ACE Weekly 05/29/2012 - 06/04/2012

All ACE spacecraft subsystems are performing as expected.

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Orbit/Attitude:

No maneuvers were completed this week.  The next attitude maneuver is
scheduled for Thursday 06/07/2012.

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OCRs:

DOY 152 (05/31/2012) 2212-2219z  SWICS-035  Change event prioritization
The SWICS instrument team changed the prioritization of events in
telemetry to try to get more events needed for science.  The Trigger
Mode was switched from Energy Only (since 10/25/2011) to Time-Of-Flight
(TOF) Only.  The basic rate boxes (mass vs mass/charge) were also
updated.

DOY 154 (06/02/2012) 0107-0110z  SWPE-043  Update Overcount Threshold
The SWEPAM instrument team doubled the SWEPAM-Electron overcount
threshold from 0x20 to 0x40.  The overcount alarm had been flagging ~45%
of the time for the past 2 months.  The overcount alarm was flagging
before and after the threshold was increased.  The instrument team may
make future adjustments after analyzing the data.

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Activities:

Data Capture:  100%  DOY 148-155 2012

The CHANDRA mission was in safe-hold and ACE gave 1.5 hours of antenna
time on Wednesday 5/30/2012.  The data playback fell further behind
after the DSN problems occurred on Friday 6/1/2012.  Fortunately,
additional antenna time was available on Saturday 6/2/2012 and the data
playback is caught up.

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Anomalies:

DOY 152 05/31/2012  S-ACE-0557  G10-0073  ITOS Disable CMD Failure
At the end of the pass, ITOS failed to disable commanding.  During the
next WIND pass, ITOS was unable to enable commanding for WIND.  When
ITOS was restarted, it rapidly generated the following event message
    "graph_process: dbLock(0, 1): dbif_lock.c line 381: semop():".
82000 messages were generated in 36 seconds before the computer was
rebooted.  This problem is rare.  It last occurred operationally on
11/19/2010 and recently during a WS1 test on 4/30/2012.
IMPACT:  WIND activities on the next pass were delayed 25 minutes.
Manual intervention required.

DOY 153 06/01/2012  S-ACE-0643  G12-0005  DSN Master Clock Assembly
Problems with the Goldstone site Master Clock Assembly (2208z) impacted
all of the Goldstone antennas including the ACE pass with DSS-27
starting at 2300z.  The MCA was eventually fixed and TLM/CMD established
at 0042z.
IMPACT:  Activities delayed 1hr 42 minutes.  No impact to NOAA SWPC
since the spacecraft was transmitting at the low data-rate.  Additional
antenna time was available on the following pass to catch up on the
playback.