ACE Weekly 06/16/2010 - 06/22/2010

All ACE spacecraft subsystems are performing nominally.

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Orbit/Attitude:

	Type        Attitude
	Date        06/22/2010
	DOY         173 2010
	Thrusters   2R 4R+ 4R-
	Duration    14:34 min
	Start       14:23:37z
	Stop        14:38:11z
	HGAStart    -6.75deg
	HGAStop     +7.77deg
	SunStart     4.89deg
	SunStop     15.47deg
	SpinStart   5.0557rpm
	SpinStop    5.0591rpm
	Nutation     0.11deg
	Firing      74 pulses
	FuelUsed      0.2331lbs
	FuelRemain  135.4116lbs
	FinalSCMass 1369.672lbs

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 164-171 2010

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Anomalies:

DOY 116  04/26/2010  S-ACE-0515  S10-0006  SEPICA Line Pressure
At the end of April (DOY 116 04/26/2010 23:45:00z), the SEPICA isobutane
line pressure (SSSLINEP) started fluctuating from 2-6psi.  The isobutane
lines are supposed to be regulated to 4-5psi.  The fluctuations occur
over hours/days.  The fluctuation could be due to either a faulty
regulator or a faulty pressure gauge.
IMPACT:  The Instrument Team has been notified and the isobutane line
pressure continues to be monitored.

Background Information
The isobutane is for 3 Proportional Counters that act as triggers for
particle detection.  The 3 valves that send gas to the Proportional
Counters have all failed during the mission, but have occasionally
opened spontaneously.  The valves have remained closed as follows
	PC1 valve closed since 02/13/1998
	PC2 valve closed since 11/24/2001
	PC3 valve closed since 02/04/2005
The line pressure is measured between the isobutane tank and the closed
valves.  The isobutane tank does not have a pressure gauge, but the tank
temperature has remained stable.