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Assessment of Satellite Earth Observation Programs 1991 (Chapter 3) Assessment of Satellite Earth Observation Programs 1991 3 Applications Programs and Other Major Issues This chapter presents a review of the recommendations of the former Space Applications Board (SAB) of the NRC with regard to the Earth observation satellite applications programs in NASA, NOAA, and the private sector. In addition, the government's progress in key program areas—the Earth Probe small missions program, data management, research and analysis, and the relation of space, airborne, and ground measurements—is evaluated. APPLICATIONS PROGRAMS REPORT MENU At the time of the SAB report Remote Sensing of the Earth from Space: A NOTICE Program in Crisis (SAB, 1985), the operation of Landsat was being transferred to MEMBERSHIP the private sector and the expectation of the government was that the Landsat FOREWORD program would soon become self-sustaining as a commercial operation. That SUMMARY CHAPTER 1 "privatization" process has been widely criticized, and the prospects for the CHAPTER 2 system's commercial success remain very much in doubt. The U.S. Global CHAPTER 3 Change Research Program (USGCRP) also had not yet been established as the REFERENCES scientific and programmatic rationale for the Earth Observing System (EOS) and ABBREVIATIONS AND the Mission to Planet Earth. Those programs now provide a new context in which ACRONYMS the earlier advice must be analyzed. A substantial number of the findings and APPENDIX recommendations of the 1985 SAB report have been either addressed or made obsolete because the circumstances have changed. The following is an analysis of the findings and recommendations from the 1985 SAB report that in the view of the Committee on Earth Studies (CES) remain largely relevant. Recommendation II(A): Earth remote sensing should be an established and significant part of the nation's civil space enterprise. file:///C|/SSB_old_web/seo91ch3.htm (1 of 17) [6/18/2004 1:38:19 PM]

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Assessment of Satellite Earth Observation Programs 1991 (Chapter 3) The civil space enterprise consists of government and private-sector spacecraft conducting both routine operational and experimental research missions. Over the years, NASA has led the world in developing a broad range of instrumentation and techniques for Earth remote sensing, and NOAA has provided international leadership through its operational polar orbiting and geostationary environmental satellite programs. The Landsat program, despite significant problems encountered in its transfer to the private sector, has nonetheless provided an uninterrupted stream of data and images since 1972, which has established a unique record of the world's changing landscape. The National Aeronautics and Space Administration is currently attempting to integrate over three decades of experience into a comprehensive observational program—Mission to Planet Earth—consisting of EOS, the Earth Probe mission line, the EOS Data and Information System (EOSDIS), and in the more distant future, geostationary platforms. NASA's initiative is coordinated with the NOAA operational programs and the Earth observation programs of many other nations. The recent top-level Report of the Advisory Committee on the Future of the U.S. Space Program (NASA, 1990) has supported Mission to Planet Earth as a high priority. In short, the committee concludes that the implementation of Mission to Planet Earth, together with the modernization of NOAA's environmental satellite programs and the continuation of vigorous research and development of remote sensing and related technologies, will ensure United States leadership in Earth remote sensing. Recommendation II(B): Special attention should be devoted to improving the cost-effectiveness of the federal effort in civil remote sensing (for example, by flying both operational and research instruments on the same satellite platforms). Some of the operational meteorological sensors from the NOAA satellites will be flown on both the EOS and European spacecraft. A European satellite series is being planned to replace one of the two NOAA polar-orbiting satellite series at the end of this decade. Further, NOAA has selected six of the research sensors scheduled for EOS as "pre-operational," for eventual transfer to operational NOAA spacecraft. These developments indicate progress toward meeting the sense of this recommendation. Recommendation IV(B): Operational land remote sensing for civil purposes should be accomplished in the future by a system owned and managed by the private sector (if at all feasible). At least in the early years, funding will have to come, in large part, from government. The Landsat system was transferred to the Earth Observation Satellite (EOSAT) Company in 1985. The experience to date indicates that this transfer was premature because of the lack of a sufficiently developed commercial market for the data. Also, the transfer was poorly implemented. Under the terms of the transfer, the government agreed to subsidize the operation of Landsat-4 and -5, file:///C|/SSB_old_web/seo91ch3.htm (2 of 17) [6/18/2004 1:38:19 PM]

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Assessment of Satellite Earth Observation Programs 1991 (Chapter 3) in addition to the procurement and launch of Landsat-6 and -7. For several years following the transfer, however, the budgets proposed by the Office of Management and Budget failed to honor the commitment. After much debate, funding was restored every year by a reluctant Congress. Funding uncertainties caused delays and cost overruns in the development of Landsat-6, postponed the development of Landsat-7, and made it more difficult for EOSAT to develop a market for Landsat data products. Also, EOSAT has charged relatively high prices for most Landsat data, with the result that the scientific community has used these data considerably less than anticipated. As a result of these and other problems, the future of this valuable remote sensing program remains uncertain. The effective integration of the Landsat data into the research framework of the Mission to Planet Earth and U.S. Global Change Research Program is especially important. FINDING VII. From a purely technical point of view, the partition of the civil Earth remote sensing program into private- and public-sector components and into operations and research is an unnecessary complication that has thus far only added to the cost and difficulty of creating and maintaining a successful operational program. In an Earth-viewing system that uses space platforms and other hardware with a maximum degree of cost-effectiveness, each satellite could carry land, atmosphere, and ocean sensors, and each could carry operational and experimental sensors. Observational and orbital requirements, not institutional or programmatic labels, would determine on what satellite a given sensor was flown. The separation of Earth observation activities into research, operational, and commercial categories has often led to significant duplications of effort, and contradictory data policies. The interagency CEES coordination activities appear to be reducing a number of the inconsistencies in the policies under which the nation's civil remote sensing programs are operated, particularly with regard to the availability of data from government agencies. Full coordination among federal agency, commercial, and foreign Earth observation programs remains elusive, however, and it is unclear whether the Mission to Planet Earth can be operated with maximum efficiency under existing government procurement and commercial remote sensing policies. FINDING VIII. The volume of data flow in civil Earth remote sensing is growing rapidly and will eventually exceed 1013 bits per day. Data processing, evaluation, analysis, dissemination, and archiving are becoming more difficult and costly. A substantial effort is needed to plan and operate the required data- handling systems. (This finding is discussed under the Data Management section later in this chapter.) Recommendation IX(A): NOAA (in cooperation with NASA) should develop a long-range plan for the federal role in operational Earth remote sensing. To the maximum degree possible, this plan should facilitate common use of spacecraft and data-handling systems by institutions (public and private) that mount Earth remote sensing programs. To help control costs, the number of special-purpose satellites must be held to a minimum. file:///C|/SSB_old_web/seo91ch3.htm (3 of 17) [6/18/2004 1:38:19 PM]

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Assessment of Satellite Earth Observation Programs 1991 (Chapter 3) The coordination between NASA's EOS and NOAA's POES system has made a significant step in this direction and incorporates many of the principles given in this finding. Although substantial portions of the EOS program, especially the ground segments, are benefitting from the coordinated effort, a comprehensive long-range plan between NASA and NOAA has not yet been developed. Significant problems remain, in particular, in NOAA's development of the next-generation GOES system in conjunction with NASA and its contractors. The new GOES system has had severe cost overruns and schedule delays, and one of the two remaining GOES has experienced on-orbit failure. As a result, the nation is at risk of losing all of its synoptic meteorological observations and the linchpin of its severe weather warning capability prior to the completion and launch of the new GOES system, now scheduled for the fall of 1992. In this regard, the committee would like to underscore the recommendations for increasing the POES and GOES R&D funding that were made in the Report of the Advisory Committee on the Future of the U.S. Space Program (NASA, 1990). The Earth Probe line plus possible special-orbit satellites in the EOS program, such as the advanced SAR, make up the set of special-purpose satellites referred to in recommendation IX(A). Contrary to the advice of the SAB, the CES considers these special-purpose spacecraft to be an essential component of Mission to Planet Earth and the USGCRP. The scientific rationale for such missions was reviewed in detail in the committee's report Strategy for Earth Explorers in Global Earth Sciences (SSB, 1988), which is discussed in the next section, Earth Probe Mission Line. Recommendation IX(B): The system plan should center around the needs of operational programs . . . Whenever possible, space should be made available for research sensors on vehicles that are used primarily for operational purposes. The potentialities of the Earth orbiting platforms (to be launched as part of the space station program) should be fully exploited. The polar orbiting space platform is especially important for Earth remote sensing. With the exception of space for research sensors on the NOAA satellites, this recommendation appears to have been followed well by NASA in the EOS program and with its international collaborators. The EOS-A orbit is similar to the orbit of the NOAA POES, but the "platform" is no longer a part of the Space Station program. The committee agrees with the SAB that the polar-orbiting EOS spacecraft are "especially important" for Earth remote sensing. The recommendation that NOAA make space available for research sensors remains appropriate. In fact, some limited space on NOAA satellites is available, at least for small instruments on an occasional basis. A recent example was the flight of the ERBE scanner on the NOAA POES. Recommendation IX(C): The present effort to encourage increased multinational cooperation in the Earth remote sensing program is promising and should be continued and expanded. This will promote international good will and will further help to limit national expenditures. file:///C|/SSB_old_web/seo91ch3.htm (4 of 17) [6/18/2004 1:38:19 PM]

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Assessment of Satellite Earth Observation Programs 1991 (Chapter 3) International collaboration related to the NASA and NOAA Earth observation satellite programs has provided progress in this direction through joint program planning, exchange of instruments, and mutual access to data. Although there have already been substantial cost savings through international cooperation in the programs of both agencies, current plans call for NASA's and NOAA's foreign partners to fund an even greater share of the joint programs. For example, the European Meteorological Satellite (EUMETSAT) organization is expected to assume the responsibility in the late 1990s for building and operating one of the two POES currently operated by NOAA, and several nations are planning to contribute instruments to the EOS program. The USGCRP, which has been developed since this recommendation was drafted, has generally justified increased expenditures for remote sensing by all of the cooperating nations. It is important to emphasize that a number of other nations now have significant technological capabilities for conducting Earth observations from space. Many of the proposed sensors on the planned satellite missions of various nations have very similar measurement capabilities in terms of their spectral and spatial resolution. While such overlapping capabilities provide a hedge against the loss of our ability to acquire specific types of data in the event of the failure of an individual sensor system, and are essential for observing important phenomena with diurnal variations, excessive redundancy in sensor characteristics is inefficient. In light of limited federal budgetary resources, the committee considers it important for NASA, in collaboration with the scientific community and its interagency and international partners, to develop an integrated, global observational strategy and an equitable and appropriate division of labor that maximizes observational coverage by (1) eliminating observational gaps in coverage of the electromagnetic spectrum and, (2) reducing redundancies, with the exception of those redundancies that help maintain continuity of key measurements and that provide multiple observations of variables, such as those related to clouds, energy budgets, and vegetation, which require measurements throughout the day. Both the development and implementation of this comprehensive observational strategy should be done in concert with the independent scientific community. For additional discussion of the importance of developing such an observational strategy, see NRC (1990). Recommendation X(A): NASA should launch and operate the space platforms and design and manage the downlinks to be developed as part of the space station program. Operational Earth remote sensors (NOAA and commercial) should be given high priority on the polar orbiting platform. NASA should also develop station tending and repair capabilities for space platforms and retrieval capabilities for other Earth-orbiting satellites (including those in geostationary orbit). NASA should develop new sensors for operations, in consultation with NOAA and other users, and should carry out basic space-oriented R&D on the physics and chemistry of atmosphere, ocean, and land systems. With the exception of the Space Station servicing scheme, the spirit of this recommendation is well reflected in the planned programs. The Earth Observing System is no longer linked to the Space Station program, primarily file:///C|/SSB_old_web/seo91ch3.htm (5 of 17) [6/18/2004 1:38:19 PM]

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Assessment of Satellite Earth Observation Programs 1991 (Chapter 3) because the EOS spacecraft cannot be serviced either from the proposed Space Station or from the Shuttle. The committee considers this decoupling from the Space Station program to have been a positive step for the implementation of the research objectives. The operational sensors for NOAA satellites generally have been given high priority, although, as mentioned above, the development of the next generation of GOES sensors and spacecraft has encountered serious difficulties. Also, Landsat is still not well integrated into these plans. A number of instruments developed by NASA in the past, such as the Earth Radiation Budget Experiment (ERBE) scanner, the Coastal Zone Color Scanner (CZCS), and the Total Ozone Mapping Spectrometer (TOMS), have not been transferred to NOAA for operational status despite the demonstrated maturity of the technology and the well-recognized need for such continuous measurements. Although NASA and NOAA have reached a tentative agreement on the designation of several EOS instruments as "preoperational," the framework of the eventual transfer has not been worked out, and the agencies have not yet agreed on the future status of the important MODIS instrument. Past difficulties in transferring well-tested experimental instruments to operational status underscores the imperative for the federal government to arrive at a firm and comprehensive agreement on NASA's and NOAA's responsibilities and funding for the eventual transfer of key EOS instruments to a long-term monitoring program. The National Aeronautics and Space Administration is carrying out its responsibilities in the research areas listed in the recommendation, as well as in other areas. The Earth Observing System is the "centerpiece" of the USGCRP and has been assessed in the report of the Committee on Global Change (NRC, 1990) and in the "Space Studies Board Position on the NASA Earth Observing System" (SSB, 1991) as generally meeting the established scientific priorities. Recommendation X(B): NOAA should build and (under contract with NASA) launch operational satellites or lease space on commercial spacecraft. It should own and manage the atmosphere-ocean operational observing system and provide federal oversight (and, as appropriate, initial federal subsidy) for the commercially operated land remote sensing system. NOAA should carry out research on application of space-derived information, should be responsible for archiving all Earth remote sensing data, and should disseminate atmosphere and ocean data to the user community. The National Oceanic and Atmospheric Administration is performing many of these functions, in principle, although the agency has not received funding adequate to support ocean remote sensing on an operational basis. The selection of several EOS ocean remote sensing instruments for preoperational status, however, has been an important step in this direction. Responsibility for archiving remote sensing data in support of global change research is shared by NASA, NOAA, and USGS. file:///C|/SSB_old_web/seo91ch3.htm (6 of 17) [6/18/2004 1:38:19 PM]

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Assessment of Satellite Earth Observation Programs 1991 (Chapter 3) At the time this recommendation was drafted, the SAB was reviewing the roles and missions of NASA and NOAA, and the division of responsibilities between the federal agencies and the commercial sector. These institutional aspects considered by the SAB have been largely overtaken by events, notably by the interagency approach to a nationally and internationally integrated Mission to Planet Earth. The SAB's attempt to assign roles among the various remote sensing satellite operators therefore needs to be reassessed in the new context; however, such an analysis is beyond the scope of this report. Recommendation X(C): The commercial sector should own and manage the operational land remote sensing system, purchasing space when appropriate on NASA and NOAA satellites. It should build new operational sensors and should fly its own satellites as it deems necessary (leasing space when appropriate to NOAA or NASA). The commercial sector should also be responsible for marketing space-derived land remote sensing data to the various user communities, including government departments such as Agriculture and the Interior. As has already been pointed out, this process was initiated with the Landsat program, and it has not been satisfactory. The USGCRP provides a new imperative that all data that can be used in such research be widely available, inexpensive, and easy to access. Consistent with the recommendations of the 1990 NRC report, several aspects of the Landsat legislation should be reexamined and changed to facilitate access to the Landsat data for scientific researchers and to lift restrictions on NASA in the release of EOS data. Recommendation XVIII(A): Programs to support academic research facilities, student training, and scientist visits and exchanges should be increased. The timely flow to research institutions of data from both operational and research and development satellites should be assured. This recommendation remains relevant and important. The substantial increase in engineering and science activities related to satellite remote sensing has already exceeded the capacity of existing educational programs. Although there is a recognition of this problem in the EOS program (i.e., 0.25 percent of the EOS budget has been devoted to educational fellowships), concerns remain as to whether this program alone can produce a sufficient number of new remote sensing experts to fully exploit the research and applications potential of the many planned missions. The National Oceanic and Atmospheric Administration established several new university research centers in the 1980s, some of which are focusing on remote sensing applications. A rigorous review of the existing and projected skilled personnel base in relation to the requirements identified for the Mission to Planet Earth program and the USGCRP by the principal agencies funding those programs would be especially useful. In addition, it is important to note that NASA has no formal procedure in place for adding new investigators to the EOS program. It is essential for NASA to develop a mechanism for bringing new co-investigators and guest investigators into the EOS program over tote program's lifetime, and to adequately support research opportunities outside the Principal Investigator program, including those related to remote sensing engineering. file:///C|/SSB_old_web/seo91ch3.htm (7 of 17) [6/18/2004 1:38:19 PM]

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Assessment of Satellite Earth Observation Programs 1991 (Chapter 3) Recommendation XVIII(B): Research scientists at the universities and in government should be consulted with regard to the design of (and plans to improve) operational satellite systems. These systems provide information necessary to advance basic science. This recommendation has not been implemented. In a briefing by NOAA officials, the Committee on Earth Studies was informed that the specifications for the next set of operational instruments for the NOAA polar orbiters were established internally by NOAA through consultations with its line organizations. No direct attempt was made to obtain operational and research requirements from user groups outside the agency. Research scientists at universities and in government can provide valuable advice. The establishment of a formal process at NOAA for consulting with knowledgeable individuals outside the agency, as well as with major user groups, would help ensure maximum utility of the data collected by its satellites. Recommendation XIX: Further development of a value-added industry that uses (or enhances) and markets remotely sensed data should be encouraged. A necessary requirement is a federal commitment to the continuity and timely dissemination of satellite observations. The federal government devotes little attention to developing commercial remote sensing applications. Despite the fact that many instruments in Mission to Planet Earth will provide information potentially useful for a broad range of socioeconomic applications, both the research programs and data-dissemination plans at NASA generally do not support the development of those applications. The primary emphasis is on climatology, long-term global change, and ecology—with the latter ignoring the impact on ecology of the large fraction of land area covered with crops and urban development. Although NOAA and the commercial sector have primary responsibility for operational remote sensing, NASA has a mandate for supporting research in and development of broad remote sensing applications. It is important for the agency to incorporate potential applications of the EOS system into its planning for the program, while preserving the primacy of the EOS program's scientific goals and objectives. These activities would best be coordinated with industry and with the commercial and government applications communities. The committee believes that NASA's plans for Mission to Planet Earth, together with the operational environmental satellite observations of NOAA and the satellite programs of other nations, could adequately fulfill the general requirement for continuity of observations. Nevertheless, the agencies still need to develop a comprehensive strategy with appropriate contingency planning, in addition to full instrument calibration and data validation for intercomparison of observations from different sensors over the long term. As the various Earth observation programs progress, NASA, NOAA, and their foreign space agency partners should preserve long-term continuity and intercomparability of measurements in the process of upgrading instruments and responding to evolving research priorities. In particular, the committee considers file:///C|/SSB_old_web/seo91ch3.htm (8 of 17) [6/18/2004 1:38:19 PM]

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Assessment of Satellite Earth Observation Programs 1991 (Chapter 3) it vital that the agencies mount a special effort to ensure the continuous absolute calibration and intercalibration of all EOS instruments and the instruments of other related national and foreign Earth observation spacecraft to the highest achievable accuracy. It is also important for NASA to continue to formulate a backup strategy and policy to be implemented in case of an instrument failure. This strategy may consist of the generation of alternative geophysical parameters, albeit less effective ones, from either complementary EOS instruments or from sensors flying on other NASA, U.S., or foreign spacecraft. The backup strategy ought to aim for the smoothest possible transition from the full complement of EOS sensors to the backup geophysical parameters calculated in case of primary sensor failure(s). Concerning the timely dissemination of the data, the committee finds the data distribution plans in the EOS program to be responsive to the requirements of the scientific research community. The data distribution policies for the broader applications and commercial sectors, however, need to be reviewed. EARTH PROBE MISSION LINE Summary of Recommendations The report Strategy for Earth Explorers in Global Earth Sciences (SSB, 1988) provided the scientific rationale and strategy for a line of small- to moderate-size research satellites within NASA's Earth Science and Applications Division. The principal recommendations in that report were as follows: The Committee on Earth Sciences recommends that a new Earth Explorer mission series be funded at a level that would allow the construction of two small missions per year, or one moderate mission every 3 years. Announcements of opportunity for such missions should be divided according to two separate solicitations, one for missions and instruments costing less than $30 million and one for missions in the $30 million to $150 million range. The traditional strength of the existing NASA Explorer line has been easy, frequent, and inexpensive access to space. The recommendations that follow are designed to return similar opportunities to the earth sciences. 1.Each Earth Explorer mission should be sharply focused on significant scientific issues. A mission should explore important scientific issues or fill in gaps that may arise in the collection of long-term data sets. The program could also provide the collateral benefit of advancing technology development in achieving its objectives. In any case, the missions should be justified by their own scientific merit. The Earth Explorers should not be used for the engineering development and flight testing of instruments for large missions or platforms. 2. Programmatic continuity and flexibility must be maintained. In order for the recommended program to have a significant impact on the earth sciences, it must be started with a clear expectation of maintaining uninterrupted continuity. The program should also be designed for flexibility, both in choosing the most important scientific questions to address and in allowing for reasonably wide file:///C|/SSB_old_web/seo91ch3.htm (9 of 17) [6/18/2004 1:38:19 PM]

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Assessment of Satellite Earth Observation Programs 1991 (Chapter 3) variations in the scale of the missions. Rapid response times are necessary to react in a timely manner to sudden changes in our environment, or to take advantage of opportunities to collaborate with other agencies. 3. Costs must be rigorously controlled in all phases of the program. The key to the success of the Earth Explorer program will be to obtain the maximum scientific value per dollar expended. The spiraling costs of instruments for observations from space can be controlled by sharply focusing the scientific objectives, by assigning principal investigators the prime responsibility for quality and cost control, and by carefully assessing the tradeoff between reliability and multiple copies of instruments. Standard satellite buses and launch vehicles should be used whenever this is both scientifically and economically advantageous. 4. Given the emphasis on strongly focused missions, the data transmission and processing activities are likely to be relatively modest. Nevertheless, strict schedules and reliability requirements must be met, and the data should be made available as quickly as possible to scientific archives or to open networks in scientific formats. Careful planning and experimentation with the integration over networks of data from diverse sources will be essential. 5. A significant fraction of the total costs for each mission should be allocated to data analysis, interpretation, and related theoretical modeling work. Because the scientific objectives for any mission are achieved only after the data have been distributed and thoroughly analyzed, adequate funding for this purpose is fundamental to the mission's success. The committee strongly recommends that the appropriate resource levels be allocated to the mission operations and data analysis budget to support such activities. 6. A basic goal of the Earth Explorer program must be to speed up the conversion of concepts into satellite missions and of raw data into scientific results. The time scales of the program must be designed to attract leading scientists and talented students, and to avoid the mounting costs of protracted space projects. Therefore it is essential that the missions be launched within 2 to 3 years of acceptance of engineering design for the smallest missions, and 3 to 4 years for the moderate-size ones. 7. The Earth Explorer program must develop a selection process that encourages the best ideas and does not require inordinate investments in engineering design during the initial proposal phase. To achieve this objective the selection process should proceed in two phases. In the first phase, proposals should be requested that emphasize the scientific issues and the instrument concepts, with only a limited discussion of engineering issues. In the second phase, only the most promising concepts should be chosen for further development and preliminary instrument design in order to compete in a further selection process. This approach will minimize the total community investment in preparing proposals, and will make it attractive for scientists with good ideas but limited resources to compete in the preliminary phase of Earth Explorer selection. The over selection of missions or instruments should be assiduously avoided. 8. Interagency and international collaboration must be optimized. Collaboration with other agencies and nations fosters the development of a stronger space science program at reduced cost to NASA. Every opportunity for cooperation in utilizing and financing Earth Explorer missions should be considered. Current Status Significant opportunities exist for gathering key global change data through missions flown under an Earth Explorer line, which NASA has named the Earth Probe series. Because Earth Probes are intended to be smaller satellites with relatively short development times, they can advance the time in which some file:///C|/SSB_old_web/seo91ch3.htm (10 of 17) [6/18/2004 1:38:19 PM]

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Assessment of Satellite Earth Observation Programs 1991 (Chapter 3) of the measurements critical to understanding global change could be made. An important concern in the near term is the interruption of key measurements, such as global stratospheric ozone levels, the Earth's radiation budget, and the biological productivity of the oceans, made by satellite missions launched in the 1980s. The Earth Probe line provides an opportunity for extending those measurements until acquisition of the data sets is resumed by the EOS spacecraft. The Earth Probes can also provide global information on a discrete set of variables or phenomena not fully measured by a dedicated mission before, such as the gravity and magnetic fields, and the topography of the land surface. Some measurements—for instance, biological processes and radiation studies related to cloud motion—require sampling at various times of the day, and they cannot be made from sun-synchronous, polar-orbiting spacecraft such as EOS. To the extent that these measurements are critical to achieving the objectives of global change research, the Earth Probe lime can provide a flexible mechanism for such observations from more appropriate orbits or for measurements that require unique orbits. During the EOS era, Earth Probe missions will also be essential for complementing the EOS measurements by flying instruments that may be incompatible with the design and orbit of the EOS platforms. It is expected that the Earth Probes will be augmented by foreign spacecraft, some of which will provide flight opportunities for U.S. instruments. The National Aeronautics and Space Administration's response to the committee's 1988 recommendations, while not yet fully developed, has been positive. Following incremental increases in the FY 1990 and 1991 budgets, NASA's proposed budget for FY 1992 includes over $70 million for the Earth Probe line and related activities. If approved by Congress, these funds would be used to support the development and launch of four very small and two somewhat larger instruments or missions. A concomitant increase for the subsequent analysis of the data from these missions will also need to be made. The very small missions include the separate flights of three TOMS, which will continue the historic stratospheric ozone measurements made by the TOMS on Nimbus-7. The first of these follow-on missions will place a TOMS on the Soviet Meteor-3 weather satellite, currently scheduled for launch in August 1991. The second TOMS would be launched on a small dedicated spacecraft in 1993, and the third on the Japanese ADEOS mission in 1995. Later in the decade, the ozone monitoring functions are expected to be performed by the NOAA POES and the NASA EOS. The other very small mission involves the purchase of ocean color data from the commercial remote sensing mission, SeaWIFS, that is expected to be launched in 1993. This will reestablish the important global observations of the ocean's biological cycles that were begun by the Coastal Zone Color Scanner on the Nimbus-7 satellite in the early 1980s (see the discussion on ocean color measurements in the previous chapter's Global Biology section). Two larger missions are also being developed. These are a scatterometer instrument, which will be flown on the ADEOS mission, and the Tropical Rainfall Monitoring Mission (TRMM), which is being pursued as a joint program with file:///C|/SSB_old_web/seo91ch3.htm (11 of 17) [6/18/2004 1:38:19 PM]

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Assessment of Satellite Earth Observation Programs 1991 (Chapter 3) Japan and is also scheduled for a 1995 launch. Anticipated Improvements and Additional Needs Missions under active consideration by NASA for the second half of the decade would provide measurements of the Earth's gravity and magnetic fields, topography, and radiation balance. The importance of these missions is discussed in Chapter 2 and in Strategy for Earth Explorers in Global Earth Sciences (SSB, 1988). The committee endorses the vigorous program already under way as well as the Earth radiation, gravity, magnetic field, and topography missions that are being considered. Finally, the committee considers it important that NASA request proposals from the scientific community for future Earth Probe missions through the customary open solicitation process. DATA MANAGEMENT In the past, data management and related support for data analysis have been the Achilles' heel of Earth observation satellite programs. During the 1980s, a number of influential reports recommended a broad set of improvements in the way in which NASA and NOAA manage their data. Below are key recommendations excerpted from several NRC reports that the committee considers particularly relevant to the management and use of data in Earth observation research programs. Summary of Recommendations The following advice appeared in the report Data Management and Computation, Volume I: Issues and Recommendations (SSB, 1982b), which was written by the SSB Committee on Data Management and Computation (CODMAC): Scientific Involvement. There should be active involvement of scientists from inception to completion of space missions, projects, and programs in order to assure production of, and access to, high-quality data sets. Scientists should be involved in planning, acquisition, processing, and archiving of data. Such involvement will maximize the science return on both science-oriented and applications-oriented missions and improve the quality of applications data for application users. Scientific Oversight. Oversight of scientific data-management activities should be implemented through a peer-review process that involves the user community. Data Availability. Data should be made available to the scientific user community in a file:///C|/SSB_old_web/seo91ch3.htm (12 of 17) [6/18/2004 1:38:19 PM]

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Assessment of Satellite Earth Observation Programs 1991 (Chapter 3) manner suited to scientific research needs . . . . Data System Funding. Adequate financial resources should be set aside early in each project to complete data-base management and computation activities; these resources should be clearly protected from loss due to overruns in costs in other parts of a given project. The 1985 CES report (SSB, 1985) endorsed the CODMAC (SSB, 1982b) recommendations and added the following: In particular, the committee recommends that an earth science information system be developed through appropriate interagency and international cooperation. This information system should consider three classes of data and the problems associated with the collection and management of each: data that already exist in archives, data to be acquired from future operational satellites, and data to be gained from future research missions. The committee also recommends that the existing satellite data be archived in a form convenient for outside users, and that proper attention be given to documenting, storing and distributing these reduced data sets. Finally, the 1985 SAB report included the following finding: Finding VIII: The volume of data flow in civil Earth remote sensing is growing rapidly and will eventually exceed 1013 bits per day. Data processing, evaluation, analysis, dissemination, and archiving are becoming more difficult and costly. A substantial effort is needed to plan and operate the required data- handling systems. Current Status The National Aeronautics and Space Administration has made a great deal of progress in improving and developing new data management systems. Central data cataloging and archiving facilities have been established at the National Space Science Data Center (NSSDC) of the Goddard Space Flight Center. An on-line master directory of space and earth science data, which will be accessible worldwide, is being developed at NSSDC. This master directory will provide scientists with summary information on NASA's data holdings, and will point users to catalogs and archives where more detailed data-set information can be found and where data can be browsed or extracted. Some earth science data sets reside in the NSSDC central archive; other data reside in distributed archives located at other . NASA centers and universities. These distributed archives are mission- or discipline-oriented and include the Upper Atmospheric Research Pilot Data System, Crustal Dynamics Project Data System, SAR Data Catalog System, NASA Ocean Data System, Pilot Climate Data System, and Pilot Land Data System. Anticipated Improvements and Additional Needs file:///C|/SSB_old_web/seo91ch3.htm (13 of 17) [6/18/2004 1:38:19 PM]

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Assessment of Satellite Earth Observation Programs 1991 (Chapter 3) Although NASA has made significant improvements in existing information systems and data bases in recent years, the EOS program, Mission to Planet Earth, and USGCRP will require an effort that is several orders of magnitude greater. Much to the agency's credit, the EOS program places great emphasis on its Data and Information System. The EOSDIS is planned to acquire a comprehensive, global, 15-year data set; to maximize the utility of this data set for scientific purposes; and to facilitate its easy access by the research community. It is expected to be implemented as a distributed, interactive, and evolutionary data system to handle both historical and newly collected EOS data. The EOSDIS is proposed to begin with seven existing data centers, called Distributed Active Archive Centers (DAACs), which will include the participation of scientists in their operation and are expected to emphasize science users' needs. The DAACs will be linked to other operational data centers, such as those currently operated by NOAA, the Department of Energy, and the Environmental Protection Agency. Starting with version 0, which will begin operating in 1994, the EOSDIS will archive, manage, and distribute satellite and related in situ data sets. Critical developments for the success of the EOSDIS are the ability to "browse" the DAAC data holdings and to have the requested data delivered online or offline. Catalogs, directories, and other data management functions will be performed at each of the DAACs. In addition to the data management capabilities, the later version-1 EOSDIS will include the ability to schedule and operate the EOS instruments and payloads. The committee considers this high emphasis placed by NASA on the EOSDIS to be appropriate. The creation of the EOSDIS Science Advisory Panel was an important step forward in the development of the data system. It has already contributed to a major revision of EOSDIS, away from the centralized design that was originally proposed. The CES supports the recommendations of that advisory panel, which were strongly influenced by the 1982 CODMAC report, for a distributed system that encourages user input, provides higher-level, user- defined products, and seeks to unify software and data delivery systems. There is a serious concern, however, that these important features will not be implemented in the final design phase after award of the contract to help ensure that the system will meet the needs of the research community. These issues should remain at the forefront of attention, both within NASA and in its advisory groups. (See also, The U.S. Global Change Research Program: An Assessment of the FY 1991 Plans; NRC, 1990.) It is important to note that progress in the management of Earth observation satellite data and related in situ data is being made across the federal agencies, including NOAA. Comprehensive data policies and programs are being developed by the interagency Committee on Earth and Environmental Sciences (CEES) and by the Interagency Working Group on Data Management for Global Change in the context of the USGCRP. According to the CEES budget report, Our Changing Planet: The FY 1992 U.S. Global Change Research Program (CEES, 1991), the focus is on an "early and continuing agency commitment to the production and preservation of high-quality, long-term data file:///C|/SSB_old_web/seo91ch3.htm (14 of 17) [6/18/2004 1:38:19 PM]

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Assessment of Satellite Earth Observation Programs 1991 (Chapter 3) sets, data exchange standards, data access, and maintaining the lowest possible cost of data for research purposes." (p. 67) Evidence of this cooperation is the early "Pathfinder" data sets being created for the EOSDIS. These data sets are based in part on select historical data sets from NOAA satellites and are processed by NASA onto longer-lasting storage media for copy and distribution by the version-0 DAACs. This Pathfinder activity is a critical component of the new NOAA data management initiative that is part of the NOAA Global and Climate Change Program. New data sets obtained in the early 1990s, such as those collected by the ERS-1, UARS, and TOPEX/Poseidon missions, need to be used to develop a baseline for the operational characteristics of the initial version of EOSDIS. The ERS-1 data are particularly important because they provide a comprehensive set of microwave and optical measurements collected by a foreign space agency, which will help to establish the ground rules for the international exchange of satellite data in support of the Mission to Planet Earth and the USGCRP. It is important for NASA to continue to develop existing pathfinder data sets and to include the data sets that will be collected by ERS-1, UARS, and TOPEX/Poseidon for prototype studies in developing the EOSDIS. Despite the significant progress made by the agencies in their management of Earth observation satellite data, a number of concerns remain. Recent reports by the General Accounting Office (Space Operations—NASA Is Not Archiving All Potentially Valuable Data, GAO, November 1990; and Environmental Data—Major Effort Is Needed to Improve NOAA's Data Management and Archiving, GAO, November 1990) have documented some serious deficiencies in the archiving of historical research satellite data by NASA, of GOES and POES data by NOAA, and of Landsat data by USGS. Some of the data sets from individual sensors, particularly the oldest ones, are in jeopardy of being irretrievably lost due to the degradation of storage media and substandard archival facilities. Although all three agencies have begun to address these problems, it is vital that they continue to emphasize those activities necessary to rescue and properly maintain historical data sets. RESEARCH AND ANALYSIS The 1982 SSB/CES report stated that: Vigorous support of theoretical and laboratory investigations should be an essential component of the future program for earth science from space. Over the past 10 years, the annual budget for research and analysis (R&A) programs at the NASA Earth Science and Applications Division has been consistently well supported. In the future, interdisciplinary modeling will play a larger role in assimilating the results of process studies and laboratory investigations. As expenditures for flight hardware increase with the file:///C|/SSB_old_web/seo91ch3.htm (15 of 17) [6/18/2004 1:38:19 PM]

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Assessment of Satellite Earth Observation Programs 1991 (Chapter 3) implementation of EOS and other flight projects in the Mission to Planet Earth, pressures will likely build to sacrifice R&A funds to meet hardware budget deficiencies, or other contingencies. The National Aeronautics and Space Administration management should continue to work together with other agencies in the CEES and with the research community to assure that the R&A programs, so vital to the success of the USGCRP, remain vigorously supported. RELATION OF SPACE, AIRBORNE, AND GROUND MEASUREMENTS The 1982 SSB/CES report urged that: On both scientific and strategic grounds, a coordination of space, airborne, and ground measurements and an integration of the results from all types of experiments should be indispensable aspects of a global program of earth science. We recommend that sufficient planning and resources be devoted to ensure that the ground and airborne measurements necessary to accomplish this strategy can be conducted in the next decade. This recommendation is even more compelling in the context of today's interdisciplinary and international global change research. The responsibility for making ground-based and in situ observations is spread among numerous agencies in the United States and in many other nations worldwide. In conducting this review, the committee found that the plans for these types of observations, which are now being coordinated nationally through the interagency CEES, are not yet as coherent as those for spaceborne observations. In conjunction with the other agencies involved in global change research, it is important for NASA and NOAA to continue to develop a comprehensive plan for the surface and in situ data-gathering technologies and programs that are needed to complement Earth observations from space. The NASA aircraft and suborbital programs are essential elements of this plan. This issue of conducting a balanced observational program was included in a broader context of maintaining an "appropriate balance" within the USGCRP in the report The U.S. Global Change Research Program: An Assessment of the FY 1991 Plans (NRC, 1990). It defines appropriate balance as "one in which resources are allocated to the program components in a manner that will best achieve overall program goals." It goes on to evaluate balance in six contexts: between long-term and short-term investments; between extramural and agency- based research; between "big" and "little" science; among observations, process studies, and modeling; between established and emerging programs; and among science priorities. The committee agrees with the conclusions and recommendations reached on these six areas in that report. file:///C|/SSB_old_web/seo91ch3.htm (16 of 17) [6/18/2004 1:38:19 PM]