Landsat-7 mission update and on-orbit ETM+ radiometric performance

As of this writing in mid-March 1999, Landsat-7 is scheduled for a 15 April 1999 launch. After an approximately 75 day on-orbit check out phase which includes an underfly of the Landsat-5 satellite and testing of the new ETM+ calibration hardware, routine acquisition of world wide coverage will begin. Preliminary on-orbit results will be presented at the symposium. Pre-launch radiometric performance testing of the ETM+ instrument, both off and on the satellite has been completed. Ambient radiometric calibration testing has shown that the reflective bands of the instrument have been stable in responsivity to within ±1% over the 18 months of pre-launch testing. Precision of the pre-launch calibration is typically at the 0.1% level and it is believed that accuracy of better than 5% is being achieved. Results from thermal vacuum testing of the instrument are still being analyzed and have been complicated by instabilities in the sources used in thermal vacuum