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Case #:PM_MOD_21264 Opening date: 09/21/21 Last update: 12/05/22 Status: Note Users of MODIS Science data products are requested to note that MODIS Terra is scheduled to exit the 'Morning Constellation' of Earth Science satellites by October, 2022. Because of onboard fuel shortage, the last of Terra mission maneuver was done on February 27, 2020 to maintain the mean local time (MLT) of 10:30 AM. Thereafter, Terra has been drifting slowly from its MLT and will reach and exceed 10:15 AM MLT by October 2022, when it will make the constellation exit with a lowered orbit altitude of 694kms. More information in this regard can be found here and here. Please note that this does not indicate the end of life for Terra mission and Terra is expected to remain operational for at least another 5 more years and NASA SIPS will continue to produce and distribute science quality data through Fall of 2025. There may be some limited impact on the science data because of the changing MLT and the lowering of orbital altitude but overall, it is not expected to have any major impact on the science data quality. We will continue to provide further updates in this regard as we get further inputs from the different land science teams. Terra Constellation Exit: UPDATE 12.05.22 ************************************************C61/Terra post-CEM reprocessing: The recent Terra lunar calibration results indicated significant changes of cross-talk effects to some detectors in PV LWIR bands (bands 27-30) after the Constellation Exit Maneuver (CEM). MCST recommends to reprocess the Terra C6.1 L1B data (2022/296, 2200 onwards) after the CEMs using the updated LUT delivery, V6.2.2.81. The same L1B LUTs that resolves this drift in the PV-LWIR cross-talk has been operational in the C61 forward processing stream, starting 2022-11-22 (DOY 2022/326). Based on MCST's recommendation, following the CEMs, Terra L1Bs, LST (MOD21*) and L2 atmospheric products will be reprocessed for the period 2022-10-23 (DOY 2022/296) thru 2022-11-21 (DOY 2022/325 included). Terra Constellation Exit: UPDATE 11.04.22 ************************************************The Terra MODIS instrument is operating in nominal status and all Terra MODIS operational production for C6 and C61 has resumed starting on 10.23.22 (2022.296) at 22:35 UTC. Terra Constellation Exit: UPDATE 10.28.22 ************************************************All Terra NRT data production from NASA LANCE has resumed as of October 28 at 00:00, following a prolonged outage because of two successive Constellation Exit Maneuvers (CEM) that were performed on October 12 and 19 respectively.Following the CEMs, the space and nadir view doors were opened on October 21, and the MODIS formatter resumed nominal day/night mode operations from October 22. All instrument temperatures had attained their nominal values by October 23. Assessments carried out by the MODIS validation team now indicates nominal performance and no major cause for concerns, barring slight gain changes that have been noticed for some of the SWIR bands (mainly for Band 5), and possibly slight change in cross-talk behaviors for some of the PV-LWIR detectors. Users are being warned, not to use any Terra MODIS data products that may be available from nrt3 or nrt4 servers, prior to October 28 (DOY 301) resumption of Terra data from LANCE NRT, as all instrument status and performance may not have been nominal till then. MODAPS is also expected to resume the operational forward processing of all MODIS Terra products, shortly. Terra Constellation Exit: UPDATE 10.25.22 ************************************************Over the past few days, the MODIS IOT commanded the MODIS instrument back into nominal science mode after a 24-hour outgas period. The return to nominal command was issued at 2022/294 19:59:10z. The nadir and SV doors have been opened and the CFPAs and BB are in the process of returning to their nominal temperatures. These temperatures will take a few days to settle, after which time MCST will begin to evaluate the performance of each band. The Day/Night formatter has returned to normal starting on day 295, with the first granule with daytime data starting at 2022295.0040. Terra Constellation Exit: UPDATE 10.20.22 ************************************************Terra Constellation Exit Maneuver (CEM) #2 was completed successfully on October 19. The loss of pointing accuracy times are: LOPA: 2022/292 19:03:45-22:48:44. Starting today, October 20, MODIS IOT will begin commanding to return the sensor back to nominal operations. Following that, MCST will begin to assess the instrument status next week. MODAPS will resume all Terra data production, once confirmation and updated LUTs are received from MCST. Terra Constellation Exit: UPDATE 10.12.22 ************************************************The first of the Terra Constellation Exit Maneuver (CEM) was completed successfully on October 12, between 14:20:54 - 15:05:10. All Terra MODIS data production and distribution are to remain on-hold from both STD and NRT streams, following the last Terra Constellation Exit Maneuver (CEM) on October 19, for at least a week, till around October 26 or slightly more. During this time, the MODIS calibration team (MCST) will review all instrument performance and will most likely provide updated LUTs to address any drifts or issues. Following the confirmation of all Terra MODIS instrument status and the delivery of updated LUTs, MODAPS will resume all Terra MODIS data production from both, STD and NRT streams and may also reprocess some of the days following the end of the last CEM on October 19, with the updated LUTs. Terra Constellation Exit: UPDATE 09.26.22 ************************************************The initial Terra Constellation Exit Maneuver (CEM) is scheduled for October 12, 2022, around 7:30 am EDT. The CEM will be carried out through two successive maneuvers, on October 12 and 19, respectively. Users should expect Terra MODIS data outage, starting October 10 till October 19. Following the last maneuver on October 19, an outgas procedure will be performed and all things are expected to stabilize within 48 hours after that. MCST will monitor the telemetry and an update will be provided when all instruments approach their nominal operating temperatures. Users should exercise caution, while using the Terra MODIS data between October 19 - October 21, as all instruments are still recovering, after the outage. Special LUT deliveries are expected to account for any gain changes that may occur in the instrument upon recovery. Terra Constellation Exit: UPDATE 09.20.22 ************************************************The initial Terra Constellation Exit Maneuver (CEM) is scheduled for October 12, 2022, around 7:30 am EDT. The CEM will be carried out through two successive maneuvers, on October 12 and 19, respectively. All science data acquisition will remain suspended during, between, and following these two successive maneuvers, for a period of about 10 days, as MODIS will remain in a 'CEM configuration' mode between the CEMs, where SV and EV doors will remain closed, Blackbody will be turned off and the SMIR and LWIR focal plane/heaters will be turned off as well. Post CEM, some more time will be needed to bring all instruments back to their nominal status. Post-CEM calibrations will be performed over the following weeks and LUT updates will occur as needed. MODIS data users of both NRT and operational processing streams are requested to take note of this and expect data outage for at least 10 days, starting October 12. This note will be further updated after the event, once all instruments are back to their nominal status and both NRT / operational production has resumed. Occurrence: TERRA C6 / C61 L1B and all Downstream products for the times listed above. PGE: |