Aqua Daily Report May 9, 2002 1130 GMT - May 10, 2002 1130 GMT

Status Report From: Goddard Space Flight Center
Posted: Friday, May 10, 2002

The following activities were completed:

  1. The Master Command Load (MCL) for day 130 was loaded at 1908z and activated at 0000z.
  2. The daily spacecraft ephemeris table was loaded at 2040z.
  3. The FMU/SSR Reconfiguration SCSs were loaded at 2206z.
  4. Successfully transitioned from Earth Point Mode to Fine Point Mode (FPM) at 1836z. The spacecraft is currently maintaining FPM within the Aqua science tolerances. Activities included:
    1. Enabled Attitude Propagation with the IRU.
    2. Activated Star Trackers.
    3. Uplinked Attitude Quaternion.
    4. Initialized Star Identification.
    5. Enabled Fault Management related to Fine Point Mode.
  5. The Ultra Stable Oscillator (USO) Frequency Adjust to GIRD and GIIS occurred at 2127z. The adjustment was performed to calibrate the on-board clocks. To minimize clock adjusts this will not be scheduled for more than once per week.
  6. Performed AIRS Memory Dump at 0616z.
  7. The Direct Broadcast Control SCSs were uploaded at 0314z.
  8. Loaded and dumped the Delta-V Maneuver SCSs at 0935z in preparation for the Delta-V demo Yaw burn on May 10.

The following activities are scheduled for the next 24 hours:

  1. Uplink and activate the Master Command Load (MCL) for day 131.
  2. Uplink daily spacecraft ephemeris with continuity check.
  3. Activities related to the Delta-V demonstration maneuver include:
    1. Open Isovalve
    2. Turn ON Cat Bed Heater
    3. Demonstration of Yaw Maneuver to Offset Attitude
    4. Zero Duration Burn
    5. Yaw Maneuver to Nominal Attitude
    6. Turn OFF Cat Bed Heaters
    7. Re-enable FPM Fault management
    8. Load and Dump Delta-V Maneuver SCSs for demo burn
  4. X-Band Communication Subsystem Activation
  5. First planned X-Band SSR Playback, containing State-of-Health Data
  6. Partition SSR for Science Data
  7. Route Science Data to SSR only
  8. Enable CERES Instrument Science Transactions
  9. First Dump of SSR with Science Partitioning

Aqua Spacecraft Status:

  1. Spacecraft State is currently Standby.
  2. GNC Mode is Fine Point Mode, HiFi Ephemeris.

Aqua Instrument Status:

  1. AIRS is in Decontaminate state, Quiet bus is ON, Noisy bus is ON, Cryocooler is OFF, Scan mirror rotating is OFF and earth shield is CLOSED.
  2. AMSR-E is in Modified Sleep mode, rotating at 4 RPM.
  3. AMSU A1 is in Survival mode and the antenna is in the TARGET position.
  4. AMSU A2 is in Survival mode and the antenna is in the TARGET position.
  5. CERES Aft is in Safe mode and the covers are CLOSED.
  6. CERES Fore is in Safe mode and the covers are CLOSED.
  7. HSB is in Survival mode and the antenna is in the TARGET position.
  8. MODIS is in Standby mode, Nadir Door is Unlatched and CLOSED, Solar Diffuser Door is Unlatched and CLOSED, and the Space View Door is Unlatched and CLOSED.

Activities Deferred:

Spacecraft transition to Fine Point Mode (FPM) which was originally delayed, was successfully completed on May 9th.

    1. Delta-V demonstration Yaw Maneuver is scheduled for Friday, May 10.
    2. Remaining activation activities impacted by the FPM delay will be rescheduled.


  1. The ground system has experienced 2 anomalous passes on SGS, 1 occurred on May 6, and 1 occurred on May 7 where data were missing in S-Band playbacks.
    1. (Correction to status reported on May 9) SSR data were replayed in subsequent passes to ensure no data loss. Later analysis of the original playback proved that no SSR data were lost in the original playback.
    2. EOC Mission Operations Systems (EMOS) personnel and CSOC personnel have concluded that the actual playback data were good, and only idle frames at the beginning of the pass are affected. The FOT did not anticipate the affects of the low power levels of the RF signal at the horizon (manifested as Reed-Solomon corrupted CADUs) because all pre-launch testing was done with the RF signal at a constant power level. The phenomenon is seen only at the Norway stations because of the Norwegian antennas’ position on the plateau, they can see the true horizon (zero degrees elevation). The stations are operating within normal parameters.
  2. There is an apparent misalignment of approximately 0.2 degrees between Star Tracker Assembly (STA) 1 and STA2.
    1. Most probable causes are:
      1. Measurement or mathematical error in generation of original alignment matrices.
      2. Rotation about STA1 boresight axis.
      3. Rotation about STA2 Y-axis.
    2. Actions underway:
      1. For probable cause (i) a comprehensive review of measurements, calibrations, and calculations is being performed by independent alignment experts at TRW Space Park
      2. For probable causes (ii) and (iii) discussion has been initiated with instrument teams in case geolocation assistance is needed to distinguish between (ii) and (iii).
  3. Commands dropped for AIRS (May 6 and 7) and MODIS (May 7) (formerly referred to as Code Word Errors).
    1. Caused by AGS and SGS transmitting with incorrect polarization. Ground stations have been reconfigured and communications are nominal.
  4. Command Telemetry Controller (CTC) received incomplete transfer frames from Transponder Interface Electronics (TIE) – (formerly CLCW errors not associated with commands). This anomaly has not affected the ability to command the spacecraft and it has been safe at all times. There have been a total of 13 occurrences.
    1. Most probable cause is “rogue” codeblocks processed by TIE and sent to CTC in the absence of, or as a result of, anomalous commanding. Potential sources of these “rogue” codeblocks are:
      1. Inadvertent reception of another spacecraft’s CCSDS uplink.
      2. TIE processing random data bits produced by transponder when no signal is present.
      3. Anomalous uplink near AOS.
    2. Actions underway for probable causes (i) through (iii).
      1. Patch loaded to telemeter codeblock data. Awaiting event recurrence and fault data processing.
      2. Organizing and analyzing all existing telemetry data.
      3. Analyzing flight software functions.
      4. Analyzing transponder/TIE design/operation.
      5. Reviewing ground network pre-contact operations.
      6. Correlating event times with proximity of other spacecraft using CCSDS.

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