Over the coming decades the United States and the world face growing challenges related to an increasing population, rising demand for natural resources, concerns about food security, and a changing climate. According to the National Intelligence Council’s Global Trends 20301 report, the demand globally for food and water represents one of the eight tectonic shifts that it foresees over the next decades. The report projects that “demand for food is expected to rise at least 35 percent by 2030, while demand for water is expected to rise by 40 percent. Nearly half the world’s population will live in areas experiencing severe water stress. Fragile states in Africa and the Middle East are most at risk of experiencing food and water shortages, but China and India are also vulnerable.”2
The global land surface covers 150 million km2, about 29 percent of Earth’s surface. Outside ice-covered regions, humans occupy or use more than 75 percent of that land area, with roughly 40 percent in either rangeland or cropland.3 To meet these challenges over such broad regions, decision makers will require data on the spatial and temporal distribution of land surface characteristics and land use. To address this need, satellite-based land imaging provides synoptic, repetitive data on the physical, chemical, and biological characteristics of the land surface, which includes the rock and soil and the vegetation covering it, along with snow, ice, and inland waters.
From 1972 to the present, moderate-resolution images from the Landsat series of satellites (Figure 1.1), along with information from aircraft, commercial satellites, and foreign missions, have recorded the human imprint on the land surface. The 40-year record of Earth’s surface as seen from space has transformed the understanding of regional, national, and global-scale agriculture, forestry, urbanization, hydrology, homeland security, disaster mitigation, and other changes in land use and land cover. With populations growing from 7 billion today to 9 billion by 2050, effective land management will be essential to feed and protect people throughout the world.
1 National Intelligence Council, Global Trends 2030: Alternative Worlds, NIC 2012-001, 2012, available at http://www.dni.gov/files/documents/GlobalTrends_2030.pdf.
2 Ibid., p. v.
3 E.C. Ellis and N. Ramankutty, Putting people in the map: Anthropogenic biomes of the world, Frontiers in Ecology and the Environment 6:439-447, 2008.
FIGURE 1.1 History of the Landsat suite of remote sensing satellites. When Landsat 6 failed on launch in 1993, a gap in data collection was avoided by the fortuitous survival of Landsat 5 far beyond its design life of 3 years. It was finally decommissioned in 2013. In 2003, Landsat 7 suffered the loss of the scan line corrector on the Enhanced Thematic Mapper Plus instrument, resulting in the loss of 25 percent of the data for any given scene. NOTE: LDCM, Landsat Data Continuity Mission, now Landsat 8. SOURCE: U.S. Geological Survey, “Landsat 1 History. July 23, 1972-January 6, 1978,” available at http://landsat.usgs.gov/about_mission_history.php.
Land imaging data from the Landsat series of satellites forms the basis and model for civil remote sensing in the United States and has been used for applications ranging from wildfire management, to urban planning, to disaster mitigation and response. Figure 1.2, for example, shows urban growth in the Las Vegas, Nevada, area between 1990 and 2010. Landsat data are used operationally by virtually every U.S. land management agency to define broad land cover categories—through the U.S. Geological Survey (USGS) National Land Cover Database—and to monitor rapid changes, such as pre- and postburn forest conditions (Table 1.1). The federal government owns between 635 and 640 million acres of land, which constitutes 28 percent of the 2.27 billion acres of land in the United States. Four agencies administer 609 million acres of this land: the U.S. Forest Service (USFS) in the Department of Agriculture and the National Park Service, Bureau of Land Management, and the Fish and Wildlife Service in the Department of the Interior (DOI). Most of these lands are in the western states and Alaska. In addition, the Department of Defense (DOD) administers 19 million acres in military bases, training ranges, and more.4
Specific examples of benefits to the United States made possible by analysis of Landsat data include the following:
• Agricultural forecasting and management— The U.S. Department of Agriculture uses Landsat data to monitor global crop supplies and stocks to forecast shortfalls or gluts of various crops on the market. The multimillion-dollar U.S. agricultural commodities market relies on these crop predictions when conducting futures trading.5 These important functions benefit U.S. food and economic security as well as national security.
• Monitoring climate change impacts— Landsat data facilitate the monitoring of the distribution and rates of impacts of climate change on remote regions, including glaciers, rainforests, and permafrost, and coral reefs—often early harbingers of climate and temperature change.6 The U.S. Climate Change Science Program, representing 15 federal agencies, has identified Landsat as a critical observatory for climate and environmental change research due to the unbroken length of the Landsat record and its importance to identifying the root causes and impacts
4 R.W. Gorte, C.H. Vincent, L.A. Hanson, and M.R. Rosenblum, Federal Land Ownership: Overview and Data, R42346, Congressional Research Service, available at http://www.fas.org/sgp/crs/misc/R42346.pdf, July 29, 2013.
5 J.R. Irons, Landsat’s Critical Role in Agriculture, NASA/USGS Fact Sheet, 2012, available at http://landsat.gsfc.nasa.gov/pdf_archive/Landsat_AG_fs_4web.pdf.
6 For example, F. Paul, A. Kääb, and W. Haeberli, Recent glacier changes in the Alps observed by satellite: Consequences for future monitoring strategies, Global and Planetary Change 56:111-122, 2007; A.C. Baker, P.W. Glynn, and B. Riegl, Climate change and coral reef bleaching: An ecological assessment of long-term impacts, recovery trends and future outlook, Estuarine, Coastal and Shelf Science 80:435-447, 2008.
FIGURE 1.2 Global Land Survey Landsat images of Las Vegas, Nevada, and Lake Mead in 1990 (top) and 2010 (bottom). The images were acquired by Landsat 5 from the Thematic Mapper instrument. The urban areas have expanded into the surrounding desert, and Lake Mead has diminished because of below-average snow and rainfall in the Rocky Mountains. SOURCE: U.S. Geological Survey LandsatLook Viewer, available at http://landsatlook.usgs.gov.
TABLE 1.1 Operational Programs Currently Using Moderate-Resolution Land Imaging Data
Carbon cycle monitoring
Coastal change analysis
Design of defense systems
Detecting and monitoring volcanic activity
Invasive species monitoring
Inventorying toxic releases
Land use and land cover change
Mapping groundwater discharge zones
Monitoring grant performance
Snow and ice monitoring
Soil analysis and sediment redistribution
Support of Department of Defense operations
Water resource planning and administration
Water rights monitoring
Wildland fire risk assessment
SOURCE: Executive Office of the President, Future of Land Imaging Interagency Working Group, A Plan for a U.S. National Land Imaging Program, August 2007, available at http://www.landimaging.gov.
of climate change.7 Such comprehensive monitoring helps anticipate the types and scales of adaptation strategies needed in the United States and throughout the world.
• Monitoring natural defenses to natural disasters —Coastal wetlands and mangrove swamps provide important protection against hurricane winds and storm surges. The National Oceanic and Atmospheric Administration’s (NOAA’s) Coastal Change Analysis Program8 uses Landsat data as the most cost-effective way to track changes in these wetlands areas. The Landsat data are integrated with aerial photography and field data to identify those coastal regions most crucial for protecting vulnerable populations and infrastructure.
• Wildfire risk management —USFS and USGS utilize Landsat data to assess fire susceptibility, to estimate the percentage of vegetation and trees killed by fire, and to identify improvements in management strategies to reduce future fire risk.9
The science accomplishments from Landsat data are equally important and include the following:
• Landsat provided the basis for the quantitative estimation of deforestation and ended a decades-long debate over its magnitude,10 thus providing a critical constraint on the global carbon cycle. Australia’s National Carbon Accounting System, for example, utilizes a time series of Landsat mosaics to quantify land cover change and the associated changes in the terrestrial carbon stock in Australia (Figure 1.3).
• Landsat’s coverage and longevity have allowed it to be used for long-term studies of ecological change at scales fine enough to detect effects of herbivores, disease, and other processes whose spatial signatures are too fine for instruments with daily temporal resolution but coarser spatial resolution, such as MODIS aboard the Terra and Aqua satellites and AVHRR aboard the NOAA polar-orbiting satellites. In the area of policy, Landsat data are used to evaluate worldwide deforestation and degradation, and this information is useful to the United Nations Collaborative Programme on Reducing Emissions from Deforestation and Forest Degradation in Developing Countries.11
7 J.R. Irons, Landsat and Climate, NASA/USGS Fact Sheet, 2012, available at http://landsat.gsfc.nasa.gov/pdf_archive/landsat+climate_vf_4web.pdf.
9 J.R. Irons, Landsat’s Critical Role in Managing Forest Fires, NASA/USGS Fact Sheet, 2012, available at http://landsat.gsfc.nasa.gov/pdf_archive/LandsatFireFactSheet.pdf.
10 D.L. Skole, W.H. Chomentowski, W.A. Salas, and A.D. Nobre, Physical and human dimensions of deforestation in Amazonia, BioScience 44(5), 1994.
11 K.G. Holly, B. Sandra, O.N. John, and A.F. Jonathan, Monitoring and estimating tropical forest carbon stocks: Making REDD a reality, Environmental Research Letters 2:045023, 2007.
FIGURE 1.3 Mosaic of Australia from 369 Landsat 7 scenes acquired in 1999-2000. The color composite maps red, green, and blue to three different spectral bands (7, 4, and 2, respectively). Time series of such mosaics are used to map land cover change and associated changes in terrestrial carbon stocks. SOURCE: Australian Greenhouse Office, Landsat-7 Picture Mosaic Map of Australia, Scale: 1:5,000,000, Commonwealth of Australia (Geoscience Australia) 2013. Available at https://www.ga.gov.au/products/servlet/controller?event=GEOCAT_DETAILS&catno=48410.
• The basis for monitoring vegetation from space requires differentiating the spectral responses of soil from those of healthy and moisture-stressed vegetation. In the 1970s, early Landsat data were used to derive the tasseled cap model of vegetation,12 relevant for understanding vegetation stress, and thereby enabling forecasts of worldwide agricultural productivity.
12 E.P. Crist and R.J. Kauth, The tasseled cap demystified, Photogrammetric Engineering and Remote Sensing 52:81-86, 1986.
• Analysis of seasonal and permanent snow and ice cover13 provide data for hydrologic modeling and for estimating glacier velocities. These analyses were made possible by scientists who developed and tested algorithms with Landsats 4 and 5, which enabled snow-cloud discrimination (Figure 1.4).
• The combination of Landsat-like images—with 15-to 100-m spatial resolution and 8-to 16-day temporal resolution—with coarser-resolution daily imagery allows for useful synergy, whereby the data with daily temporal resolution identify changes to the dynamic surface, and the moderate-resolution imagery provides spatial detail. The correlations between sensor resolution and temporal repeat are shown in Table 1.2. For example, Landsat thermal infrared data help estimate evapotranspiration from agricultural lands at the scale of individual fields. These estimates are used to monitor agricultural water use and to model plausible scenarios resulting from climate change.
Continuing the long record of land imaging has both scientific and management benefits. As the record lengthens, the ability of Landsat-class data to observe environmental change continues to increase in value, recording effects of climate variability, invasive species, and land use that have no direct analog in past events. Long observation records are needed to differentiate between short-term climate variability (e.g., El Niño, North Atlantic Oscillation) and longer-term trends.
Landsat images make critical contributions to the U.S. economy, environment, and security. Specific economic analyses of some of the benefits derived from the Landsat series of satellites demonstrate its great value for the nation. Most of the analyses use imagery provided without charge by USGS, so their value is not set by market forces. However, analyses of just 10 selected applications—including consumptive water use, mapping of agriculture and flood mitigation, and change detection among them—show more than $1.7 billion in annual value for focused operational management in the United States.14 This is compared to a cost (including design, launch, and data management) of about $1 billion amortized over 5 to 7 years of mission life.
Although the increase in scientific knowledge is more difficult to assess, approximately 1,700 scientific papers describing the use of Landsat data in a tremendous variety of scientific applications have been published in refereed journals every year.15 Many of those papers document not only the ability to measure biological and geophysical variables from space, but also the use of such spatially extensive and temporally consistent measurements to reveal new knowledge about Earth.
The continuous collection of land remote sensing data from space has long been recognized as providing benefits of critical importance to the United States. In the Land Remote Sensing Policy Act of 1992,16 Congress declared that
The continuous collection and utilization of land remote sensing data from space are of major benefit in studying and understanding human impacts on the global environment, in managing the Earth’s natural resources, in carrying out national security functions, and in planning and conducting many other activities of scientific, economic, and social importance… . The national interest of the United States lies in maintaining international leadership in satellite land remote sensing and in broadly promoting the beneficial use of remote sensing data.
13 J. Dozier, Spectral signature of alpine snow cover from the Landsat Thematic Mapper, Remote Sensing of Environment 28:9-22, 1989.
14 V. Adams and E. Pindilli, “Improving the Way Government Does Business. The Value of Landsat Moderate Resolution Imagery in Improving Decision-Making,” 2012, available at http://calval.cr.usgs.gov/wordpress/wp-content/uploads/Pindilli_JACIE_Presentation_final.pdf.
15 From ISI Web of Knowledge, Topic=landsat. From 2009 through February 2012, 6,752 papers have been published that reference Landsat.
16 See 1992 National Space Policy Directive 5 (NSPD-5), “Landsat Remote Sensing Strategy,” Public Law 102-555, “Land Remote Sensing Policy Act of 1992,” 1994 Presidential Decision Directive NSTC-3, “Landsat Remote Sensing Strategy,” U.S. National Space Policy of the United States of America 2006, 2007 White House Office of Science and Technology Policy Report, A Plan for a U.S. National Land Imaging Program, and 2007 National Research Council report Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond, The National Academies Press, Washington, D.C.
FIGURE 1.4 Snow-cloud discrimination in the Sierra Nevada (Mono Lake is near the top of the images) from the Landsat 4 Thematic Mapper. The top image maps the displayed color to true color, such that red-green-blue maps to bands 3, 2, and 1, and the clouds are difficult to distinguish from the snow cover. In the bottom image, the bands are 5, 4, and 2; snow is bright in band 2, less bright in band 4, and dark in band 5, whereas clouds are bright in all the bands. SOURCE: Courtesy of U.S. Geological Survey, processing by Jeff Dozier, University of California, Santa Barbara.
TABLE 1.2 Characteristics of Space-Based Land Imaging Satellites
|Type of Sensor||Spatial Resolution (m)||Geographic Coverage Swath per Image (km)||Frequency of Repeat Coverage of Every Locationa|
|High resolution||<5||10-15||Months to years|
|Moderate resolution||10-100||50-200||15-30 days|
|Low resolution||>100||500-2500||1-2 days|
a With a pointable instrument, high-resolution sensors can achieve frequent coverage at some locations but not all.
NOTE: Sensors with high resolution cover a small area of Earth’s surface with each image and take a longer time to return to view the same area again. Sensors with lower resolution cover a larger surface area, but this also allows for a faster return. Landsat-like sensors have moderate resolutions (10-100 m) and 15-30 day repeat frequencies.
However, the procurement of the series of Landsat satellites has been ad hoc and has had a chaotic history, characterized by frequent shifting of responsibilities among government agencies and the private sector.17Indeed, despite the documented record of achievements and the proven necessity for the data, the future of moderate-resolution U.S.-provided land remote sensing continues to be at risk. The Landsat series has never truly been a “program.” The satellites have been justified, planned, and executed separately or at most in pairs (Landsat 1-2, Landsat 4-5), and the 40-year record owes more to the remarkable survival of Landsat 5 for two decades beyond its design life than to careful planning. Landsat 7 is currently operating in a degraded mode, and Landsat 8, launched on February 11, 2013, will soon begin returning data. Landsat 8 has only a 5-year design life,18 and there is no assured successor. Landsat 9 is under discussion in the U.S. executive and congressional branches, but its configuration remains under debate. Prospects for missions beyond Landsat 9 are unclear, and the sharing of responsibilities with commercial and foreign contributors has not been articulated.
Following the initial Landsat launches in 1972 and 1975, NASA launched Landsat 3 in 1978. The major sensor on all three of those Landsats was the Multispectral Scanning System, with four spectral bands at 79-m spatial resolution plus a thermal band added to Landsat 3. The imaging capabilities expanded to the Thematic Mapper (TM) on Landsat 4 in 1982 and Landsat 5 in 1984, with six spectral bands at 30-m resolution and a thermal band at coarser (120-m) resolution, then to the Enhanced Thematic Mapper (ETM+) on Landsat 7 in 1999, which added a 15-m panchromatic band and refined the thermal band’s resolution to 60 m. Although a 1987 failure in the downlink capability severely restricted collection of data worldwide, Landsat 5 operated for 27 years, until November 2011, more than 20 years beyond its design life. Landsat 6 failed on launch in 1993. Landsat 7 operated flawlessly until the scan line corrector failed in 2003, compromising about 22 percent of the data. Landsat 8, whose characteristics are described in Box 1.1, launched in February 2013. In Chapter 2, Tables 2.1 and 2.2 describe the spatial and spectral properties of the bands on all Landsat missions.
The Land Remote Sensing Commercialization Act of 198419 shifted responsibility for Landsat from the government agencies that had previously managed the satellites (NOAA, NASA, and the DOI) to NOAA, with the intent of then transferring satellite development and operations to the private sector. NOAA selected EOSAT, Inc., a private consortium, to run Landsat. NOAA retained responsibility for overall system operation. When sales fell short of those needed to make the EOSAT commercial venture profitable, the parent organizations were forced to incrementally raise the prices for Landsat images, eventually increasing them to as much as $4,400 per image.20 With each price increase, sales fell further. Additionally, uncertainty regarding the commercial development of
17 Since NASA’s initial launch in 1972, the responsibility for the Landsat program has changed hands to NOAA, to NOAA/private industry, to DOD/NASA, to NASA/NOAA, to NASA/NOAA/USGS, and currently to NASA/USGS.
18 The Thermal Infrared Sensor (TIRS) has a design life of 3 years. The 5-year requirement was relaxed to expedite instrument development. See http://ldcm.gsfc.nasa.gov/spacecraft_instruments/tirs_reqs.html.
About the Landsat Data Continuity Mission (LDCM), Renamed Landsat 8
The latest satellite in the Landsat series, Landsat 8, launched on February 11, 2013. Landsat 8 orbits at an altitude of 705 km and an inclination of 98.2 degrees; the orbit is Sun-synchronous, with a descending node over the equator at a mean local time of 10:11 a.m. (see Figure 1.1.1). Because the orbit is near polar, the spacecraft is able to image all but the Earth’s polar regions above about 82 degrees latitude. The sensor swath width is 185 km, identical to that of Landsat 7; the swath is diagrammed in Figure 1.1.2. The spacecraft orbits the earth every 98 minutes, and repeats the same ground track every 16 days. The spacecraft has a design life of 5 years and fuel life of 10 years.1,2
Landsat 8 has two main instruments on board: the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS). The OLI is a “push-broom” style sensor array, with over 7,000 detectors per spectral band. The OLI images in nine spectral bands: the seven heritage bands of Landsat 7, six of which have improved sensitivity; a deep blue visible band designed for water and coastal zone investigations (shown as Band 1 on Figure 1.1.3); and a shortwave infrared band designed for the detection of cirrus clouds (shown as Band 9 on Figure 1.1.3). TIRS was added to Landsat 8 to enable continued study of the Earth’s thermal energy, as well as to support new applications such as mapping evapotranspiration for water resource management. Like OLI, TIRS is a push-broom style sensor, and has a 185-km field of view and spatial resolution of 100 m. TIRS was added to the Landsat 8 payload after mission design was under way, as the importance of the thermal data from previous Landsat missions became evident. One consequence of the belated development is that the design life of TIRS was set to only 3 years.3,4
1 Landsat Data Continuity Mission Press Kit, NASA/USGS, February 2013.
2 Landsat Data Continuity Mission, “Continuously Exploring Your World,” NASA/USGS Mission Brochure, 2012.
3 Landsat Data Continuity Mission, “Continuously Exploring Your World,” 2012.
FIGURE 1.1.1 Orbit mechanics of the current Landsat missions. Note the mean solar time varies for each spacecraft.
SOURCE: NASA Landsat 7 Science Data Users Handbook.
FIGURE 1.1.2 Sensor swath for both Landsat 7 and Landsat 8. SOURCE: NASA Landsat 7 Science Data Users Handbook.
FIGURE 1.1.3 Comparison between the bands of Landsat 8 (upper row) and legacy missions (lower row). SOURCE: NASA Landsat Data Continuity Mission, available at http://landsat.gsfc.nasa.gov/about/ldcm.html, accessed May 15, 2013.
Landsat 7 left data continuity at risk.21 Thus, the Land Remote Sensing Policy Act of 199222 repealed the 1984 act and shifted responsibility for Landsat 7 entirely back to the government (DOD and NASA). The death knell of this commercialization attempt was the failure of EOSAT’s Landsat 6 to achieve orbit in 1993.
As Landsat 7 approached launch in 1999, in accordance with the Land Remote Sensing Policy Act of 1992 and responding to increased pressure from Congress, NASA started considering the possibility of implementing the next Landsat as a data purchase. The concept was known as the Landsat Data Continuity Mission (LDCM) and resulted in a competition between Boeing-backed Resource 21, a private-sector consortium, and DigitalGlobe. However, the original LDCM data purchase concept was cancelled in 2003 when no agreement could be reached, partially caused by the perception of a limited commercial market for moderate-resolution imagery.
In 2004, an attempt was made to fly a Landsat instrument on NPOESS, an ambitious weather satellite program originally involving DOD, NASA, and NOAA. However, accommodation of Landsat on the National Polar-orbiting Operational Environmental Satellite System (NPOESS) proved to be costly, and other instruments on NPOESS were beginning to overrun substantially, so this effort was terminated in 2005. Thus, responsibility for implementation of the Landsat space segment was assigned, once again, to NASA. The resulting revised LDCM approach resulted in the launch of Landsat 8 on February 11, 2013.
In 2005, then Science Advisor and Office of Science and Technology Policy (OSTP) Director John Marburger, recognizing the value of Landsat’s continuous monitoring of Earth’s land surface as well as its chaotic and ad hoc administrative history, tasked an interagency working group to develop a long-term plan for future land imaging. He specifically requested options to achieve technical, financial, and managerial stability for operational land imaging ensuring future U.S. needs will be met. The findings and policy recommendations of the interagency working group were presented in the 2007 report A Plan for a U.S. National Land Imaging Program. 23 The principal recommendations of the report were the following:
The U.S. must commit to continue the collection of moderate-resolution land imagery (p. 3).
The United States should establish and maintain a core operational capability to collect moderate-resolution land imagery through the procurement and launch of a series of U.S.-owned satellites (p. 6).
The 2007 report also recommended that DOI would be the appropriate department to lead the proposed program. Since that report, an attempt has been made by the administration to follow its recommendations and shift the responsibility for Landsat to the USGS via the 2010 National Space Policy.24 The USGS was to provide data requirements and funding, and NASA was to build the Landsat satellites for the USGS on a reimbursable basis, much as NOAA funds NASA to implement U.S. weather satellites.25 The USGS responded in the 2012 President’s budget request for DOI by requesting $48 million in fiscal year (FY) 2012 to establish a permanent program for Landsat 9, but Congress appropriated $2 million for program development only, expressing doubt as to whether USGS was the right home for Landsat.26 In early 2012, at the request of the Office of Management and Budget/
21 U.S. Congress, Office of Technology Assessment, Civilian Satellite Remote Sensing: A Strategic Approach, OTA-ISS-607, U.S. Government Printing Office, Washington, D.C., September 1994.
24 National Space Policy of the United States of America, June 28, 2010, http://www.whitehouse.gov/sites/default/files/national_space_policy_6-28-10.pdf.
25 Statement of Ken Salazar, Secretary of the Interior, before the Subcommittee on Interior, Environment, and Related Agencies, Senate Committee on Appropriations, on the 2012 President’s budget request.
26 “The conferees have not agreed to transfer budgetary authority for the launch of Landsat satellites 9 and 10 from [NASA] to the Survey [USGS]… There is little doubt that resources will not be available within the Interior Appropriations bill to support these very large increases without decimating all other Survey programs… [B]oth technological advances and a vastly different economic environment may point to other, less costly, options for obtaining Landsat data.” See Military Construction and Veterans Affairs and Related Agencies Appropriations Act, 2012, Conference Report (To accompany H.R. 2055), p. 1059, available at http://www.gpo.gov/fdsys/pkg/CRPT-112hrpt331/pdf/CRPT-112hrpt331.pdf.
OSTP, and recognizing that the estimated $1 billion27 or more required to implement Landsat 9 was unlikely to be forthcoming, USGS issued a request for information (RFI) on creative, innovative implementation approaches for a much lower cost mission. The results of this RFI have not been released to the public, but in the FY 2014 budget request, the intent to begin a sustained land imaging program in the USGS has been reversed, and budgetary responsibility for operating, building, and launching future Landsat satellites is once again to be assigned to NASA.
In 2014, USGS will work with the National Aeronautics and Space Administration to analyze user requirements and develop a successor mission to Landsat 8, formerly known as the Landsat Data Continuity Mission. Funding to begin work on the successor mission is provided in the 2014 budget for NASA, which will be responsible for development of Landsat-class land imaging satellites going forward. The USGS will continue its operational role in managing the collection, archiving, and dissemination of Landsat data to users.28
Although funding to begin the next mission would be promising, the necessary budget appropriation has not yet been enacted. No sustained program has been established to ensure the future of land imaging, and it is clear that the continuation of the Landsat program is once again in jeopardy. Landsat 5 has stopped operating and was officially retired on January 6, 2013. Landsat 7 is operating in a degraded mode. Had the launch of Landsat 8 failed, the nation would soon be without its own source of moderate-resolution data.
Against the backdrop of this chaotic history and uncertainties about the future of Landsat, USGS tasked the National Research Council (NRC) Committee on Implementation of a Sustained Land Imaging Program to assess the needs and opportunities to develop a national space-based operational land imaging capability. The tasks in that charge are the following (see Appendix A for the committee’s statement of task):
Task 1—Identify and/or validate primary organizations and segments of society and their fundamental historical, present-day, near-future, and long-term data, information, and service requirements that need to be supported by a sustained land imaging program.
Chapters 2 and 3 address the elements of what the committee finds to be the critical core elements of any future land imaging system, based on continuity with earlier systems and technical characteristics their users employ.
Task 2—Identify and recommend characteristics and critical program support areas expected of a sustained land imaging program including, but not limited to, the continuous operation and refinement of U.S. government-owned, spaceborne land imaging capabilities (e.g., passive, as in optical land imaging; active, as in LiDAR or [synthetic aperture radar] SAR measurements).
Chapter 3 expands the discussion in Chapter 2 to include the elements of a fully capable land imaging system. The chapter describes the committee’s vision for a Sustained and Enhanced Land Imaging Program (SELIP) and gives an overview of potential new observing capabilities. The role of commercial and international partners is also discussed.
Task 3—Suggest critical baseline products and services derived from sustained land imaging capabilities, including higher-level information products such as climate data records [CDRs] and terrestrial essential climate variables [ECVs].
27 As of the NASA FY 2013 Earth Science budget request, the total life-cycle cost of LDCM was $931.2 million, not including the cost of the USGS ground system. See http://www.nasa.gov/pdf/632679main_NASA_FY13_Budget_Science-Earth-Science-508.pdf.
28 Quote from Bureau Highlights, U.S. Geological Survey, p. BH-55, in Office of Management and Budget, Fiscal 2014 Budget of the U.S. Government, Executive Office of the President, Washington, D.C., available at http://www.whitehouse.gov/omb/budget/Overview.
Chapter 4 focuses on data systems. As discussed in the chapter, to achieve a sustained land imaging capability requires not only plans for data acquisition, but also the development of data products (including CDRs and ECVs), their management, and considerations of data availability.
Task 4—Considering the requirements for an operational land imaging capability, provide recommendations to facilitate the transition of single-mission NASA research-based land imaging technology or missions to sustained USGS land imaging program technology or missions, including the relationships between USGS, NASA, and NOAA in developing, maintaining, and effectively utilizing land imaging capabilities.
Chapter 5 includes detailed recommendations about program governance. Chapter 5 also discusses the committee’s view regarding future opportunities and the path forward with particular attention to alternative sensor design strategies and lower-cost acquisition strategies for future land imaging systems.
Although Task 4 includes the request for recommendations to facilitate the transition of single-mission NASA research-based land imaging technology or missions to sustained USGS land imaging program technology or missions, the committee recognizes the limits to this charge given continuing instability in national policy for space-based land remote sensing.29 In the committee’s opinion recommending how the government should make this organizational decision would not be appropriate for a number of reasons. There are considerable challenges, for instance, in having the two agencies involved, NASA and the USGS, supporting such a program when their appropriations are under the authority of different congressional appropriations subcommittees. In addition, the assignment of land imaging activities to one agency or another involves issues that go beyond land imaging to the broader issue of the roles, responsibilities, and authority for observational space systems that provide sustained observations of key data. In addition, any chance that the establishment of SELIP in one location or the other might harm the operation of other necessary programs at either agency would have to be mitigated. Implementing the recommendations in this report may require that a sustained land imaging program be established at a level of government where there is sufficient authority to make organizational decisions, and that in turn might require executive or legislative actions that this committee was not tasked with recommending. What the committee has done is recommend key elements of a successful program no matter where the federal government decides it should reside.
Based on a series of meetings with stakeholders, including DOI, NASA, OSTP, NOAA, USDA, USFS, commercial data providers, and multiple land imaging data users, as well as analysis of prior reports regarding the uses and value of Landsat and discussion among committee members, the committee offers the following findings:
• The United States pioneered global, synoptic, frequent-repeat global imaging. Other nations are now developing systems whose capability rivals or exceeds that of U.S. systems. National needs require the United States to reassert leadership and maintain and expand capabilities.
• Space-based land imaging is essential to U.S. national security as it is a critical resource for ensuring our food, energy, health, environmental, and economic interests.
• The economic and scientific benefits to the United States of Landsat imagery far exceed the investment in the system.
• To best serve the needs of the United States, the land imaging program of the future requires an overarching national strategy and long-term commitment, including clearly defined program requirements, management responsibilities, and funding.
• The continuity of Landsat imagery has never been ensured through the development of a sustained government program. Instead, responsibility has been shifted from one organization to another over Landsat’s 40-year history, resulting in persistent uncertainty for the future of this important asset.
29 See the section “A Chaotic History” for a detailed discussion of the chaotic political history of the Landsat series of satellites.
• NASA has demonstrated that it is the civil agency with the technical capacity and the congressional support to design and build civilian space missions.
• The USGS-operated data management and distribution systems function effectively and efficiently.
• NOAA uses Landsat data to monitor Earth’s coastal regions, but NOAA’s primary use of satellite data focuses on the ocean and the atmosphere.
• Building a satellite sequence with new requirements and technologies for each individual instrument is an expensive way to acquire land imaging data and inhibits the addition of new capabilities.
• A sustained land imaging program will not be viable under the current mission development and management practices.
The committee’s primary recommendation is that the U.S. government should establish a Sustained and Enhanced Land Imaging Program with persistent funding to respond to current and future national needs. Such a program would
• Develop a plan for a comprehensive, integrated program that capitalizes on the strengths of USGS and NASA, maintains current capability and the existing archive, and enhances the program as technology enables new imaging capabilities and data products;
• Ensure acquisition of land imaging data continuously from orbital platforms and, periodically, from airborne platforms, to respond to the needs of producers and consumers of derived data products along with users who analyze imagery;
• Establish partnerships with commercial firms and international land imaging programs to leverage enhanced capabilities;
• Coordinate land imaging data buys across the U.S. government; and
• Include a research and development component to improve data products based on core measurements and to develop new measurement methods and consider evolving requirements.
For the Sustained and Enhanced Land Imaging Program to be successful, program responsibilities should be divided between USGS and NASA such that the agency responsible for balancing science requirements with mission complexity and cost is also provided with the necessary budget. Both agencies should participate in an iterative process to design missions that meet the needs of research and operational communities, but final decisions should be made by the agency that has been given the budget.
The committee has not recommended where in the government the SELIP should reside. In the committee’s opinion, recommending how the government should make this organizational decision would not be appropriate. A discussion of the committee’s reasoning for this decision is included in the section “Charge to the Committee.”