Federal agencies have invested in astronomical facilities in space, on the ground, and even underground to take advantage of technological advances leading to unique opportunities for research into many aspects of the universe. There are critical issues associated with these investments that must be addressed by the astronomical community and the sponsoring governmental agencies. How can astronomers, returning value to the nation, contribute to the national effort to improve science education and to stimulate interest in science or engineering as an attractive career? What is the proper balance between construction of new facilities, the maintenance and refurbishment of existing facilities, and support of individual researchers? What are the roles of large space missions, such as the Great Observatories, and of smaller, more frequent missions? What can be done to shorten the time between conception and completion of space programs? Under what circumstances should the United States carry out a project with international partners, and what kinds of projects are best carried out with national resources?
Before addressing these difficult problems, the committee first outlines some of the agency-related activities in astronomy in the 1980s. It then describes paramount concerns for the 1990s: an educational initiative in astronomy, the urgent need to revive ground-based astronomy, the opportunities and frustrations of space astrophysics, and the circumstances under which international collaborations are most fruitful.
THE PREVIOUS DECADE
During the 1980s, Congress and the relevant federal agencies responded positively to the advice offered by the previous Astronomy Survey Committee in the “Field Report” (NRC, 1982). The success in implementing recommended programs despite limited resources was possible in large part because of the work of dedicated people in government service.
The National Science Foundation (NSF) implemented, fully or partially, several of the Field Committee recommendations for new ground-based facilities. For example, the Very Long Baseline Array (VLBA) for radio astronomy is now nearly completed. The NSF also provided partial support to build two new 4-m-class telescopes at universities and initiated design work on 8-m-class telescopes. The NSF also supported the construction of a submillimeter telescope on Mauna Kea.
In addition, the NSF Astronomy Division responded to the astronomical community's enthusiasm in initiating the solar Global Oscillations Network Group (GONG) project. Through the Division of Polar Programs, the NSF supported an innovative research program that exploits the unique advantages of the South Pole for astronomy, and through the Physics Division, NSF carried out major programs in particle astrophysics such as the Fly's Eye telescope, the Chicago Airshower Array (CASA) project, and theoretical investigations.
Despite the scientific and technical accomplishments of the past decade, a major crisis has developed in the support of ground-based astronomy. The number of observers doubled, and major new observational facilities were added, because fundamental scientific problems were ripe for solution and required ground-based facilities. Nevertheless the support for facilities and basic research has decreased in purchasing power to 36 percent of what it was, per astronomer, in 1970, resulting in a serious erosion of the research infrastructure.
The policy framework for the National Aeronautics and Space Administration's (NASA) space astronomy and astrophysics program was provided by the Strategic Plan (NASA, 1988, 1989) for the Office of Space Science and Applications. The strategic plan strongly supported the four Great Observatories recommended by the Field Committee in 1982. The Hubble Space Telescope (HST) is operating, and instruments that will correct for the flawed mirror are expected to be available in a few years. The Gamma Ray Observatory (GRO) is scheduled to be launched in 1991. The Advanced X-ray Astrophysics Facility (AXAF) is under construction, with final approval contingent on successful tests of the mirrors. NASA's goal of providing new windows to the universe, if successfully completed, will be among the most important organized intellectual efforts of the 20th century.
The second-ranked intermediate program of the Field Committee, the Far Ultraviolet Spectroscopy Explorer (FUSE), is now under development, and the
highest-priority moderate new initiative of this committee is to provide an independent spacecraft for FUSE. The overall budget for Explorer satellites was increased in the 1980s, although fewer Explorer missions were launched then than in the 1970s. Small Explorer (SMEX) missions, and a continuing suborbital program including rockets, balloons, and aircraft, made possible important scientific advances in the 1980s. NASA's Astrophysics Division supported important international collaborations on European, Japanese, and Soviet missions and began modernizing the university infrastructure necessary for research. The growth of the NASA grants program during the 1980s tracked the overall growth of the number of astronomers (Appendix B) and is a positive sign of NASA's willingness to support the research activities of scientists interested in data from space missions.
While maintaining primary responsibilities for ground-based and space astronomy, respectively, NSF and NASA sometimes worked together effectively during the 1980s toward the common goal of understanding the universe. Both agencies recognized that complementary data obtained from space and from the ground are essential for the solution of many important scientific problems. NSF's distribution to ground observatories of NASA-developed advanced detectors is a particularly successful example of this cooperation.
Despite the major advances of the 1980s, the decade was also a period of frustration for astronomers, NASA, and the nation. Only 2 American astronomical satellites were launched in the 1980s, compared to 10 in the 1970s. The time for development of a space mission has stretched to more than a decade and seriously interferes with the productivity of missions. These problems are due in part to NASA's reliance, in the early 1980s, on the Space Shuttle as a launch vehicle for astrophysics missions, a policy that has since changed. From 1981 to 1989, the average rate of Shuttle launches was about four per year, which was not adequate to accomplish all that the Shuttle was designed to do.
The greatest scientific disappointment to astronomers, and to the nation, was caused by the discovery in June 1990 of the flaw in the HST mirror produced almost a decade earlier. The committee discussed, in the brief interval between this writing and the revelation of the mirror's imperfection, ways that astronomers could try to help prevent similar disasters in the future. In the “Balanced Space Astrophysics Program” section below, the committee comments on some strategies that may reduce technical risks and make NASA's space astronomy program more efficient.
Scientists supported by the Department of Energy (DOE) at universities or at DOE's national laboratories have performed pioneering theoretical research and made important astronomical discoveries for more than 25 years. With DOE support, the field of observational neutrino astronomy was founded, and DOE continues to play a crucial role in this research area. DOE scientists at Lawrence Livermore and Los Alamos National Laboratories have been leaders
in calculations of gravitational collapse, supernova explosions, stellar pulsations, nucleosynthesis, equations of state of dense matter, and stellar opacity, as well as in observing x-ray and gamma-ray sources.
The DOE appreciates the interaction between different areas of fundamental research and the impossibility of knowing a priori the directions in which pure research will lead. As a response to a number of scientific developments in the 1980s, the Directorate of High-Energy and Nuclear Physics has informed this committee that in the 1990s it will consider supporting astrophysical research that is related to its mission of seeking a deeper understanding of the nature of matter and energy and the basic forces that exist between the fundamental constituents of matter.
Some of the basic research and technology programs at the Department of Defense (DOD) make essential contributions to astronomical research. Examples include astrometry and optical interferometry at the U.S. Naval Observatory, development of space instrumentation by the Naval Research Laboratory, innovations in infrared detector technology by the Air Force Office of Scientific Research, and cryogenic and adaptive optics technologies developed as a result of the Strategic Defense Initiative. New opportunities exist for synergism between astronomical research and the nation 's defense needs. The committee believes that these opportunities should be exploited.
The education of young people is the foundation for future scientific and technical advances. Thus the committee begins its discussion of policy issues with a discussion of an educational initiative in astronomy.
The nation's colleges and universities are training too few Americans in science, engineering, and mathematics (A Nation at Risk; NCEE, 1983). In a world in which technical skills and quantitative reasoning are increasingly important, the nation needs more individuals with scientific knowledge in order to improve the quality of daily life and to help secure our economic competitiveness. Too few American students enter college with an adequate background in science and mathematics and with the intention of pursuing scientific careers. Of those entering college with an initial interest in science, too many ultimately obtain degrees in other areas, exacerbating the problem. Unless current trends are reversed, our nation will soon suffer a critical shortage of trained individuals who can take advantage of opportunities for scientific discovery or for technical innovation. As astronomers, the committee is committed to helping solve this national problem.
Television and the popular press expose young people to many challenges in business, law, and medicine but usually fail to present the exciting opportunities in science and technology. As discussed in Chapter 8, astronomy has a special
appeal to young people and is particularly effective in stimulating interest in science and engineering at an early age.
The committee emphasizes below programs relating to precollege education. Several additional proposals have been described in the document An Educational Initiative in Astronomy (Brown, 1990) and in the study by the Policy Panel in the Working Papers (NRC, 1991) of this report.
The committee recommends that NSF establish, at one or more of the major U.S. observatories, an office for astronomical education with responsibility for involving professional research astronomers in educational activities, for making available material about astronomy, for assisting with teacher workshops, for promoting student involvement in research, and for providing guidance on curriculum matters.
The education offices at NASA centers are doing an excellent job with limited resources and should be strengthened.
The committee recommends the expansion of summer programs and workshops at universities and national research centers for paid in-service training of science teachers.
Such workshops provide excellent opportunities for science teachers to gain direct experience with modern astronomical research and to make contacts with astronomers who are committed to improving science education. Workshops are particularly effective when they attract master teachers who are developing curriculum materials and training other teachers.
The committee recommends that NSF establish a national Astronomy Fellowship program that will allow each state to select an outstanding high school student as a state fellow in astronomy.
The state fellows would serve as paid science interns during the summer months at one of the major national or private observatories, where they would participate as assistants in the research of the professional staff. The program would show young people that a career in science is feasible and exciting. The committee suggests that one of the national astronomy research centers act, in cooperation with the appropriate agencies and other major astronomical institutions, as the organizer and coordinator of the Astronomy Fellowship program.
The committee recommends that the American Astronomical Society establish an annual prize in recognition of outstanding contributions to secondary or college science education.
The educational programs in astronomy should be a joint effort involving both the educational and the research branches of the relevant agencies. The
educational directorates, which would supply the primary funding for these activities, can help researchers bring the excitement of modern astronomy into the nation's classrooms.
Adequate public education at all grade levels from kindergarten to college, starting with basic numeracy and literacy and ending with a solid grounding in humanistic and scientific concepts, is a long-term solution to the numerical imbalances in racial, ethnic, and sexual representation in different fields of science, including astronomy (Appendix B). In addition to the recommendations made above, the committee urges astronomers to take personal action to improve science education in their communities through presentations at local schools and by visits of students to nearby astronomical facilities.
As noted in Appendix B, there are many more active astronomers than there are faculty positions. Establishing additional faculty positions would bring more of the excitement of astronomy directly to students. The committee commends NASA's attempts to work with universities to provide additional tenure-track positions in astronomy for those young astronomers interested in teaching.
REVIVING GROUND-BASED ASTRONOMY
Ground-based astronomy is imperiled by inadequate funding and the consequent deterioration of major facilities and loss of key personnel. Without adequate support for ground-based work, the United States will lose many of the fruits of both the space and the ground astronomy programs.
The current crisis in the U.S. ground-based program is due to the long-term funding history of the NSF, which has held astronomy to essentially the same base budget (in Consumer Price Index-adjusted dollars) for the past 20 years. In response to the explosive growth in scientific opportunities, new facilities have been constructed and the number of astronomers using ground-based facilities has doubled since 1970, but funding to operate and maintain these facilities and to conduct basic research has been constant. The National Optical Astronomy Observatories (NOAO) has opened two new 4-m optical telescopes and has absorbed the operation of Sacramento Peak Solar Observatory. The National Radio Astronomy Observatory (NRAO) has opened the Very Large Array (VLA) and has begun to operate the VLBA network. At the same time, improvements in astronomical instrumentation have greatly increased the capabilities of optical and radio telescopes, and the total number of visiting observers at all national observatory sites has tripled. Despite these increased responsibilities, staffs at the national observatories have been cut. Because of funding constraints, available instrumentation and computing systems lag behind the state of the art, precious data have been inadequately analyzed, and expensive equipment has been poorly maintained.
The lack of adequate NSF funding for grants and for the infrastructure has
created serious problems throughout ground-based astronomy; some examples are listed below.
The success rate for first-time proposals from young scientists has fallen to 1 in 10. The purchasing power of the average grant, and the per capita funding available to astronomers, have both dropped by about a factor of 2 since 1980 (Appendix B). The number of postdoctoral positions supported by grants has fallen by 20 percent. The operations budgets of the NRAO, NOAO, and the National Astronomy and Ionosphere Center (NAIC) dropped by 20 to 35 percent in the 1980s. The staffing levels at the national observatories dropped by more than 15 percent in the 1980s. Cuts at NOAO led to closure of a heavily used 36-in. telescope, suspension of travel support for observers going to the Kitt Peak (Arizona) and Cerro Tololo (Chile) telescopes, and closing of the advanced projects group responsible for the development of innovative optics concepts such as adaptive optics and interferometry. Cuts at NRAO led to deferred maintenance that reduced the efficiency of the VLA, a lack of the computer resources needed to process spectral-line data at the VLA, and an extended and more expensive construction schedule for the VLBA.
The committee has expressed its view in Chapter 1 that the highest funding priority for the 1990s in ground-based astronomy is restoring support for the scientific infrastructure, especially for grants to individual researchers and for maintenance and refurbishment of frontier national facilities.
The number of U.S. astronomers has increased by about 40 percent over the last decade (Appendix B). New PhDs account for only about half of the new astronomers; the remainder have moved into astronomy from other fields. The increase in the number of professional astronomers indicates the intellectual excitement that astronomy provides for students and for scientists in other fields.
The committee judges that the number of astronomers and their current rate of production is appropriate to the capital investment being made by the United States in new telescopes. NASA has estimated that a pool of astronomers at least as large as the present research community, or perhaps slightly larger, will be required to analyze the important data that will be returned from its space missions over the next 10 years.
BALANCED SPACE ASTROPHYSICS PROGRAM
The Strategic Plan (NASA, 1988, 1989) developed for NASA's Office of Space Science and Applications incorporates the unfinished astrophysics missions, recommended by the astronomical community, that were selected and started in the 1970s and 1980s. The completion of this strategic plan will determine most of the astrophysics missions to be launched until the late 1990s. The committee endorses this plan. The recommendations made here are intended primarily to affect the process by which NASA will select and carry
out the astrophysics missions to be started during the latter half of the 1990s and beyond.
The success of the U.S. space astrophysics program depends on a proper balance between large, moderate, and small missions. Large missions such as the Great Observatories have capabilities that cannot be matched by smaller missions. They provide leaps in capability needed to solve many of the problems at the frontiers of the universe. Large missions involve many researchers in innovative instrument development, support broad community participation in creative observing, attract students, and capture the public imagination. For example, data from the Einstein Observatory have been analyzed in more than 1,000 published papers, nearly all of which were written by individuals or by small groups of investigators. Large missions in astronomy provide for “small science with big facilities.” Amortized over their lifetimes, large missions can be efficient and cost-effective.
However, large missions are also complex and expensive. NASA and the scientific community must be alert to possible technical and management simplifications to assure scientific success on the fastest schedule and at the lowest cost. The manufacturing flaw in the HST mirrors constitutes a sober lesson, but HST problems must be viewed alongside a list of stunning successes in other complex missions such as the Viking and Voyager planetary flybys and the High-Energy Astronomical Observatory (HEAO) program, including the Einstein Observatory. The astronomical community and NASA must use the lessons of HST, and of other complex NASA science projects, to learn how to improve the management of future large missions.
At the same time, moderate and small missions add a vital dimension to NASA's space science program: the ability to deploy new instrumental technology into space on relatively short time scales. Smaller programs can provide new approaches to well-defined scientific problems of great significance that are not easily addressed with the large missions. The opportunity for rapid access to space allows for quick responses to scientific and technical developments, stimulates progress in technology, and attracts young instrumentalists who are essential for a successful future in space science. Many of the outstanding astronomical missions of the past were of moderate or small size, such as the Uhuru x-ray telescope, the International Ultraviolet Explorer (IUE), the Infrared Astronomical Satellite (IRAS), and the Cosmic Background Explorer (COBE) satellite. The small suborbital program made major contributions to the study of Supernova 1987A.
The committee recommends that NASA continue to develop a vigorous program of moderate and small missions of limited complexity and shorter development times, with increased use of expendable launch vehicles.
Recent NASA Announcements of Opportunity have stimulated many innovative proposals for scientific payloads for small and moderate missions. In addition, exciting astrophysics missions currently under development by Japanese and European space agencies will use mission concepts and instrumental technologies that were invented and developed by U.S. astrophysicists. A number of Explorer-level proposals of great scientific importance are described in Chapter 1 and in the panel reports contained in the Working Papers (NRC, 1991) of this report. NASA has recognized the need for a more frequent launch rate of small and moderate-sized astrophysics missions and has begun to respond to this need within its Strategic Plan (NASA, 1988, 1989).
The committee recommends that NASA increase the rate of Explorer missions for astronomy and astrophysics to six Delta-class and five SMEX missions per decade.
The committee believes that the most successful and cost-effective projects, large, moderate, and small, involve an intimate partnership between university scientists and the NASA and industrial communities. For large programs, active participation by NASA and non-NASA scientists at the project level facilitates the most cost-effective allocation of resources and helps ensure that scientific objectives are met. The committee believes that the most qualified astronomers should assume major responsibilities for important projects and that large programs are more likely to succeed if one accomplished individual has full knowledge and appropriate responsibility for each project. In smaller programs, the shorter schedules and more limited budgets require still closer ties among the different participants in the program. National Research Council studies of the Explorer program (NRC, 1984, 1986b) have called for simplified project control of moderate and small missions, including clear authority for a scientific principal investigator. Specific proposals for ways to make moderate and small missions more effective are also contained in the Working Papers (NRC, 1991). NASA is exploring such approaches in several small missions.
The committee believes that NASA should increase the role of scientists in the management of large, moderate, and small projects.
Long development times and high costs for small and moderate missions have limited in recent years the effectiveness of the Explorer program. In addition to the management issues just cited, the National Research Council studies of the Explorer program called for a return to missions with well-defined scientific objectives, careful attention to mission cost in the selection process, and appropriate levels of formal requirements for reliability and quality assurance. The High-Energy Transit Experiment (HETE; a shuttle-launched satellite package for detecting gamma rays) is being developed in this way
by NASA though a grant to university scientists. NASA is also moving to implement these recommendations in the SMEX program.
The committee urges NASA to continue streamlining management practices to assure well-defined science objectives, accurate cost control in the selection process, and appropriate requirements for reliability and quality assurance.
The committee is worried that the operation of the next three Delta-class Explorer missions is currently based on a single, reusable spacecraft called the Explorer platform. The current plan is to launch the Extreme Ultraviolet Explorer (EUVE) attached to the Explorer platform with a Delta rocket. Subsequent Explorers would be launched with Space Shuttle missions during which astronauts would exchange EUVE (or its successor) for a different observatory to be operated on the orbiting platform. The committee believes that this serial approach involves a significant risk for long and expensive delays, reduces mission lifetime, and restricts projects to low-earth, Shuttle-accessible orbits. The committee's highest-priority moderate space initiative is, as discussed in Chapter 1, an independent spacecraft for FUSE, which would obviate dependence on the single, reusable Explorer platform and would enhance science opportunities for the FUSE mission. The committee notes that a previous endorsement of refurbishable shuttle-serviced spacecraft by the NRC 's Committee on Space Astronomy and Astrophysics (NRC, 1986b) was made before the full implications of the Challenger tragedy were recognized.
The committee believes that there are scientific, programmatic, and financial advantages to using independent spacecraft, versus a reusable shuttle-serviced platform, for Explorer missions.
Research in astronomy and astrophysics is an international enterprise. Recent examples of successful international collaborations include the GONG project for studying the motions of the sun's surface, the IUE and IRAS satellites, and intercontinental radio interferometry, which maps distant quasars and the motions of terrestrial continents. The United States provides access on a competitive basis for scientists of all countries to a number of major U.S. national facilities. In turn, the United States should expect that other countries will provide reciprocal access to their major facilities.
International cooperation in building major facilities is most effective when the project draws on the complementary capabilities of different nations, or when the projects are too expensive for individual nations to afford. Some projects, such as a permanent observatory on the moon, are so large and complex that international collaboration may be essential.
Substantial extra costs can be incurred, however, when facilities are built by more than one nation, arising, for example, from the increased complexity of coordinating technical interfaces and the necessity for duplicating some administrative efforts. Sometimes, international collaboration and scientific goals are most effectively advanced when nations build their own unique facilities, providing access to qualified scientists from other nations.
The committee recommends that international cooperation be considered for the development of a major initiative if such a project draws on complementary capabilities of different nations or requires resources beyond those that can be provided by the United States alone.