ACE Weekly 06/23/2010 - 06/29/2010

All ACE spacecraft subsystems are performing nominally.

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Orbit/Attitude:

No maneuvers were completed this week.  The next attitude maneuver is
scheduled for Thursday 07/01/2010.

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OCRs:

None

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Activities:

Data Capture:  100%  DOY 171-178 2010

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Anomalies:


DOY 175  06/24/2010  S-ACE-0516  G10-0034  Incorrect Clock Calibration
The procedure, ace_pass.proc, calculates a clock calibration at the end
of each pass using the support's telemetry file.  The anomalous clock
calibration was calculated on a day when the BOT time was on a different
DOY than the BOA (BOA was on DOY 174 and BOT was on DOY 175).  The clock
calibration report was generated and automatically delivered during
post-pass activities at 175/0345z.  NOAA notified the FOT that they were
unable to process telemetry at 175/1214z.  As a result, the FOT decided
to staff the next ACE support scheduled to start at 175/1520z.  The bad
clock calibration problem was realized at 175/1600z and a corrected
clock calibration report was delivered to NOAA and ASC at 1608z.
IMPACT:  FOT reloaded End of Track (EOT) time tag loads at 175/1617z.
NOAA unable to process ACE RTSW until clock calibration was corrected
(~12 hours).

MOCR 183 has been implemented to keep track of the telemetry filename
created for each pass.  MOCR 185 has been implemented to send an email
notification if the clock calibration results are bad.

Background Information
ACE does not have an onboard UTC clock.  It has a counter that
increments roughly once per second.  On the ground the counter is
converted to a time.
      UTC = (slope * SpacecraftCounter) + offset + epoch - leap seconds
The slope and offset values are sent to ASC and NOAA in the clock
calibration report each day.  The epoch is DOY 237 1997 at 15:46:28z.


NOTE, WIND anomaly reports will be included when problems with MMOC
software/equipment would have impacted ACE operations.  Note that the
ITOS tm_controller problem occurs randomly, half of the time before ACE
passes and half of the time before WIND passes.

DOY 174  06/23/2010  S-WIND-0446          ITOS tm_controller
Before Beginning Of Track, ITOS had problems connecting telemetry,
"timeout reading from tm_controller".  ITOS was stopped and restarted
and the WIND pass was taken successfully.  This problem occurs
approximately once every 2 weeks.  DR CDSID#00027515 has been submitted
for ITOS developers.
IMPACT:  Manual intervention required.