ACE Weekly 11/16/2010 - 11/22/2010
All ACE spacecraft subsystems are performing nominally.
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Orbit/Attitude:
Type Attitude
Date 11/17/2010
DOY 321 2010
Thrusters 2R 4R+ 4R-
Duration 17:49 min
Start 15:22:38z
Stop 15:40:27z
HGAStart -6.60deg
HGAStop 7.32deg
SunStart 8.43deg
SunStop 5.82deg
SpinStart 5.0655rpm
SpinStop 5.0708rpm
Nutation 0.07deg
Firing 91 pulses
FuelUsed 0.2811lbs
FuelRemain 132.6892lbs
FinalSCMass 1366.949lbs
The next attitude maneuver is scheduled for Tuesday 11/23/2010.
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OCRs:
None
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Activities:
Data Capture: 100% DOY 318-325 2010
Operations transitioned to the backup system on Saturday 11/20/2010 (DOY
324) due to Anomaly #G10-0058.
There is a higher than normal risk of data loss from October 2010
through February 2011. If there are problems with the passes, it may
not be possible to acquire additional DSN time.
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Anomalies:
DOY 320 11/16/2010 S-ACE-0556 G10-0072 DSS-27 Stopped Tracking
20 minutes before End Of Track (EOT), DSS-27 unexpectedly stopped
tracking. A reset needed to be done at the antenna and was not done
before EOT.
IMPACT: All commanding and redumps had already been performed.
However, NOAA Space Weather did not receive telemetry for the final 20
minutes of the pass.
DOY 321 11/17/2010 S-WIND-0413 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.
IMPACT: Manual intervention required.
DOY 323 11/19/2010 S-ACE-0557 G10-0073 ITOS Disable CMD Failure
At the end of the pass, ITOS failed to disable the "com.graph". The
procedure was continued to completion. ITOS was restarted and further
problems occurred (AR#G10-0074). This problem last occurred on
4/8/2010, AR#G10-0020.
IMPACT: Manual intervention required.
DOY 323 11/19/2010 S-ACE-0558 G10-0074 ITOS unable to start
When restarting ITOS from AR#G10-0073, ITOS continually generated the
following error message
error graph_process yy-ddd-hh:mm:ss: graph_process:dblock(0,1):
dbif_lock.c line 381:semop():(43) identifier removed
It took ~10 hours to remove the error event messages that were generated
in ~30 minutes using the ITOS provided event archiving tool.
IMPACT: Operations was transitioned to the backup computer for
Saturday's pass.
Background information:
For both of the "ITOS Disable CMD Failure" problems (4/8/2010 &
11/19/2010), there were further problems until the computer was
rebooted. Unfortunately, the "ITOS Disable CMD Failure" problem cannot
be replicated for investigation. However, the system administrators
have recently removed the user's ability to reboot the computer in order
to comply with IT Policies. Negotiations are ongoing to reinstate the
reboot ability.
**************************************************************************
Andrew J. Davis, Caltech, Mail Code 292-17, Pasadena CA 91125.
Phone: 360-681-3020, 626-429-0844 (cell)
Email: ad@srl.caltech.edu Web: http://www.srl.caltech.edu/ACE/ASC