Maintaining Landsat data continuity by providing data that are consistent in terms of data acquisition, geometry, spatial resolution, calibration, coverage characteristics, and spectral characteristics with previous Landsat data. Generating and periodically refreshing a global archive of substantially cloud-free, Sun-lit, land-mass imagery. Continuing to make remote sensing satellite data available to domestic and international users and expanding the use of such data for global change research in both the Government and private commercial sectors. Promoting interdisciplinary research via synergism with other EOS observations, in particular, orbiting in tandem with the EOS Terra satellite for near coincident observations.
The Landsat-7 system is another step in the development and application of remotely sensed satellite data for use in managing the Earth's land resources. As with earlier Landsat systems, the Landsat-7 platform, along with its enhanced thematic mapping sensor, provides for new capabilities in remote sensing of the Earth's land surface.
Landsat-7 data are collected from a nominal altitude of 705 kilometers in a near-polar, near-circular, Sun-synchronous orbit at an inclination of 98.2 degrees, imaging the same 183-km swath of the Earth's surface every 16 days. Some of the browse images you encounter may appear black or empty. These are engineering data known as FAC=Full Aperture Calibrator. FAC is a white painted panel that is deployed in front of the ETM+ aperture and diffusely reflects solar radiation into the full aperture of the instrument. FAC scenes will typically be gathered on a daily basis and constitute roughly 10 scenes for each FAC collected. So, about 10 of the ~250 scenes per day that Landsat will be delivering to EDC will be FAC scenes. Eventually, this engineering data will be gleaned out of the database.