MODIS IOT Aqua Weekly Report

Mission Operations Days: 2002/138 to 2002/144
May 18, 2002 00:00:00 GMT to May 24, 2002 00:00:00 GMT

Aqua Spacecraft and MODIS Instrument Status:

This Week's Completed MODIS Activities:

None

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2002/144 01:58:17 - 02:00:39 Turned on MODIS: MOD_TURN_ON_PM('PS2', 'CPB')
2002/144 02:18:18 - 02:19:22 Stepped SVD out 750 steps: MOD_STEP_DOOR('SVD', 750, 'OUT')
2002/144 02:19:51 - 02:20:49 Moved SVD to outgas position: MOD_SVD_TO_OG
2002/144 02:21:19 - 02:21:48 Turned on Cold Stage Outgas Heater: MOD_OG_HTR('ON', 'OFF', 'OFF')
2002/144 02:24:21 - 02:24:48 Turned on Intermediate Stage Outgas Heater: MOD_OG_HTR('ON', 'ON', 'OFF')
2002/144 03:07:16 - 03:08:07 Turned on Outer Stage Outgas Heater: MOD_OG_HTR('ON', 'ON', 'ON')

This Week's Scheduled MODIS Activities Not Completed:

Upcoming MODIS Events:

The next events in the MODIS activation are:

• Multi-partition CP Table load and dump (to verify Instrument to Spacecraft to Ground capability).
• Moving the SVD from the Outgas to Open position.
• Loading the MODIS SCS loads to the ISC.
• Turning off the MODIS Outgas Heaters.
• Transition MODIS to Science Mode.

The exact dates for the above activities are currently being rescheduled due to schedule shifts from the EPS induced DOY 139 Survival Mode transition.

Maneuvers:

The first Delta-V maneuver was successful but less effective than expected. Planning has begun for the next Delta-V.

• Ascent 1 on May 13, 2002 at 12:14 for 335.000 seconds - Successful
• Burn #2: June 5th, 2002 at 15:13:00, 1168 second duration
• Burn #3: June 8th, 2002 at 13:02:00, 793.5 second duration
• Burn #4: June 10th, 2002 at 12:43:00, 1004 second duration
• Burn #5: June 13th, 2002 at 13:51:00, 694 second duration
• Burn #6: June 18th, 2002 at 16:40:00, 755 second duration

MODIS Anomalies:

52 (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)" [Joe Auchter]. 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 2002/144-11:13:57.

General Instrument Comments:

At 139/16:09:42, MODIS went to survival mode (see below).

At 144/02:00:39, MODIS was powered on to its Standby Mode and subsequent activities placed it in the initial stages of Outgassing.

MODIS is currently On in B-Side Standby Mode (Power Supply 2, Control Processor B) with the Space View Door open to its Outgas Position. All 3 outgas heaters (Cold Stage, Intermediate Stage, and Outer Stage) are powered and duty cycling nominally.

MODIS Telemetry Trends:

The current MODIS telemetry is consistent with what is expected with MODIS in Standby Mode with Outgassing.

Non-MODIS Significant Events:

137/12:57, A 'time jam' was performed to eliminate the overall GIIS time error. The jam was done and had no impact on the MODIS instrument. The GIIS error was reduced to zero and the time drift is approximately -0.4 ms/day.
138/22:32, AMSR/e spin-up from 21 RPM to 24 RPM
AMSR/e has performed many OBM adjustments in order to eliminate the attitude errors caused by its rotation. As of 138/22:40, there is only a 1 to 3 arc second peak-to-peak pitch error due to its rotation.

On 2002/139 at 16:09:42, the spacecraft triggered a "911" after it went into sun pointing survival mode. The "911" acquired TDRS early at 4K Engineering telemetry rate. The spacecraft survival mode transition commanded the instruments to their survival modes. The "911" call was initiated by an EPS Fault Management Response to a Spacecraft Battery Depth of Discharge at Eclipse Entry Trigger. The anomaly investigation is still underway (said trigger is currently disabled).

140/17:40, the Aqua spacecraft re-acquired the Earth and transitioned to Earth Point Mode.
140/19:47, the spacecraft transitioned from Survival mode to Safe mode.

AQUA spacecraft transitioned to fine pointing mode.

142/13:42, AMSR/e spun up from 4 rpm to 29 rpm.
AMSR/e OBM adjustments performed.

143/14:52, AMSR/e spun up from 29 rpm to 34 rpm.
143/17:20, AMSR/e spun up from 34 rpm to 40 rpm.
AMSR/e OBM adjustments performed.

AMSR/e OBM calibrations complete.
AMSR/e produced its first image.
AMSU-A1 and A2 have both been returned to Full Scan Mode.

Limited Life Item Status:

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