 MAIN PAGEMODIS INFOINSTRUMENT OPS
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Aqua MODIS Instrument Performance History |
HistoryMODIS was launched on the EOS Aqua spacecraft at 09:54:58 UT on Saturday, May 4, 2002. MODIS Aqua "First Light" was achieved when the MODIS Nadir Aperture Door opened on June 24, 2002 at 23:22:48 UT. The Aqua MODIS instrument began taking data using side-B electronics. The Aqua spacecraft went to Earth Pointing Safe Mode on June 27, 2002 at 15:40 UT. MODIS returned to Science Data Mode on July 2, 2002 at 15:15 UT. On July 29, 2002 at 20:23 UT Aqua entered Earth Pointing Safe Mode. The Aqua MODIS instrument returned to Science Mode on August 6, 2002 at 14:52 UT. Aqua MODIS cold focal plane assemblies reached their normal operating termperature of 83K on August 7, 2002 at 23:15 UT. On August 13, 2002 at 11:24 UT, AQUA MODIS playback data was incomplete. MODIS did not transition to DAY mode as scheduled, resulting in some science data loss. At 13:03, MODIS did successfully transition to DAY mode, and science data is being recorded as normal. The cause of this event is under investigation by the instrument operations team. The Aqua spacecraft and the MODIS instrument entered Safe Mode at approximately 13:37 UT Sept. 12, 2002 (2002/255). Aqua recommenced recording Science Data Mode data on September 12, 2002 at 21:56 UT. On October 16, 2002 between 12:56 and 13:42 UT data was mistakenly collected in night mode instead of day mode. On October 17, 2002, there was a data loss between 18:58 and 19:06 UT due to commanding problems. A second data loss occurred later the same day between 21:57 and 22:31 UT. Beginning 15:18 UT April 22, 2003, there were errors associated with the Aqua MODIS sector definitions. A Terra LUT was mistakenly uploaded instead of the correct Aqua LUT. This resulted in the earth view sector definitions being shifted "early" by about 9 to 16 frames. The problems was corrected at 21:32 UT April 23, 2003. Ground station limitations and SSR overflow caused an unrecoverable Aqua MODIS data loss on day 2005191 (July 10, 2005) from 16:23:54 to 17:52:47 UT. Operator error caused data loss on day 2005291 (October 18, 2005) from 09:43:01 to 10:47:59 UT. A ground systems communication failure caused non-recoverable data loss from 03:45:53 - 07:25:15 UT on 2006158 (June 7, 2006). An irrecoverable science data loss occurred on 2006/186 (July 5, 2006) from 00:56:28 to 07:22:32 UT and from 08:38:23 to 08:55:45 UT. An unrecoverable data loss occurred on 2007/153 (June 2) between 02:24:58 and 02:41:24 UT. Playback errors and SSR buffer overflow caused a data loss on 2007/203 (July 22, 2007) from 06:03:17 to 07:20:34 UT. An anomaly occurred on December 2nd (2007/336) when a series of Flight Operations Team (FOT) operator errors led to Partition #6 of the Solid State Recorder (SSR) becoming write disabled. Partition #6 contains spacecraft engineering data and Ground Based Attitude Determination (GBAD) data generated by the spacecraft, used by all Aqua instrument in the processing of their science data. The SSR anomaly resulted in unrecoverable data losses between 00:42:30 - 01:07:53 and 02:35:36 - 05:41:33 UT. There are numerous other missing data granules over the 5 day period beginning on Dec. 2, 2007. All other SSR partitions are functioning normally. The FOT and the spacecraft developer, NGST, successfully implemented a ground-based work-around fix to the anomaly and science data processing has returned to normal. An unrecoverable data loss due to a playback/ground station contact error occurred from 8:27:59 UTC until 9:58:14 UTC on 2008/107 (4/16/08) . An unrecoverable data loss from 18:49:18 to 19:08:52 UTC on 2008/211 (7/29/08) occurred due to ground station contact errors causing a SSR buffer overwrite. An unrecoverable data loss due to loss of contact between the satellite and ground stations occurred from 344/23:21:47 to 344/23:34:11 and from 344/23:47:22 to 345/00:32:45 UTC. Additional smaller data losses are described and tabulated on password protected links at the site: http://jupiter02.gsfc.nasa.gov/links/links.htm The sensor operational configuration, detector biases, and lookup table parameters are time-dependent quantities that have been changed to optimize sensor performance. The reflectance factor was determined using the pre-launch calibration coefficient value for m1 prior to the 07/29/2002 Safe Mode anomaly. On-orbit calibration is used after 08/06/2002, LUT version V3.1.0.2. Degradation of the solar diffuser is taken into account after 10/14/2002, LUT version V3.1.0.3. Changes are documented in the metadata and many changes are accessible from the Operational Configurations links on this page.The Aqua MODIS Itwk Vdet history and calibration activities are available at MODIS Instrument Operations Team Event History. PerformanceThe performance of the sensors and the on-board calibrators (the Solar Diffuser and its accompanying Solar Diffuser Stability Monitor, the Spectro-radiometric Calibration Assembly, the On-Board Calibrator Blackbody, and Space View port) have been very good. Several features of the performance lead to characteristics in the data set that merit special attention. These items are described on this web page and links herein. The sensor operational configuration, detector biases, and lookup table parameters are time-dependent quantities that have been changed to optimize sensor performance. Areas where caution must be exercised in the use of the current Level 1B product are:
Signal-to-noise-ratios (SNRs) for the reflected solar radiation bands (RSB; Bands 1 to 19 and 26) and noise-equivalent temperature intervals (NEdTs) for the thermal infrared bands (TEB; Bands 20-25, and 27-36) are meeting specifications in most instances. Summary of Key MODIS Operational Configurations The data are aligned in rows within each calibration month from June 2002. The first row indicates whether science data is present in the Level 1 product for that day. Row two represents the value of the focal plane bias for the SW/MWIR for the preponderance of each day. Row three indicates whether the cooled focal planes were held at the nominal operating temperature of 83 K for the entire period of the day, whether they were uncontrolled over a portion of each orbit on that day and whether they were uncontrolled throughout the entire day. Row four indicates whether A-side or B-side electronics are being used for that day.
Please contact Jack Xiong with any technical questions concerning these pages. |
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