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Space Studies Board Annual Report 2000 3 Summaries of Major Reports 3.1 Future Biotechnology Research on the International Space Station A Report of the Task Group for the Evaluation of NASA's Biotechnology Facility for the International Space Station Executive Summary BACKGROUND AND SCIENTIFIC SCOPE OF NASA PROGRAMS The National Aeronautics and Space Administration (NASA) manages research programs in two areas of the rapidly expanding field of biotechnology: protein crystal growth and cell science. The protein crystal growth work focuses on using microgravity to produce higher quality macromolecular crystals for structure determination and on improving understanding of the crystal growth process. The cell science work focuses on basic research that contributes to understanding how the microgravity environment affects the fundamental behavior of cells, particularly in relation to tissue formation and the effects of space exploration on living organisms. The National Research Council 's Task Group for the Evaluation of NASA's Biotechnology Facility for the International Space Station was formed to examine and evaluate the use of the International Space Station (ISS) as a platform for research in these two areas. In this report, the task group offers a variety of recommendations and suggestions for improving the NASA biotechnology research program. It believes these changes are necessary if the NASA program is to fulfill the potential for scientific discovery and impact that is also outlined in this report. Protein Crystal Growth The task group heard a great deal about experiments to date in NASA 's macromolecular crystallography program. The results so far are inconclusive, and the impact of microgravity crystallization on structural biology as a whole has been extremely limited. At this time, one cannot point to a single case where a space-based crystallization effort was the crucial step in achieving a landmark scientific result. In many of the cases that have so far been listed as successful, the improvements obtained have been incremental rather than fundamental. In addition, the difficulty of mounting simultaneous efforts to produce the best possible crystals both on the ground NOTE: "Executive Summary" reprinted from Future Biotechnology Research on the International Space Station, National Academy Press,Washington, D.C., 2000, pp. 1-9
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Space Studies Board Annual Report 2000 and in space has limited the ability of researchers to make the comparisons between microgravity and Earth crystals that would be necessary to demonstrate that the microgravity environment can produce superior crystals. Finding: The results from the collection of experiments performed on microgravity's effect on protein crystal growth are inconclusive. The improvements in crystal quality that have been observed are often only incremental, and the difficulty of producing the appropriate controls limit investigators' ability to definitively assess if improvements can be reliably credited to the microgravity environment. To date, the impact of microgravity crystallization on structural biology as a whole has been extremely limited. Despite the lack of impact of microgravity research on structural biology up to now, there is reason to believe that the potential exists for crystallization in the microgravity environment to contribute to future advances in structure determination. Today's ground-based protein crystallization projects are increasingly sophisticated, and yet the diffraction characteristics of crystals of many important targets are still suboptimal. Improvements in diffraction that move a system from the margins of structure determination to well beyond that boundary will have a significant impact on the ability of the resulting structure to provide important insights into biological mechanisms. All research on protein crystallization in space has, up to now, been done under suboptimal conditions (short-duration experiments, insufficient vibration control, etc.), so the improved conditions for research provided by the ISS have the potential to produce much better results. Finding: While enormous strides have been made in protein crystallization in the last decade, it is still the case that there are very important classes of compelling biological problems where the difficulty of obtaining crystals that diffract to high resolution remains the chief barrier to structural analysis of the crystals. It is here that the NASA program must look to maximize its impact. In order to engage the research community, NASA must focus its support on programs that are developing technologically innovative equipment and engaging in the structure determination of crystals with important biological implications. While past NASA-supported research on the crystallization process has not been without value, NASA's priority should now be to resolve the community's questions about the usefulness of protein crystal growth in the microgravity environment for tackling important biological questions. Until the uncertainty about the value of space-based crystallization is resolved, a program of this fiscal magnitude is bound to engender resentment in the scientific community. Although many pharmaceutical and biotechnology companies have participated in microgravity crystallization research, not one has yet committed substantial financial resources to the program. This is likely to remain the case until the benefits of microgravity can be convincingly documented by basic researchers and until facilities in space can handle greatly increased numbers of samples in a much more user-friendly manner. Cell Science NASA's cell science program focuses on studying the influence of low gravity on fundamental cell biology as it relates to tissue formation, and on providing insight into the effects of microgravity on cell, tissue, and organ system function, especially as it might affect participants in space exploration. Finding: It is appropriate for NASA to support a cell science program aimed at exploring the fundamental effects of the microgravity environment on biological systems at the cellular level. Results from such basic research experiments could have a significant impact on the fields of cell science and tissue engineering. However, the specific important questions within cell biology that can best be tackled on the ISS do not seem to have been defined yet. Narrowing the broad sweep of the current program may focus instrument development efforts and accelerate progress toward complete understanding of the effects of microgravity on specific biological phenomena. A key to determining the success of cell science experiments in space will be designing appropriate controls for experiments. In space, cell cultures experience a low gravitational environment that reduces convection, buoyancy-driven flows, and sedimentation, and it is difficult to separate the various factors causing differences between space-and Earth-grown samples. In addition, the tremendous progress that has been made in three-dimensional tissue
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Space Studies Board Annual Report 2000 development on Earth, under unit gravity, provides a wide range of options for ground-based experiments that may produce results similar to those achieved in microgravity. To evaluate the relative merits of various experimental control groups, and also to enable the detailed evaluation of samples returned from space, it is important that quantitative measures of cell and tissue structure and function be developed and studied. Finding: Appropriate experimental controls for space-based cell science experiments have not yet been determined. The best controls would be those that enable researchers to separate and investigate the multiple factors—including launch and reentry, effects of microgravity on the culture medium, and direct effects of microgravity on cellular behavior—that produce the changes observed in cells and tissues grown in space. Analytical techniques that measure the molecular mechanisms underlying cellular functions will be essential to provide data for comparing proposed experimental controls and quantifying the observed changes in cell and tissue samples. At NASA, the work viewed by the task group was being carried out in the biotechnology section of the Microgravity Research Division. The themes of the cell science research under way in this program overlap with the scope of work ongoing in the NASA Life Sciences Division. The complementary nature of these two programs needs to be recognized so that NASA personnel and external researchers can take full advantage of the potential synergies. While there is already a sharing of flight hardware, a mechanism to establish projects that are jointly funded by the Life Sciences Division and the Microgravity Research Division should be considered. Recommendation: The research strategies and projects of the cell science work in the biotechnology section of the Microgravity Research Division should be more closely coordinated with the work of NASA 's Life Sciences Division to take advantage of overlapping work on bone and muscle constructs and of potential synergies between in vitro and in vivo research projects. INSTRUMENTATION The International Space Station (ISS) is currently under construction; assembly is scheduled to be complete in 2005. However, NASA plans to begin research on the facility as early as 2000, using equipment that has been flown on the shuttle and that can be temporarily installed in modules of the ISS as they are completed. As the ISS grows and more station-specific hardware is ready, the research program will expand and more permanent instrumentation will be fitted into the ISS. Protein Crystal Growth A variety of equipment has already been used to grow and observe crystals in space, and innovative hardware continues to be developed today. Having multiple laboratories involved in this process encourages variety and creativity and also prevents NASA from getting locked in to a single hardware approach. However, the efforts of hardware developers need to be coordinated and communications between them must be improved to ensure that different programs are not producing instruments with duplicative capabilities and that technological advances are quickly shared and integrated into all equipment where appropriate. Recommendation: The efforts of external hardware developers should be coordinated to ensure that instruments are compatible, to prevent duplication of efforts, to ensure that technical innovations are shared, and to facilitate input from the scientific community in defining the goals and capabilities of protein crystal growth equipment for the ISS. NASA must also be prepared to discontinue development projects that do not use cutting-edge technologies or that are out of tune with the most current scientific goals. A significant factor affecting equipment development is the instability in the budget for the ISS. If money is repeatedly siphoned off from the hardware development work, the equipment on the ISS will be of much lower quality than the cutting-edge hardware available on the ground, and researchers will not be interested in using the outdated equipment or willing to entrust precious samples to it. The equipment developed by and for NASA should aim to provide a high level of control over samples, equipment, and procedures. On the ISS, crew time will be limited, and the human access to samples and the
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Space Studies Board Annual Report 2000 feedback to the investigators enabled by shuttle trips will be infrequent, so automation and ground-based control of experiments are essential. If principal investigators are able to make decisions about experimental parameters and to adjust experiments in real time, the research results produced in each experiment will be of higher quality, and involvement in the NASA program will be more attractive. Therefore, hardware development efforts should emphasize the importance of automation, monitoring, real-time feedback, telemanagement, and sample recovery (via mounting and freezing). Effective analysis, preservation, and reentry of promising crystal samples is especially necessary given the key role synchrotrons are playing in protein structure determination. If the NASA program is to attract researchers interested in important and challenging biological problems, ISS hardware must be designed to produce and safely return to Earth crystals of the appropriate size and quality to be analyzed at a synchrotron. However, it is not NASA's responsibility to arrange or guarantee this next step. Building a synchrotron beam line is expensive and would not be the most efficient use of NASA's scarce resources. Assuming that NASA's peer review process is selecting the most scientifically rigorous and interesting projects, successful crystallization should enable researchers to compete effectively for the necessary beam time, and success in this extra layer of peer review should further validate the NASA program within the scientific community. The X-ray Crystallography Facility (XCF) being designed for the ISS is a multipurpose facility designed to provide for and coordinate all elements of protein crystal growth experiments in space: sample growth, monitoring, mounting, freezing, and X-ray diffraction. The task group was impressed by the XCF, the robotics, the remote control, and the range of experimental capabilities provided. The X-ray diffraction module provides valuable information about whether a given crystal will diffract—this real-time feedback is key to making decisions about the success or failure of a particular crystallization experiment and will help allocate scarce freezer resources by ensuring that the most promising crystals are preserved and returned to Earth. Finding: Automation, monitoring, real-time feedback, telemanagement, and sample recovery (via mounting and freezing) will be vital for successful protein crystal growth experiments on the ISS. The XCF, through its use of robotics and a variety of experimental and observational capabilities, provides many of the tools researchers need to take full advantage of the microgravity environment. The XCF is typical of several hardware development projects for NASA in that the technologies it employs can be applied to ground-based research capabilities as well as to those based in space. Currently, however, the scientific community is mostly unaware of the quality of the automation displayed in the prototype of the robotic crystal sample preparation system and of the combined capabilities of the X-ray optics and the low-power source that will be used in the XCF. While commercial entities may need to protect their proprietary work, scientists must have access to full information about all relevant technologies and equipment for the ISS in order to effectively design and execute cutting-edge research in space. Cell Science A variety of instruments are being developed to support cell science research on the ISS, including a basic incubator, a perfused stationary culture system, and a rotating-wall perfused vessel (a bioreactor). Overall, the NASA-funded cell science work to date has emphasized the use of bioreactors to support three-dimensional tissue growth. While the development of rotating-wall vessels has had, and should continue to have, a significant impact on cell and tissue culturing methodology on the ground, the task group has a variety of concerns about the effectiveness and appropriateness of this approach for research in the microgravity environment. Issues include the relatively small amounts of data generated per unit volume and the difficulty of accessing the vessel on orbit. Recommendation: Given the current status of equipment in development, finite fiscal resources at NASA, and the limited amount of volume on the ISS, the task group recommends that future research on the ISS should deemphasize the use of rotating-wall vessel bioreactors, which are already established, and continue to encourage the development of new technologies such as miniaturized culture systems and compact analytical devices. The final determination on what sort of instrumentation will be most effective for cell and tissue growth in microgravity has yet to be made, and it is important that the relative merits of various pieces of instrumentation be
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Space Studies Board Annual Report 2000 carefully evaluated and that NASA maintain the necessary administrative and engineering flexibility to adopt the most effective systems employing the most advanced technologies and to discontinue hardware development projects that are not attuned to the most current scientific needs of the cell science communities. Close interaction is needed between scientists and the NASA operational personnel responsible for developing and constructing the hardware to ensure maximum flexibility and responsiveness to evolving research goals. Cellular systems are very sensitive to environmental perturbations. A continuous power supply to maintain appropriate and stable environments during experiments and for sample storage and transport is essential to ensure valid results. A variety of systems are under development to manage power distribution, and care must be taken, particularly during ISS construction, to ensure that cell science experiments are not compromised by power fluctuations. Another issue that will be problematic, particularly during ISS construction but also after the station is complete, is the limited amount of crew time available for research. The automation of routine tasks and groundbased control of experiments will be essential if investigators are to make efficient use of the ISS platform. Two key supports for automation and ground-based control are (1) sensors to enable physiological control of the cell/tissue culture media environment and (2) analytical equipment to provide feedback about the status of cell and tissue samples. The data from the sensors and the on-orbit analyses should be transmitted electronically in real time to investigators to enable ground-based control of experiments. Scientists on the ground then could select the most important samples for the scarce storage space and could study the changes wrought in samples by freezing and reentry. Finding: The limited amount of crew time available for research-related work and the infrequency with which investigators will have access to their samples via shuttle trips mean that automation of routine tasks, ground-based control of experiments, on-orbit analytical capabilities, and real-time transmission of digital data are vital for conducting effective cell science research on the ISS. Refrigeration and freezer capability and transport space are not the only factors limiting the throughput of cell science research on the ISS. Other factors that will affect the size of the program and the number of primary publications include crew time required for the experiments, the amount and reliability of the power supply, adequate storage space and appropriate environments for samples and supplies, shuttle flight schedules to and from the ISS, the volume of materials to be transported, and, of course, the size of the budget provided for cell science hardware development and research support. A window of opportunity has been created by the advances in molecular, cellular, and biochemical approaches (e.g., functional genomics and proteomics) that are occurring as the ISS research platform becomes available. The task group recommends that to most efficiently exploit this opportunity, emphasis should be placed on integration of the different approaches and on collaboration between principal investigators and other researchers inside and outside NASA. Recommendation: Mechanisms should be developed to enable collaborative research projects that maximize the amount of data obtained from each cell or tissue sample by executing multiple analyses on each sample. Overall Volume Allotment for Biotechnology Research on the ISS Currently, NASA plans call for peer-reviewed biotechnology research to occur within one rack on the ISS. This rack would be shared by protein crystal growth and cell science work. In addition, two racks are reserved for the hardware associated with the X-ray Crystallography Facility (XCF) being developed for the NASA Space Product Development Division. The task group considered this arrangement and the needs of the various research communities and recommends a shift in the allotments. Namely, the XCF rack devoted to crystal growth and monitoring should be transferred from Space Product Development to the Microgravity Research Division's protein crystal growth program, where experiments are selected by a centralized peer-review process and a full complement of hardware is available. The rack currently scheduled to be shared by cell science and protein crystal growth can then be dedicated entirely to cell science research. The task group makes this recommendation based on several considerations. A primary issue is the basic incompatibility between the technical needs of cell science and protein crystal growth equipment on the ISS. The flow of gases and fluids required to maintain rigorous environmental control for cell and tissue culture will produce
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Space Studies Board Annual Report 2000 vibrations that cannot be tolerated by a crystal growth facility. If cell science and protein crystal growth equipment are housed in one rack, one or both of the disciplines will be forced to operate under suboptimal conditions. The task group also carefully considered the needs of the various research communities expected to use the biotechnology facilities on the ISS. For cell science, there was concern that the amount of data and results generated by half a rack of equipment would not be substantial enough to maintain interest within the scientific community, whereas a full rack's worth of instrumentation could raise the program to a critical threshold. For protein crystal growth, the research community is still uncertain about the benefits of growing crystals in a microgravity environment, so protein sample flight programs are undersubscribed and commercial interest is low. By focusing the protein crystal growth research efforts on biologically challenging problems and by emphasizing hardware capable of monitoring and preserving samples, NASA could direct its resources to validating the program. The current volume commitment of half a rack of general macromolecular research is insufficient to establish the value of the crystal growth program, but a full rack, filled with peer-reviewed experiments that employ all types of available hardware and have access to the capabilities of the XCF, should be adequate to give the program a fair chance of success. If, after several years, the results from the protein crystal growth work have provided sufficient proof of microgravity 's benefits and the academic and commercial demand for facilities on the ISS increases, then high-throughput hardware should be developed and the allotment of space on the ISS reconsidered based not only on the demand for macromolecular crystallography research volume but also on the results to that point from the cell science program. Alternatively, if the work done through the augmented commitment recommended here fails to clearly demonstrate the value of microgravity for work on structural biology, then the protein crystal growth program can justifiably be terminated. Recommendation: The volume allotment for biotechnology work on the ISS should be redistributed as follows: The mounting, freezing, and diffracting equipment of the X-ray Crystallography Facility (XCF) should occupy one rack (as currently planned). The cell science work should occupy the entirety of what is currently designated the Biotechnology Facility. The rack presently assigned to the XCF growth equipment and managed by NASA Space Product Development should be officially dedicated to the peer-reviewed macromolecular research run out of the Microgravity Research Division. SELECTION AND OUTREACH NASA research in cell science and protein crystal growth is funded through a collection of approximately 90 active 4-year grants; the total size of the program is roughly $19 million per year. Both ground-based and flight projects are selected through a peer-review process that occurs every other year. While the current grant solicitation mechanism (NASA Research Announcements, or NRAs) is appropriate, it is inadequate to attract the involvement of the best scientists and bioengineers. The task group believes that as the program goes forward, it would benefit from a strengthening of the outreach, selection, and support offered by NASA to ensure that the proposals submitted for consideration are of the highest quality and that everything possible is done to give flight experiments the best chance of success. Both protein crystal growth scientists and cell science researchers identify themselves with a variety of professional organizations, publications, and conferences, so NRAs should be disseminated to a wider variety of newsletters and announcements in order to reach the multiple communities that might be interested in using NASA biotechnology facilities on the ISS. Another approach to expanding the pool of potential researchers would be to issue NRAs in collaboration with other federal agencies, such as the National Institutes of Health (NIH), the Biotechnology Program in the Engineering Directorate of the National Science Foundation (NSF), the NSF Biological Sciences and Regulatory Biology Divisions, and the Department of Energy. More could also be done to provide sufficient background information for potential investigators who are not familiar with NASA programs. More detail about the special opportunities and constraints of space-based research as well as about the hardware available for the ISS would make it easier for NASA to recruit new applicants for its grants and for those researchers unfamiliar with the NASA program to put together appropriate proposals. Access to information about failed projects would also improve the quality of experiments designed with NRAs in mind and would increase the likelihood of success. In general, results of projects already under way could be more broadly disseminated;
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Space Studies Board Annual Report 2000 however, the task group cautions that presentations should give a balanced portrayal of successes and limitations so as not to raise unrealistic expectations. Misperceptions about the accomplishments of NASA programs can also be gained from press releases that target the general public and portray potential future applications of NASA-funded research as completed or current work. This dissemination of vague or even inaccurate descriptions of its programs seriously diminishes NASA's credibility within the scientific communities. Recommendation: NASA should improve its outreach activities in order to involve a broader segment of the scientific community in its biotechnology research program and to increase the number of cutting-edge projects submitted for funding. It needs to disseminate NRAs and program results more widely and to provide more complete background information on failed projects and how to design flight experiments. As the pool of applicants expands, the process of evaluating proposals may also need to be adjusted. NASA's program suffers from longer time scales than are compatible with the current pace of biotechnology research. For example, the 2-year gap between NRA grant submission opportunities is likely to inhibit applications directed at the most cutting-edge research issues. Also, the delay between project selection and flight manifesting of an experiment means that NASA does not always have the hardware flexibility to respond to changes in the field based on new developments in ground-based research (for example, the increased reliance on cryoprotection and freezing of crystals or the use of scaffolding for three-dimensional tissue constructs). Finally, the uncertainties surrounding the NASA budget and the continual schedule changes make people cautious about getting involved in a program that is unable to reliably predict how much money will be available or the schedule for access to the ISS. One critical step toward raising the profile of the NASA program and the quality of the grant application pool would be to counter the current perception of recipients of NASA funds as a closed community with a fixed membership. On the whole, external input into NASA' s priorities for the biotechnology program seems to be relatively limited. Advisory groups are composed of many of the same people that make up the pool of grantees and contribute to the perception that NASA is not really interested in outside input. By reaching out to a broader slice of the protein crystal growth and cell science communities, NASA would not only increase the quality of the advice it receives but would also be able to educate a new group of people about its programs. According to NASA, the biotechnology Discipline Working Group (DWG) is the main mechanism for receiving advice about the strategic direction of the Microgravity Research Division's biotechnology programs. The group is responsible for providing input to both the protein crystal growth and cell science sides of the program, but in view of the very different scientific objectives and instrumental requirements, having a single working group for these two disparate areas serves no real purpose. If the DWG is split into two groups, each would be able to focus on the issues most relevant to its own scientific area, and the increased number of slots available for each area would give greater breadth to the groups. Care must be taken in selecting new members to ensure that there is not a bias towards those already working with the NASA program. To attract prominent outside researchers to the DWG, the task group suggests that the name be changed to more accurately reflect the group's role as a high-level advisory panel with input on the scope of research announcements, peer review practices, and future programmatic directions. Recommendation: The separate identities of the protein crystal growth and cell science sections of NASA's biotechnology research program should be emphasized. One key step should be splitting the Discipline Working Group into two strategic advisory committees to reflect the different issues facing each area of research. Prominent scientists not familiar with NASA's programs but aware of the broader issues facing the fields should be recruited to serve on these committees. An important issue for execution of research in the unforgiving environment of space is the potential for conflict between the scientific goals of an experiment and the engineering limitations associated with a space-based platform like the ISS. Within the biotechnology scientific community, there is the perception that the NASA culture does not emphasize the importance of communication between scientists and operations personnel, nor does it provide tangible assurances to the research community that the execution of high-quality research in hardware designed to answer the most cutting-edge scientific questions is a NASA priority. The community would be reassured by seeing NASA place bioengineers and biological scientists with the appropriate appreciation of
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Space Studies Board Annual Report 2000 research goals and scientifically oriented reflex responses in high enough decision-making positions to ensure that research opportunities are optimally utilized. Recommendation: The NASA culture tends to limit communication and coordination between operations personnel and researchers during hardware development; between astronauts and investigators before and during experiment execution; and between decision makers and scientists about the allotment of resources in times of crisis. To attract the best investigators to its biotechnology program, NASA must create an environment geared toward maximizing their ability to perform successful experiments. Protein Crystal Growth At present, the primary goal of NASA's protein crystal growth program should be to demonstrate microgravity 's effect on protein crystal growth and to determine whether studies of macromolecular assemblies with important biological implications will be advanced by use of the microgravity environment. To this end, the task group proposes that NASA iniate a high-profile, nationwide series of grants to support researchers engaging in simultaneous efforts to get both the best possible crystal on the ground and the best possible crystal in space of biologically important macromolecules. The projects funded by these grants should address the uncertainties that have plagued the NASA protein crystal growth program, by using the ISS for a reliable, long-term microgravity environment, by comparing space-grown crystals to the best ground crystals, and by focusing on challenging systems and hot scientific problems. Their results should definitively show whether the use of microgravity can produce crystals of a higher quality than those grown using the best technologies available on Earth. If none of the projects produces a space-grown crystal that enables a breakthrough for the structure determination of a biologically important macromolecular assembly, then NASA should be prepared to terminate its protein crystal growth program. However, if the projects supported by this high-profile, nationwide series of grants succeed in validating the use of crystallization in microgravity to tackle important and challenging problems in biology, demand for the facilities on the ISS can be expected to increase. At that time, NASA should develop an external user program (similar to synchrotron user programs) in which projects are selected by a peer-review committee that includes NASA staff representatives. Recommendation: NASA should fund a series of high-profile grants to support research that uses microgravity to produce crystals of macromolecular assemblies with important implications for cutting-edge biology problems. The success or failure of these research efforts would definitively resolve the issue of whether the microgravity environment can be a valuable tool for researchers and would determine the future of the NASA protein crystal growth program. Cell Science NASA has built a very productive relationship with the NIH based on the development and use of rotating-wall vessels. The NASA/NIH Center for Three-Dimensional Tissue Culture was started in 1994 to expose a wider community to bioreactor technology by allowing researchers from government agencies (e.g., NIH, the Food and Drug Administration, and the Department of the Navy) to test new model systems for biomedical research and basic cell and molecular biology in the rotating-wall vessel hardware with technical assistance from experienced NASA personnel. The task group believes that this outreach program is an excellent idea and recommends that a wider range of investigators be reached by opening this introductory phase of this program to extramural (nongovernment) researchers.
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Space Studies Board Annual Report 2000 3.2 Assessment of Mission Size Trade-offs for NASA's Earth and Space Science Missions A Report of the Ad Hoc Committee on the Assessment of Mission Size Trade-offs for Earth and Space Science Missions Executive Summary This report addresses fundamental issues of mission architecture in the nation's scientific space program and responds to the FY99 Senate conference report,1 which requested that NASA commission a study to assess the strengths and weaknesses of small, medium, and large missions. To that end, three tasks were set for the Ad Hoc Committee on the Assessment of Mission Size Trade-offs for Earth and Space Science Missions: Evaluate the general strengths and weaknesses of small, medium, and large missions2 in terms of their potential scientific productivity, responsiveness to evolving opportunities, ability to take advantage of technological progress, and other factors that may be identified during the study; Identify which elements of the SSB and NASA science strategies will require medium or large missions to accomplish high-priority science objectives; and Recommend general principles or criteria for evaluating the mix of mission sizes in Earth and space science programs. The factors to be considered will include not only scientific, technological, and cost trade-offs but also institutional and structural issues pertaining to the vigor of the research community, government-industry-university partnerships, graduate student training, and the like. The committee approached these questions in light of the changing environment at NASA, which has been conducting an increasing number of smaller space and Earth science missions having shorter development times and using streamlined management methods, advanced technologies, and more compact platforms than had been employed in the past. The committee referred to this approach as the faster-better-cheaper (FBC) paradigm, a variant of “smaller, faster, cheaper, better” and similar phrases that have been used to describe the changing environment for space research missions. The committee interpreted the FBC paradigm as a set of principles (including, but not limited to, streamlined management, flexibility, and technological capability) that are independent of the size or scope of a mission but can be matched appropriately to the science objectives and requirements for a given mission. It understood the term “mission” to mean the entire process of carrying out a space-based research activity, including scientific conception, spacecraft and instrument design and development, selection of development contractors, development costs, selection of launch capability, launch costs, mission operations, data analysis, and dissemination of scientific results. It is within this broad context that the committee considered questions about the emerging FBC paradigm and its implications for mission size mixes in NASA's Earth and space science programs. How FBC is defined and how FBC principles are applied to programs of any scale have many implications for the space program: its tolerance for risk; its ability to carry out strategic plans; the scope, scale, and diversity of science investigated; the results and analytical products of its missions; the ways it trains young scientists and engineers; the role of international cooperation and the ease with which it can be incorporated into NASA's programs and plans; the role of universities, industry, government laboratories, and NASA centers in conducting space research missions; and the general health and vitality of the space science and Earth science enterprises. Policy makers looking for guidance on these programs in terms of cost and size trade-offs should be made aware that the variables are more numerous and much more complex than might at first be supposed. NOTE: "Executive Summary" reprinted from Assessment of Mission Size Trade-offs for NASA's Earth and Space Science Missions,National Academy Press, Washington, D.C., pp. 1-5. 1 U.S. Senate. 1998. Department of Veterans Affairs, Housing and Urban Development, and Independent Agencies Appropriations Bill, 1999, 105th Congress, 2nd Sess., S. Rept. 105-216. 2 For the purposes of this study, NASA defined “small” as missions with total life-cycle costs less than $150 million, “medium” as between $150 million and $350 million, and “large” as more than $350 million.
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Space Studies Board Annual Report 2000 The FBC approach emerged from the widely held belief that some large, traditional NASA missions had become unwieldy. With development times of over a decade (which often resulted in flying less capable technologies) and escalating costs, such missions came under increasing scrutiny, even given the magnificence of their promised (and realized) scientific returns. Traditional missions called into question the ability of NASA's Earth and space science research programs to obtain the highest quality and quantity of research return in the most timely and efficient fashion. Cuts in NASA's budget beginning in the early 1990s further encouraged new approaches for obtaining scientific returns in more efficient and cost-effective ways, albeit with added risk. “Faster” missions can be made so by streamlining the management and development effort, by shortening the development schedule, by using the best available technology, and perhaps even by knowingly accepting more risk. In general, such methods will also lead to a “cheaper” mission. However, for NASA research programs, technological or managerial innovation are not ends unto themselves: the clear and obvious meaning of “ better” is that more science—more knowledge and better quality and quantity of measurements—about some aspects of the universe around us is returned for a given investment and that such returns occur in a timely manner. The impression that faster-better-cheaper also means “smaller” has raised concerns that there is a growing shift away from larger-scale endeavors in the Earth and space science programs. However, the tendency to equate FBC with the size or cost of a space or Earth science mission can overlook a number of things: the requirements unique to different disciplines, the complexities of scientific objectives, time and spatial scales, and techniques for implementing a mission. Total costs, mission capabilities, and the ultimate scientific results of space programs rely on a complex combination of the skill and performance of everyone associated with mission development, schedules, approaches to handling technical and management risks, technological implementation, and management style. Through the careful planning processes that now characterize both the Earth science and the space science enterprises, the key outstanding questions of each discipline can be framed. Each such science question or disciplinary quest must then be examined in terms of the science community's priorities, the measurement requirements, and the technological readiness to determine which mission approach (or approaches) might be employed to address it. These science-based decisions on missions and approaches also incorporate strategies to engage and educate the general public and contribute to broader goals such as human exploration and development of space. A major consideration in all cases is the fiscal constraint that applies at any given time and the level of risk that can be tolerated by the mission's scientific priority and its role in NASA's strategic plan. The ad hoc committee recognizes that the recent losses of missions conducted using the FBC approach—Lewis, the Wide-Field Infrared Explorer, Mars Climate Observer, and Mars Polar Lander—are in many ways calling into question some elements of the philosophy of FBC. Although it is beyond the scope of the committee's charge to assess individual mission failures (this is a task for the mission failure review boards), the committee calls attention to the potential implications of these losses for science and, especially, for the direction of the NASA Mars program. Is the Mars program committed to a technology path that is proving to be riskier than its proponents originally anticipated? Are recent losses turning the program toward sample return missions that lack the critical precursors recommended in science strategy reports? How seriously have the scientific rationale and robustness of the Mars program been affected by the information lost from recent mission failures? Do current and future mission programs have ample time and budgets to integrate the lessons learned from previous failures? These and other ramifications of the recent series of losses of missions implemented under the FBC paradigm are of pressing and paramount concern. FINDINGS The committee supports several principles being implemented in the FBC methodology. Specifically, it found a number of positive aspects of the FBC approach, including the following: A mixed portfolio of mission sizes is crucial in virtually all Earth and space science disciplines to accomplish the various research objectives. The FBC approach has produced useful improvements across the spectrum of programs regardless of absolute mission size or cost. Shorter development cycles have enhanced scientific responsiveness, lowered costs, involved a larger community, and enabled the use of the best available technologies. The increased frequency of missions has broadened research opportunities for the Earth and space sciences. Scientific objectives can be met with greater flexibility by spreading a program over several missions.
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Space Studies Board Annual Report 2000 Nonetheless, some problems exist in the practical application of the FBC approach, including the following: The heavy emphasis on cost and schedule has too often compromised scientific outcomes (scope of mission, data return, and analysis of results). Technology development is a cornerstone of the FBC approach for science missions but is often not aligned with science-based mission objectives. The cost and schedule constraints for some missions may lead to choosing designs, management practices, and technologies that introduce additional risks. The nation's launch infrastructure is limited in its ability to accommodate smaller spacecraft in a timely, reliable, and cost-effective way. RECOMMENDATIONS TO NASA Faster-Better-Cheaper Principles Faster-better-cheaper methods of management, technology infusion, and implementation have produced useful improvements regardless of absolute mission size or cost. However, while improvements in administrative procedures have proven their worth in shortening the time to science, experience from mission losses (Mars Climate Observer and Lewis, for example) has shown that great care must be exercised in making changes to technical management techniques lest mission success be compromised. Recommendation 1: Transfer appropriate elements of the faster-better-cheaper management principles to the entire portfolio of space science and Earth science mission sizes and cost ranges and tailor the management approach of each project to the size, complexity, scientific value, and cost of its mission. Science Scope and Balance The nature of the phenomena to be observed and the technological means of executing such observations are constrained fundamentally by the laws of physics, such that some worthwhile science objectives cannot be met by small satellites. The strength and appeal of faster-better-cheaper is to promote efficiency in design and timely execution—shorter time to science—of space missions in comparison with what are perceived as less efficient or more costly traditional methods. A mixed portfolio of mission sizes is crucial in virtually all space and Earth science disciplines in order to accomplish a variety of significant research objectives. An emphasis on medium-size missions is currently precluding comprehensive payloads on planetary missions and has tended to discourage planning for large, extensive missions. Recommendation 2: Ensure that science objectives—and their relative importance in a given discipline—are the primary determinants of what missions are carried out and their sizes, and ensure that mission planning responds to (1) the link between science priorities and science payload, (2) timeliness in meeting science objectives, and (3) risks associated with the mission. Technology and Instrumentation Technology development is a cornerstone of first-rate Earth and space science programs. Advanced technology for instruments and spacecraft systems and its timely infusion into space research missions are essential for carrying out almost all space missions in each of the disciplines, irrespective of mission size. The fundamental goal of technology infusion is to obtain the highest performance at the lowest cost.
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Space Studies Board Annual Report 2000 3.11 Issues in the Integration of Research and Operational Satellite Systems for Climate Research: I. Science and Design A Report of the Committee on Earth Studies Executive Summary INTRODUCTION Currently, the Departments of Defense (DOD) and Commerce (DOC) acquire and operate separate polar-orbiting environmental satellite systems that collect data needed for military and civil weather forecasting. The National Performance Review (NPR)1 and subsequent Presidential Decision Directive (PDD)/NSTC-2, dated May 5, 1994, directed the DOD (Air Force) and the DOC (National Oceanic and Atmospheric Administration, NOAA) to establish a converged national weather satellite program that would meet U.S. civil and national security requirements and fulfill international obligations.2 NASA's Earth Observing System (EOS), and potentially other NASA programs, were included in the converged program to provide new remote sensing and spacecraft technologies that could improve the operational capabilities of the converged system. The program that followed, called the National Polar-orbiting Operational Environmental Satellite System (NPOESS), combined the follow-on to the DOD's Defense Meteorological Satellite Program and the DOC's Polar-orbiting Operational Environmental Satellite (POES) program. The tri-agency Integrated Program Office (IPO) for NPOESS was subsequently established to manage the acquisition and operations of the converged satellite. NASA officials have long envisioned developing operational versions of some of the advanced climate and weather monitoring instruments planned for EOS. In its 1995 EOS “Reshape” exercise, NASA adopted the assumption that some of the planned measurements in the second afternoon (PM) satellite series would be supplied by NPOESS. Although NASA has altered its earlier plans for the PM satellite and other follow-on missions to the first EOS series, its intent to integrate NPOESS into its Earth observation missions remains intact. This report, the result of the first phase of a study by the Committee on Earth Studies, analyzes issues related to the integration of EOS and NPOESS, especially as they affect research and monitoring activities related to Earth's climate and whether it is changing.3 The development of high-quality, long-term satellite-based time series suitable for detection of climate change as well as for characterization of climate-related processes poses numerous challenges. In particular, achieving NASA research aims on an NPOESS satellite designed to meet the high-priority operational needs of the civil and defense communities will require agreement on program requirements, as well as coordination of instrument development activities, launch schedules, and precursor flight activities. The study of climate processes requires a coherent, comprehensive system that carefully balances research requirements that are sometimes in conflict with operational requirements. Long-term, consistent data sets require careful calibration, reprocessing, and analysis that may not be necessary to meet the needs of short-term forecasting. Acquisition of multiple copies of a satellite sensor may be the simplest and most cost-effective means to ensure data continuity, but this strategy may preclude the insertion of new techniques to improve the observations in response to lessons learned during analysis of long data records. Such conflicts are difficult to resolve and are complicated by differences in agency cultures, charters, and financial resources. NOTE: "Executive Summary" reprinted from Issues in the Integration of Research and Operational Satellite Systems for Climate Research:I. Science and Design, National Academy Press, Washington, D.C., 2000, pp. 1-6. 1 See DOC12: “Establish a Single Civilian Operational Environmental Polar Satellite Program,” in Appendix A of From Red Tape to Results: Creating a Government that Works Better and Costs Less (National Performance Review Part I). Available on the World Wide Web at < http://www.npr.gov/library/nprrpt/annrpt/redtpe93/index.html >. 2 “Fact Sheet: U.S. Polar-Orbiting Operational Environmental Satellite Systems and Convergence of U.S. Polar-Orbiting Operational Environmental Satellite Systems and Landsat Remote Sensing Strategy,” statement by the White House Press Secretary, May 10, 1994. Available on the World Wide Web at < http://www.whitehouse.gov/WH/EOP/OSTP/NSTC/html/pdd2.html >. 3 The committee's forthcoming phase two report, Issues in the Integration of Research and Operational Satellite Systems for Climate Research: II. Implementation (NRC, 2000), addresses systems engineering issues related to sensor replenishment and technology insertion, explores technical approaches to data continuity and interoperability from the standpoint of data stability, and considers issues in instrument calibration and data product validation.
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Space Studies Board Annual Report 2000 APPROACH AND OBSERVATIONS In performing its assessment, the committee reviewed eight variables (eight measurement areas) that it believed to be representative of the wide-ranging set of potential variables to be measured in a climate research and monitoring program. The committee adopted this strategy in part because there is no unique set of “climate variables,” nor is there consensus on what might constitute a minimal set of variables to be monitored in a climate research program. The committee assessed the eight variables in terms of their value to climate science and whether the present state of measurements and their associated algorithms were adequate to produce “climate-quality” data products. Included in the committee's analysis is an assessment of the role of new technology or new measurement strategies in enhancing existing climate data products or delivering new data products of interest. Common Issues In its review of the eight representative climate variables the committee identified the following common issues: Need for a comprehensive long-term strategy. Systems for observing climate-related processes must be part of a comprehensive, wide-ranging, long-term strategy. Monitoring over long time periods is essential to detecting trends such as changes in sea-surface temperature and to understanding critical processes characterized by low-frequency variability. The committee notes that an observing system developed for long-term climate observations may also very well reveal unexpected phenomena, as was the case with observations of the large-scale, low-frequency El Niño/Southern Oscillation. Desirability of multiple measurements of the same variable using different techniques. Corroborating results from a variety of observing techniques increases confidence in the data; conflicting measurements suggest problems in data quality or newly emerging science questions that must be resolved. Diversity of satellite observations and sampling strategies and support for ground-based networks. While plans for NPOESS and EOS have focused primarily on polar-orbiting satellites, satellite observations from other orbits (low inclination, geostationary) have important roles in the development of a climate observing system. Differing sampling strategies will also be needed to tailor measurement requirements to instrument capabilities in a cost-effective manner. Ground-based networks support and extend the space-based observations. They are critical for calibrating and validating space-based measurements; they also complement space-based measurements and often provide the high-resolution measurements in both time and space needed to carry out the process studies that elucidate the mechanisms underlying climate-related phenomena. In reviewing its notional set of eight climate variables, the committee found that more attention to development of ground-based networks was warranted. Preserving the quality of data acquired in a series of measurements. A particular challenge in the design of a climate observing system is how to preserve data quality and facilitate valid comparisons of observations that extend over a series of spacecraft. With the regular insertion of new technology driven by interest in reducing costs and/or improving performance also comes the need to separate the effects of changes in the Earth system from effects ascribable to changes and gaps in the observing system. Effective, ongoing programs of sensor calibration and validation, sensor characterization, data continuity, and strategies for ensuring overlap across successive sensors are thus essential. Data systems should be designed to meet the need for periodic reprocessing of the entire data set. The role of data analysis and reprocessing. An active, continuous program of data analysis and reprocessing adds value to existing data sets and enables the development of new algorithms and new data products. Technology development and improved measurement capabilities. New sensors are needed to reduce costs and to improve existing measurement capabilities. In addition, some climate-related variables, for example, soil moisture, cannot be measured adequately with existing capabilities. Moreover, it is not clear that all critical climate-related variables have even been identified. With improved coordination with NOAA and the IPO for NPOESS, NASA technology development efforts would better address these issues and help provide increased capabilities for the operational meteorological system.
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Space Studies Board Annual Report 2000 Carrying Out Climate Research from Space-Based Platforms Operational agencies generally respond to short-term demands for data products; research agencies are also under increasing pressure to respond to short-term demands for technology development and science missions that can be accomplished in a few years. As a result, political and programmatic pressures for short-term returns (both in terms of science and protection of life and property) have resulted in an operational agency focus on the acute problems of storms, earthquakes, and other severe events—even though there is growing evidence that the long-term trends associated with climate will have significant economic and social impacts. Addressing the issues associated with climate will require a long-term focus and a commitment to maintain long-term, high-quality observing systems. Climate research and monitoring require a blend of short-term, focused measurements as well as systematic, long-term measurements. While the generally shorter-term and more detailed studies that characterize process studies might appear to be in opposition to a long-term program of systematic measurements, the committee emphasizes that climate-related processes are often revealed only through the study of data from long-term systematic measurements. Achieving an appropriate balance across agencies between short-term and long-term activities related to climate research, such as a balance between process studies and monitoring activities, has proved difficult. Recent NRC studies have recommended that the Executive Branch establish an office to develop and manage a climate observing strategy.4 NPOESS and Climate Research The 1994 Presidential Directive to converge DOD and DOC meteorological programs initiated a lengthy process among Air Force and NOAA operational and research users to produce a detailed list of measurement requirements. The culmination of this effort was the Integrated Operational Requirements Document (IORD-1) that was formally endorsed by NOAA, DOD, and NASA.5 The IORD-1 consists of 61 environmental data records (EDRs) deemed necessary to the success of NPOESS. The EDRs are distributed among six categories: atmospheric parameters, cloud parameters, Earth radiation budget parameters, land parameters, ocean and water parameters, and space environmental parameters. The EDRs developed in the IORD-1 describe a well-defined, detailed set of measurements that have demonstrable value in the primary NPOESS mission of short-term weather forecasting. Climate research and modeling, however, require assimilation and analysis of a much broader set of measurements that may also be characterized by different time and space scales. Instrument stability is a key consideration in the analysis of whether climate variables are changing, yet it is undefined for many of the EDRs. Further, the IORD-1 does not set requirements on the stability or longevity of the stipulated measurements. Despite these problems, the committee believes that NPOESS offers a unique opportunity to establish a satellite-based observing system for climate research and monitoring. Although the NPOESS and NASA EOS missions as currently planned may not be optimum for climate research, many of the critical components are already in place. These include an initial commitment to data stability on the part of the NPOESS IPO, an active program of data analysis and data product validation by NASA's Earth Science Enterprise (ESE), and an active plan for NASA and NOAA collaborative missions such as the NPOESS Preparatory Project. The committee is concerned, however, that budget pressures, shifting programmatic interests, and a lack of overall vision and leadership may continue to inhibit the establishment of a coherent Earth observing system for climate research and monitoring.6 Challenges in the Integration of NASA/ESE and NOAA/NPOESS Programs Division of responsibility in the integration of research and operational missions. Climate research and monitoring raise issues that transcend the capabilities of any single federal agency. Yet, in the committee 's view, no 4 See, for example, NRC (1998, 1999b). 5 An updated IORD and other documentation related to the NPOESS program are available online at < http://npoesslib.ipo.noaa.gov/ElectLib.htm >. 6 An additional set of issues relates to the development of suitable long-term climate data archive, the subject of another study by the committee, Ensuring the Climate Record from the NPP and NPOESS Meteorological Satellites, currently in press.
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Space Studies Board Annual Report 2000 effective structure is currently in place in the federal government that can address such multiagency issues as the balance between satellite-and ground-based observations, long-term and exploratory missions, and research and operational needs. The committee concurs with recent NRC reports that have expressed concern over the lack of overall authority and accountability, the division of responsibility, and the lack of progress in achieving a long-term climate observing system. 7 The challenges in integrating ESE research satellite missions and NPOESS operational satellite missions underscore these critical issues. Adequacy of NPOESS environmental data requirements for climate research. The EDR process established by the IPO supports the primary operational goals of DOD and NOAA but was not intended to yield instrument specifications that meet climate research requirements. For example, many climate research studies require access to unprocessed sensor-level data, whereas the EDR approach focuses on the final data products. In many cases, the current EDRs are not completely specified, and in some, they are not adequate for climate research. A particular issue is the absence of measurement stability and longevity specifications for many of the EDRs. Ensuring the long-term (systematic) record begun by EOS. NASA's ESE plans that certain measurements begun on EOS satellites will be integrated later into the NPOESS program. However, given the budgetary and programmatic uncertainties that have historically characterized the EOS program, there can be no assurance that this integration will be successful. Further, the committee notes that while long-term observations are essential for climate studies, NASA's new EOS plan focuses on short-term (3 to 5 years) missions. For NASA to be able to pursue a science-based strategy that leverages NPOESS capabilities where possible, the agency will probably also have to fly complementary missions and collect specialized data sets. Satellite observing systems are developed for a range of objectives that sometimes conflict, leading to the need for a framework to evaluate trade-offs and to manage risk. The NPOESS Preparatory Project (NPP) under consideration by NASA and the IPO is an encouraging step toward addressing the need to maintain continuity of critical data sets between the end of the EOS platforms and the launch of the first NPOESS platforms. Development of sustainable instrumentation. Sensors developed for NASA ESE research missions are generally intended to make ambitious state-of-the-art measurements. They are typically relatively complex and often are developed in small numbers, or even as one of a kind. In contrast, sensors for operational weather forecasting missions are generally less expensive to build and operate and are designed with reliability as a key requirement. Repeat flights of identical sensors are typical in NOAA operational meteorology programs. Developing instruments appropriate for both research- and operational-type missions that can be sustained over the longer periods characteristic of a climate research program will be a particular challenge as EOS and NPOESS satellites are integrated. Prioritizing and establishing an observing strategy. The climate research community has not yet prioritized critical data sets or developed an overall national observing strategy, including algorithm development, calibration and validation, ground observations, and new technology. Climate research priorities should reflect scientific need, while recognizing technological, fiscal, and programmatic constraints. Other important aspects of such a strategy will be periodic evaluation and readjustment of specific mechanisms for transferring data sets from research to operations. Articulation of a long-term context, spanning as much as a century or more, will be paramount in developing a credible climate observing policy. RECOMMENDATIONS The following recommendations are directed to the climate research community, NASA's Earth Science Enterprise, and the NPOESS Integrated Program Office. They derive from consideration of the common issues associated with the space-based measurement of climate variables and committee concerns related to the conduct of climate research. Recommendation 1. Climate research and monitoring capabilities should be balanced with the requirements for operational weather observation and forecasting within an overall U.S. strategy for future satellite observing systems. The committee proposes the following specific actions to achieve this recommendation: 7 See, for example, NRC (1998, 1999a,b).
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Space Studies Board Annual Report 2000 The Executive Branch should establish a panel within the federal government that will assess the U.S. remote sensing programs and their ability to meet the science and policy needs for climate research and monitoring and the requirements for operational weather observation and forecasting. The panel should be convened under the auspices of the National Science and Technology Council and draw upon input from agency representatives, climate researchers, and operational users. The panel should convene a series of open workshops with broad participation by the remote sensing and climate research communities, and by operational users, to begin the development of a national climate observing strategy that would leverage existing satellite-based and ground-based components. Recommendation 2. The Integrated Program Office for NPOESS should give increased consideration to the use of NPOESS for climate research and monitoring. The committee proposes the following specific actions to achieve this recommendation: The IPO should consider the climate research and monitoring capabilities of NPOESS along with other NPOESS requirements. For those NPOESS measurements that are deemed to be critical for climate research and monitoring, the IPO should establish a science oversight team with specific responsibilities for each associated sensor suite. The IPO should begin to establish plans for sensor calibration and data product validation as well as for data processing and delivery that consider the needs for climate research. Recommendation 3. The NASA Earth Science Enterprise should continue to play an active role in the acquisition and analysis of systematic measurements for climate research as well as in the provision of new technology for NPOESS. The committee proposes the following specific actions to achieve this recommendation: NASA/ESE should develop specific technology programs aimed at the development of sustainable instrumentation for NPOESS. NASA/ESE should ensure that systematic measurements that are integrated into operational systems continue to meet science requirements. NASA/ESE should continue satellite missions for many measurements that are critical for climate research and monitoring. Recommendation 4. Joint research and operational opportunities such as the NPOESS Preparatory Project should become a permanent part of the U.S. Earth observing remote sensing strategy. The committee proposes the following specific actions to achieve this recommendation: The NPP concept should be made a permanent part of the U.S. climate observing strategy as a joint NASA-IPO activity. Some space should be reserved on the NPOESS platforms for research sensors and technology demonstrations as well as to provide adequate data downlink and ground segment capability. NPP and NPOESS resources should be developed and allocated with the full participation of the Earth science community. REFERENCES National Research Council (NRC). 1998. Overview, Global Environmental Change: Research Pathways for the Next Decade. Washington, D.C.: National Academy Press. National Research Council (NRC). 1999a. The Adequacy of Climate Observing Systems. Washington, D.C.: National Academy Press. National Research Council (NRC), Space Studies Board. 1999b. “Assessment of NASA's Plans for Post-2002 Earth Observing Missions,” short report to Dr. Ghassem Asrar, NASA's Associate Administrator for Earth Science, April 8. National Research Council, Space Studies Board. 2000. Issues in the Integration of Research and Operational Satellite Systems for Climate Research: II. Implementation. Washington, D.C.: National Academy Press, forthcoming.
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Space Studies Board Annual Report 2000 3.12 Issues in the Integration of Research and Operational Satellite Systems for Climate Research: II. Implementation A Report of the Committee on Earth Studies Executive Summary A key objective of climate research and monitoring programs is to deliver scientifically valid knowledge that can be used by the public and by policymakers to make informed decisions about large-scale environmental issues. Because Earth's climate involves a complex interplay among the atmosphere, oceans, cryosphere, and biosphere, meeting this objective will require a comprehensive strategy that includes observations, data analysis, technology development, modeling, and data archiving and distribution. Satellite observations are an essential part of this strategy as they can record global-scale phenomena and collect information on many critical physical, chemical, and biological processes. However, there are challenges in utilizing current satellite observation programs to support climate research and monitoring. The requirements of the climate research community are sometimes at odds with the capabilities of both the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA). Further, both agencies are likely to continue to operate in a highly constrained fiscal environment. For these reasons, this report and its phase one companion, Science and Design (NRC, 2000), focus on approaches to leverage existing and planned operational and research satellite assets to meet the needs of climate research. Operational satellite missions are designed primarily to provide observations to support short-term environmental forecasts, while research satellite missions are often designed primarily to study specific processes of scientific interest or to test new observing technologies. Obtaining long-term, well-calibrated measurements from space often falls between these agency objectives. Yet the Committee on Earth Studies believes that, while challenging, the integration of operational and research missions to advance the objectives of climate research is possible and that a unique opportunity to demonstrate such integration is presented by the National Polar-orbiting Operational Environmental Satellite System (NPOESS) and the redesigned NASA/Earth Science Enterprise (ESE) missions. NPOESS and the NPOESS Preparatory Project (NPP) offer significant improvements over the capabilities of the two existing separate operational polar-orbiting systems: NOAA's Polar-orbiting Operational Environmental Satellites (POES) and the Department of Defense's Defense Meteorological Satellite Program (DMSP). Moreover, the redesigned NASA/ESE missions focus on critical science questions in the area of climate research, and NASA's new strategy of employing a larger number of smaller spacecraft provides a high level of flexibility. NPOESS will collect critical data sets on variables that are not currently included in operational measurements (such as radiation budget, total ozone, wind speed and direction, ocean topography, and ocean color) and will offer improved quality for some variables now being measured (such as atmospheric moisture and temperature profiles, all-weather sea surface temperature, and vegetation indices). Moreover, the orbits of NPOESS satellites will have stable equator-crossing times, which will significantly improve the utility of the data for climate research. The next set of NASA/ESE missions will not be based on copies of the first Earth Observing System (EOS) series. Instead, they will be divided into systematic missions (i.e., emphasizing measurements of processes dominated by long-term variability) and exploratory missions (i.e., focused on specific scientific questions that can be answered with a single mission). Because systematic measurements are an essential element of the NASA/ESE strategy, special attention is being given to NPOESS. In this context, NPP is important as a testbed for the incorporation of NASA/ESE science requirements into an operational mission. The present report emphasizes two themes. First, data stability—enabled by long-term, consistent data sets—is a critical requirement for climate research. Second, system flexibility is necessary to enable pursuit of new science objectives as well as new technology and to respond to surprises that will emerge in the Earth system. Further discussion of both themes can be found in the “Pathways” report (NRC, 1998). NOTE: "Executive Summary" reprinted from Issues in the Integration of Research and Operational Satellite Systems for Climate Research: II Implementation, National Academy Press, Washington, D.C., 2000, pp. 1-6.
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Space Studies Board Annual Report 2000 DATA STABILITY Because natural signals are often small, it is difficult to ascribe particular events or processes to climate change. This is especially true in the area of anthropogenic forcing, or global warming. Natural events such as the El Niño/ Southern Oscillation represent enormous, global-scale perturbations in a variety of Earth system variables, such as ocean winds and sea surface temperature, precipitation, and atmospheric carbon dioxide. For this reason, long-term, high-quality measurements are needed to discern subtle shifts in Earth's climate. Such measurements require an observing strategy emphasizing a strong commitment to maintaining data quality and minimizing gaps in coverage. Operational satellites represent a unique asset that could produce long time series with sufficient quality, although their primary mission is not climate research. NPOESS officials appear to be making significant progress toward facilitating such data records, particularly in their attempts to set stability requirements for some of the critical data sets. Currently, however, some NPOESS environmental data records do not have stability requirements, while others have incomplete or insufficient requirements. In addition, no strategy to test the stability requirements for NPOESS measurements has been defined or developed. The committee considered data stability from three perspectives: Sensor calibration and data product validation, Requirements for and approaches to data continuity, and Data systems. Calibration and Validation Findings Long-term studies such as those needed for documenting and understanding global climate change require not only that a remote sensing instrument be accurately characterized and calibrated but also that its characteristics and calibration be stable over the life of the mission. Calibration and validation should be considered as a process that encompasses the entire system, from the sensor performance to the derivation of the data products. The process can be considered to consist of five steps. In the approximate order of performance they are (1) instrument characterization, (2) sensor calibration, (3) calibration verification, (4) data quality assessment, and (5) data product validation. Recommendations The committee makes the following recommendations with regard to calibration and validation: A continuous and effective on-board reference system is needed to verify the stability of the calibration and sensor characteristics from the launch through the life of the mission. Radiometric characterization of the Moon should be continued and possibly expanded to include measurements made at multiple institutions in order to verify the NASA results. If the new reflectance calibration paradigm is adopted (see Appendix C), then the objective of the lunar characterization program should be to measure changes in the relative reflectance as a function of the phase and position of Earth, the Sun, and the Moon rather than absolute spectral radiance. The establishment of traceability by national measurement institutions in addition to the National Institute of Standards and Technology should be considered to determine if improved accuracy, reduced uncertainty in the measurement chain, and/or better documentation might be achieved, perhaps even at a lower cost. The results of sensitivity studies on the parameters in the data product algorithms should be summarized in a requirements document that specifies the characterization measurements for each channel in the sensor. Blanket specifications covering all channels should be avoided unless justified by the sensitivity studies. Quality assessment should be an intrinsic part of operational data production and should be provided in the form of metadata with the data product. Validation, an essential part of the information system, should be undertaken for each data product or data record to provide a quantitative estimate of the accuracy of the product over the range of environmental conditions for which the product is provided.
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Space Studies Board Annual Report 2000 Wavelengths and bandwidths of channels in the solar spectral region should be selected to avoid absorption features of the atmosphere, if possible. Calibration of thermal sensing instruments such as CERES (Clouds and the Earth's Radiation Energy System) and the thermal bands of MODIS (Moderate-resolution Imaging Spectroradiometer) should continue to be traceable to the SI unit of temperature via the Planckian radiator, blackbody technology. Data Continuity Findings Continuity is concerned with more than the presence or absence of data. It includes the continuous and accurate characterization of the properties that affect the construction of the time series. The most useful data for climate research purposes are time series that are continuous and for which the characterization of error, in terms of precision and bias, is known. Such errors should be minimized as much as possible in order to detect the often small, climate-related signal. Recommendations The committee recommends taking the following steps to ensure data continuity: A policy that ensures overlapping observations of at least 1 year (more for solar instruments) should be adopted. The IPO should examine the relation between this requirement and the launch-on-failure strategy and should include a clear definition of spacecraft or instrument failure and an assessment of still-functioning instruments. Competitive selection of instrument science teams should be adopted to follow the progress of the instrument from design and fabrication through integration, launch, operation, and finally, data archiving, thereby promoting more thorough instrument characterization. As instruments are developed for future missions, the IPO should make a determination of threats to the continuity of currently monitored radiances in the design requirements. Out-year funding should be provided to maximize the investment made in climate and operational observing instruments.1 Free-flier status should be evaluated for key climate parameters such as solar radiance and sea-level altimetry whose measurement appears to be endangered by the NPOESS single-platform configuration. Proven active microwave sensors should be considered for ocean vector winds, another key climate (and operational) parameter. Data Systems Findings The development of an NPOESS climate data system (NCDS) represents a significant challenge. Care will be needed to ensure that the design and specifications for the data system are given a broad review prior to their implementation. In addition, special attention will be needed in areas including calibration and validation, data product continuity, data archiving, archive access, reprocessing, and cost. The NPP will serve for the early testing of instruments and data systems. It will be a joint activity between NASA and the Integrated Program Office (IPO) and as such will provide an opportunity for NPOESS to benefit from the progress NASA is making in data system development. The development of an NCDS can clearly benefit from adopting the best elements of the current NASA and NOAA data systems. However, it will not be enough to simply expand existing facilities. A successful NCDS will also require a new vision in which innovation and competition play a central role. Observations of Earth will 1 For climate studies, there is a need for continuing investment in sensor studies and tests—programs for operational instruments typically do not fund such activities beyond initial checkout.
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Space Studies Board Annual Report 2000 increase by an order of magnitude when NPOESS begins operation, which could lead to an enormous increase in our understanding of Earth. To realize this potential, the huge volumes of raw data must be converted to usable products and information. The responsibility for doing this should be given to those groups and organizations that demonstrate the vision, innovation, and expertise needed to meet the NPOESS challenge. Recommendations The committee recommends meeting the following basic data-systems requirements in addition to what is needed for operational processing: A long-term archiving system is needed that provides easy and affordable access for a large number of scientists in many different fields. Data should be supported by metadata that carefully document sensor performance history and data processing algorithms. The system should have the ability to reprocess large data sets as understanding of sensor performance, algorithms, and Earth science improves. Examples of sources of new information that would warrant data reprocessing include the discovery of processing errors, the detection of sensor calibration drift, the availability of better ancillary data sets, and better geophysical models. Science teams responsible for algorithm development, data set continuity, and calibration and validation should be selected via an open, peer-reviewed process (in contrast to the approach taken with the operational integrated data processing system (IDPS) and algorithms, which are being developed by sensor contractors for NPOESS). The research community and government agencies should take the initiative and begin planning for a research-oriented NCDS and the associated science participation. SYSTEM FLEXIBILITY Because the forcing and response of Earth's climate to natural and anthropogenic variability is a complex, nonlinear process, it can be anticipated that unforeseen properties will emerge. These are the “surprises” discussed in the “Pathways” report (NRC, 1998). Scientific advances will require new observing tools. Moreover, technological advances may reduce costs or improve system performance. A rigid plan of flying exact copies of sensors will not accommodate such changes. Therefore, a way will have to be found to infuse new technology into the system while maintaining data continuity and without driving up costs. Technology insertion is defined as introduction of any new and/or improved capability (either through hardware or software innovations) into an established operational system. NASA/ESE will play an especially important role in this regard, given its experience in technology development. The committee considered the issue of system flexibility primarily from this vantage point. Technology Insertion Qualifying technological innovations span a wide range of implied changes and, thus, impose a wide range of risk levels on the operational performance of the system. For example, replacing a computer with a faster model that preserves the form, fit, and function of the earlier model is quite different from changing the computer's operating system or data processing algorithm. There is risk in any change to the design, but some changes may ripple throughout the system, forcing additional changes to accommodate the first. Additional risk is anathema for an operational system, for which reliability and continuity are the prime considerations. Any potential change must be examined carefully and conservatively, no matter how well justified the augmented capabilities may be from a scientific point of view. Findings The committee's findings are as follows:
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Space Studies Board Annual Report 2000 Operational agencies exhibit a natural tendency to resist change; any candidate technology enhancement to increase the science content of data products must satisfy rigorous prequalification before being accepted into an operational payload. The challenge for an operational system such as NPOESS is to accommodate technological change in a timely manner, while ensuring that the modified system will sustain operational functionality. In general, the means of technology insertion into operational missions is not well determined. Indeed, there appears to be a gap between the development of instruments in the science stream and their adoption in the operational stream. If the NPOESS program is to be used to support the science community as well as the operational weather agency, then a careful assessment of the pertinent science requirements must be made in the early phases of the program. Technology insertion always will be subject to limitations. Any downstream change in the on-board technology must fit within the spacecraft resources (mass, power, data bandwidth, data volume, etc.) that may remain over and above the requirements of the baseline system. It is likely that the development and qualification of any new measurement capability that might be required for scientific purposes would have to be funded from non-IPO sources, unless that instrument were deemed to be critical to the NPOESS operational mission. Clearly, vision and well-coordinated interagency planning are needed to sustain the development of suitable instruments in synchronization with NPOESS flight opportunities. Unlike the relatively short design lifetimes of their predecessors, the NPOESS satellites are meant to have a 10-year lifetime. Whereas a 10-year design life is laudable for an ongoing operational facility, it adds further roadblocks to the process of technology insertion. Under current policy, whether an instrument provides data that are important to a climate science record has no bearing on the criteria for launch of an NPOESS replacement spacecraft. Partial failure, even of a mission-critical instrument, may have such a small impact for operational weather purposes that it does not trigger a replacement launch. However, the same fault could induce degradations that would be far more significant for scientific purposes. An opportunity to prove in practice the value of a candidate instrument is often a pivotal step in the effort to transform a scientific measurement into an operational tool. A satellite program such as NPP could provide such opportunities. It is noteworthy that NASA's ESE Technology Development Plan does not provide for the transitioning of technology from scientific status to operational status. This fact is central to the question of technology insertion into NPOESS in support of climate or other scientific objectives. Even if a new technological innovation is proven to offer unique scientific value and is shown to be technically feasible, there are no firm plans to guide its transition onto NPOESS. Recommendations The IPO and NASA should strive to accommodate technological change in a timely manner, while ensuring that the modified system will sustain operational functionality. The committee's recommendations with regard to technology insertion are as follows: The IPO should identify a person or group to review the system requirements and the design to ensure that both the Integrated Operational Requirements Document (IORD; IPO, 1996) and the contractor approaches will support flexibility and change. NASA should provide a list of science requirements (ostensibly from the Science Plan) and climate requirements that are candidates for implementation on NPOESS. The IPO should plan for the insertion of new or enhanced measurement capabilities into NPOESS that would likely have to be funded from non-IPO sources. NASA ESE should implement its Technology Development Plan with firm plans linked to missions and ensure that any necessary NPOESS enabling technologies are covered in the plan. NASA and the IPO should devise an approach to support announcing and accepting additional experiments on NPOESS.
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Space Studies Board Annual Report 2000 It is essential that the process of incorporating research requirements into NPOESS be started now and be allowed to influence the program development and risk reduction phase that is in progress, without disrupting the primary NPOESS mission. Opportunities for change after the launch are limited by the longer satellite life and longer time between launches. REFERENCES Integrated Program Office (IPO), National Polar-orbiting Operational Environmental Satellite System (NPOESS). 1996. Integrated Operational Requirements Document (First Version) (IORD-1) 1996. Issued by Office of Primary Responsibility: Joint Agency Requirements Group (JARG) Administrators, March 28. The updated IORD and other documents related to NPOESS are available online at < http://npoesslib.ipo.noaa.gov/ElectLib.htm.> National Research Council (NRC). 1998. Overview, Global Environmental Change: Research Pathways for the Next Decade. National Academy Press, Washington, D.C. National Research Council (NRC), Space Studies Board, Committee on Earth Studies. 2000. Issues in the Integration of Research and Operational Satellite Systems for Climate Research: I. Science and Design. National Academy Press, Washington, D.C.
Representative terms from entire chapter: