Landsat 7: maintaining Landsat data continuity into the 21st Century

Abstract

The Land Remote Sensing Policy Act of 1992 identified Landsat data continuity as the fundamental goal of the Landsat 7 program. Furthermore, a Presidential Decision Directive in 1994 placed the development and operation of the Landsat 7 program in the domain of three Federal agencies: NASA has the responsibility to build and launch the spacecraft and instrument package; NOAA is charged with the day-to-day operational management of the mission; and the USGS EROS Data Center (EDC) will receive, archive, process and distribute Landsat 7 data products on behalf of NOAA. The Landsat 7 program, on target for a launch in early 1999, has been designed to preserve data continuity by placing the Enhanced Thematic Mapper Plus (ETM+) sensor in orbit The ETM/sup +/ is based on the heritage design of the Thematic Mapper (TM) instruments flown aboard Landsat 4/5, and it will provide: (a) repetitive, synoptic coverage of global land surfaces; (b) spectral bands in the visible, near IR, short-wave IR, and thermal IR regions; (c) spatial resolution of 15m, 30m and 60m; and (d) significantly improved absolute radiometric calibration. Significant enhancements have also been incorporated into the ground data processing system to be located at EDC. Plans call for the daily acquisition and archival of 250 scenes of data at EDC, with a goal of refreshing archival coverage of the global land mass periodically. The system is being sized to generate up to 100 systematically corrected Level 1 scene products per day, and these data will be sold for less than $600 per scene. An Image Assessment System (IAS) is also being developed to facilitate data quality assessment and to maintain up-to-date calibration of the ETM/sup +/ sensor throughout the duration of the mission.