ACE Weekly 08/30/2011 - 09/05/2011

The SWICS instrument has not been generating science data since high
voltages were disabled on 8/26/2011 (DOY 238).  SWICS was powered off on
9/2/2011 (DOY 245) and will be powered on in the upcoming week.  All
other ACE spacecraft subsystems are performing as expected.

========================================================================
Orbit/Attitude:

	Type        Attitude
	Date        08/30/2011
	DOY         242 2011
	Thrusters   2R 4R+ 4R-
	Duration    15:52 min
	Start       14:04:44z
	Stop        14:20:36z
	HGAStart    -7.12deg
	HGAStop     +8.12deg
	SunStart    11.60deg
	SunStop      6.26deg
	SpinStart   5.0110rpm
	SpinStop    5.0142rpm
	Nutation     0.05deg
	Firing      80 pulses
	FuelUsed      0.2523lbs
	FuelRemain  127.0312lbs
	FinalSCMass 1361.291lbs

The next attitude maneuver is scheduled for Wednesday 09/21/2011.

=======================================================================
OCRs:

DOY 245 (09/02/2011)  1556-1604z  SWICS MOCR 338
SWICS was powered down on 09/02/2011 as part of the investigation into
the increased trigger rates anomaly (AR#S11-0002).  The instrument
team's analysis shows that the most likely cause is a malfunction with
the hybrid timing discriminator in the time-of-flight (TOF) electronics.
The powering off should reduce the temperature of the TOF electronics.
The instrument will be powered back in the upcoming week.  The high
voltages will be raised if the instrument returns to its normal
operating state.

The SWICS internal temperature dropped 1C (1.5 to 0.5C) when the
voltages were disabled on DOY 238.  The internal temperature dropped
another 0.5C (0.5 to 0C) after the attitude maneuver on DOY 242.  And
the temperature dropped 5C (0 to -5C) after SWICS was powered off on DOY
245.

========================================================================
Activities:

Data Capture:  100%  DOY 240-247 2011

The GRAIL mission is expected to launch 09/08/2011.  ACE has reduced DSN
antenna time during September.  The current schedule has ACE losing ~15%
data over 3 weeks in September.  The data loss will be greater if there
are problems with any of the passes.


========================================================================
Anomalies:

None