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The NASA Earth Observer 1 Mission

The Earth Observing One (EO-1) Satellite was launched on November 21, 2000. EO-1 is the first Earth observing platform of NASA’s New Millennium Program (NMP). The NMP develops new technologies and strategies for improving the quality of observations for NASA’s future planetary and earth missions, while reducing cost and development time.

The EO-1 satellite contains three observing instruments supported by a variety of newly developed space technologies. The Advanced Land Imager (ALI) is a prototype for a Landsat-7 replacement instrument. The Hyperion Imaging Spectrometer is the first civilian high spatial resolution imaging spectrometer to orbit the earth. The LEISA (Linear Etalon Imaging Spectral Array) Atmospheric Corrector (LAC) is an extremely high spectral resolution wedge imaging spectrometer, well suited to measuring atmospheric water vapor content.

The EO-1 orbit is slightly to the east of Landsat-7, with an equatorial crossing time one minute later than that of Landsat-7. This results in EO-1 passing over the same ground-track as Landsat-7, one minute later. In a broader sense, EO-1 is not merely formation flying with Landsat-7, but joins a constellation of earth observing satellites, including SAC-C and TERRA, all examining electromagnetic radiation along the same ground track with different swath widths and with a range of spatial and spectral resolution.

EO-1 instruments use the sun and moon to maintain consistent calibration. In the solar calibration, each of the three instruments views the sun through some sort of diffusing mechanism. The lunar calibration, which allows the detector system to view the lunar surface through the same optical path as when viewing the earth, can be used to measure overall detector system stability and thus will serve the role of solar diffuser monitor.

The operational flexibility of the EO-1 satellite has presented opportunities for carrying out many unique experiments to help quantitatively analyse the performance of each of the instruments and their value for applications. Among the more novel experiments, an active illumination experiment over Edwards Air Force Base, lunar views, planetary views, and stellar views have provided NASA with the ability to assess stray light performance as well as radiometric and geometric characteristics of ALI and Hyperion.

Hyperion, as the first civilian hyperspectral sensor to image the earth from a space platform has now provided information for performance assessment that has proved its capacity as well beyond what was anticipated. Hyperion has 242 spectral channels in the range 400 nm to 2500 nm. The bands have 10 nm bandwidth and its signal to noise capabilities are sufficient to resolve many of the finer features that such spectral data can bring to remote sensing.

Australia has been participating in the EO-1 experiment as a member of the Science Validation Team. Very significant applications results have emerged from Australian sites involving:

Calibration Lakes Frome, SA and Argyle, WA
Geology Mt Fitton, SA & Panorama, WA
Agriculture Coleambally Irrigation Area, NSW
Forestry Tumbarumba, NSW
Coastal Waters Moreton Bay, QLD
Rangelands Kunoth Paddock, NT

Field studies at Cape Tribulation for rainforests, sugar and reefs and Kakadu for mine site monitoring and vegetation environment are under way at this time. More information on the Australian proof of concept studies can be found on the CSIRO EOC web site at

Following the success of the first year of operation, NASA is proposing to have an extended mission with data purchase open to researchers, companies and agencies to undertake their own extended studies of the value that comes from these advanced instruments. More information is available here.

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