ACE Weekly 11/19/2008 - 11/25/2008

All ACE spacecraft subsystems are performing nominally.

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Orbit/Attitude:

	Type        Attitude
	Date        11/24/2008
	DOY         329 2008
	Thrusters   2R 4R+ 4R-
	Duration    14:41 min
	Start       20:35:03z
	Stop        20:49:44z
	HGAStart    -7.28deg
	HGAStop     +7.20deg
	SunStart    14.32deg
	SunStop      6.26deg
	Nutation     0.24deg
	Firing      74 pulses
	FuelUsed      0.2405lbs
	FuelRemain  146.5068lbs
	FinalSCMass 1380.767lbs

The next attitude maneuver is scheduled for Wednesday 12/03/2008.

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OCRs:

DOY 325 (11/20/2008)  2000-2030z  GND-195
A Contingency Exercise is performed annually to confirm that the spacecraft
can be commanded from a software backup.  This exercise runs the TPOCC
software and sends a NO_OP command from a workstation with software from a
backup archive.  This was last performed 11/19/2007 (GND-190).

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Activities:

Data Capture:  100%  DOY 321-328 2008

There is a higher than normal risk of data loss from October 2008 through
February 2009.  If there are problems with the passes, it may not be
possible to acquire additional DSN time.  This higher-risk period has been
occurring every winter for the past couple of years.  For more information
refer to 10/14/2008 weekly.

From Wednesday DOY 324 through Friday DOY 333, ACE has only had southern
hemisphere ranging.  The reason is that DSS-46 is readily available but the
other sites have been utilized by other missions.  With maneuvers on DOY
319, 329 and 338, there will still be range data from other DSN sites
inbetween these maneuvers.  However, the team will work to avoid having such
a long stretch of range data from only one site in the future.

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Anomalies:

Update AR#S08-0004
SEPICA is operating as expected after switching to Standby Mode on
11/11/2008, power cycling on 11/13/2008 and restoring configuration on
11/18/2008.  However, there continues to be a lack of isobutane gas which
means the instrument cannot do mass or charge state composition
measurements.  The Fan 3 valve (the last open valve) has remained closed
since 02/04/2005.  The valves have opened spontaneously in the past and
could do so again in the future.


DOY 324  11/19/2008  S-ACE-0381  G08-0115  DSS-46 Intermittent Data Loss
DSS-46 receiver (MFR) had intermittent data loss from 1915-1920z.  The
station switched to ATS2 which resolved the problem.  Further intermittent
data loss occurred from 2050-2058z.  The station increased the RF Loop
Bandwidth to 750Hz which resolved the problem.  DR#C106638
IMPACT:  Data redumps were completed on the following pass.

DOY 329  11/24/2008  S-ACE-0382  G08-0116  DSS-46 FCLTU SLE Problems
DSS-46 was not radiating commands at Beginning Of Track (BOT).  The station
toggled command system several times without success.  The station then
reloaded the desktop which resolved the problems.  DR#C106648
IMPACT:  Activities delayed 30 minutes.

DOY 329  11/24/2008  S-ACE-0383  G08-0117  C&C/ROBOTT Froze & Re-executed
The ACE MOC automation software (ROBOTT/C&C) froze during the DSS-46
commanding problems (AR#G08-0116).  The TPOCC software successfully
completed the initial commanding sequence after the DSS-46 problems were
resolved.  However, after the reboot of the MOC automation software,
ROBOTT/C&C re-executed the initial commanding sequence.
IMPACT:  Fortunately, the FOT had designed the procedures to handle the
contingency of double execution.  Data playback commands were skipped during
the second execution of the procedure.