MODIS IOT Aqua Weekly Report

Mission Operations Days: 2002/131 to 2002/137
May 11, 2002 00:00:00 GMT to May 18, 2002 00:00:00 GMT

Aqua Spacecraft and MODIS Instrument Status:

This Week's Completed MODIS Activities:

2002/131 13:54:00 - 13:54:35 Real-Time Executed the procedure MOD_MEM_PM_DUMP to dump the operand addresses ACA1 - ACA4.

2002/131 17:24:00 - 17:24:30 30 second Delta-V burn maneuver.

None

2002/133 12:20:00-12:25:35 335 second Delta-V burn maneuver.

None

None

None

None

This Week's Scheduled MODIS Activities Not Completed:

Upcoming MODIS Events:

The next MODIS events will be to step the Space View Door (SVD) out by 750 counts, move the SVD to the outgas position, and enable the outgas heaters (individually). These activities are scheduled to occur on mission elapsed day sixteen (Monday, May 19th, 2002).

Maneuvers:

There was a 30 second Delta-V burn on 131/17:24. The spacecraft experienced a 5.5 degree pitch error during the burn. This is well within the 12 degrees allowed. There was a 335 second burn on day 133/12:20:00. The resulting change in spacecraft velocity was only about 70% of the predicted increase. Therefore, future burn durations have been extended.

MODIS Anomalies:

40 (post turn on sequence) CP_EVENT messages have been observed. They have occurred in pairs of (hexadecimal) 5D followed immediately by 77. 5D is the TLM Format/Collect Mismatch message, and 77 is the TLM Late Telemetry Formatting message. SBRS says they have seen these messages during Thermal Vac (around CDH bus activities). The 5D message occurs when something upsets the sector timing or the CP. Since the 5D and 77 are coming together, there may be something going on with the 1553 bus. The events are shortly followed (within 5 seconds) by a telemetry packet with the same MOD_SS_CP1553_MAJCYC value. However, it appears that the telemetry in said packet is a second reporting of the prior packet, with updates in the one second region. No updates to the data in the 8 and 64 second regions occurred, because the telemetry for that cycle was not sampled (as noted by event 5D). An Aqua Discrepancy Report (ADR) has been submitted to document the situation.

So far, there does not appear to be any recognizable pattern or discernable event that is triggering the CP to generate these event messages. Analysis of telemetry continues.

The last event set occurred at 2002/137-07:11:24.

General Instrument Comments:

MODIS is in a low-power Standby Mode using Power Supply 2 (PS2) and Control Processor B (CPB). The instrument survival heaters are enabled and all three doors are unlatched.

MODIS Telemetry Trends:

Some of the MODIS ISC Passive Analog Temperatures (SAM Radiator and OB Bulkhead) cooled off faster than predicted (based on TV, Terra, and Simulation data). The temperatures leveled out and demonstrated orbital and survival heater cycling at their expected temperatures. The Optical Bench Bulkhead temperature reached temperatures as low as -28.25C.

Once the Space Craft transitioned to EPM, the passive temperatures on MODIS increased to a range between -8 and -17 C. The OB Bulkhead temperature rose to -14.1 C.

The instrument survival heaters are cycling as expected. The Format Engine A & B side temperatures are also varying with the survival heater cycle and are dropping below their designated yellow alarm limits at their coldest temperatures. It currently takes about six hours to complete one cycle of the format engine temperatures.

The blackbody temperatures are 'pegged' low as expected. These temperatures will remain below the yellow limits until after MODIS transitions to Science Mode so the alarms have been disabled until that time.

There are a few project database issues regarding MODIS telemetry points. This is a result of having duplicate EPOCH (for I & T) and EMOS (for operations) sets of telemetry limits for mnemonics that needed derived parameters to account for the different CPA and CPB calibration coefficients. The offending alarms have been disabled and corrections will be made in the first post-launch database update (currently scheduled for Launch +60 days).

Non-MODIS Significant Events:

• Aqua's SSR was reconfigured for the partition formats to store science data at 02:04.
• Aqua's first dump of the SSR science partitions was completed successfully.
• CERES AFT and FORE science transactions enabled at 02:43.
• 30 second (Engineering Test) Delta-V maneuver at 17:24.

• AMSU-A1 powered ON at 16:25.
• AMSU-A2 powered ON at 16:40.

• AMSU-A1 and AMSU-A2 are parked for Delta-V maneuver at 08:26.
• Ascent #1 Delta-V at 12:14 for 335 seconds.

• HSB is turned ON at 18:20.
• Failover to secondary (ground system) configuration at 20:43.
• HSB is in normal mode at 20:53.

• -25 degree yaw for GNC calibration at 01:43.
• +25 degree yaw at 04:57.
• Fault management (FM) re-enabled after yaws at 06:30.
• CERES AFT AZ brake released at 09:55.
• CERES FORE AZ brake released at 10:41.
• +25 degree pitch at 14:38.
• -25 degree pitch at 19:45.
• USO adjusted at 21:29.

• +25 degree roll at 02:19.
• -25 degree roll at 06:04. It is rolled back prematurely due to operator error.
• AMSR/e starts spin up to 12 rpm at 14:31.
• AMSR/e spins up to 18 rpm at 17:53.
• (It appears that the AMSR/e spinning is causing some attitude errors in the spacecraft)

• USO gets a negative adjustment for the GIRD clock at 01:33.
• AMSR/e SPS is turned off at 02:58.
• AMSR/e SPS is turned on at 03:01.
• AMSU-A1 is parked at the cold soak target at 05:57.
• AMSU-A2 is parked at the cold soak target at 07:31.
• HSB parked at space view position at 09:09.
• (AMSU and HSB parked so that the attitude errors may be isolated to AMSR/e while it adjusts it's OBM)
• CDH performs a clock jam which drops the absolute error on the GIIS for 270ms to 0 ms at 12:57.
• AMSR/e cycles their heaters on and off at 15:28.
• AMSR/e spins up to 21 rpm at 18:44.
• AMSR/e adjusts it's OBM (ballasts) by 3 steps at 19:43.
• AMSR/e adjusts it's OBM 10 steps at 22:37.
• (Since the OBM adjustments, there has been a noticeable improvement in the attitude errors)

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Last Update: Tuesday, 03-Dec-2002 13:08:56 EST