near future. All of the large and many of the moderate programs recommended in

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

the report of the previous Astronomy and Astrophysics Survey Committee, The Decade of Discovery in Astronomy and Astrophysics (NRC, 1991; known as the Bahcall report and referred to in the current report as the 1991 survey), have been initiated. The top priority, the Space Infrared Telescope Facility (SIRTF), is scheduled for launch in 2002. SIRTF is the last of the Great Observatories, begun with the Hubble Space Telescope in the 1980s and successfully continued with the Compton Gamma Ray Observatory and the Chandra X-ray Observatory in the 1990s. SIRTF’s remarkable sensitivity in the infrared will enable it to make fundamental advances in the study of brown dwarfs, in tracing the formation and evolution of galaxies, and in better understanding quasars. The first of the two ground-based Gemini optical-infrared telescopes was completed in 1999, and the second is scheduled to open in 2001. Each telescope mirror has a diameter of 8 m. These telescopes will enable study of some of the same sources as SIRTF, but at shorter wavelengths and with much finer angular resolution. The Millimeter Array, which has become part of the more powerful Atacama Large Millimeter Array (ALMA), is nearing the end of its design phase with construction poised to start. ALMA will trace the processes by which interstellar gas turns into stars, on small scales in our galaxy and on much larger scales in the distant universe.

Adaptive optics, the 1991 survey’s top-priority moderate program, advanced substantially during the 1990s and received a major boost with the selection of the Center for Adaptive Optics as a National Science Foundation (NSF) Science and Technology Center. By eliminating the smearing effects of the atmosphere, adaptive optics will enable astronomers to see fainter objects and far greater detail with existing ground-based telescopes. The Astrometric Interferometry Mission has evolved into the far more capable Space Interferometry Mission (SIM). Measuring positions on the sky with unprecedented precision, SIM will enable the discovery of planets much more similar to Earth in mass and orbit than those detectable now, and it should permit astronomers to survey the Milky Way Galaxy 1,000 times more accurately than is possible now. Through the National Optical Astronomy Observatories, the NSF has contributed to two new 4-m-class telescopes, providing powerful new tools for astronomical investigations. Studies of the cosmic microwave background radiation, the top priority of the Task Group on Space Astronomy and Astrophysics (NRC, 1997), are being pursued through NASA’s Microwave Anisotropy Probe (MAP), the European Space Agency’s Planck Surveyor mission, and a vigorous ground-based and

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

suborbital program. These studies will determine the large-scale properties of the universe and the fundamental cosmological parameters with remarkable precision. The dramatic increases in computer power foreseen a decade ago have been realized, enabling enormous advances in astrophysical simulation.

We must begin planning now to take advantage of the discoveries these new facilities will make possible. Continued progress requires new ideas for the next generation of facilities and innovative plans for operating them most effectively.

APPROACH AND SCOPE

IMPLEMENTATION OF THE CHARGE

To help carry out its charge (stated in full in the preface), the committee established nine panels with a total of 105 members.1 These panels developed the cases for all the projects and almost all the policies that were then evaluated and prioritized by the committee according to the criteria given below. The chairs of the panels participated in almost all the deliberations of the committee, but as advocates for their disciplines they did not vote on priorities. The majority of the panels were organized on the basis of observational technique rather than scientific subdiscipline, so as to facilitate selection of the projects to be considered by the committee. To treat issues that did not fit neatly into the panel organization, cross-panel working groups were established in four areas: (1) astronomical surveys, (2) extrasolar planets, (3) laboratory astrophysics, and (4) NSF-funded national observatories. The comments of these working groups provided input to the panels and to the committee. The committee also benefited from the National Research Council report Federal Funding of Astronomical Research (NRC, 2000), which addressed demographic and funding issues raised in previous astronomy surveys.

In their deliberations, the panels and the committee received input from a broad cross section of the community. Sessions were held at two meetings of the American Astronomical Society (AAS), each attended by more than 300 people. The AAS also organized the Decadal Issues Discussion Forum on the World Wide Web, which attracted a number of thoughtful contributions. More than 100 individuals made presentations to the panels. Members of the committee and panel chairs organized

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

more than 20 meetings in their local institutions to gather further input. Hundreds of e-mail messages were received by the panels and the committee. Members of the committee consulted with representatives of the funding agencies and of the Office of Management and Budget and with congressional staff. Eight distinguished members of the international astronomical community2 attended most of the second meeting of the committee, adding valuable insights to the deliberations. International astronomers contributed to the work of the panels as well.

The members of the panels and of the committee all share a primary expertise in astronomical science, and the scientific merit of the proposed programs was the primary basis for determining priorities. However, the committee also considered technical readiness, cost-effectiveness, impact on education and public outreach, and the relation to other projects, both in the United States and abroad.

The committee made a careful attempt to define the boundary between projects it would consider and those it would not. First, judging that the Explorer and Discovery programs at NASA are suitably peerreviewed, the committee did not make any recommendations on individual projects in these programs. Second, for evaluation of two NASA projects under consideration that will make both in situ measurements and remote observations—Solar Probe and Interstellar Probe—the committee decided to defer to the Committee on Solar and Space Physics of the Space Studies Board. Third, in the case of the interdisciplinary field of particle astrophysics, the committee evaluated projects that use particles as tools for remote observation, but not projects that focus on the physics of the particles themselves. Finally, based on informal discussions with the Committee on Gravitational Physics of the Board on Physics and Astronomy, the committee did not evaluate possible future upgrades to the Laser Interferometer Gravitational-wave Observatory (LIGO) project. This project is discussed in the NRC report Gravitational Physics: Exploring the Structure of Space and Time (NRC, 1999).

PURPOSE AND CONTENT OF THE TWO VOLUMES

This astronomy and astrophysics survey includes the report of the survey committee (this volume) plus a separate volume, Astronomy and Astrophysics in the New Millennium: Panel Reports (NRC, 2001), comprising the reports of seven of the nine panels. The reports of the Panel on Astronomy Education and Policy and the Panel on Benefits to

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

the Nation from Astronomy and Astrophysics have been incorporated into this volume. This volume reflects the consensus of the Astronomy and Astrophysics Survey Committee; each chapter in the Panel Reports reflects the consensus of the corresponding panel. Every effort has been made to ensure that the recommendations in the two volumes are consistent; if any discrepancy between the report of the committee and a report of a panel remains, the report of the committee takes precedence. The purpose of the panel reports is to describe the new initiatives in more detail, to provide more extensive justification for the priorities, and to give additional priorities, applying typically to small projects, appropriate for individual subfields of astronomy and astrophysics.

The committee’s primary recommendations for new initiatives are summarized in the remainder of the present chapter. Chapter 2 describes the scientific case underlying each recommendation. Programs already in operation or that have been recommended in previous astronomy surveys are summarized in Chapter 3, which also gives full explanations of the proposed new initiatives. Chapters 4 through 6, respectively, describe the benefits that astronomy and astrophysics provide to the nation, discuss the role of astronomy in education, and offer policy recommendations aimed at maintaining the health of the discipline and enhancing its contributions to science in general. A glossary of technical terms and a list of abbreviations and acronyms are included in an appendix to this volume.

OPTIMIZING THE RETURN ON THE NATION’S INVESTMENT IN ASTRONOMY AND ASTROPHYSICS

The United States has made and continues to make a significant investment in exploring the universe. In exchange, the nation deserves the maximum scientific return for this investment and widespread dissemination of the results. The astronomy and astrophysics enterprise depends on highly trained and motivated people, on technologically sophisticated facilities and missions, and on institutions properly equipped to manage them. How can this system be optimized to address the frontier scientific problems most effectively, both now and in the future?

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

BALANCING NEW INITIATIVES WITH THE ONGOING PROGRAM

The first step in optimizing the program is to achieve a proper balance between new initiatives and the ongoing program. Congress specifically asked the committee to address this issue, and its response and discussion are given in Chapter 6. Many of the policy recommendations discussed there are directly relevant to the question of balance.

  • The committee reaffirms the recommendations of the 1991 Astronomy and Astrophysics Survey Committee (NRC, 1991) by endorsing the completion of the Space Infrared Telescope Facility (SIRTF), the Millimeter Array (MMA; now part of the Atacama Large Millimeter Array, or ALMA), the Stratospheric Observatory for Infrared Astronomy (SOFIA), and the Astrometric Interferometry Mission (now called the Space Interferometry Mission, or SIM). Consistent with the recommendations of the Task Group on Space Astronomy and Astrophysics (NRC, 1997), the committee stresses the importance of studying the cosmic microwave background with the Microwave Anisotropy Probe (MAP) mission, the European Planck Surveyor mission, and ground-based and balloon programs.

A particular attraction of SIM is its dual capability: It enables both the detection of planets through narrow-angle astrometry and the mapping of the structure of our galaxy and nearby galaxies through wideangle astrometry. It is critical that an accuracy of a few microarcseconds for wide-angle measurements be achieved in order to address a wide variety of fundamental problems throughout the decade.

The committee endorses U.S. participation in the European Far Infrared Space Telescope (FIRST), which gives U.S. astronomers the chance to observe the entire far-infrared and submillimeter regions of the spectrum with no impediments from the residual atmosphere that can hinder observing from airborne platforms. The committee also endorses NASA’s decision to continue to operate the Hubble Space Telescope at a reduced cost until the end of the decade to maintain the capability for critical space-based ultraviolet and optical observations.

  • To achieve the full scientific potential of a new facility, it is essential that, prior to construction, funds be identified for operation of the facility, for renewal of its instrumentation,

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

and for grants for data analysis and the development of associated theory.

NASA follows the spirit of this recommendation in large part by including the costs of Mission Operations and Data Analysis (MO&DA) in budgetary planning for new missions. The wisdom of this approach is manifest in the wealth of discoveries and new interpretations published during the prime years of NASA missions. The committee recommends that funds for closely related theory be included in MO&DA as well; a specific proposal for “Theory Challenges” is outlined below.

The committee further recommends that the NSF include funds for (1) operations, (2) facility instruments and other capabilities that enable full exploitation of the new facility, and (3) grants for the ground-breaking research—both observational and theoretical—enabled by the new facility during its early, highly productive years. These recommendations are consistent with those of the 1991 survey. Based on the experience with several recently completed facilities, the committee has budgeted operations at 7 percent of the capital cost per year and instrumentation at 3 percent per year for the first 5 years of operation (see Chapter 6); the actual percentages should be based on the particular circumstances of the individual facility. To enable observers and theorists to explore and develop the full capabilities of new facilities, the committee recommends budgeting “facility grants” for research associated with major facilities at about 3 percent of the capital cost per year for the first 5 years. A cost-effective and competitive grants program for moderate facilities requires a somewhat higher percentage, and the committee recommends that facility grants for such facilities be budgeted at about 5 percent per year. No facility grants are recommended for small projects since the funds available would be too small. Funds for operations, instrumentation, and facility grants for a period of 5 years are included in the committee’s cost estimates for most ground-based initiatives (see the section below, “Proposed Priorities for Ground- and Space-Based Initiatives”).

  • Adequate funding for unrestricted grants that provide broad support for research, students, and postdoctoral associates is required to ensure the future vitality of the field; therefore new initiatives should not be undertaken at the expense of the unrestricted grants program.

A strong grants program is critical both to realize the full science value from state-of-the-art facilities and to ensure the future health of the

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

field. On the basis of the NASA experience, the committee believes that grants associated with new ground-based facilities, as proposed above, should address the data analysis and science needs for those facilities as well. Such grants should also support some postdoctoral associates and graduate students. However, past experience shows that it is often the individual investigator grants that are not tied to a specific facility or program—the unrestricted grants—that support the innovative new research that drives the future directions of astronomy. Previous decadal astronomy surveys have also emphasized the importance of unrestricted grants in advancing the field.

STRENGTHENING GROUND-BASED ASTRONOMY AND ASTROPHYSICS

The United States is fortunate to enjoy substantial state and private funding for ground-based optical and infrared facilities and, to a lesser extent, radio and solar facilities. To optimize the return on federal investment in ground-based astronomy, the committee recommends that:

  • U.S. ground-based optical and infrared facilities, radio facilities, and solar facilities should each be viewed by the National Science Foundation and the astronomical community as a single integrated system drawing on both federal and nonfederal funding sources.

The NSF must draw on the strengths of the independent observatories to achieve its goals in ground-based astronomy. Independent observations are playing their appropriate roles effectively in both radio and solar astronomy, but less so in optical and infrared astronomy. Several of the committee’s recommendations should help to build the partnership between federal and independent observatories in both radio astronomy (the Combined Array for Research in Millimeter-wave Astronomy and the Square Kilometer Array technology development) and optical and infrared astronomy (the Telescope System Instrumentation Program).

  • Effective national organizations are essential to coordinate, and to ensure the success and efficiency of, these systems.

These national organizations should work with the universities and independent observatories in developing the next generation of telescopes. The National Radio Astronomy Observatory (NRAO) and the

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

National Astronomy and Ionosphere Center (NAIC) currently fulfill the committee’s recommended role for radio astronomy, and the National Solar Observatory (NSO) does so for the solar physics community. The National Optical Astronomy Observatories (NOAO) as currently functioning and overseen does not fulfill this role for the community of ground-based optical and infrared observers. A plan for the transition of this organization should be developed, and a high-level external review, using appropriate criteria, should be initiated (see Chapter 6).

  • As part of the effort to develop effective systems of telescope facilities, universities and independent observatories should work with the national organizations to develop coherent strategic plans for each system (optical, solar, and radio) and to develop those facilities that are too large or expensive to fit within the resources of a single institution or consortium. Universities should assume the responsibility for purchasing, instrumenting, and operating small telescopes needed for their students and faculty.

Optimizing the overall program also requires a mechanism to achieve the correct balance among existing facilities to address the important scientific problems as they evolve.

  • Cross-disciplinary competitive reviews should be held about every 5 years for all NSF astronomy facilities. In these reviews, it should be standard policy to set priorities and consider possible closure or privatization. New facilities should undergo their first competitive review between 5 and 10 years after they become operational.

NASA holds a senior review of its MO&DA programs every 2 or 3 years; the greater frequency is appropriate in view of the shorter lifetime of space missions. The recommended 5-year reviews should provide input to NSF’s Division of Astronomical Sciences (AST), enabling it to adjust its entire portfolio to meet changing scientific priorities and to satisfy its strategic plan.

The Department of Energy (DOE) supports a broad range of programs in particle and nuclear astrophysics and in cosmology. Such investigations probe the fundamental forces and the nature of matter in ways that directly complement accelerator-based experiments and basic theoretical research. DOE research in plasma physics also has many synergies with astrophysics. The scientific payoff of these programs

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

would be even stronger with a clearly articulated strategic plan for DOE’s programs that involve astrophysics.

  • Given the increasing involvement of the Department of Energy in projects that involve astrophysics, the committee recommends that DOE develop a strategic plan for astrophysics that would lend programmatic coherence and facilitate coordination and cooperation with other agencies on science of mutual interest.

ENSURING THE DIVERSITY OF NASA MISSIONS

NASA’s program during the past decade has been extraordinarily successful. Three of the four Great Observatories are now operational, and the fourth is nearing readiness for launch. The Explorer program is very successful and has elicited many highly innovative, cost-effective proposals for small missions from the community. The committee endorses the continuation of a vigorous Explorer program by NASA.

Opportunities for moderate-scale missions are less readily available, however. In the past, there were a number of extraordinarily successful moderate-sized missions, including the Infrared Astronomical Satellite (IRAS), the Cosmic Background Explorer (COBE), the International Ultraviolet Explorer (IUE), the Extreme Ultraviolet Explorer (EUVE), and the Rossi X-ray Timing Explorer (RXTE). Moderate missions such as these no longer fit within the cost cap of the Explorer program.

  • NASA should continue to encourage the development of a diverse range of mission sizes, including small, moderate, and major, to ensure the most effective returns from the U.S. space program.

Consistent with this recommendation, several moderate space missions are recommended for this decade.

INTEGRATING THEORY CHALLENGES WITH NEW INITIATIVES

Astronomy advances by innovation in instrumentation, observation, and theory. This report recommends a number of projects with technologically advanced instrumentation that will enable observers to extend the frontiers of knowledge. In many instances, astrophysical theorists provide the ideas that guide the choice of instrumentation, the decisions

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

about what to observe, and the interpretation of data. Adequate support of theory is therefore essential in optimizing the nation’s investment in astronomy and astrophysics.

  • To encourage theorists to contribute to the planning of missions and facilities and to the interpretation and understanding of the results, one or more explicitly funded theory challenges should be integrated with most moderate or major initiatives.

A theory challenge is an initiative to focus the attention of the research community on a theoretical problem or area, broadly or narrowly defined, that is ripe for theoretical progress and relevant to a particular mission or facility. For ground-based projects, the theory challenges would be part of the associated facility grants; as pointed out above, small ground-based projects do not have facility grants and thus would not have theory challenges. By encouraging coordinated efforts to addresss broad theoretical problems relevant to new programs, this recommendation provides the opportunity for a qualitatively new approach to advancing researchers’ conceptual understanding. Numerical simulation will play an important role in the theory challenges, both in advancing our understanding and in enabling detailed comparison with observation. The theory challenges should significantly enhance the effectiveness of theoretical research related to specific missions. The committee believes that broadly based theoretical research not tied to specific missions is also vital to astrophysics, and it should continue to be supported by the unrestricted grants program at the NSF and by the Astrophysics Theory Program at NASA. Indeed, one of the committee’s recommended small initiatives is to augment the NASA Astrophysics Theory Program.

COORDINATING PROGRAMS AMONG FEDERAL AGENCIES

The section “Congressional Questions” in Chapter 6 of this report addresses several specific questions posed by the House of Representatives Science Committee (as specified in the committee’s charge; see the preface). Among these is the question of an optimal strategy for the coordination of astronomical initiatives funded through NASA and NSF, and perhaps other federal agencies. The enormous scale of many astronomical problems requires a coordinated national approach. In

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

many cases, investigations that span different wavelength bands and disciplinary boundaries are needed in order to achieve a fundamental understanding of the phenomena under study. Interagency coordination and cooperation are often essential for such a multidisciplinary approach.

Both ground- and space-based facilities can be used to address the scientific themes identified by the committee as ripe for progress throughout this decade. Such facilities are traditionally supported by NSF and NASA, respectively. In addition, some of the important outstanding problems lie in the domain of DOE, including ones linked to particle physics, nuclear physics, and cosmology. The committee recommends that each agency build on its own unique capabilities while recognizing those of related agencies, taking steps toward collaborations that it believes will prove fruitful. Each agency should have a strategic plan for astronomy and astrophysics in place and should also have scientific committees (such as DOE and NSF’s Scientific Assessment Group for Experiments in Non-Accelerator Physics [SAGENAP] and NASA’s Space Science Advisory Committee [SSAC]) available to evaluate proposed interagency collaborations. The Office of Science and Technology Policy could facilitate such interagency collaborations.

COLLABORATING WITH INTERNATIONAL PARTNERS

International collaboration enables projects that are too costly for the United States to carry out on its own, and it enhances the scientific return on projects by engaging the scientific and technical expertise of international partners. The Hubble Space Telescope (HST), the Gemini Telescope Project, and ALMA are all critically dependent on international collaboration, as is very long baseline interferometry, which by necessity is carried out using radio telescopes around the world. In many cases, international collaboration provides additional opportunities for U.S. astronomers to participate in major projects at the advancing edge of science, as in the case of the European Solar and Heliospheric Observatory, XMM-Newton, the Planck Surveyor and FIRST missions, and the Japanese Advanced Satellite for Cosmology and Astrophysics mission. Valuable opportunities for international collaboration exist for smaller missions as well. Many aspects of international collaboration are analyzed in the joint National Research Council-European Science Foundation report U.S.-European Collaboration in Space Science (NRC-ESF, 1998). The prerequisites for successful collaboration include (1) clear agreement on the financial commitments on each side; (2) close coordination in planning to minimize the risks associated with missed cost,

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

schedule, or technical guidelines by any of the partners; (3) a significant, clearly defined contribution from each participant; and (4) a commitment to the free exchange of scientific data and results. Collaborations on major projects require the full support of the participating scientific communities, which can be ensured if the projects are among the very highest priorities of all of the participants.

To facilitate coordination in planning for future international collaborations, the committee invited a number of leading astronomers from other nations to its second meeting and engaged them in discussion of the projects under consideration for priority setting by the committee. To attempt to address some of the most challenging scientific questions facing them, astronomers will increasingly need “world facilities,” which are so large that they require the participation of many nations to succeed. ALMA, a joint U.S., Canadian, European, and possibly Japanese project, will be the first true world facility in astronomy. The committee affirms the value of international collaboration for ground-based and space-based projects of all sizes. International collaboration plays a crucial role in a number of the programs recommended by this committee, including the Next Generation Space Telescope, the Expanded Very Large Array, the Gamma-ray Large Area Space Telescope, the Laser Interferometer Space Antenna, the Advanced Solar Telescope, and the Square Kilometer Array technology development. International participation in the 30-m-class Giant Segmented Mirror Telescope (GSMT) would offer many benefits. The significantly more ambitious 100-m “OWL” telescope under development by the European Southern Observatory represents an excellent opportunity for shared technology development and possible eventual U.S. collaboration. Terrestrial Planet Finder (TPF) offers a promising opportunity for collaboration with the European Space Agency (ESA), which is considering a similar mission called Darwin.

NEW INVESTMENTS IN ASTRONOMY AND ASTROPHYSICS

PROPOSED PRIORITIES FOR GROUND- AND SPACE-BASED INITIATIVES

Despite the enormous progress in astronomy and astrophysics in the past decade, many mysteries remain. How did the universe begin? Recent evidence indicates that the expansion of the universe is accelerat-

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

ing—what is the nature of the “dark energy” causing the acceleration? Most of the matter in the universe is invisible, and the nature of this dark matter remains a mystery. At present there is a vast gap in our knowledge of the evolution of the universe between the time at which the cosmic background radiation was produced, about 300,000 years after the Big Bang, and the time at which the most distant known galaxies emitted the light we see today, about a billion years later. This span of time includes the “dark ages,” when the only radiation was the glow left over from the Big Bang, and the dawn of the modern universe, when the first stars and galaxies formed. Researchers believe that supermassive black holes formed at about the same time that galaxies did, but nothing is known about how this occurred. Much smaller black holes are forming even today by processes that are poorly understood. Star formation drives the evolution of galaxies and leads to planet formation, yet there are far more questions than answers about how this process works. The discovery of extrasolar planets in the past decade has presented many new mysteries, since all the planetary systems observed so far are completely different from our solar system. How did such planetary systems form and evolve? What is their relation to our solar system, and which is the norm? Finally, when we look at our own Sun, we find that its light varies slightly with time. These variations may have significant effects on Earth’s climate, yet they are not now understood. To address these pressing scientific issues, and many others, the committee developed a comprehensive set of new initiatives in astronomy and astrophysics that will both vastly increase our knowledge of the universe and lead to many new discoveries. More important, these initiatives should enable us to achieve a greater understanding of the complex phenomena leading from the origin of the universe in the Big Bang to the existence of a life-bearing planet like Earth.

  • The Astronomy and Astrophysics Survey Committee recommends the approval and funding of the prioritized new initiatives listed in Table 1.1.

Table 1.1 presents the priorities for initiatives for the decade 2000 to 2010. The priorities are listed separately for ground-based and space-based initiatives, both because the funding agencies are different (NSF, DOE, and DOD primarily for ground; NASA primarily for space) and because space facilities are intrinsically more expensive. Major and moderate projects are prioritized separately. The small initiatives consist

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

TABLE 1.1 Prioritized Initiatives and Estimated Federal Costs for the Decade 2000 to 2010

Ground-baseda

Costb ($M)

Space-basedc

Costb ($M)

Major Initiatives

Giant Segmented Mirror Telescope (GSMT)d

350

Next Generation Space Telescope (NGST)d

1,000

Expanded Very Large Array (EVLA)d

140

Constellation-X Observatory (Con-X)

800

Large-aperture Synoptic Survey Telescope (LSST)

170

Terrestrial Planet Finder (TPF)e

200

 

 

Single Aperture Far Infrared (SAFIR) Observatorye

100

Subtotal ground-based

660

Subtotal space-based

2,100

Moderate Initiatives

Telescope System Instrumentation Program (TSIP)

50

Gamma-ray Large Area Space Telescope (GLAST)d

300

Advanced Solar Telescope (AST)d

60

Laser Interferometer Space Antenna (LISA)d

250

Square Kilometer Array (SKA) technology development

22

Solar Dynamics Observatory (SDO)

300

Combined Array for Research in Millimeterwave Astronomy (CARMA)d

11

Energetic X-ray Imaging Survey Telescope (EXIST)

150

Very Energetic Radiation Imaging Telescope Array System (VERITAS)

35

Advanced Radio Interferometry between Space and Earth (ARISE)

350

Frequency Agile Solar Radio telescope (FASR)

26

 

 

South Pole Submillimeter-wave Telescope (SPST)

50

 

 

Subtotal ground-based

254

Subtotal space-based

1,350

Small Initiatives

National Virtual Observatory (NVO)

15

National Virtual Observatory (NVO)

45

Laboratory Astrophysics Program

5

Advanced Cosmic-ray Composition Experiment for the Space Station (ACCESS)

100

Low Frequency Array (LOFAR)

8

 

 

National Astrophysical Theory Postdoctoral Program

6

Augmentation of the Astrophysics Theory Program

30

Synoptic Optical Long-term Investigation of the Sun (SOLIS) expansion

8

Laboratory Astrophysics Program

40

 

 

National Astrophysical Theory Postdoctoral Program

14

 

 

Ultralong-Duration Balloon Program

35

Subtotal ground-based

42

Subtotal space-based

264

Total ground-based

956

Total space-based

3,714

DECADE TOTAL

 

 

4,670

aCost estimates for ground-based capital projects include technology development plus funds for operations, new instrumentation, and facility grants for 5 years.

bBest available estimated costs to U.S. government agencies in millions of FY2000 dollars and rounded. Full costs are given for all initiatives except TPF and the SAFIR Observatory.

cCost estimates for space-based projects exclude technology development.

dCost estimate for this initiative assumes significant additional funding to be provided by international or private partner; see Astronomy and Astrophysics in the New Millennium: Panel Reports (NRC, 2001) for details.

eThese missions could start at the turn of the decade. The committee attributes $200 million of the $1,700 million total estimated cost of TPF to the current decade and $100 million of the $600 million total estimated cost of the SAFIR Observatory to the current decade.

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

of programs such as the National Virtual Observatory (NVO) and the Laboratory Astrophysics Program, plus illustrative small facilities and missions. The NVO is the top priority among these initiatives. The remaining ones are not prioritized, since small projects often have a gestation time of less than a decade. In particular, the committee has not recommended any projects for NASA’s extremely successful Explorer program, since missions are selected through competitive peer review.

The size categories for new initiatives are based on the capital cost for ground-based projects and on the total cost, excluding technology development, for space-based projects. Only costs to be borne by the federal government are included. The committee’s cost estimates for these initiatives are based on discussions with agency personnel and on presentations to the panels; they are given in FY2000 dollars. For ground-based projects, small projects have capital costs of up to $5 million; moderate, from $5 million to $50 million; and major, above $50 million. In contrast to the practice in previous astronomy and astrophysics decadal surveys, the tabulated costs for ground-based capital projects include operations and new instrumentation for a period of 5 years at rates of 7 percent and 3 percent of the capital cost per year. In addition, grants for data analysis and associated theory are included at a rate of 3 percent of the capital cost per year for major projects, 5 percent for moderate projects, and 0 percent for small projects. The total costs for ground-based initiatives are thus typically 1.65, 1.75, and 1.50 times the capital costs for major, moderate, and small initiatives, respectively. Exceptions are SKA technology development, which includes only funds for a theory challenge, budgeted at $200,000 per year for the decade; the Telescope System Instrumentation Program, which as an instrumentation program does not require operations or instrumentation funds and is too fragmented to have a grants program; and NVO, the National Astrophysical Theory Postdoctoral Program, and the Laboratory Astrophysics Program, which are not capital projects and therefore have no added costs. The Large-area Synoptic Survey Telescope is expected to have significant expenses for data analysis, and so the estimate of the total operations cost by the Panel on Optical and Infrared Astronomy from the Ground (see Panel Reports; NRC, 2001) was used for this project.

The costs of space-based initiatives given in Table 1.1 do not include technology development. NASA has adopted a policy of deferring construction of new missions until all major technological problems have been solved, a policy the committee endorses. These costs amount to typically about 30 percent of the construction costs of a mission. In some

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

cases, entire missions will serve as precursors for other missions, for example, SIM for TPF as currently envisioned. Explorer and Discovery missions are regarded as small initiatives. Since they are peer-reviewed, the committee did not prioritize them. Moderate space-based missions are those with construction, launch, and operations costs between the $140 million cap on Explorer missions and $500 million; major missions have estimated costs above $500 million.

Many of the projects listed in Table 1.1 have been studied extensively and should have reasonably accurate cost estimates (see the discussions of individual projects in the Panel Reports; NRC, 2001). For others, such as TPF and GSMT, more accurate cost estimates must await the outcome of future technology developments. To compare the total cost of the recommended new initiatives with that of the initiatives recommended in the 1991 survey, it is first necessary to correct for inflation. In FY2000 dollars, the 1991 survey recommended about $640 million for ground-based initiatives and $3.3 billion for space-based initiatives, for a total of $3.9 billion. The total cost of the current committee’s recommendations for ground-based astronomy, $956 million, is higher than that of the 1991 survey’s recommendations because it includes 5 years’ worth of operating costs, new instruments, and grants—expenses that were not included in the 1991 survey’s estimates. If these costs are removed, the committee’s recommendation for ground-based astronomy is about $600 million, slightly less than that of the 1991 survey.

The estimated decade cost of the committee’s recommended initiatives for space-based astronomy is about $3.7 billion. Two of the projects, TPF and the SAFIR Observatory, could start around the end of this decade. TPF is included in NASA’s strategic plan for this decade and is under active development at this time; however, the technical challenges facing this mission could delay its start until after 2010. The SAFIR Observatory could also start in this decade, but delays in its precursor mission, NGST, could push SAFIR’s start into the following decade. The committee believes that it is essential that all missions be subject to timely review independent of their phasing with respect to decadal surveys, and for this reason it has prioritized both missions. The committee notes that NASA was so successful in addressing the space-based initiatives recommended by the 1991 survey that the NRC was asked to convene the Task Group on Space Astronomy and Astrophysics in the mid-1990s to prioritize science for further NASA missions (NRC, 1997). The committee assumed that about 15 percent of the total cost of TPF and SAFIR will fall in this decade.

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

The committee’s priorities for major and moderate programs, independent of whether they are ground- or space-based, and independent of funding agency, are presented in Table 1.2.

EXPLANATION OF NEW INITIATIVES

Brief descriptions of the recommended new initiatives are given here, in priority order for each size category. More detailed information can be found in Chapter 3 and in the Panel Reports (NRC, 2001)

MAJOR INITIATIVES

Next Generation Space Telescope. NGST is the top priority for this decade because it will reveal the first epoch of star formation and trace the evolution of galaxies from their birth to the present. It will also provide a unique window onto the birth of stars and planets in our own galaxy. Having NGST’s sensitivity extend to 27 µm would substantially improve its ability to study Kuiper Belt objects (KBOs) in our solar system, the formation of stars and planets in our galaxy, and the dust emission from galaxies out to redshifts of 3. As an 8-m-class passively cooled space telescope, it will be more than 100 times as sensitive as HST or SIRTF in the infrared and will improve image sharpness by an order of magnitude. Its potential for new discoveries will easily rival that of HST when it was launched. The European Space Agency and the Canadian Space Agency plan to make substantial contributions to the instrumentation of NGST.

Giant Segmented Mirror Telescope. The second priority overall, and the top priority for ground-based astronomy, is to develop the technology for and begin construction of a giant (30-m-class) segmented-mirror telescope equipped with adaptive optics. GSMT, with its higher spatial resolving power and its greater capability for high-resolution spectroscopy, will be a powerful complement to NGST in tracing the evolution of galaxies and in studying the formation of stars and planets. It will exceed NGST in sensitivity below a wavelength of 2 µm, but atmospheric and thermal effects will compromise its sensitivity at longer wavelengths. GSMT will be a uniquely powerful instrument for studies of the evolution of the intergalactic medium and the history of star formation in the Milky Way Galaxy and its nearest neighbors. The ability to add new instruments means that GSMT will be able to respond to new scientific opportunities and take advantage of novel technological developments in

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
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TABLE 1.2 Prioritized Initiatives (Combined Ground and Space) and Estimated Federal Costs for the Decade 2000 to 2010a,b

Initiative

Costc ($M)

Major Initiatives

Next Generation Space Telescope (NGST)d

1,000

Giant Segmented Mirror Telescope (GSMT)d

350

Constellation-X Observatory (Con-X)

800

Expanded Very Large Array (EVLA)d

140

Large-aperture Synoptic Survey Telescope (LSST)

170

Terrestrial Planet Finder (TPF)e

200

Single Aperture Far Infrared (SAFIR) Observatorye

100

Subtotal for major initiatives

2,760

Moderate Initiatives

Telescope System Instrumentation Program (TSIP)

50

Gamma-ray Large Area Space Telescope (GLAST)d

300

Laser Interferometer Space Antenna (LISA)d

250

Advanced Solar Telescope (AST)d

60

Square Kilometer Array (SKA) technology development

22

Solar Dynamics Observatory (SDO)

300

Combined Array for Research in Millimeter-wave Astronomy (CARMA)d

11

Energetic X-ray Imaging Survey Telescope (EXIST)

150

Very Energetic Radiation Imaging Telescope Array System (VERITAS)

35

Advanced Radio Interferometry between Space and Earth (ARISE)

350

Frequency Agile Solar Radio telescope (FASR)

26

South Pole Submillimeter-wave Telescope (SPST)

50

Subtotal for moderate initiatives

1,604

Small Initiatives

National Virtual Observatory (NVO)

60

Other small initiatives

246

Subtotal for small initiatives

306

DECADE TOTAL

4,670

aCost estimates for ground-based capital projects include technology development plus funds for operations, new instrumentation, and facility grants for 5 years.

bCost estimates for space-based projects exclude technology development.

cBest available estimated costs to U.S. government agencies in millions of FY2000 dollars and rounded. Full costs are given for all initiatives except TPF and the SAFIR Observatory.

dCost estimate for this initiative assumes significant additional funding to be provided by international or private partner; see Panel Reports (NRC, 2001) for details.

eThese missions could start at the turn of the decade. The committee attributes $200 million of the $1,700 million total estimated cost of TPF to the current decade and $100 million of the $600 million total estimated cost of the SAFIR Observatory to the current decade.

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

instrumentation. The committee recommends an immediate start for the technology development needed to reduce the cost of construction and to develop the adaptive optics. The cost of technology development and construction is estimated to be about $400 million. It is assumed that half of these costs and half of the operations costs will be borne by private and/or international partners; the cost estimates in Tables 1.1 and 1.2 are therefore based on a federal capital cost of $200 million. Open access to GSMT by the U.S. astronomical community should be directly proportional to the investment by the NSF.

Constellation-X Observatory. The premier instrument to probe the formation and evolution of black holes—both stellar black holes in our galaxy and supermassive black holes in the nuclei of other galaxies—Constellation-X will also measure the physical conditions in the first clusters of galaxies, study quasars at high redshift, contribute to nuclear physics by measuring the radii of neutron stars, and trace the formation of the chemical elements. To achieve the sensitivity needed to meet these goals, Constellation-X will consist of four x-ray telescopes in separate spacecraft. Each telescope will have high spectral resolution over a broad energy range, ~ 0.25 to 40 keV. Constellation-X has been under active study for more than 5 years, and the technology issues are well in hand for a start in the middle of the decade.

Expanded Very Large Array. The VLA is currently the premier centimeter-wavelength radio telescope in the world, despite being based on the technology of 20 to 30 years ago. Replacing key components with modern technology will provide an order-of-magnitude increase in sensitivity with unprecedented image quality and a 1,000-fold increase in spectroscopic capability, all at a fraction of the cost of constructing a new facility. The addition of eight new antennas will provide an order-of-magnitude increase in angular resolution, making it comparable to that of ALMA and NGST. The EVLA will be a powerful instrument for studying the formation of protoplanetary disks and stars, as well as the formation and evolution of the first galaxies.

Large-aperture Synoptic Survey Telescope. By surveying the visible sky every week to a much fainter level than can be achieved with existing optical surveys, LSST will open a new frontier in addressing time-variable phenomena in astronomy. This 6.5-m-class optical telescope will detect 90 percent of the near-Earth objects larger than 300 m in diameter within

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

a decade, and will enable assessment of the potential hazard each poses to Earth. It will take a census of some 10,000 of the most primitive bodies in the solar system, located in the Kuiper Belt. It will also contribute to the study of the structure of the universe by observing thousands of supernovae, both nearby and at large redshift, and by measuring the distribution of dark matter through gravitational lensing. LSST will produce a terabyte of data per night, all of which will be accessible to scientists and the public alike through the National Virtual Observatory.

Terrestrial Planet Finder. The main goal of TPF is nothing less than to search for evidence of life on terrestrial planets around nearby stars. The present concept calls for a space-based infrared interferometer of enormous sensitivity, capable of nulling out the light from the host star. TPF’s angular resolution will also enable it to peer into the innermost regions of protoplanetary disks, galactic nuclei, starburst galaxies, and galaxies at high redshift. By a large margin, TPF is the most costly and the most technically challenging mission discussed in this report. Both SIM and NGST involve key technologies that must be successfully demonstrated if TPF as currently envisioned is to go forward. The committee’s recommendation of this mission is predicated on the assumptions that TPF will revolutionize major areas of both planetary and nonplanetary science, and that, prior to the start of TPF, ground- and space-based searches will confirm the expectation that terrestrial planets are common around solartype stars. NASA should pursue a vigorous program of technology development to enable the construction of TPF to begin in this decade.

Single Aperture Far Infrared Observatory. The SAFIR Observatory will take advantage of the technology developed for NGST to study the relatively unexplored region of the spectrum between 30 and 300 µm. It will investigate the earliest stage of star formation and galaxy formation by revealing regions too shrouded by dust to be studied with NGST and too warm to be studied effectively with ALMA. An 8-m-class space-based telescope that is diffraction-limited at 30 µm, it will be more than 100 times as sensitive as SIRTF or the European FIRST mission. It will have the capability of becoming part of an interferometer at a later time.

MODERATE INITIATIVES

Telescope System Instrumentation Program. Universities and independent observatories operate the majority of the large optical and infrared

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
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telescopes in the United States. The top priority for moderate projects for the new decade is TSIP, an NSF program that will maximize the scientific effectiveness of these telescopes by instrumenting them and by making them accessible to the entire astronomical community. It will have a multiplier effect by encouraging the continuation of substantial nonfederal investments, while at the same time helping to bring the national and private observatories together as a coherent research system. Under this initiative, the NSF would fund the construction of peer-reviewed new instrumentation at private observatories in exchange for telescope time or other equally valuable benefits for the community at large. The value of the observing time (determined from the cost of operations and the amortized investment) should be 50 percent of the granted funds.

Gamma-ray Large Area Space Telescope. GLAST, the second priority for moderate projects, is a powerful gamma-ray telescope with a sensitivity 30 times greater than that of its predecessor, the Energetic Gamma Ray Experiment (EGRET) instrument on the Compton Gamma Ray Observatory. GLAST will study powerful jets from the supermassive black holes in the centers of distant galaxies, the acceleration mechanisms of cosmic rays, and the origin of tremendous bursts of gamma-ray radiation from the distant universe. GLAST has the potential for breakthrough discoveries, such as by observing gamma rays from dark matter annihilation. It will detect gamma rays in the photon energy range between 10 MeV and 300 GeV with unprecedented positional accuracy. The committee applauds the crucial technical contributions of DOE to this important NASA mission.

Laser Interferometer Space Antenna. LISA is unique among the recommended new initiatives in that it is designed to detect the gravitational radiation predicted by Einstein’s theory of general relativity. The direct measurement of gravitational radiation from astrophysical sources will open a new window onto the universe and enable investigations of the physics of strong gravitational fields. LISA consists of three spacecraft spaced 5 million km apart in an equilateral triangle, with lasers accurately monitoring their separation. It will be sensitive to gravitational-wave frequencies between 10−1 to 10−4 Hz, frequencies too low to be detected by the ground-based LIGO. For the first time, it will be possible to observe evidence of the coalescence of supermassive black holes as distant galaxies merge, and the gravitational radiation from white dwarf

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

binaries in our own galaxy. It is assumed that LISA will be a joint mission between NASA and ESA, with costs shared approximately equally.

Advanced Solar Telescope. AST will observe solar plasma processes and magnetic fields with unprecedented resolution in space and time. It will provide critical information needed to solve the mysteries associated with the generation, structure, and dynamics of the surface magnetic fields, which govern the solar wind, solar flares, and short-term solar variability. AST is a ground-based, 4-m-class, adaptive-optics-equipped facility that will operate in the wavelength band from 0.3 to 35 µm. It is proposed as a joint project with international partners, in which the United States would provide about half the costs.

Square Kilometer Array Technology Development. The SKA is an international ground-based centimeter-wave radio telescope array with 106 square meters of collecting area that will enable study of the first structures and the first luminous objects to form during the dawn of the modern universe, and will provide unprecedented images of protostellar disks and the neutral jets launched by young stars. SKA’s sensitivity will be a factor of 100 greater than that of existing centimeter-wave facilities. The increase in sensitivity has great discovery potential, and SKA will revolutionize the study of objects and phenomena that are currently undetectable at centimeter wavelengths. The U.S. SKA development program will, in collaboration with the international radio astronomy community, aggressively pursue technology and technique development in this decade that will enable the construction of the SKA in the following decade.

Solar Dynamics Observatory. SDO will probe the outer layers of the Sun to determine the connections between the interior dynamics and the activity of the solar corona, the origin of sunspots and solar active regions, and the origin of coronal mass ejections and solar flares. SDO is a space-based mission that will carry a number of instruments and small telescopes to monitor the Sun continuously at ultraviolet and optical wavelengths (0.02 to 1 µm).

Combined Array for Research in Millimeter-wave Astronomy. CARMA is the planned combination of the Berkeley-Illinois-Maryland Association (BIMA) and the Owens Valley Radio Observatory (OVRO) millimeterwave arrays at a superior site along with the addition of new, smaller

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
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antennas. The resulting hybrid array will have unique imaging qualities, sensitive to both small and large scales. It will study star formation at all epochs, and it will measure the small distortions in the cosmic (Big Bang) microwave background caused by the hot gas in distant clusters of galaxies along the line of sight. Its Northern Hemisphere location will provide sky coverage complementary to ALMA. Of the construction costs, 60 percent will come from nonfederal sources.

Energetic X-ray Imaging Survey Telescope. EXIST will survey the entire sky every 90 minutes to search for weak and often time-variable astronomical sources of 5- to 600-keV x-ray photons. Such x rays emanate from many sources, including supermassive black holes in the centers of galaxies, stellar mass black holes, neutron stars, and embedded supernovae in our galaxy, and the mysterious distant sources of gamma-ray bursts of radiation. Attached to the International Space Station, EXIST will survey sources 1,000 times weaker than the sources in the previous hard x-ray survey by the High Energy Astronomical Observatory (HEAO-1). EXIST’s repeated surveys of the entire sky in the hard x-ray region will complement those by LSST at optical wavelengths.

Very Energetic Radiation Imaging Telescope Array System. VERITAS will perform the first sensitive sky survey for astronomical sources of extremely energetic photons—those with energies from 100 to 10,000 GeV. VERITAS will complement GLAST and EXIST in studying the cosmic sources of relativistic particles such as supermassive black holes, gammaray burst sources, pulsars, and supernova remnants. Making use of the established technology of the 10-m reflector at the Whipple Observatory, VERITAS consists of an array of seven 10-m-diameter reflectors that will achieve more than an order-of-magnitude improvement in sensitivity and have a far greater ability than existing instruments to locate sources.

Advanced Radio Interferometry between Space and Earth. ARISE is a sensitive, Earth-orbiting radio antenna with a diameter of about 25 m that will improve the angular resolution of the ground-based Very Long Baseline Array by a factor 6. It will probe the regions near supermassive black holes, which are thought to produce relativistic jets, and will enable the study of maser sources, both in the Milky Way and in the nuclei of other galaxies.

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
×

Frequency Agile Solar Radio Telescope. Radio waves from the Sun bring information about the heating of the corona, the nature and evolution of coronal magnetic fields, the structure of the solar atmosphere, and the origin of the solar wind. FASR will analyze this radiation over a frequency range from 0.3 to 30 GHz, and it will improve on existing facilities by operating at hundreds of frequencies and providing a factor-of-10 better spatial resolution.

South Pole Submillimeter-wave Telescope. The SPST will take advantage of the superb atmospheric transmission conditions between wavelengths of 200 µm and 1 mm at the South Pole to survey the dusty universe, study small variations in the background radiation emanating from the early pregalactic universe, and identify primordial galaxies.

OTHER PROJECTS

Two areas in which the committee considered it premature to set priorities are cosmic microwave background experiments and particle astrophysics. In both disciplines, projects are often experiments rather than observatories. As a result, it is difficult to plan far in advance, since the best strategy may depend critically on the outcome of ongoing experiments.

Observations of the cosmic microwave background can determine the large-scale properties of the universe and reveal the tiny fluctuations that were the seeds of all the structure we see today. These observations are of fundamental importance to both astronomy and physics. Together with ground-based and balloon experiments, NASA’s MAP mission, to be launched in spring 2001, will revolutionize knowledge of the microwave background, and the committee believes that no decision on the next major or moderate microwave background project should be made until the results from that mission are available. ESA’s Planck mission later in the decade will also provide important information, but it will be possible to decide on the next step before its results are available. Together, MAP and Planck will test the most promising ideas about the very early universe as well as determine cosmological parameters to high precision. The next frontier is to measure the polarization of the cosmic microwave background, which has the potential of probing even earlier times, close to the Big Bang itself.

Particle astrophysicists view the universe through different eyes than

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
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do most astronomers: Instead of photons, they observe energetic particles, and they search for exotic new particles that could account for the dark matter. The committee decided that it was too early to prioritize the Northern Hemisphere Auger project or Telescope Array for ultrahigh-energy cosmic rays and the Ice Cube experiment for high-energy neutrinos. In each case, ongoing experiments—the Southern Hemisphere Pierre Auger Observatory project and the Antarctic Muon and Neutrino Detector Array (AMANDA) experiment at the South Pole—will provide critical information that will enable an informed decision to be made soon. The decision on how to pursue future searches for dark matter will be guided by the outcome of experiments now just starting.

SMALL INITIATIVES

National Virtual Observatory. The NVO is the committee’s top-priority small initiative. NVO involves the integration of all major astronomical data archives into a digital database stored on a network of computers, the provision of advanced data exploration services for the astronomical community, and the development of data standards and tools for data mining. It will create a powerful resource for public education and outreach by making near-real-time observations accessible over the Internet. NVO will enable professional astronomers, educators, and the public to take full advantage of the wealth of data from existing and planned surveys such as LSST. NVO is made possible by huge advances in the past decade in computer speed, widespread access to high-speed networks, a dramatic decrease in the cost of computing and data storage capabilities, and an ongoing revolution in techniques to extract science from a large data set. The committee recommends coordinated support from both NASA and the NSF, since NVO will serve both the space- and ground-based science communities.

Additional Small Intiatives. The remaining recommendations for small initiatives are listed alphabetically and are not prioritized, but they represent a number of exciting opportunities for making a relatively small investment to potentially achieve a major gain in capability and scientific return. Several of these opportunities span both space- and ground-based astronomy, like NVO. To facilitate the interpretation of the tremendous harvest of data throughout the decade, the committee recommends (1) augmentation of NASA’s Astrophysics Theory Program and (2) initiation of a NASA- and NSF-funded National Astrophysical

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
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Theory Postdoctoral Program that would award 10 portable 3-year postdoctoral positions each year. In view of the tremendous increase in the volume and complexity of the spectroscopic data to be gathered across the electromagnetic spectrum by new facilities over the course of the decade, the committee recommends the establishment of a Laboratory Astrophysics Program funded by both NASA and the NSF. The Ultralong-Duration Balloon (ULDB) program offers the prospect of carrying payloads that weigh several tons to roughly 40-km altitudes for flights that last several months. For certain types of experiments, this program offers an alternative to small space experiments at a fraction of their cost. The committee recommends an augmentation of the ULDB program for the development of a steering capability that would increase both the duration and the probability of success of the balloon flights. The Advanced Cosmic-ray Composition Experiment for the Space Station (ACCESS) will measure the spectrum and composition of cosmic rays with energies up to 1,000 TeV. This experiment will provide unique data for studying the origin of cosmic rays and the mechanism by which they are accelerated. The Low Frequency Array (LOFAR), a joint project now under way between the Netherlands Foundation for Research in Astronomy and the U.S. Naval Research Laboratory, provides a 100- to 1,000-fold improvement in sensitivity and resolution over existing radio telescopes in the wavelength range from 2 to 20 m. It has the potential to discover the hydrogen clouds out of which the first galaxies formed. The committee recommends that the NSF contribute to LOFAR so that it will be available to the entire astronomical community. Expansion of the Synoptic Optical Long-term Investigation of the Sun (SOLIS) from one station to a three-station network would permit continuous, 24-hour monitoring of magnetic fields on the solar surface. An expanded SOLIS promises crucial data for understanding the magnetic origin of solar variability and a far greater capability to forecast the space weather that so adversely affects space satellites.

TECHNOLOGY

Technological innovation has often enabled astronomical discovery. Most of the major discoveries listed at the beginning of this chapter were possible only because of the remarkable advances in technology in the past two decades. Continued investment in technology in this decade is required for many of the initiatives recommended in this report: For example, GSMT and AST require advances in adaptive optics, and TPF

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
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requires the development of space interferometry. For the space-based initiatives, technology investment as specified in the existing NASA technology road map is an assumed prerequisite for the cost estimates in Table 1.1. It is essential to maintain funding for the planned technology development if NASA is to keep these missions on schedule and within budget. Targeted technology programs involving a joint effort between engineers and scientists will be essential to success in these projects. As noted above, the committee endorses NASA’s policy of completing the technological development of a mission prior to starting it. The NSF is applying a similar approach the design and development of ALMA, a policy the committee endorses.

Longer-range investments in technology in this decade are needed to enable the major projects in the next decade—and to make them more cost-effective. Space-based projects that could be started in the decade 2010 to 2020 include a large 8-m-class ultraviolet telescope, a far-infrared interferometer, an x-ray interferometer, and an x-ray telescope with an effective area of 100 square meters. The best-defined ground-based project for the decade 2010 to 2020 is the Square Kilometer Array, for which the committee has recommended technology development. Other possible ground-based projects for that decade include the next step beyond GSMT in optical telescopes and large interferometers that operate at infrared wavelengths.

To make these projects feasible in the decade 2010 to 2020, the committee recommends investing in the technologies listed in Table 1.3; priorities for these technologies have not been established. For ground-based astronomy, the committee recommends development of very large, high-speed digital correlators for radio astronomy; infrared interferometry; and specialized dark-matter detectors. Space-based astronomy requires investments in spacecraft communication to enable high rates of data transmission from distant telescopes to ground-based stations. The estimated cost for the development of a suitable radio transmitter is listed in Table 1.3. In addition, the committee suggests that NASA consider establishing an optical communications link at “L2,” the proposed site for NGST and other future NASA missions. The committee recommends investing in the development of x-ray interferometry, which has the potential of actually imaging the event horizon of a black hole, and in technology for the next generation of space observatories: energy-resolving array detectors for optical, ultraviolet, and x-ray wavelengths; far-infrared array detectors; refrigerators to maintain the cryogenic temperatures needed by these detectors; large, lightweight optics (some-

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
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TABLE 1.3 Technology Development for Future Initiatives and Estimated Costs

Technology Initiative

Decade Cost ($M)

Ground-based

Megacorrelators

10

Infrared interferometry

40

Dark matter detectors

12

Subtotal for ground-based technology

62

Space-based

Spacecraft communication

70

X-ray interferometry

60

Technology for next-generation observatories: Energy-resolving array detectors

40

Far-infrared array detectors

10

Refrigerators for space experiments

50

Large, lightweight optics

80

MeV detector technology

10

Subtotal for space-based technology

320

TOTAL

382

times referred to as “gossamer optics”) for infrared, optical, ultraviolet, and x-ray wavelengths; and sensitive gamma-ray (MeV) detectors. These proposed technology developments are discussed in greater detail in the Panel Reports (NRC, 2001).

ASTRONOMY’S ROLE IN EDUCATION

Astronomers have a vital role to play in contributing to the development of science education in the United States. Among scientists, astronomers make a disproportionately large contribution to the improvement of public science literacy relative to the comparatively small size of the astronomical community because of the broad appeal of astronomical concepts and ideas. Astronomy resonates with some of the most basic questions of humanity: When did the universe begin? How has it evolved? What will be its ultimate fate? Is there life elsewhere?

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
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How will the universe around us affect the development and continued existence of the human species?

Astronomy provides a gateway for increased public understanding of humanity’s place in the universe and of the nature of science. Each year 28 million visits are made to planetariums in the United States. More than 200,000 college students take an astronomy course each year. Thus, roughly 10 percent of all U.S. college students will take an astronomy course before they graduate, and for many of these astronomy will be the only science course they ever take. Astronomy is heavily covered by the media, has attracted millions of people on the Web, and enjoys the support of hundreds of thousands of amateur astronomers.

The committee recognizes the tremendous importance of improving the scientific literacy of the nation. Recommendations to enhance astronomy’s role in education are discussed in Chapter 5. The key recommendations are as follows:

  • The engagement of astronomers in outreach to the K-12 community should be expanded and improved by ensuring (1) appropriate incentives for their involvement; (2) training and coordination for effective and high-leverage impact; (3) careful scrutiny of major initiatives and widespread dissemination of information regarding their successes and failures; and (4) recognition of the value of this work by the scientific community.

  • More universities with both astronomy and education departments should establish pilot partnerships to bring scientists, educators, and experienced teachers together to design exemplary astronomy-based science courses for preservice teachers, with the goal of contributing to the achievement of long-term systemic reform in K-12 science education.

  • Federal agencies charged with increasing the contribution of professional scientists to educational initiatives should work with astronomers and educators to develop a common set of goals, pathways to achieve them, and mutually accepted standards for measuring success.

Suggested Citation:"1. Recommendations." National Research Council. 2001. Astronomy and Astrophysics in the New Millennium. Washington, DC: The National Academies Press. doi: 10.17226/9839.
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  • NSF should invest additional resources in improving public recognition of the achievements of all NSF-funded facilities and projects. Astronomy, with its wide public appeal, could provide a starting point.

Achieving better recognition for NSF-sponsored successes would require that a stronger interface be established between the media and the NSF through the efforts of dedicated press officers. The NSF also should develop a stronger presence on the Internet. NSF centers and facilities should develop informative Web pages, maintain state-of-the-art visitors centers, and expand outreach into the local communities.

NOTES

1.  

Panel members are listed in the front matter.

2.  

Catherine Cesarsky, DSM Orme des Merisiers, now Director General, European Southern Observatory; Edward van den Heuvel, University of Amsterdam; Don Morton, Herzberg Institute of Astrophysics, National Research Council of Canada; Luis Rodriguez, Instituto de Astronomiá, National Autonomous University of Mexico; Yasuo Tanaka, Institute of Space and Astronautical Sciences, Japan, and Max-Planck-Institut für extraterrestrische Physik; Reinhard Genzel, Max-Planck-Institut für extraterrestrische Physik; Sami Solanki, ETH Zürich Institute of Astronomy, Switzerland; and Roger Davies, Durham University, United Kingdom.

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Next: 2. The Science Behind the Recommendations »
Astronomy and Astrophysics in the New Millennium Get This Book
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In this new book, a distinguished panel makes recommendations for the nation's programs in astronomy and astrophysics, including a number of new initiatives for observing the universe. With the goal of optimum value, the recommendations address the role of federal research agencies, allocation of funding, training for scientists, competition and collaboration among space facilities, and much more.

The book identifies the most pressing science questions and explains how specific efforts, from the Next Generation Space Telescope to theoretical studies, will help reveal the answers. Discussions of how emerging information technologies can help scientists make sense of the wealth of data available are also included.

Astronomy has significant impact on science in general as well as on public imagination. The committee discusses how to integrate astronomical discoveries into our education system and our national life.

In preparing the New Millennium report, the AASC made use of a series of panel reports that address various aspects of ground- and space-based astronomy and astrophysics. These reports provide in-depth technical detail.

Astronomy and Astrophysics in the New Millenium: An Overview summarizes the science goals and recommended initiatives in a short, richly illustrated, non-technical booklet.

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