MODIS IOT Aqua Weekly Report

Mission Operations Days: 2002/250 to 2002/256
September 7th, 2002 00:00:00 GMT to September 14th, 2002 00:00:00 GMT

Note: The Aqua spacecraft autonomously entered Safe Mode at 13:31 GMT on September 12th, 2002. The FM1 MODIS instrument transitioned to Safe Mode with the Nadir and Space View doors closed. The MODIS instrument was recovered to Science Mode (with doors opened) on the same day, but the instrument focal planes have not yet cooled to 83K.

See the "Non-MODIS Significant Events" section below for more details on the cause of the Safe hold anomaly.

Aqua Spacecraft and MODIS Instrument Status:

This Week's Completed MODIS Activities:

None

None

None

None

2002/254 12:18:47 - 12:32:45 MCL OA16: SD/SDSM Screened, B-side
2002/254 13:57:39 - 14:11:37 MCL OA15: SD/SDSM Open, B-side

2002/255 13:31 Aqua autonomously enters Safe Mode; MODIS sent to Safe Mode MODIS Nadir door and Space View door close

2002/255 21:40:35-21:42:19 Real-time MOD_STBY_PM_TXTN('B') Transition from Safe Mode to Standby Mode (B-Side)
2002/255 21:42:47-21:45:10 Real-time MOD_SVD_TO_OPEN Open the Space View Door (closed from Safe Mode entry)
2002/255 21:45:42-21:48:05 Real-time MOD_NAD_TO_OPEN Open the Nadir Door (closed from Safe Mode entry)
2002/255 21:52:56-21:55:08 Real-time MOD_SCI_PM_TXTN('B') Transition from Standby Mode to Science Mode (B-Side)
2002/255 21:55:54-21:56:05 Real-time CDH_FMU_TAXI('MODIS','B','ENAB') Enabling the FMU recording of the MODIS Science Data (B-Side Taxi Port)
2002/255 21:56:58-21:57:15 Real-time MOD_FR_MODE('NIGHT') Set the Formatter to Night Rate
2002/255 22:05:28-22:05:58 Real-time MOD_MEM_PM_DUMP('MOTOR_POS_WHEN_HIT',12,0,0,1,1) Diagnostic Memory Dump of Door Movement Data.
2002/255 23:25:50-23:26:44 Real-time MOD_BB_ON('B','B') Turn on the Black Body (B-Side Cal. Electronics and B-Side BB Heater)
2002/255 23:26:58-23:27:24 Real-time MOD_SET_BB_TEMP(1733) Set the Blackbody temperature (1733 translates to 285 K)

None

This Week's Scheduled MODIS Activities Not Completed:

None

Upcoming MODIS Events:

259/17:33:05 - 17:47:03 MCL OA16: SD/SDSM Screened, B-side
259/19:11:58 - 19:25:56 MCL OA15: SD/SDSM Open, B-side

During the month of September, an SRCA Full Radiometric and an SRCA Full Spatial calibration will be performed as well as weekly SD/SDSM calibrations.

Maneuvers:

The Drag Make-up maneuver planned for Thursday, September 12th (2002/255) at 15:23 GMT was cancelled due to problems creating stored command sequence products. The maneuver has been re- scheduled for approximately 15:00 GMT on Monday, September 16th (2002/259).

There will not be a lunar calibration roll maneuver for Aqua in September. The required roll angle would have exceeded the limit of -20 degrees.

The Deep Space Calibration pitch maneuver(s) have been indefinitely suspended pending mission review.

MODIS Anomalies:

The MODIS commanding anomaly is still being investigated. The fault management Stored Command Sequence (SCS) changes to disable the spacecraft "I am OK" (IMOK) signal to MODIS are expected to be delivered to the Aqua FOT for testing on Monday, September 16th, 2002. The memory patch to switch the MODIS ground-command timing slots with the MODIS stored-command timing slots is expected to be delivered to the FOT during the week of September 23rd, 2002.

General Instrument Comments:

FM1 MODIS is in Science Mode. The SVD and NAD are Open, the survival heaters are enabled, and the Black Body is heated to 285 K. The cold focal planes are at approximately 91K and cooling as of this writing.

MODIS Telemetry Trends:

The FM1 MODIS instrument telemetry is trending nominally. The cold focal planes are expected to reach 83K Saturday afternoon.

Non-MODIS Significant Events:

The Aqua spacecraft autonomously entered Safe Mode at approximately 13:31 GMT on Thursday, September 12th, 2002. The drag make-up maneuver for that day had been cancelled, but the ephemeris onboard the spacecraft had been built assuming the burn would be performed. The Aqua FOT was going to uplink a new ephemeris with the effect of the drag make-up burn removed. In order to do this, a lower fidelity ephemeris (based on strictly circular orbit) had to be enabled while the new higher fidelity ephemeris was loaded. Unfortunately, when the spacecraft was commanded to the low fidelity mode, the actual spacecraft roll angle and the predicted roll angle of the low fidelity ephemeris differed by 1.7 degrees which was greater than the 1 degree limit. This attitude error tripped a level two fault, thus putting the Aqua spacecraft (and all of the instruments) into Safe Mode.

The Aqua spacecraft was recovered to Fine Pointing Mode on the afternoon of September 12th. The MODIS instrument was also recovered to Science Mode that evening.

The EMOS mission status webpage (which includes instrument data loss records) can be found at the following URL. Note that a password is now required to access the EOS mission links webpages. There are directions at the URL below for how to obtain a username/password.

Limited Life Item Status:

SRCA 10W Lamp #1: 206.4 of 500 hours
SRCA 10W Lamp #2: 179.5 of 500 hours
SRCA 10W Lamp #3: 182.3 of 500 hours
SRCA 10W Lamp #4: 57.7 of 500 hours

SRCA 1W Lamp #1: 500.4 of 5000 hours
SRCA 1W Lamp #2: 269.8 of 5000 hours

Solar Diffuser Door: 1810 of 3022 Movements
Nadir Aperture Door: 1053 of 1316 Movements
Space View Door: 632 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: Tuesday, 03-Dec-2002 13:09:00 EST