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	In December 2012, a launch of vital importance to the global Earth observation science community is scheduled to take place at California's Vandenberg Air Force Base. The Landsat Data Continuity Mission (LDCM) will build on the nearly 40-year record of Earth observations by the Landsat satellite series and greatly expand the program's capabilities. LDCM—in effect, Landsat 8—will provide moderate-resolution data consistent with previous Landsat data and will strengthen the valuable Landsat record well into the future. Early Development Landsat 8 really began in 1992. The Land Remote Sensing Policy Act of 1992 directed Landsat Program managers to study options for a Landsat 7 successor mission, one that would "… adequately serve the civilian, national security, commercial and foreign policy interests of the United States …" and maintain data continuity with the previous and current Landsat missions. When Landsat 7 was launched on April 15, 1999, engineers were well aware of the need to anticipate a successor mission. Landsat 7 was designed to last up to five years. Its predecessor, Landsat 5, launched in 1984, was operating well past its design life of three years. Hence, there was a widely recognized need for a follow-on mission to provide data continuity to the global science community. But will it happen in time to avoid data gaps should Landsats 5 and 7 fail?


	Ensuring Data Continuity Fortunately, Landsats 5 and 7 continue to provide data, though each with diminished capacity. With concerns about the potential failure of the current Landsat satellites before Landsat 8's launch, however, program managers at the U.S. Geological Survey (USGS) are reviewing alternative data sources in case the need arises. Although there are several options available from commercial and international sources, no consistent substitute is available for moderate-resolution, 16-day coverage, using the spectral and thermal bands from the later Landsat missions. Consequently, the need for a reliable successor to the Landsat missions is urgently needed by the global science community. Landsat 8 will satisfy future requirements. NASA and USGS share responsibility for Landsat 8. NASA will acquire the space segment, mission operations systems and launch services. The primary instrument, the Operational Land Imager (OLI), is under construction by Ball Aerospace & Technologies (www.ballaerospace.com). The spacecraft is being developed by General Dynamics Advanced Information Systems (www.gd-ais.com), and the launch vehicle, an Atlas V from United Launch Alliance (www.ulalaunch.com), has been selected. NASA is responsible for overall mission systems engineering and integration, and after a post-launch testing period will transition operations responsibility to USGS.


	USGS is responsible for acquiring and operating the ground system, including data networks, image collection scheduling, archiving, processing and distribution systems. Following on-orbit acceptance, USGS will operate and maintain the mission. Landsats 5 and 7 provide data to a network of more than 20 International Cooperators and campaign stations. Managers of those receiving capabilities have expressed strong support for Landsat 8 and anticipate joining the future network once Landsat 8 becomes operational. Satellite Improvements Since the launch of Landsat 1 in 1972, each generation of Landsat sensors has offered improved data-collection capability. The Landsat 8 sensor package will build on the successful record of Landsats 5 and 7. LDCM has a five-year life expectancy, with 10 years of consumables. Orbit design calls for a 16-day repeat cycle, with a mid-morning equatorial crossing. Plans call for collecting 400 scenes per day, 150 more than Landsat 7. Processed data will be calibrated consistently with previous Landsat products before distribution. The OLI instrument will permit, under limited priority direction, an off-nadir collection capability.


	Landsat 7 carried a sensor collecting data in eight spectral bands from the visible to the thermal infrared. Landsat 8 will record in many of the same bands, with modifications designed to enhance the data collection (see table above). For example, OLI will include new deep blue and cirrus bands. The deep blue band will be especially useful for coastal studies. The 30-meter resolution for the primary band collections will be consistent with Landsat 5 and 7 capabilities. There's still a question of whether to include a thermal infrared capability aboard Landsat 8. Congress provided funds to initiate the development of a thermal infrared sensor, and NASA has been directed to identify the earliest and least expensive development approach to provide an appropriate thermal infrared sensor on Landsat 8. The final decision will be made in fall 2009. Data distribution will follow the established policy set by USGS for the full archive of Landsat data. The agency is committed to ensuring timely and dependable data delivery to the full spectrum of civilian, national security, commercial and foreign users. The standard Landsat 8 product will be an orthorectified, precision terrain-corrected image in a GeoTIFF format and will be available as a free download via the Internet.


	Enhanced Application Development Landsat 8 will continue and greatly expand the Landsat record of Earth observations. The expanded daily collects, from 250 scenes per day to 400, will increase support for global land studies. The data, cross-calibrated with the nearly 40 years of observations in the Landsat archive, will let scientists undertake new applications over larger areas and longer periods of time, at a lower cost than previously available. The enhanced OLI spectral bands offer the potential of a wider range of applications and improved image quality for traditional studies. NASA and USGS see the value of continuing the Earth observation record well beyond Landsat 8. NASA has been directed by Congress to develop, in cooperation with the Office of Science and Technology Policy and USGS, a plan for a follow-on mission to Landsat 8 consistent with the recommendations of the National Science and Technology Council's report, A Plan for a U.S. National Land Imaging Program. Due by the end of summer 2009, the plan will be an important step in assuring the global science community of U.S. interest in continuing the remarkable record of moderate-resolution Landsat observations.

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