MODIS IOT Terra Weekly Report

Mission Operations Days: 2002/012 to 2002/018
January 11, 2002 20:00:00 GMT to January 18, 2002 20:00:00 GMT

Terra Spacecraft and MODIS Instrument Status:

This Week's Completed MODIS Activities:

None

None

None

None

2002/016 20:49:47-21:02:58 ATC OA15: SDD Opened, Fixed View At SD - A Side
2002/016 22:28:40-22:41:51 ATC OA16: SDD Screened, Fixed View At Sun - A Side

None.

This Week's Scheduled MODIS Activities Not Completed:

2002/016 21:41:37-22:15:10 ATC OA19: SRCA Full Radiometric - B Side

2002/017 14:10:26-15:07:57 ATC OA22: SRCA Full Spatial - B Side
2002/017 22:22:20-23:19:51 ATC OA23: SRCA Full Spectral (Part 1) - B Side

2002/018 00:17:08-01:14:39 ATC OA22: SRCA Full Spectral (Part 2) - B Side
2002/018 01:39:35-02:30:51 ATC OA22: SRCA Full Spectral (Part 3) - B Side
2002/018 03:34:53-04:26:09 ATC OA22: SRCA Full Spectral (Part 4) - B Side

Upcoming Week's MODIS Events:

2002/018 21:00:00 ATC OA26: BB Temperature Stepping (BB to 270K) - B Side

2002/019 15:00:00 ATC OA26: BB Temperature Stepping (BB to 280K) - B Side
2002/019 19:00:00 ATC OA26: BB Temperature Stepping (BB to 285K) - B Side
2002/019 22:00:00 ATC OA26: BB Temperature Stepping (BB to 290K) - B Side

2002/020 02:00:00 ATC OA26: BB Temperature Stepping (BB to 295K) - B Side
2002/020 02:00:30 ATC OA26: BB Temperature Stepping (BB Duty Cycle to FULL)
2002/020 04:00:00 ATC OA26: BB Temperature Stepping (BB to 300K) - B Side
2002/020 06:00:00 ATC OA26: BB Temperature Stepping (BB to 315K) - B Side
2002/020 09:00:00 ATC OA26: BB Temperature Stepping (BB to 270K) - B Side
2002/020 09:00:30 ATC OA26: BB Temperature Stepping (BB Duty Cycle to THIRD)

2002/021 05:00:00 ATC OA26: BB Temperature Stepping (BB to 290K) - B Side

Maneuvers:

The next MODIS Lunar Calibration via a spacecraft roll maneuver is scheduled for February 3rd, 2002 (2002/032) with data collection from 20:19:21 to 20:25:51. The roll angle will be -3.4357 degrees.

A Drag Make-Up (DMU) maneuver of 17 seconds on Wednesday, January 9, 2002, at 20:12:40, completed successfully.

The Inclination Adjust Maneuver (2 of 6), originally scheduled for January 16, 2002, was postponed. The EOC required a network reconfiguration to solve sporadic network anomalies recently witnessed by the FOT. The IAM will be rescheduled for some time in the next two weeks.

The DMU planned to follow the IAM by one week was advanced to Wednesday, January 16, 2002, at 15:39:00 for 14 seconds. DMU Maneuvers are much shorter and less complex than IAMs, as no attitude changes or significant instrument re-configurations are required. Therefore, the maneuver was deemed safe and not susceptible to major impact by the sporadic network events. As a safety precaution, Terra Flight Operations Team (FOT) personnel were stationed in the backup EOC to take over operational responsibility in the event of any problems. There were no network issues during the maneuver.

The IOT has been notified that the Terra Deep Space Calibration Maneuver has been postponed once again. The maneuver is not expected to be performed until late summer of 2002 at the earliest. The reasoning for this delay was to allow the EOS Operations Center (EOC) time to adjust to operating Terra and Aqua spacecraft simultaneously.

MODIS Anomalies:

At the end of last week, we scheduled our set of monthly calibrations for January. These included SDSM, SRCA, and BB calibrations. An error was made when scheduling these activities and B-side SRCA and BB calibrations were scheduled instead of A-side calibrations. The SDSM calibrations were scheduled (A side) correctly.

The BB activities ran as scheduled which turns on the B-side calibration electronics, turns on the B-side blackbody heater circuit, sets the BB temperature to a variety of values, and toggles the BB heater duty cycle.

The B-side SRCA calibrations did not run because there is no cross-strapping capability between PS1 and SRCA B-side. The SRCA commands were issued (which will cause the motor step numbers to change), but no SRCA components were actually powered.

There are two problems with what occurred:

1. The calibrations did not execute as intended. The SRCA calibrations were not executed; they need to be rescheduled. The MODIS IOT is waiting for MCST to either verify that the B-side BB activity was suffice or if they would prefer an A-side BB calibration?
2. We had not powered the instrument B-side components since the PS2 shutdown anomaly last June. There was concern as to whether or not any of the B-side loads had been damaged and as a result would further damage other components if powered. Based on the observed telemetry, the B-side BB calibration performed nominally without affecting other components, but we did not wish to take this route until necessary.

We have identified means to prevent such a mishap from occurring again:

1. Be more verbose in our scheduling notification E-mails to include the full name of the calibration being performed: i.e. "SRCA A-side Full Radiometric" instead of just "SRCA Full Radiometric". This would provide an opportunity for other team members to spot the scheduling error in time to change the command load.
2. Add additional MMS constraint checking abilities to the MODIS resources. This would involve adding a new scheduling resource for the instrument configuration (A-side, B-side, or Cross-strapped). Then, constraints would be defined to warn the team if an A-side calibration was scheduled while the instrument was in a B-side configuration. This feature would take some time to develop, but it would be autonomous once in place.

We have some additional analysis to perform to gather all of the telemetry from last week's calibrations and will let you know if we identify anything out of the ordinary. We apologize for this error and will do our best to ensure it does not happen again.

The Formatter Error Count has now passed 9 Million Events.

The Formatter Error Rate has been fairly steady for the past few weeks with the counter rollover time approximately every seven hours and five minutes.

Error tracking spreadsheets have been updated and can be retrieved from:

An MS Excel spreadsheet called, AM1_FR_error_rollovers_MMDDYY.xls contains the data for the times each of the error count "roll over" occurs (with the MMDDYY denoting the date the spreadsheet was made, the more recent date containing the most up-to-date information).

General Instrument Comments:

MODIS is in Science Mode on the A-side with the SVD and NAD open, operating with the Formatter Resolution Flight Software Patches (FRFSP).

MODIS Telemetry Trends:

No abnormal telemetry trends are being observed.

Non-MODIS Significant Events:

Science Data Loss Reports can be viewed at:

Select "Search Data Losses", and choose Data Type: MOD

Then press the big SUBMIT button.

Limited Life Item Status:

SRCA 10W Lamp #1: 192.8 of 500 hours
SRCA 10W Lamp #2: 147.2 of 500 hours
SRCA 10W Lamp #3: 156.4 of 500 hours
SRCA 10W Lamp #4: 61.5 of 500 hours

SRCA 1W Lamp #1: 558.6 of 4000 hours
SRCA 1W Lamp #2: 276.3 of 4000 hours

Solar Diffuser Door: 1799 of 3022 Movements
Nadir Aperture Door: 534 of 1316 Movements
Space View Door: 437 of 1316 Movements

Email the MODIS IOT to report any problem with the MODIS IOT Web Pages.
Email the MCST Webmaster to report any problem with the MCST Web Pages.
Email the MCST Helpdesk to ask a question about Level 1B usage, algorithms or software.

Last Update: Thursday, 04-Sep-2003 18:14:23 EDT