National Aeronautics and Space Administration


Washington, DC 20546-0001

NOV 20 2007

Reply to Attn of:

SMD/Earth Science Division

Drs. Siegel and Yoder

University of California , California 93106

Dear Drs. Siegel and Yoder:

Thank you of the letter of October 2, 2007. The letter clearly stated community concerns regarding the status of the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP) Visible/Infrared Imager/Radiometer Suite (VIIRS) for ocean color data. NASA values the scientific information and perspectives provided by the scientific community, and I thank you for offering your views regarding the future of ocean color remote sensing.

On October 5, 2007, the NPOESS Executive Committee (EXCOM) met and decided to remain with the baseline filter for VIIRS given the replacement risks and lack of clear path to improved performance. The Integrated Program Office (IPO) will continue to pursue all other options (including the cherry-picked filter characterization, the remanufactured integrated filter assembly (IFA), and the new design IFA) to improve Color Imagery (CI) performance. In the event of major schedule disruption to the NPP unit as result of other problems, the EXCOM would reconsider the NPP IFA status.

NASA recognizes the well-founded concerns of the community. Ocean color is an important data record for climate science, and we acknowledge that the anticipated performance of VIIRS of NPP puts that record at risk and wish to remedy this situation. We are doing our best within existing constraints to continue the time series of key climate observations (from the Earth Observing System era) on which NASA depends for its mission in Earth System Science. We will continue to work within the U.S. Government to identify acceptable solutions to this problem and encourage community involvement in that process. We look forward to continuing this dialogue.


S. Alan Stern

Associate Administrator for Science Mission Directorate

The National Academies of Sciences, Engineering, and Medicine
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